Patent Description:
Tsetse flies (Diptera: Glossinidae) transmit trypanosomes that cause sleeping sickness in humans (Human African Trypanosomiasis) and nagana in animals (Animal African Trypanosomiasis) in sub-Saharan Africa. While the number of cases of sleeping sickness continues to decline, the disease burden on animals is a major impediment to agricultural development on the continent. Following insemination, the female tsetse produces a single larva at a time by nourishing it from milk glands in its abdomen for some <NUM>-<NUM> days. The fly can undertake multiple pregnancy cycles during her lifespan of <NUM>-<NUM> months. This high investment in progeny and low birth rate results in a slow increase in population growth such that any increase in daily mortality has a profound effect on population decline. Daily elimination of just <NUM>% of flies in a population is sufficient for control (Vale, Bursell and Hargrove, <NUM>). For this reason, tsetse populations are vulnerable to the use of visually attractive traps and insecticide-impregnated targets designed to remove flies from a population. Both types of devices depend on the attraction of tsetse to objects with blue and black colours, and the distance over which the devices attract flies can be improved by baiting them with animal odours. Traps are usually monoconical, pyramidal or biconical in shape, inducing flies to enter from below and then move upwards to light inside the device to be caught in an insect-netting cone at the trap apex. In view of the high level of susceptibility of tsetse to insecticides, simpler insecticide-impregnated 2D targets were developed to induce flies to land on them and so come into contact with an insecticide for the purpose of killing them. 2D visual targets have been developed over decades for tsetse fly population control and are now known to be most effective when endowed with combination of blue-black colours (Challier et al. , <NUM>; Vale, <NUM>; Lindh et al. , <NUM>; Rayaisse et al. Such visually-attractive targets consist of combinations of cloth and insect-netting screens that can vary in size from <NUM><NUM> to <NUM><NUM>, depending on the tsetse species being targeted. From studies in Zimbabwe, for example, it has been estimated that a density of <NUM> odour-baited targets per km<NUM> is sufficient to control savannah tsetse species (Hargrove, <NUM>).

The blood-feeding stable fly, Stomoxys calcitrans (Diptera, Muscidae), is one of the major biting fly pests on cattle, horses and other livestock worldwide. This aggressive fly requires a number of blood meals to produce its first batch of some <NUM>-<NUM> eggs that it lays in rotting vegetable material and can produce multiple clutches of eggs during its <NUM>-<NUM> day life span. Stable fly larvae breed in a range of moist rotting deposits associated with livestock production including manure, animal feedstuff spillover, soiled animal bedding, old hay and silage pits, all of which can be found around traditional cow-houses and stables. This fly poses an ever-increasing problem in modern intensive livestock-producing facilities and feedlots where silage from maze is used as a feedstock (Skovgård and Nachman, <NUM>). When fly numbers exceed <NUM> per animal the discomfort suffered due to biting results in the animals bunching together which induces heat stress. Animals consequently feed less, resulting in major economic losses due to reduced weight gain in calves and feeder animals, and to reduced milk production by lactating cows (Cook et al. , <NUM>; Skovgård and Nachman, <NUM>). Global annual losses because of this biting fly on animal production runs into tens of billions of dollars.

Poultry manure mixed with sawdust recycled as a fertilizer in soil for horticultural production and rotting vegetable matter left on the ground at vegetable production sites provides an ideal medium for stable fly propagation in Western Australia (Cook et al. In Costa Rica, where residues from pineapple production are recycled in the soil, nearby dairy farms regularly suffer massive stable fly infestations with over <NUM> flies per animal (Solórzano et al. Sugar-cane waste associated with increasing production of alcohol as a biofuel in Brazil contributes to an increasing number of stable fly population explosions on dairy farms and cattle ranches in the southern part of the country (Ferreira de Souza Dominghetti et al. The ability of stable flies to breed in lawn clippings, seaweed and within zoos has allowed the stable fly to become a pest of man in urban and recreational settings.

Sanitation practices on animal production facilities predominate as methods for controlling stable flies. Treating oviposition sites around facilities with insecticides has only a moderate effect due to the variety and complexity of substrates on which the female stable fly can lay her eggs, and the fact that the developing larvae and pupal stages of the fly are well protected inside the organic matter. For this reason, the use of traps and targets for stable fly control has been investigated, but not to the same extent as for tsetse. Stable fly traps can consist of translucent fiberglass panels (Williams, <NUM>), a fiberglass cylinder (Broce, <NUM>) or other types of plastic cylinders (Taylor and Berkebile, <NUM>; Hogsette and Kline, <NUM>) covered with adhesive film or glue that serves to capture the flies that land. However, compared to the fiberglass traps, a 2D half-blue and half-black cloth target, like that used for tsetse, can catch over <NUM> times more stable flies (Foil et al. , <NUM>), and different 2D white plastic panels catch two times or more stable flies (Berseford and Sutcliffe, <NUM>; Zhu et al. Experiments with weathered insecticide-impregnated blue fabrics suggest that treated targets like those used for tsetse population management could be used for stable fly control (Hogsette et al. White panel targets treated with insecticide deployed on dairy farms in Canada were shown to significantly reduce the population growth rate of stables flies as a result of the lethal dose of insecticide the stably fly acquires once it lands on a treated target (Beresford and Sutcliffe, <NUM>).

Practical considerations have dictated that visually attractive targets for biting flies such as tsetse and stable flies should have the shape of a flat panel or screen, but such a design results in loss of efficiency in attracting such flying insects. In practice, 2D visual targets are unavoidably affected by parallax since their apparent size as seen by insects orbiting or flying by changes continuously and they are hardly visible when seen by the flying insect from the side. This has the consequence that an insect flying by or circling a 2D target will unavoidably lose visual contact with it periodically even though it is highly probable that insects such as biting flies need to keep continuous visual contact with an object to successfully land on it. While newly developed blue/black small 2D visual targets are remarkably good at attracting tsetse flies, only about half of the attracted flies land on them (Lindh et al. The challenge is to change the overall topology of visual targets to help to overcome drawbacks without increasing costs. Simple truly 3D visual targets made of robust self-supporting structures that are constantly visible to an approaching insect irrespective of its positions in space offer a superior alternative. 3D devices can also incorporate surfaces less exposed to weather. Some of these aspects are currently incorporated into existing tsetse traps (Challier et al. , <NUM>; Colvin and Gibson, <NUM>), but these devices are very poor at inducing biting tsetse flies that land on them to enter as invariably less than <NUM>% get trapped (Lindh et al. , <NUM>; Rayaisse et al.

Whereas an insect attracted to a visually attractive device initially undertakes an oriented flight track to approach it, within the vicinity of the device the insect invariably increases its angular velocity by, for example, circling it. Insects have compound eyes that compensate for motion parallax with densely packed smaller ommatidia in the frontal eye region and larger ommatidia laterally. A biting fly circling an object mostly in the horizontal plane is able to provide itself with a near constant optical flow provided the object that has attracted it presents a homogeneous aspect over a range of heights when viewed from the side. Although some currently used traps for tsetse flies have an approximate circular shape, they are not efficient enough.

Other aspects of fly behaviour need to be taken into account when the aim is to induce an insect to land - the crucial step required on a visually attractive device treated with a contact insecticide. One is the habit of biting flies to drop to at lower flight level around the base of an attractive host animal or device. This has been systematically observed in laboratory experiments with tsetse flies. Tsetse, stable flies and horse flies do the same on hosts where they eventually land on the legs and underbelly of large mammals to take a blood-meal. The propensity of flies to fly around the bottom of objects has been a major issue in terms of increasing field efficiency of traps for tsetse. These traps are mostly made of textiles and their attraction efficiency is too low to be really useful. In early designs both savannah and forest tsetse species escaped in high numbers from the bottom of traps they had successfully entered. Later trap designs incorporated complicated-to-sow trap floors and sloping sheets of textile to funnel entering flies into trap cages. There is thus a need for a new and better device that has a much higher efficiency for biting flies compared to all the solutions of prior art which all remain unsatisfactory. <CIT> discloses a device for attracting and inducing blood-feeding biting flies to land on it and to kill them.

It is the aim of this invention to provide a considerable improved device to attract and induce blood-feeding biting insects such as tsetse flies, stable flies and other biting insects to land on it and to kill them. The device of the invention allows to obtain much higher efficiency, i.e. a much higher landing rate, and so a higher killing rate, than what can be achieved with visual targets of prior art.

More precisely the invention relates to tubular shaped devices, also defined as visual targets, which comprise insecticide-treated or adhesive-treated surfaces and which have much higher attraction and efficiencies in inducing the attracted insects to land relative to 2D targets or other devices of prior art. The characteristic of the tubular body to present a homogeneous aspect over a range of heights when viewed from the side by an orbiting biting fly is crucial in that it allows the insect to stabilize its flight around the object. Next, the insect needs to decrease its forward speed to land at a velocity that is close to zero at touchdown. To achieve this deceleration, all the flying insect needs to do is reduce its speed proportional to the perceived angular speed (Brady, 1972a) of the attractive surface which it is approaching. In this scenario, an attractive tubular body set with its central axis parallel to the local vector of gravitational acceleration (vertical) can provide the appropriate visual cues.

A behaviour to be exploited to biting flies to land is their propensity to alight on borders, rims and edges of objects. Whereas image expansion and flight speed deceleration accompany object approach, local visual features of an object like rims and edges serve as salient visual cues for a point on which to land. 2D objects with a high perimeter to surface area ratio have been shown to serve as better landing stimuli for tsetse, and these biting flies land preferentially on the corners and lower edges of visually attractive devices. The propensity of biting flies to exploit the lower parts of visually attractive objects has not been exploited in prior art devices developed for their control, for even where a tubular body has been employed for tsetse flies it has been presented with its central axis set horizontally with respect to the ground (Hargrove, <NUM>). To solve these problems the invention proposes a tubular body whose walls are oriented parallel to the local vector of gravitational acceleration (vertical) and which is fixed or suspended with its lower rim above the ground, freely accessible to the biting flies. Additionally, the tubular body has a well determined geometrical shape and the combination of that shape with a specific colour provides a surprising effect and considerably improves the efficiency in terms of the number of flies that land on it because of its particular geometrical and colour characteristics.

More precisely the invention is achieved by a device for attracting and inducing blood-feeding biting flies to land on it, as described in the claims <NUM> to <NUM>.

Further details of the invention will be more apparent upon reading the following description accompanied by the appended figures:.

For purposes of clarity, the term biting fly/flies used here means those fly species (Class Insecta; Order Diptera) that bite man and animals. Also, in this document it is understood that reflected light means reflected and/or scattered and/or diffused or diffracted back by the surfaces of the device. A reference value of reflection R is defined as a reflection for a wavelength of <NUM>. The wording "efficiency" in this document has to be understood broadly and refers generally to the efficiency of attracting and/or fixing and/or killing biting flies that land on a surface of the device of the invention but that may also be killed in the close neighbourhood of the device.

<FIG> shows a preferred embodiment of the device of the invention to attract and induce blood-feeding biting flies to land on it. The device <NUM> comprises a tubular body <NUM> that is defined by a central axis <NUM> and has a height H defined by the length of said central axis <NUM>. The tubular body <NUM> comprising a wall <NUM> parallel to said central axis <NUM> and defining cross sections perpendicular to said central axis <NUM>.

When in use, the central axis <NUM> of the said tubular body <NUM> is oriented preferably parallel to the local vector of gravitational acceleration (vertical) and the tubular body is placed above the local ground surface on which it is fixed or suspended. The tubular body <NUM> has a first opening <NUM> defining a first rim <NUM> and a second opening <NUM> defining a second rim <NUM>. Said first rim <NUM> and second rim <NUM> are connected by said wall <NUM> which has an outer surface 6a and an inner surface 6b as illustrated in <FIG>. As further explained in detail, the device has a lateral dimension greater than its height, the wording lateral being defined as in any plane comprising said first rim.

The said outer surface 6a or said inner surface 6b has a blue colour or is substantially colourless. As explained in detail in the experimental section it is the combination of the specific shape of the device with the colours of said outer surface 6a and said inner surface 6b that provides the surprising high attraction and, consequently, the high efficiency of the device <NUM> at inducing biting flies to land on it.

In embodiments said outer surface 6a or inner surface 6b has a blue colour having x, y coordinates defined in the <NUM> CIE colour diagram, having an x value defined between <NUM> and <NUM> and a y value defined between <NUM> and <NUM>.

In embodiments said outer surface 6a or said inner surface 6b is substantially colourless, and having in the <NUM> CIE colour diagram an x value defined between <NUM> and <NUM> and a y value defined between <NUM> and <NUM>.

In embodiments said outer surface 6a or said inner surface 6b is a black surface. The highest efficiencies are obtained by the following combinations:.

In variants, the outer surface 6a or the inner surface 6b may have any dark colour such as a dark brown colour.

In an advantageous embodiment the outer surface 6a of the tubular body has a blue colour defined in the x-y coordinates of the <NUM> CIE colour diagram. In that <NUM> CIE colour diagram the colour has an x value defined between <NUM> and <NUM> and with a y value defined between <NUM> and <NUM>. This CIE value range covers phthalogen blue and turquoise blue colours (<FIG>). In advantageous embodiments the outer surface has a maximum reflectivity Rmax lower than <NUM>% within the wavelength range between <NUM> and <NUM>, the reflectivity being defined as the fraction of light being reflected and/or scattered by said surfaces.

In an embodiment said blue colour is phthalogen blue or equivalent. In another embodiment said blue colour is turquoise blue as defined hereafter.

In an embodiment the range of said x, y values are between, respectively, <NUM>-<NUM> (x range) and <NUM>-<NUM> (y range) for phthalogen blue and between, respectively, <NUM>-<NUM> (x range) and <NUM>-<NUM> (y range) for turquoise blue.

In a preferred embodiment said inner surface 6b has a lower reflectivity than said outer surface 6a. The reflectivity of said inner surface 6b is defined as the fraction of light being reflected and/or scattered by its surface and is defined for illuminating light having wavelengths between <NUM> and <NUM>. The value of the reflection of said inner surface 6b is lower than the reflection of said outer surface 6a by <NUM>% preferably lower by <NUM>%, even more preferably lower by <NUM>%. In embodiments, the reflection of the outer surface 6a and/or the inner surface 6b has a flat spectral shape, defined in that said reflection has a value between <NUM> x R and <NUM> x R defined over a wavelength range between <NUM> and <NUM>, preferably having a value between <NUM> x R and <NUM> x R defined over a wavelength range between <NUM> and <NUM>, wherein R is a reference reflectivity defined at <NUM>. The formula <NUM> x R means that the reflectivity is <NUM>% of the reflectivity R at <NUM> and the formula <NUM> x R means that the reflectivity is <NUM>% of the reflectivity R at <NUM>.

Said inner surface 6b is preferably colourless defined in the <NUM> CIE colour diagram. A colourless surface may be grey of matt black and has preferably an x value defined between <NUM> and <NUM> and a y value defined between <NUM> and <NUM> in the <NUM> CIE colour diagram (<FIG>). Said inner surface 6b has a flat reflection spectrum, as defined above, within the wavelength range between <NUM> and <NUM> (see <FIG>).

The largest dimension, defined in any horizontal cross section <NUM> of the tubular body <NUM>, defined perpendicular to said central axis <NUM>, is greater than said height H.

In an embodiment said largest dimension, perpendicular to said central axis <NUM>, is smaller than <NUM> and at least <NUM> times greater than said height H.

In a preferred embodiment said largest dimension is at least <NUM> times greater than said height H. In an advantageous embodiment said tubular body <NUM> is a cylinder whose largest dimension in said cross section <NUM> is greater than <NUM> and smaller than <NUM> and equals or is greater than said height H. In an embodiment said tubular body <NUM> is a cylinder whose largest dimension in said cross section <NUM> is <NUM> and is <NUM> in any vertical plane comprising said axis <NUM>.

It is understood that the tubular body <NUM> needs not be a perfect cylinder but may have a cylindrical shape and may have different cross sections, defined in any plane perpendicular to said axis <NUM>, along the length of said axis <NUM>. Cross sections may for example have a convex polygon shape having at least <NUM> sides or the wall may have a corrugated shape defined in a plane comprising central axis <NUM>. In a variant, the border of cross sections defined in any plane perpendicular to said axis <NUM> may also have a corrugated shape. In an embodiment said tubular body <NUM> has different shaped lateral cross sections <NUM> along the length of said central axis <NUM>. In an embodiment at least one of said cross sections has a greatest dimension, defined perpendicular to said central axis <NUM>, which is smaller than <NUM> and at least <NUM> times greater than said height H.

It is understood that said first opening <NUM> defining the first rim <NUM> and said second opening <NUM> defining the second rim <NUM> need not be equal in size. The lateral dimension of said second opening <NUM>, defined in a plane <NUM> substantially perpendicular to said central axis <NUM>, can vary between <NUM> and <NUM> times said first opening <NUM>.

In an embodiment said tubular body may be closed in the cross section <NUM> comprising said first opening <NUM> defining a first rim <NUM> and/or in the cross section <NUM> comprising said second opening <NUM>. The closure may be realized by material whose outer surface has the same colour as the outer surface of the tubular body. In variants, the closure may be realized by material whose outer surface has any of said tubular body surface colours. In another variant, closure of first opening <NUM> and of second opening <NUM> may be realized in a different one of said colours. It is also understood that, in variants, closure of first opening <NUM> and/or of second opening <NUM> may comprise on the outer surface a plurality of portions that have different reflectivities, i.e. the surface of the closure must not necessarily be a uniformly reflecting surface.

In an embodiment said tubular body <NUM> comprises inner 6b and outer 6a surfaces of said wall <NUM> of which at least the outer surface 6a has been treated with at least an UV absorber substance. In a variant said outer surface 6a may comprise an UV absorbing surface.

In an embodiment said tubular body <NUM> comprises an inner surface 6b and outer surface 6a of which at least the outer surface 6a has been treated with a chemical substance. In an embodiment said inner surface 6b and/or said outer surface 6a may comprise portions treated with an UV absorber and/or portions treated with a chemical substance. For example, in a variant only the side of the wall <NUM> comprising said first rim <NUM> and/or said second rim <NUM> may comprise a chemical substance or a surface impregnated with a chemical substance, and/or an UV absorber and/or an UV absorber surface.

In an embodiment said chemical substance is preferably any biodegradable insecticide with the ability to poison biting flies when contacting with their cuticle after landing on the tubular body. The preferred group of substances are synthetic, in which case the preferred substance is deltamethrin.

In an embodiment said chemical substance is any insecticide operating upon contact with it and possessing the ability to poison biting flies. It is generally understood that said chemical substance may be a mixture of chemical substances, or a mixture of isomers of the same substance. In variants, said chemical substance is any contact insecticide. In an embodiment any element or a portion of such an element of the device <NUM> may be treated with insecticide. It is understood that at least said outer surface 6a may comprise physical elements and microstructures to improve contact with an insecticide by the biting flies once they have landed on the tubular body <NUM>.

In an embodiment said tubular body comprises at least said outer surface 6a carrying or treated with insect glue to retain biting flies that subsequently die after landing on the tubular body. In an embodiment said tubular body comprises at least one surface carrying or treated with insect glue for mass trapping of biting flies.

In an embodiment said device <NUM> comprises preferably stationary fixing means such as a pole <NUM> as illustrated in <FIG>. The tubular body of the device may be attached by any means such as screws <NUM>'. In a variant said device <NUM> comprises suspension means to fix, in use of the device, said tubular body <NUM> above the ground using a pole oriented parallel to the local vector of gravitational acceleration (set vertically). The pole may be attached, for example, laterally preferably to the inside side of the tubular body wall (<FIG>). It is understood that the device may comprise said pole, or, in a variant, that the device is attached, in use, to an existing pole, a tree trunk, or to a portion of a construction that is smaller in diameter than any diameter of the tubular body, defined parallel to said axis <NUM>.

In embodiments different suspension means may be devised such as suspension wires <NUM>, <NUM>, as illustrated in <FIG>. Suspension wires may be attached to an upper part <NUM> of a pole <NUM> that is outside the volume of the device <NUM> as illustrated in <FIG>. Suspension means may be also tape or cords or elastic suspension means. Suspending a device to a support is well known to the person skilled in the art and will not be further commented here. In a variant, said suspension means and/or said pole may comprise chemical substances.

In methods to capture biting insects the tubular body may also be deployed on the ground so that its second rim <NUM> is at least partially in contact with the surface relative to which the device is deployed. When the device <NUM> is intended to be deployed so that at least a portion of said tubular body is in contact with said ground, the device may comprise, in an embodiment, stabilisation means to assure its stability of position relative to the surface on which the device is positioned. In an embodiment said stabilisation means may comprise hooks, or pins. Said stabilisation means may be the incorporation of at least a weight arranged at said lower rim <NUM>. A wide variety of stabilisation means and their combinations may be considered such as for example glue, or silicone. Said stabilisation means are chosen in function of the nature of the ground, in the case that the device is to be deployed directly in contact with said ground.

It is generally understood that said central axis <NUM> is preferably parallel with the direction of the local gravity, but in a variant said axis may have an angle to the direction of the gravity, as in the case that the tubular body is deployed in contact with the local ground or in case it is deployed at a height relative to that ground.

In use, the tubular body <NUM> is oriented preferably substantially parallel to the local vector of gravitational acceleration (i.e. set vertically) so that its central axis is oriented vertically as illustrated in <FIG>. In a variant, said suspension means comprise at least two wires attached equidistant to the said upper and lower rims of the tubular body at predetermined positions. In a variant the device comprises at least three wires arranged to suspend said device <NUM>, as illustrated in <FIG>.

It is understood also that the mass of the portion of the device to the side of said second rim <NUM> may be higher than the mass of the device to the side of said first rim <NUM>. For example, weights may be added to said lower rim <NUM> to improve the verticality of the device. Also, means may be provided to the device so that it may be dropped from an aircraft such as a drone and so the device has a high probability to land so that said central axis is vertical. In an example said means may comprise three legs arranged to said lower rim <NUM> and the device may comprise landing means to assure a substantially vertical position upon landing. Said landing means may be a tissue attached to said first rim <NUM> and/or a weight arranged to the side of said second rim <NUM>.

It is also understood that the device may comprise specific optical elements that may enhance the landing probability of the biting flies. For example, arrays of zero order filters may be adapted or integrated to at least said outer surface 6a. Such zero order filters are known to have surprisingly bright colour effects and may be produced for example in plastic at low cost (Knop, <NUM>).

In an embodiment said outer surface 6a and/or said inner surface 6b may comprise optical polarizing elements that are arranged to provide linearly polarized light. This embodiment may improve the efficiency of attracting and inducing said insects to land. In a variant said device may comprise at least one optical polarizing element and at least one zero-order filter. Said optical polarizing elements are preferably arranged on the said outer surface 6a or on said inner surface 6b to the side of said second rim <NUM>. In a variant said polarizing elements and/or said zero-order filters may be arranged as strips with their normal vector being parallel to said central axis. In a variant said polarizing elements and/or said zero-order filters may be arranged in a helicoidal arrangement relative to said central axis <NUM>.

It is understood that said outer surface 6a and/or said inner surface 6b may comprise optical elements which may improve the landing probability by the biting flies. Said optical elements may be for example, but not exclusively:.

In a variant, device <NUM> may be suspended to allow it to move in the wind in a manner to improve the probability of biting flies to land on it. In embodiments elements may be adapted to any surface of the device to enhance its movement amplitudes under windy conditions.

It is understood that said outer surface 6a may have a blue colour other than phthalogen blue or turquoise blue that serves to improve the probability of landing by a biting fly species or group of species of biting flies on the device. It is also understood that, in variants, the outer surface 6a and/or inner surface 6b may comprise a plurality of portions that have different reflectivities, i.e. the surfaces 6a and/or 6b must not necessarily uniformly reflecting surfaces.

In variants, the device of the invention <NUM> may comprise a substance that allows to kill biting flies when they are approaching the device, i. e without physical contact with any of the surfaces of the device <NUM>. For example, a volatile substance may be applied on the outer surface 6a so that a biting fly is killed by the toxicity of the substance in the vapour phase when it approaches the surface at a close distance, for example a distance of smaller than <NUM>, preferably smaller than <NUM> or a distance smaller than <NUM> from said outer (or inner) surface.

In an embodiment said volatile substance is a pyrethroid or other volatile insecticide or mixture of volatile insecticides with the ability to poison biting flies through its toxicity in the vapour phase.

The invention is also achieved by a method for attracting and inducing blood-feeding biting flies to land, comprising the steps (a-c) of:.

In an embodiment step c) comprises at least one of the following steps and in any order:.

The invention is also achieved by a method of fabrication at low cost of the device <NUM> of the invention and comprises the steps (a'-f') of:.

The method of fabrication comprising after steps e' or f' the steps g', h', i':.

In an embodiment the method of fabrication comprises a step of defining and cutting a length of said pole to achieve a predetermined height of said device <NUM> in case that said device <NUM> must be fixed in the ground with said pole.

In an embodiment of the method of fabrication, the tubular body may be mass-produced at minimal unit cost using common lamination technologies widely used for the packaging, storage and distribution of foodstuffs. The low-reflectance inside surface and phthalogen-blue or turquoise-blue outside surface of the tubular body wall can be laminated onto either side of a polymer board or other biodegradable support. A thin low-reflectance transparent multipurpose film of polyester or of another appropriate polymer is superposed on both sides of this laminated sheet. The surface of the film facing outwards from the wall is sufficiently rough or diffusely reflective to prevent specular reflection and to produce Lambertian reflection. The film provides a protective layer against rain, high air humidity and fungal attack. The film contains preferably an UV absorber to prevent fading of colours on the tubular body wall under direct sunlight. The film also serves as substrate on the tubular body wall for retention of a contact insecticide or insect glue on the outside and, as required for the biting fly species being targeted for control, on the inside tubular body wall. This multi-layered pre-treated tubular body wall is produced in big pre-creased rolls facilitating the detachment of a rectangular piece of the laminated material from the roll that, when folded along its long end to form a cylinder, forms the wall of the tubular body of a predetermined size. Each blank is pre-equipped with peel-off strips attached to adhesive points/Velcro fasteners on the blank's short borders. Joining such adhesive points permits ready formation of the tubular body. Alternatively, only the tubular body wall is produced in rolls and the mounted tubular body is covered with a replaceable transparent multipurpose film of polyester or another appropriate polymer film impregnated with an insecticide or with a transparent film than can support insect glue. For deployment, the tubular body so equipped can be attached along its inside wall to a pre-existing light metal-bar circular frame or circular plastic frame using clips regularly placed along its upper and lower inside rims at manufacture. The upper rim of the holding frame is at a height from ground that is appropriate for the biting fly species being targeted for control. The frame is screwed to the top of a stative set in a base that is filled with sand on deployment to serve as ballast to provide stability and to prohibit the mounted tubular body from being inadvertently knocked down or blown down by wind. The tubular body, or the film on the tubular body, can be replaced as required on such a circular frame set on a stative. The invention is also achieved by the use of the device <NUM> as described above for attracting, inducing to land, killing or retaining blood-feeding biting flies.

In this section the discovery of an efficient device presenting a surprisingly high efficiency for attracting and killing blood-feeding biting flies is described.

Pupae of the savannah tsetse species Glossina pallidipes were from a colony at the International Atomic Energy Agency (IAEA) Siebersdorf Laboratories, Austria, originating from flies collected near Tororo, Uganda in <NUM>. Emerging flies were sexed and separated daily, and maintained in rectangular cotton netting (<NUM>-mm mesh) cages (<NUM> W, <NUM> L, <NUM> H) in an environmental cabinet under <NUM> high frequency fluorescent lighting in the photophase at <NUM>, <NUM>% relative humidity (RH) and <NUM> scotophase at <NUM>, <NUM>% RH with <NUM> hour "dawn" and "dusk" periods in the first and last hours of the photophase. Flies were fed <NUM>-<NUM> days after emergence and then at <NUM>-day intervals with defibrinated bovine blood heated to <NUM>. Experiments with teneral and starved flies were performed following identical procedures, respectively, <NUM> ± <NUM> hours after emergence and <NUM> ± <NUM> hours after a blood-meal, in the first <NUM> minutes or the last <NUM> minutes of the photophase.

Movement per se is a visual cue long known to be attractive for tsetse (Brady, 1972a; Vale, <NUM>; Torr, <NUM>). The potential of adding motion illusion cues to 3D visual targets to attract flies was examined by presenting a barber's pole (David, <NUM>) alone and a barber's pole compared to a control pole (see below) to groups of starved flies activated with human breath in a circular free-flight arena <NUM> diam. and <NUM> high set on the floor of an environmental cabinet at <NUM> ± <NUM> and <NUM>% ± <NUM>% RH.

Objects hereafter with the barber's prefix bear an external spiral pattern and produce an illusion of continuous vertical movement in an orbiting observer. Controls incapable of inducing any motion illusion are hereafter called stationary. The arena was illuminated by the high frequency fluorescent lighting of the environmental cabinet. The upper arena rim bore a wooden ring of <NUM>/<NUM> inner/outer diam. that supported stretched black polyester insect netting (Swisstulle <NUM>/<NUM>, Münchwilen, Switzerland) to close the top of the arena. The floor and the wall of the arena were covered by matt white blotting paper (Benchguard BG50E, Sigma-Aldrich Chemie GmbH, Buchs, Switzerland, hereafter white blotting paper). The wooden ring also supported a <NUM> diam. ring of Teflon tubing (<NUM> inner diam. ) carrying <NUM> arena-pointing <NUM> diam. <NUM> long outlet tubes evenly spaced around the arena perimeter to deliver human breath as an activator for flies (hereafter injector ring). The injector ring was attached to a pump (Barant <NUM>-<NUM>, Barant CO. , Barrington, USA) that produced a continuous airflow (<NUM> / min) interrupted only for the <NUM> second period of breath exhalation into the tube through a mouthpiece. Breath constituents were removed from the arena by continuous suction through tubing at the base of the arena to the exterior. The experimenter, data recorders and pumps were located outside the cabinet.

Poles <NUM> high, <NUM> diam. were made of transparent Plexiglass®, whose top <NUM> section was covered with phthalogen blue cloth (TDV-C180, <NUM>% cotton, TDV Industries, Laval Cedex, France; hereafter phthalogen blue textile). Patterns were formed on the blue poles using strips of matt black textile (Oeko-Tex Standard <NUM><NUM>/<NUM>; hereafter matt black textile; Gubser Textile AG, CH-<NUM> Schlieren, Switzerland). Reflective spectra of the textiles were measured using a Datacolor CheckPro spectrophotometer (<FIG> shows reflective spectra of the TDV-C180 phthalogen blue <NUM>% cotton textile (solid line), the Oeko-Tex Standard <NUM> matt black textile (dotted line) used to cover the visual targets and the black cardboard (dashed line) used inside the blue drum target.

The barber's poles had a continuous <NUM> wide strip of matt black textile in a spiral at a slope of <NUM>°. The control pole had four <NUM> high rings of matt black textile spaced in parallel at <NUM> from one another along the blue pole. The top <NUM> of all poles tested in the arena and wind tunnel (explained further on) were covered with matt black textile. Fly landings on poles were continuously filmed with a Logitech QuickCam Pro <NUM> web camera (Logitech International S. , Romanel-sur-Morges, Switzerland) placed above the centre of the arena. Groups of <NUM> - <NUM> G. pallidipes were released into the arena <NUM> hour before experiments. Numbers of landings on the poles were counted from slow-motion replay of video records of fly landings following delivery of breath.

Landings by flies on the barber's pole presented alone in the free-flight arena were recorded using <NUM> groups of <NUM>-<NUM> starved flies. Landings on the pole were counted for <NUM> minute after delivering human breath and normalised to the number of individuals present in the arena. A linear model (LM) was fitted to the normalised numbers of landings recorded for groups of flies to examine whether it was significantly higher than zero (TEST <NUM>).

The preference by flies to land on a barber's pole versus a control pole without motion illusion was tested using <NUM> groups of <NUM>-<NUM> starved flies. Groups of flies were exposed to <NUM> consecutive exhalations at <NUM>-minute intervals; landings on the two poles were counted for <NUM> minutes after every exhalation. Proportions of landings on the two poles were analysed using a mixed effect generalized linear model (GLM) with a binomial error distribution and applying a logit link function (TEST <NUM>). Positions of the targets were treated as an independent factor type variable. A random factor was added to the model to account for the use of <NUM> consecutive exhalations to activate a group of flies.

Willingness of flies to land on freely rotating poles was examined by hanging a pair of <NUM> high and <NUM> diam. barber and control poles on <NUM> diam. black round rubber bands in the arena and spinning them up as torsion pendulums before delivering human breath. In these experiments presence of the examiner beside the arena and the motion illusion induced by the spinning barber's pole allowed only a qualitative description of tsetse behaviour.

A 2D square target and <NUM> cylindrical visual target designs (Table <NUM>) were tested in a climatised wind tunnel (<NUM> temperature, <NUM>% RH and <NUM>/sec air speed; see Gurba et al. , <NUM>) with a <NUM> long flight space and a flight volume of <NUM><NUM> that allowed flies to reach higher cruise speeds than in the arena. Illumination was provided by high frequency fluorescent tubes from above.

The open blue drum target (Table <NUM>) was tested under high frequency fluorescent light and in presence of a UV lamp (type UVL-<NUM>, UVP Inc. , San Gabriel, USA) substituting for the UV content of natural sunlight. The transparent floor of the tunnel was illuminated by an array of LEDs through a red colour filter (Rosco e-colour <NUM> medium red filter transmitting light at wavelengths longer than <NUM>). The side walls of the wind tunnel were covered with equispaced <NUM> wide vertical pale blue stripes <NUM> apart to provide the flying insects with an optical flow. The experimenter was not visible from inside the wind tunnel.

The cylindrical targets differed in diameter, height-to-width ratio and their ability to produce a barber's pole illusion and were supported either on a Plexiglas pole, by a <NUM> diam. black round rubber band from the roof of the wind tunnel or from <NUM> diam. transparent fishing line (Table <NUM>). Hereafter the tested visual targets are referred to by the corresponding capital letter in Table <NUM>. Hereunder we use the term 'pole' for cylindrical targets with height-to-width ratios greater than <NUM>, the term 'barrel' for cylindrical targets with height-to-width ratios between <NUM> and <NUM>, and the term 'drum' for cylindrical targets with height-to-width ratios below <NUM>. All barrel and drum targets were covered with phthalogen blue cloth on the outside and with matt black textile on the inside. Depending on treatment, targets also carried stripes of matt black textile on the outside. Pole, barrel and closed drum targets possessed a flat top of matt black textile, and a matt black textile bottom when suspended. Open drum targets had no cover on either the top or bottom giving flies free access to the inner surface of the cylinder. In addition to stationary and barber's targets, a visual target inducing an illusion of cyclic vertical movement to an orbiting observer (target E, hereafter called 'cyclic' target) was tested. Target J2 covered by phthalogen blue cloth on its outside had shiny black cardboard on its inside (<FIG> and <FIG> shows the efficacy of <NUM> visual targets tested in the wind tunnel at inducing G. pallidipes to land; black dots mark the probability of starved G. pallidipes to land on the targets as predicted by the GLM and open circles mark the log(c+<NUM>) transformed average numbers of consecutive landings made by individual flies on the targets as estimated by the LM. Whiskers mark the <NUM>% confidence intervals. Upper- and lower-case letters mark targets with significantly different means in post hoc Tukey multiple comparisons of the GLM- and LM-analysed data sets.

Tests in the wind tunnel were performed during the activity periods of tsetse and fly numbers tested for each target are indicated on Table <NUM>. Flies were put in 13x5 cm cylindrical release cages and allowed to acclimatize to the wind tunnel conditions for a minimum of <NUM> minutes. One fly at a time was placed at the centre of the downwind end of the wind tunnel <NUM> above the floor. Human breath was introduced for <NUM> sec into the air stream <NUM> sec after opening the release cage with a string (Gurba et al. Flight and landings by flies were filmed for <NUM> sec after stimulus delivery using the iSpy software (iSpyConnect open source project) run on a Dell computer (Dell Inc. , Round Rock, Texas, USA) and a pair of Logitech2000 web cameras placed against the side walls <NUM> from the release cage one on either side on the floor for pole and open drum targets. To film flies flying to and landing on closed barrel and drum targets the web camera on the left side (facing upwind) was fixed on the side wall of the wind tunnel just below the ceiling <NUM> from the release cage while the one on the right side was left on the floor against the other side wall. This allowed simultaneous observation of all the inside and outside surfaces of a target without any area being hidden from the cameras. Numbers and positions of landings by individual flies on the targets were recorded in real time from a video screen by the observer and verified from the recorded video sequences. Flies were tested only once. A given fly was considered as responding when it displayed a "setting flight response" where it left the release cage upon delivery of the breath stimulus and flew more than <NUM> upwind towards the test object. Flies staying in the cage, walking or jumping out of the cage without flying, flying onto the downwind wall of the wind tunnel or flying from the release cage before delivery of the breath stimulus were considered as non-responders. Setting flight rate A is the proportion of flies displaying a setting flight response of the total number of flies tested M for a treatment. The actual number of flies setting flight N to each treatment is presented in Table <NUM>. Landing rate L by flies on a treatment was calculated as the proportion of individuals R that landed on any part of a test object out of the N individuals displaying a setting flight response. Numbers of consecutive landings c on the target was recorded separately for each fly displaying a setting flight response.

The probability of an individual G. pallidipes displaying a setting flight reaction in presence of the blue rectangular target (target A), barrel targets (targets D and E) and drum targets (targets F, G, H, J1, J2 and K) was examined by fitting a generalized linear model (GLM) to M and N using a quasibinomial error distribution and logit link function (TEST <NUM>). Target type was considered as a factor type independent variable. Differences between factor level estimates by the model were analysed using ANOVA. Pairwise comparisons of predicted landing probabilities on targets were made by post hoc comparisons of predicted means using Tukey contrasts. Poles (targets B and C) that did not induce tsetse to land were not included in this analysis, neither was target L included as too few flies were tested for this treatment to draw any valid conclusions.

The probability of landing by individual starved G. pallidipes on the blue rectangular target (target A), on barrel targets (targets D and E) and drum targets (targets F, G, H, J1, J2 and K) was compared using a generalized linear model (GLM; TEST <NUM>). The model was fitted to N and R using a quasibinomial error distribution and logit link function. Target types were considered as factor type independent variables. Differences between factor level estimates by the model were analysed using ANOVA. Pairwise comparisons of predicted landing probabilities on targets were made by post hoc comparisons of predicted means using Tukey contrasts. The model-predicted probability of landing by individual flies was considered as the measure of the effectiveness of a visual target as a landing stimulus in the wind tunnel (black dots in <FIG>).

To quantify the ability of the <NUM> targets cited above under TESTS <NUM> and <NUM> to elicit multiple landings, the average numbers of consecutive landings by the N starved flies displaying a setting flight response were analysed by fitting a linear model (LM) to log(c+<NUM>) transformed counts of landings (TEST <NUM>). Target types and sex were considered as factor type independent variables. Pairwise comparisons of predicted numbers of consecutive landings (white circles in <FIG>) on targets were made by post hoc comparisons of predicted means using Tukey contrasts.

The difference between landing rates of teneral and starved flies on the blue square (target A) and the highly efficient blue drum (target J1) was examined using the Cochran-Mantel-Haenszel test (CMH test; TEST <NUM>). The responses of teneral flies were compared to the responses of a group of starved flies to the blue drum target J1 and phthalogen blue square target A (Table <NUM> and <FIG>). Since in TEST <NUM> no significant effect of sex was detected, proportions of landings per treatment recorded for males and females were treated as independent replicates. All analyses were performed using R (R Development Core Team, <NUM>).

Field trials were made for the stable fly on a dairy farm facility, and in a horse-stable yard and surrounding paddocks in the Jura Mountains western Switzerland during the summer of <NUM>. Field trials were made on tsetse in a national park in Tanzania in March <NUM> where high densities of the savannah tsetse species Glossina swynnertoni are found. When field trials were made on private land and facilities the owners gave permission and when made on public land the field trials were made under permit. The aim of the field trials was to establish if a suspended visual target cylindrical in shape and wider than high, of the drum target design tested successfully in the wind tunnel, could serve to attract biting flies to land on it in the field. In all field trials described below, cylindrical targets were deployed in the field with the cylinder's central axis parallel to the local vector of gravitational acceleration (vertical).

A cylindrical target <NUM> in diameter and <NUM> high that was blue on its outer surface (hereunder blue cylindrical target) was confectioned from a sleeve formed by sowing two rectangles of blue and black cloth together along their long sides to form a sleeve. The phthalogen blue cloth was the same as that used to confection devices for tests in the wind tunnel (above) and whose reflectance spectrum is presented in <FIG>. The black cloth was a <NUM>% matt polyester (<NUM>/m<NUM>, Q15093 Sunflag, Nairobi) showing negligible reflectance at wavelengths shorter than <NUM> as measured with the spectrophotometer (above). The blue/black cloth sleeve was pulled over a <NUM> thick plastic panel that served to form the cylinder wall, providing a blue outer surface and black inner surface on the cylinder. The shape of the device was maintained by spacers consisting of <NUM> timber bars <NUM> in diameter, extending <NUM> like spokes of a wheel from a <NUM> diameter central timber hub to which they were glued. Two such spacer arrangements were positioned inside the cylinder, one at the top and the other at the bottom. The spacers and central hub were painted matt black (Dupli-color®, MOTIP DUPLI GmbH, Hassmersheim, Germany). The cylinder was deployed with its lower perimeter parallel to the ground by attaching it through the outside surface with two screws one above the other and <NUM> distant from one another to the top of a timber post placed inside the cylinder (as depicted on <FIG>). The timber post, painted matt black, was <NUM> x <NUM> in cross section, <NUM> long, with two pre-bored holes <NUM> apart to accommodate the free ends of two of the spacers at the top and bottom of the cylinder inside. The screws were long enough to pass through the cylinder wall at the point where the plastic panel and cloth sleeve cover overlapped, passing successively through the cloth, pre-bored holes in the plastic panel, the inside cloth cover and the post to the ends of the timber spacers to securely attach the device. A smaller cylinder <NUM> in diameter and <NUM> high was also tested and secured to the top a <NUM> long post using spacers and attachments points of proportionally smaller dimensions. The bigger and smaller cylinders were tested for the stable fly with their lower perimeters, respectively, at <NUM> and <NUM> from the ground.

The capacity of the blue cylinders to induce stable flies to land on them was tested by covering their outer surface with adhesive film (Rentokil FE45, Liverpool, UK). These fly catches permitted measurement of biting fly landing rates, the critical behavioural response underlying the use of insecticide-impregnated visual control devices for biting flies.

In one field trial for the stable fly, the <NUM> diameter cylindrical target with a blue outer surface had a <NUM> high polyester insect-netting cone (Swisstulle <NUM>/<NUM>, Münchwilen, Switzerland) sown to its upper perimeter that served to guide flies that entered the target from below to a <NUM> liter transparent plastic bottle that trapped flies responding to light arriving at the cone apex. A closed <NUM> diameter cylindrical target with a blue outer surface was tested for the stable fly by attaching either matt blue or matt black plastic disks <NUM> in diameter, <NUM> thick, to the top and bottom cylinder perimeter and comparing it to the open blue cylindrical target. The spectral reflectance of the blue and black disks was the same as that of the corresponding phthalogen blue and black fabrics. A <NUM> diameter cylindrical target with a black outer surface was tested in another field trial for the stable fly by placing the cloth sleeve with the black cloth outside and blue cloth inside the cylinder. All these cylindrical devices were compared to the open-ended <NUM> diameter cylindrical target with a blue outer surface.

Responses of the stable fly to a <NUM> diameter cylinder with a blue outer surface was compared with a cylindrical fiberglass (Alsynite) stable fly trap <NUM> in diameter <NUM> high that is retailed with its own sticky sleeve (Olson Products Inc. , Medina, Ohio, USA), and with a 2D, <NUM> square <NUM> thick, polyoxymethylene (POM) panel with a <NUM> diameter central hole and covered with insect glue (Tanglefoot Company, Grand Rapids, Michigan, USA). This white panel trap is documented to catch twice as many stable flies as the fiberglass cylindrical stable fly trap (Zhu et al. Both the fiberglass cylinder trap and the 2D white target were set up with their lower edge at <NUM> from the ground.

Response of the savannah tsetse fly G. swynnertoni to <NUM> and <NUM> diameter cylinders with a blue outer surface were compared with a pyramidal trap made of <NUM> blue and <NUM> black pieces of cloth hanging alternately at right angles to one another (total surface area of cloth <NUM><NUM>) topped by a fly collecting cone of insect-netting and a trap, and with a 2D phthalogen blue cloth target (<NUM> x <NUM>) with its long end parallel to the ground. This 2D phthalogen blue target is the optimum design for G. swyrrentoni. Cloth pieces used in the confection of both the pyramidal trap and the 2D cloth target were the same as used for the cylindrical targets. Both the inside and outside of the cylinders were covered with adhesive film (Rentokil FE45, Liverpool, UK) to enumerate tsetse landing on the devices and they were tested with their lower perimeters at <NUM> from the ground. The pyramidal trap and 2D blue cloth target were set up with their lower edge at <NUM> from the ground as recommended for savannah tsetse species.

These indicative field trials, carried out over a single season, were made using a Latin Square design where each treatment occupied each trapping station once within an experiment. Distances between treatments (trapping stations) varied between <NUM> and <NUM> for the stable fly (details for each trial are provided in the corresponding table under Results of field trials) and the distance between treatments was <NUM> in the tsetse fly trials. Fly numbers presented in the tables are daily counts. Devices were set up shortly after sunrise on day <NUM> of a trial and flies were counted each following morning shortly after sunrise. Replicates for the stable fly were made on successive days. Three replicates of treatments tested on tsetse flies were made each day in an experiment that ran for six days and replicates were set up at between <NUM> and <NUM> distant from one another.

Flies were attracted to both the barber's pole and to the control pole in the free flight arena. Flies set flight upon stimulation with breath and approached the targets typically following a spiral path. Number of landings per individual fly on the barber's pole presented alone ranged between <NUM> and <NUM> in the <NUM> groups of flies and was significantly different from zero (LM, Intercept estimate: <NUM>, std. error <NUM>, t-value <NUM>, p = <NUM>; Test <NUM>). When tested as a pair, the probability of landing either on the barber's pole or on the control pole estimated by the mixed effect GLM was not significantly different from <NUM>% but showed a slight bias towards the control pole (average no. of landings per individual <NUM> compared to <NUM> on the barber's pole following delivery of <NUM> breath stimuli to <NUM> groups of flies; Test <NUM>). The position of the poles had no significant effect on the predicted preference of flies (ANOVA; Df <NUM>, Sum Sq <NUM>, Mean Sq <NUM>, F value <NUM>, p ~ <NUM>). Flies were willing to land on pairs of rotating barber's and control poles, performing up to <NUM> landings per individual and displayed an optomotor reaction, compensating for the rotation of the pole by walking on its surface.

The number of tsetse setting flight was very poor when poles of <NUM> diam. were presented in the wind tunnel but increased significantly with increasing target diameter (Table <NUM>, analysis of deviance tables: df <NUM>, deviance <NUM>, df. <NUM>, resid. deviance <NUM>, p < <NUM>; Test <NUM>). No systematic trend was recorded in setting flight rates of tsetse presented with cylindrical devices wider than <NUM> (Tables <NUM> and <NUM>). The barrel targets and the open and closed drum targets induced high setting flight rates but without any of them being significantly different from the others.

In the wind tunnel tsetse landed only on the blue square cloth target and on the barrel and drum targets, but not on the pole targets. The landing rate on the open barber's drum (target G) was over double that on the barber's barrel target (target D, Table <NUM>). This indicated that increasing the diameter and horizontal aspect of the cylindrical visual target could positively influence its effectiveness. Adding illusory continuous movement with the cyclic pattern (target E) as a component was not beneficial in the wind tunnel. The landing rate (<NUM>%) on the <NUM> diam. closed barber's drum (target F) was almost triple that recorded (<NUM>%) on the <NUM> diam. barber's barrel (target D) which was two times taller than the former (Tables <NUM> and <NUM>). The landing rate on the open blue drum target (target J1) not inducing motion illusion was significantly higher that on the closed barber's barrel (target D) but not significantly higher than on the closed cyclic barrel (target E) of the same diameter but with half the height of the closed barrel D (Tables <NUM> and <NUM>, and <FIG>). Landing rates were in fact not different between any of the drum targets all with a wider than high visual outline, or between the drum targets and the cyclic barrel target (target E) which had almost equal horizontal and vertical visual aspects (Tables <NUM> and <NUM>, and <FIG>).

The general pattern for flies landing on the targets was to approach either from below or at the level of the target. Flies flying at the level of the rectangular target tended to orbit it and land on the surface or leave. Flies approaching the drum targets had the tendency to fly below the level of the target. Flies made <NUM> consecutive landings on average on the closed barber's drum (target F) and most of these landings were made on its black underside (<NUM>%) and on the lower third of the blue outside (<NUM>%) with only <NUM>% of landings on its black top. Despite the overall increased landings on closed drums compared to closed barrels, we considered closed drums more complicated in structure for practical application and accordingly concentrated on simpler open drum structures that showed comparable fly-landing rates. Flies approaching the open blue drum targets (J1 and J2) preferred to land on the lower outside third (<NUM>% of landings), perch on its lower rim (<NUM>%), or fly into the drum to land on its inside (<NUM>%). Many of the latter flies explored the inside surface of the drum by flying to opposing sides of it before leaving. Flies approaching any tested visual target at a flight level higher than the level of the target seldom landed on it.

Analysis of the probability of landing on an object (GLM) and number of consecutive landings on it (LM) provided coherent conclusions for the visual targets tested in the wind tunnel. The probability of an individual starved G. pallidipes to land successively on an object was significantly lower on the blue square (target A) and on the <NUM> high barber's barrel target (target D) than on any type of drum target included in the analysis (Test <NUM>; Tables <NUM> and <NUM>, and <FIG>). Landing rates by starved and teneral flies were not significantly different on the blue square (Target A; CMH test, X<NUM> <NUM>, p = <NUM>), but starved flies landed in significantly higher numbers than teneral flies on the blue drum (Target J1; CMH test, X<NUM> <NUM>, p = <NUM>).

The sex of a fly had no influence on its propensity to make consecutive landings c on the <NUM> visual targets as examined by the LM (Test <NUM>; targets A, D, E, F, G, J1, J2, K; Df <NUM>, sum square <NUM>, mean square <NUM>, F value <NUM>, p = <NUM>). Numbers of consecutive landings were not significantly different on the blue square and on the barber's barrel target (targets A and D, on average, <NUM> and <NUM> consecutive landings, respectively) but were significantly higher (<NUM> or higher) on all drum targets (Table <NUM>). This underlines the pertinence of target diameter. Comparisons between the drum targets revealed no significant differences (Test <NUM>).

The blue drum with the matt black inside wall (target J1) induced the highest landing rate in targets without polarizers added (<FIG>). Responding starved individual tsetse made on average <NUM> consecutive landings on the blue drum target J1 and a maximum of up to <NUM> consecutive landings were made in the period of highest tsetse activity compared to an average of <NUM> per individual fly on the 2D blue square target (target A) with a maximum of <NUM> consecutive landings during the period of highest activity (<FIG> and <FIG>). <FIG> shows the efficacy of the blue cotton square (target A) and blue drum (target J1) at inducing flies to land on them expressed as a proportions of starved (A - D) and teneral (E - H) G. pallidipes that flew to the visual targets, and the numbers of consecutive landings made by these flies on visual targets in the wind tunnel (for details of target types see Table <NUM>). The blue drum target was more efficient regardless of tsetse nutritional state.

The average number of consecutive landings made by a fly at <NUM> was lower on the open blue drum lined with shiny cardboard inside (target J2) than on the open blue drum with matt black textile inside at <NUM> (target J2; Tables <NUM> and <NUM>), although the probability of consecutive landings on all blue drum targets was not significantly different (Tables <NUM> and <NUM>, and <FIG>). The number of consecutive landings on the open barber's drum target (target G) was on average <NUM>, only slightly higher than on the two open blue drum targets J1 and J2. Neither this non-significant increase, the number of consecutive landings at <NUM> recorded on the closed barber's drum target (target F), nor the <NUM> consecutive landings per fly recorded on the closed blue drum target (target H), was high enough to justify developing such complex structures. Tsetse propensity to land and make successive landings was among the highest on the blue drum targets bearing a polarizer, either inside for target K and outside for target L, indicating a probable advantage of adding polarizer stripes to drum targets but with the disadvantage of increased production costs (Table <NUM>).

The above analyses indicate that probability of landing by a fly on a test object was highly predictive of the probability of making a subsequent landing on the same object. Timing of tests in the wind tunnel relative to the start of the photophase was not predictive of whether a given fly would land or not but was predictive of the number of consecutive landings made by a fly (<FIG> shows the numbers of landings performed by individual G. pallidipes on <NUM> open drum targets during tests performed within the first <NUM> hours of the photophase. See detailed visual target descriptions in the text and Table <NUM>. Highest numbers of consecutive landings were recorded <NUM>-<NUM> minutes after onset of the photophase, the period when tsetse display maximal spontaneous activity (Brady 1972b).

Landings by the stable fly on the fiberglass sticky trap were <NUM>% of the number that landed on the blue cylindrical target in trial <NUM> (devices <NUM> apart), and <NUM>% in trial <NUM> (devices <NUM> apart; Table <NUM>). Over the two field trials, <NUM> flies/cm<NUM> were recorded landing on the blue cylindrical target compared to <NUM> flies/cm<NUM> on the cylindrical fiberglass trap.

Landings by the stable fly on the white panel target were <NUM>% of the number that landed on the blue cylindrical target, to provide a landing rate of <NUM> flies/cm<NUM> on the white panel compared to <NUM> flies/cm<NUM> on the blue cylindrical target (Table <NUM>). The number of landings by the stable fly on both the fiberglass cylindrical trap and white panel target was disproportionally low compared to the surface area of their adhesive fly-landing surfaces (Tables <NUM> and <NUM>).

Reducing the blue cylindrical target size from <NUM> in diameter x <NUM> high to <NUM> in diameter x <NUM> high, or a reduction of <NUM>% in surface area, caused the smaller blue target to induce disproportionally fewer stable flies to land on it at <NUM> fly/cm<NUM> compared to <NUM>/cm<NUM> on the bigger blue one (Table <NUM>).

Changing the outer surface of the cylindrical target from blue to black had no influence on stable fly landings: <NUM> fly landing/cm<NUM> on the blue target was practically the same as the landing rate of <NUM> fly landings/cm<NUM> the black target (Table <NUM>).

The blue cylindrical target open at its top and underside induced stable flies to land on its adhesive surface at a rate of <NUM> flies/cm<NUM> within a <NUM> dairy-cow facility. In the same trial, a blue cylindrical target closed at its top and underside perimeters with <NUM> diameter blue disks, induced <NUM>% more flies to land on its adhesive surface (Table <NUM>). However, when one takes into account the <NUM>% increase in surface area of the closed target, the <NUM>% increase in number of stable flies landing at <NUM> flies/cm<NUM> is lower than would be expected.

In this field trial the blue cylindrical target open at its top and underside induced stable flies to land on its adhesive surface at a rate of <NUM> flies/cm<NUM> in a horse-stable yard (Table <NUM>). In the same trial, a blue cylindrical target closed at its top and underside perimeters with <NUM> diameter blue disks, induced <NUM>% more flies to land on its adhesive surface at a rate of <NUM> flies/cm<NUM> (Table <NUM>). However, this rate of increase in landing rate could not be repeated in a subsequent field trial with the same devices (Table <NUM>). A second blue cylindrical target closed at its top and underside perimeters with black <NUM> diameter disks induced only marginally (<NUM>%) more flies to land on its adhesive surface (Table <NUM>). This increase is lower than would be expected for the <NUM>% increase in surface area (<NUM> flies/cm<NUM> compared to <NUM> flies/cm<NUM> on the open cylindrical target).

In this field trial a blue cylindrical target with no sticky film on its outer surface was topped with an insect-netting cone that served to guide flies entering the target from below to a bottle that trapped them at the cone apex. The device only caught <NUM> stable flies over the course of the <NUM>-day trial in a fully randomized block design where the blue cylindrical target induced <NUM> stable flies to land on its surface over the same <NUM>-day period (Table <NUM>). This indicates that practically no stable flies entered the blue cylindrical target from below. The finding was corroborated, since no stable flies were seen to rest on the inside black surface of the blue cylindrical target over the course of the numerous field experiments made with it during the summer of <NUM>.

The efficiency of the pyramidal trap at capturing the savannah tsetse species G. swynnertoni, i.e. the proportion of flies caught in the trap cage of those flies that approach the trap at close range, is estimated at <NUM>%. The pyramidal trap in fact captured G. swynnertoni at approximately that proportion compared to the 2D rectangular target of optimum dimensions for G. swynnertoni (Table <NUM>).

Landings by G. swynnertoni on the <NUM> in diameter x <NUM> high blue cylindrical target were <NUM>% of the number that landed on the 2D rectangular target which had twice the surface area of the cylindrical target (Table <NUM>). With a landing rate of <NUM> flies/cm<NUM> on the blue cylindrical target compared to <NUM> flies/cm<NUM> on the 2D rectangular target, the cylindrical target induced slightly more flies to land on it per unit surface area.

Reducing the cylindrical target size from <NUM> in diameter x <NUM> high to <NUM> in diameter x <NUM> high, or a reduction of <NUM>% in surface area, caused the smaller blue cylindrical target to induce fewer G. swynnertoni to land on it at <NUM> flies/cm<NUM> compared to <NUM>/cm<NUM> on the bigger blue one (Table <NUM>). The inner surface of these cylindrical targets was also covered with sticky film. Over the six-day experiment, only <NUM> tsetse were found to land on the inner surface of bigger cylindrical targets and <NUM> fly on the inner surface of the smaller cylindrical targets.

Visual targets currently widely used for the control of savannah tsetse species like G. pallidipes provide satisfying results, but the required high target density and vulnerability of cloth targets limits their application (Lindh et al. Any development resulting in an increased number of killed flies per unit target area are welcome. Since very small targets with an area as small as <NUM><NUM> are very efficient to lure G. fuscipes and G. tachinoides to land on them, the use of targets bigger than <NUM><NUM> for control of riverine species is not justified (Lindh et al. , <NUM>; Esterhuizen et al. , <NUM>; Oloo et al. In the case of savannah tsetse like G. pallidipes and G. morsitans morsitans, target sizes from <NUM> to <NUM><NUM> are required even though the rate of alighting is lower than <NUM>% (Vale, <NUM>; Lindh et al. Such a size makes the targets vulnerable to weather and theft. Similar arguments apply to devices for controlling stable flies and other biting flies.

An open cylindrical target structure of the invention offers, besides its surprising efficiency, several practical advantages that aid in field deployment. This simple shape is mechanically stable and self-sustaining when made of rigid materials. The target can be suspended from a single point of a tree branch or any improvised suspension device, or alternatively can be fixed to the top of a standing pole (see <FIG>).

Large round objects like the biconical trap were successfully used in earlier studies to attract and force tsetse to land. The low propensity (less than <NUM>%) of tsetse to enter the biconical trap without first landing indicates that in fact it performs better as an insecticide-impregnated fly-killing device but without the advantage of a simple structure (Lindh et al. , <NUM>; Oolo et al. Cylindrical black targets, designed to look like small host animals, suspended with their axes of symmetry placed horizontal with respect to the ground with a surface of <NUM><NUM> could practically not induce landing by G. pallidipes (Hargrove, <NUM>). We propose that similarity between a 3D visual target and the visual outline of a host animal is irrelevant, but that the attractive visual cues should be continuously visible to the approaching fly regardless of the fly's position in space relative to the target. We have found that a wider-than-high black-and-blue cylindrical object positioned with a vertical axis of symmetry fulfils this requirement and can thus serve as an efficient target for the tsetse fly species G. pallidipes and G. swynnertoni despite the fact that its surface area is less than half that of the smallest target tested by Hargrove (<NUM>).

Pole targets induced landings in the free flight arena, but when tested in the wind tunnel, only less than <NUM> in <NUM> flies undertook directed flight to such targets and no flies landed on them. What prevented a fly from leaving the release cage following stimulation with human breath in the wind tunnel could not be reliably identified. However, the high proportion of inactive flies in presence of the pole targets suggests that poles did not provide an adequate activating visual stimulus to induce flies to fly from the release cage, whereas in the free flight arena flies were confronted directly with the visual targets. The horizontal aspect of pole targets was visible under an angle of about <NUM>° from the release cage in the wind tunnel, within the range of the <NUM>° angle of view of a single ommatidium of the fly's compound eye (Hardie et al. No reaction was in fact recorded to objects with diameters lower than <NUM>, visible under an angle of about <NUM>° to the fly. This suggests that G. pallidipes reacts to a visual target only if its horizontal extent covers the visual field of at least <NUM> neighbouring ommatidia. Simple extrapolation predicts that a drum target with a diameter of <NUM> would affect tsetse flies within a range of about <NUM> meters, and a <NUM> wide oblong target within a range of <NUM> meters. This helps explain why the wider cylindrical target worked better at recruiting both tsetse and stable flies to land on them in the field, and therefore provides a much higher efficiency than devices of prior art. Such targets would need to be placed at minimum separating distances to avoid interference in the field.

The blue drum includes two critical visual cues known for attracting the tsetse species G. pallidipes and G. swynnertoni. Approaching and orbiting flies continuously perceive a wider-than-high phthalogen blue rectangle. Moreover, a continuously visible blue-black edge is presented to orbiting flies between the matt black inside and phthalogen blue outside surfaces, a factor that has been shown to be of importance by Green (<NUM> and <NUM>). The majority of the flies landed on or near this edge of the blue drum in the wind tunnel. However, adding matt black spirals to elicit a barber's pole effect in the wind tunnel experiments was not justified by significantly added landing efficacy even though it increased the length of the blue-black edges. Our blue drum target design induced the highest number of flies to land in the wind tunnel, even though the barber's drum targets lured slightly more flies to fly to them. We conclude that to induce landing the visual cues need to be stable from the perspective of the approaching tsetse. A three-dimensional target composed of <NUM> rectangular panels tested at right angle to one another in an earlier study brought no benefit compared to a 2D target as no constant shape and size in perspective was offered to the approaching fly due to changing parallax (Lindh et al.

Overall, the field trials with the blue cylindrical target covered with sticky film indicate that the device of the invention requires a minimum diameter of some <NUM> to better recruit both tsetse and stable flies to land on it. Stable fly landings on the <NUM> diameter cylindrical target with a blue or black outer surface are the same. Stable fly landings on the blue cylindrical target are far in excess of landings on correspondingly sized existing devices for this biting fly species. Tsetse landings per unit surface area on the blue cylindrical target occur at a higher rate than on the 2D blue target with almost twice the blue surface area. Field trials show that the cylindrical target can be deployed for stable flies either inside or outside dairy cattle facilities. Closing off the open cylindrical target at its upper and lower perimeters with blue disks can serve to increase the number of stable flies landing on it, but this is not the case when the disks used to close off the cylindrical target are black. Field trials with both tsetse and stable flies show that few of them enter the cylindrical target. This indicates that treating the inner surface of the cylindrical target with an insecticide would not be warranted in this independently operating technically novel tool for controlling biting flies.

Claim 1:
A device (<NUM>) for attracting and inducing blood-feeding biting flies to land on it and to kill them, comprising a tubular body (<NUM>) defining a central axis (<NUM>) and a height H defined in the length of said central axis, said tubular body (<NUM>) comprising a wall (<NUM>) parallel to said central axis (<NUM>) and defining lateral cross sections (<NUM>) perpendicular to said central axis (<NUM>), the device being characterized in that it further comprises:
- said tubular body (<NUM>) has a first opening (<NUM>) defining a first rim (<NUM>) and a second opening (<NUM>) defining a second rim (<NUM>);
- said first rim (<NUM>) and second rim (<NUM>) are connected by at least a portion of said wall (<NUM>);
- said wall (<NUM>) has an outer surface (6a) and an inner surface (6b);
- said outer surface (6a) reflects or scatters less than <NUM>% of illuminating light incident on said outer surface (6a) for wavelengths between <NUM> and <NUM> and peak reflectance less than <NUM>% on said outer surface (6a) for wavelengths between <NUM> and <NUM>;
- the color of said outer surface (6a) or said inner surface (6b) is blue or is colourless, said blue colour being defined in the <NUM> CIE colour diagram by a x value defined between <NUM> and <NUM> and a y value defined between <NUM> and <NUM>, colourless being defined in the <NUM> CIE colour diagram by a x value defined between <NUM> and <NUM> and a y value defined between <NUM> and <NUM>;
- said outer surface (6a) comprising at least a portion incorporating a substance for retaining and killing insects on or near to said outer surface 6a;
- said inner surface (6b) has a lower reflectivity than the reflectivity of said outer surface (6a), this reflectivity being defined as the fraction of reflected light of the illuminating light incident on said inner surface (6b), for wavelengths between <NUM> and <NUM>, said reflectivity being defined for reflected and/or scattered light by said inner surface (6b);
- the value of said reflectivity of said inner surface (6b) is lower than <NUM>%, preferably lower than <NUM>%, even more preferably lower than <NUM>%,
- the lateral dimension of the tubular body (<NUM>), defined in any plane (<NUM>) perpendicular to said central axis (<NUM>), is greater than said height H.