bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface properties of Culex pipiens pipiens eggs and the behaviour of the female during egg‐raft assembly
Authors: BEAMENT JAMES , CORBET SARAH A.
Published: March 2008

ABSTRACT. Eggs of the mosquito Culex pipiens pipiens L. float vertically because a flexible corolla at the anterior (lower) pole has a hydrophilic lower surface and a hydrofuge upper surface. The corolla assumes different configurations in the egg raft; the surface forces operating on eggs are briefly analysed. The outer surface of the chorion is hydrofuge, but in eggs floating on water there is a jacket of water surrounding the egg in the spaces between the tubercles of the exochorion, below the meshwork connecting them. The humidity over natural water can be low enough to cause continuous evaporation from the jacket; water is replenished through openings within the lower surface of the corolla. The disposition of the corolla prevents the uptake of materials confined to the water surface outside, but the mechanism could concentrate solutes in the jacket, with possible deleterious consequences. Eggs are joined together by inter‐digitation of the regularly spaced tubercles. The behaviour by which the female assembles the egg raft is described in detail, explaining the form of the raft and the patterns in which eggs are packed.
Hatching rhythms in the desert locust,Schistocerca gregaria
Authors: PADGHAM D. E.
Published: March 2008

ABSTRACT.The eggs ofSchistocerca gregaria(Orthoptera, Acrididae) incubated under natural conditions hatch only within a few of hours on either side of dawn. This gated hatching is controlled by a circadian clock that is phase set by the diel fluctuations in the temperature of the soil surrounding the eggs. There is a circadian fluctuation in haemolymph sugar concentration which is initiated at least 4 days before hatching. However, eggs hatch arrhythmically unless given cycled temperature incubation for at least 10 days of a 12–13‐day incubation. Increase in acetylcholine esterase content of the brain during the penultimate day suggests that increased hatching rhythmicity occurring at this time is the result of increased neural organization. Embryonic activity and respiration show no circadian rhythm but do provide confirmatory evidence of a quiescent phase prior to hatching. This quiescent phase is an integral part of gated hatching behaviour.
Diapause in a Glasgow strain of the flour moth, Ephestia kuehniella
Authors: COX P. D. , MFON M. , PARKIN S. , SEAMAN J. E.
Published: March 2008

ABSTRACT. The incidence of diapause in Ephestia kuehniella Zeller from an unhealed granary in Scotland was influenced by both photoperiod and temperature. At 25°C, nearly 50% of larvae entered diapause when reared in continuous darkness (DD) and up to 30% did so in short photoperiods. Little diapause was detected around LD 14:10 but a second, smaller peak of about 20% occurred at LD 16:8 and LD 18:6, falling away again to nearly zero in continuous light. More larvae entered diapause when reared continuously at 15 or 20°C than at 25 and 30°C. However, when larvae reared from hatch at 25°C in LD 16:8 were transferred after 1 week to 15°C in LD 9:15, almost twice as many entered diapause as did those reared at 15°C throughout. The sensitive phase for diapause induction occurred near the start of the final instar. The mean duration of diapause was between 2 and 3 months in most photoperiods at 20 and 25°C, and was shorter at 15°C. However, in DD at 25°C, it lasted about 7 months. Termination of diapause was hastened in larvae reared at 25°C in DD by transferring them to LD 14:10, and also by chilling them at 7.5°C for 6 weeks before returning to 25°C in DD. In an unhealed store in southern England, viable adults emerged from May to July and originated from larvae which terminated diapause relatively late. It would appear from the results of transferring larvae back to the laboratory at various times during the winter that some phases of diapause development were completed quite early after exposure to low temperatures, although no further development took place in the store until temperatures rose again in April.
The visual perception of relative distances in the wood‐cricket, Nemobius sylvestris
Authors: GOULET MARIE , CAMPAN RAYMOND , LAMBIN MICHEL
Published: March 2008

ABSTRACT. In post‐embryonic development, the visual system of the cricket Nemobius sylvestris (Bosc) shows a regular increase in the length and number of the ommatidia and a decrease of inter‐ommatidial angle so that the adult's is a third of the value in the first larval instar. Further, a 20° widening of the binocular visual field, in the horizontal plane at least, and a three‐fold increase of the inter‐ocular distance improve the potential for binocular vision. Behavioural experiments showed that the insect orientates with differing precision depending on the distances to targets of constant angular size. Further, in a choice situation between two such vertical targets, the cricket orientates most strongly towards the closer of the two, even at target distances of 52 and 130 cm from its point of decision. In fixed tethered animals, discrimination between a close and a distant target is still possible, but disappears when the head is waxed to the thorax, so that any relative movement between the animal and the object is prevented. As these capabilities exceed the possibilities of binocular triangulation, the possible role of other mechanisms is discussed, particularly that involving movement parallax using both eyes.
The effect of juvenile hormone on host‐plant preference in the black bean aphid, Aphis fabae
Authors: HARDIE JIM
Published: March 2008

ABSTRACT. When offered the choice between a germinating tick bean (summer host) and a detached spindle leaf (winter host) adult gynoparae of Aphis fabae Scop. showed a distinct preference for spindle, as judged by site of larviposition. However, when offered the same alternatives, all four larval instars showed a settling preference for bean. A switch in host preference therefore occurs at or shortly after final (fourth) moult. Fifth instar, supernumerary larvae induced by juvenile hormone (JH I) treatment also preferred bean, indicating that the host preference switch at the fourth moult had been inhibited. Larval/adult intermediate forms produced by JH I treatment, but which were capable of parturition, showed a significant increase in the acceptability of bean as a larviposition site. Acceptability was proportional to the degree of juvenilization. Thus, although larviposition is an adult prerogative, JH I can influence the preferred site. This may, however, be an indirect effect which reflects a juvenilized settling preference.
Effects of a daily temperature cycle on ecdysteroid and cyclic nucleotide titres in adult female crickets, Gryllus bimaculatus
Authors: HOFFMANN K. H. , BEHRENS W. , RESSIN W.
Published: March 2008

ABSTRACT. Ecdysteroid and cyclic nucleotide titres were determined in ovaries, fat body, muscles, haemolymph and the remaining carcass tissue (cyclic nucleotides only in ovaries and fat body) of females of the Mediterranean field cricket, Gryllus bimaculatus de Geer, during its adult life span. Under a daily temperature cycle 24°: 12°C (16:8h), ecdysteroid levels of the ovaries and fat body reached maximal values 5 times as great and about 10 days earlier than they did under constant 20°C. Under both temperature regimes the highest ecdysone concentrations coincided with the maximum in ovarian fresh weight as well as with the maximum oviposition rate. In the ovaries, titres of c‐AMP and c‐GMP changed roughly in parallel, the levels of c‐GMP, however, were much lower than those of c‐AMP. A comparison of the cyclic nucleotide profiles in the ovaries with the ecdysteroid profile shows that the cyclic nucleotide concentrations increase when ecdysteroid titres are still low, and that the highest cyclic nucleotide levels were reached 6–12 days earlier than the highest ecdysteroid titres.
Guidance of flying male moths by wind‐borne sex pheromone
Authors: KENNEDY J. S. , LUDLOW A. R. , SANDERS C. J.
Published: March 2008

ABSTRACT. On passing from clean air into a homogeneous cloud of sex pheromone in a wind tunnel flying male Adoxophyes orana (F.v.R.) (Lepidoptera: Tortricidae) turned more or less upwind and reduced the time and distance between their switchings of track from one side of the wind line to the other. These responses became adapted under the constant pheromone stimulation in the cloud, thereby arresting upwind progress; but the adapted moths would now ‘lock‐on’ to an added pheromone plume and advance upwind along it. Moths also locked‐on to the border of a pheromone cloud, not by turning back on losing the scent as previously supposed but by initiating the above programme of small‐amplitude, crosswind movements (reversing anemomenotaxis). The onset and cessation of the pheromone stimulus produced anemotactic responses that differed quantitatively within a continuum, not two distinct kinds of response as previously supposed. The behavioural mechanism whereby uniform permeation of an area with synthetic sex pheromone can prevent males from finding females is reconsidered.
The osmoregulatory role of the filter‐chamber in relation to phloem‐feeding in Eurymela distincta (Cicadelloidea, Homoptera)
Authors: LINDSAY K. L. , MARSHALL A. T.
Published: March 2008

ABSTRACT. The cicadelloid leaf‐hoppers, Eurymela distincta (Signoret) and Eurymela fenestrata (Le Pelletier & Serville), feed on the phloem sap of Eucalyptus spp. The osmotic pressure profile of haemolymph and gut fluids is consistent with a filtration mechanism based on passive osmosis. This is responsible for shunting water rapidly from foregut to hindgut in the relatively simple filter chamber. The osmotic gradient which drives the system is probably produced by active secretion of sodium and potassium into the Malpighian tubules and posterior midgut. Although the osmotic pressures in all parts of the system are higher, the mechanism is probably similar to that previously described for xylem‐feeding cicadas.

The major haemolymph cations are sodium and magnesium and the concentrations of sodium and magnesium in the urine are higher than potassium. A variety of storage granules in the midgut contain calcium, phosphorus (as phosphate), ferric iron, zinc, magnesium, manganese and copper.
Floral choices by honeybees in relation to the relative distances to flowers
Authors: MARDEN JAMES H. , WADDINGTON KEITH D.
Published: March 2008

ABSTRACT. Honeybees (Apis mellifera L.) were presented with a series of binary choices between two equally rewarding yellow or blue artificial flowers. When flowers were placed equidistant from each other, the bees maintained high degrees of constancy to one flower colour. When flowers were spaced unequally, the bees most often chose to visit the closest flower, as is predicted by an optimal foraging model.
Reproductive maturation in the pitcher‐plant mosquito, Wyeomyia smithii
Authors: O'MEARA G. F. , LOUNIBOS L. P.
Published: March 2008

ABSTRACT. Females of Wyeomyia smithii (Coquillett) mate immediately following adult eclosion. Those from Massachusetts emerge with their ovaries at a more advanced stage of development than those from Florida. Decapitation of teneral females prevented the completion of ovarian maturation among individuals from Florida but not from Massachusetts. Application of a JH analogue to Florida pupae induced precocious ovarian development and compensated for decapitation of adults. Juvenile hormone analogue (Altosid) treatment after decapitation at emergence did not stimulate egg development in Florida females beyond the previtellogenic stage (Stage II). Precocious ovarian maturation apparently results from the action in pupae of JH which mediates an early release of a gonotropic factor from the head.
Mandibular gland secretions of workers of Myrmica rugulosa and M.schencki: comparison with four other Myrmica species
Authors: CAMMAERTS M. C. , EVERSHED R. P. , MORGAN E. D.
Published: March 2008

ABSTRACT. The mandibular glands of the two species of ant, Myrmica schencki Em. and Myrmica rugulosa Nyl., contain mixtures of similar compounds, but in different proportions. M.rugulosa produces 3‐pentanol, 3‐hexanone, 3‐hexanol, 3‐heptanone, 3‐heptanol, 3‐octanone (by far the most abundant component), 3‐octanol, 3‐nonanol, 3‐decanone and 6‐methyl‐3‐octanone, in addition to small amounts of ethanal, acetone and methylpropanal. M.schencki produces most of these (though much less 3‐octanone and much more 3‐octanol), but also produces significant amounts of 3‐nonanol, 3‐decanol and 6‐methyl‐3‐octanol, while producing no detectable 3‐pentanol or 3‐hexanone. The mandibular gland secretions of these two species attract the workers, increase their linear speed, and reduce their sinuosity of movement. In M.schencki these behavioural activities are caused by 3‐octanol and 3‐octanone, the effect of a synthetic mixture of the two being exactly like that of an isolated mandibular gland; the two compounds act together to cause attraction and increase linear speed, and in synergy to reduce the workers' sinuosity of movement. In M.rugulosa, 3‐octanol, 3‐octanone and 6‐methyl‐3‐octanone are the major active constituents. 3‐Octanone attracts the workers, its effect being enhanced by 3‐octanol; it also increases the ants' linear speed, this effect being moderated slightly by the 3‐octanol. Presented together these two substances act synergistically to decrease the workers' sinuosity of movement, and reproduce exactly the overall behavioural activity of an isolated mandibular gland. The chemical and behavioural results are combined with those previously reported to explain the responses of M.rubra, M.ruginodis, M.rugulosa, M.sabuleti, M.schencki and M.scabrinodis workers to isolated mandibular glands of these species.
Flash communication between the sexes of the firefly,Photuris lucicrescens
Authors: CARLSON ALBERT D. , COPELAND JONATHAN , SHASKAN RONALD
Published: March 2008

ABSTRACT.The courtship signal of the male firefly,Photuris lucicrescensBarber (Coleoptera, Lampyridae), is a brilliant crescendo flash which grows in intensity, reaches a peak and abruptly terminates. It was found to be triggered by a long neural burst from the brain. Males and females produce weak, twinkling flashes which induce male crescendo flashes. Female responses were triggered by a slowly rising intensity, and female response latency is therefore variable. Male and femaleP.lucicrescensfireflies produce two different types of flashes and both these flashes play an integral part in their courtship communication.
Evasive behaviour in the cave‐cricket, Troglophilus cavicola
Authors: KASTBERGER GERALD
Published: March 2008

ABSTRACT. Cave crickets of the genus Troglophilus occur in caves of the Alps and Dinarides generally in wintertime. Most hibernation sites in caves were inclined at more than 60° to the horizontal. The crickets show a striking escape behaviour which is strongly influenced by the inclination of the surface on which they are standing: stimulated adequately, they readily jump from horizontal surfaces, but only rarely from the side walls or roofs of caves. An arena with a tiltable floor was used to quantify this and other behavioural effects in relation to the degree of inclination of the floor, and gave the following results, (a) From 0° to 60° the rate of evasive jumping was inversely related to the steepness of the floor; above 60° jumping was almost completely inhibited. (b) Below 75° more than half the crickets showed a positive thigmotaxis to the arena walls, above 75° this thigmotaxis was much weaker, (c) The effect of blinding was to reduce these levels of thigmotaxis at inclinations lower than 60° and to increase the thigmotactic response at steeper inclinations, (d) Standing orientation was generally upwards at inclinations steeper than 60°; below 45°, the steeper the floor, the greater this upward orientation tendency, (e) If the cricket was standing orientated downwards, evasive jumping was less inhibited on slopes between 15° and 60°.
Optomotor regulation of ground velocity in moths during flight to sex pheromone at different heights
Authors: KUENEN L. P. S. , BAKER T. C.
Published: March 2008

ABSTRACT. Males of two species of moths (Grapholitha molesta (Busck) and Heliothis virescens (F.)) were flown in a sustained‐flight tunnel in horizontal pheromone plumes. The up‐tunnel velocity of the moths increased with increasing height of flight and for G.molesta was independent of tunnel wind velocities. Use of moving ground patterns verified that the height of flight above the ground was the factor related to the changes in up‐tunnel velocity. Even though up‐tunnel velocity increased with increased flight height, angular velocity of image motion did not. Males appeared to use visual cues from the ground pattern and from other sources to determine their up‐tunnel velocities. The relationship of preferred retinal velocities to optomotor anemotaxis is discussed.
Coupled oscillators controlling circadian flight activity in the mosquito, Culex pipiens quinquefasciatus
Authors: JONES M. D. R.
Published: March 2008

ABSTRACT. In both virgin and inseminated female Culex pipiens quinquefasciatus Say, circadian flight‐activity has two major components: evening (E) and morning (M) in virgins, and evening (E) and night (N) in inseminated females. These components probably represent the activity of constituent oscillators of the underlying pacemaker system. In DD (constant dark) the E and M peaks are approximately 12 h apart in virgins, the E and N peaks 6–7 h apart in inseminated females. Entrainment to regimes between LD 6:18 and 18:6 appears to have only small effects on the relative position of these components, and after a change to DD they quickly relax towards a common phase‐relation. Entrainment to LD 12:12 followed by release into DD or constant dim light (intensities 0.005‐5 be) showed that light has a differential effect on the components, initially increasing the period of the E component more than that of the apparently more stable M and N components. Thus with increasing light intensity a bimodal cycle fuses into a unimodal cycle. Light also affected the level of activity, causing big increases in the activity of both virgin and inseminated females at 0.05 lx, but depressing activity, at least initially, at 5 lx. These results indicate that, under natural conditions, moonlight may have big effects, both on the level of activity and on the underlying circadian pacemaker.
The articulation of cricket palps: morphology and movement patterns in behaviour
Authors: KLEIN ULLA
Published: March 2008

ABSTRACT. The morphology of the palp joints in Gryllus bimaculatus DeGeer is described in the context of their use in various behavioural situations. Two patterns of movements are distinguished: the goal‐directed movement of each individual palp, as seen during grooming and food intake actions, and the rhythmic probing movement of the two maxillary palps together during exploratory behaviour and walking. Their details were studied by single frame analysis of video and cine records. The functional characteristics of the maxillary palps with regard to the dimensions of space within which they move in these patterns (‘operational space’) and the potential sensory stimuli they receive (‘reception space’) are compared with those of the antennae and discussed from the viewpoint of division of labour.
Influence of social situation on food consumption and growth in nymphs of the house cricket, Acheta domesticus
Authors: WATLER DOREEN
Published: March 2008

ABSTRACT. Grouped nymphs of Acheta domesticus L. (Orth., Gryllidae), which mature faster than isolated ones (Chauvin, 1958), consumed more food per milligram of body weight and converted it to body tissue more efficiently than did isolated nymphs, during the fifth and sixth instars. Grouped nymphs; usually had fewer instars than isolated ones. Feeding and growth rates did not decline after isolation part‐way through development. Previously isolated females, paired at 25 days, matured as rapidly as females paired throughout development, but isolated males paired at 25 days matured no faster than males which remained isolated. Nymphs paired with an older cricket gained weight as fast as nymphs in same‐age pairs in early instars, but their rate of weight gain declined in later instars, and their maturation was slower. However, all females, and males paired with older males, were heavier at emergence as adults than were adults from same‐age pairs. When grouped with both an older cricket and one of the same age, females developed at normal rates, but males still showed some retardation.
Observations on the intensity of diapause and cold tolerance in larvae from twelve populations and two reciprocal crosses of the Indian meal moth, Plodia interpunctella
Authors: BELL C. H.
Published: March 2008

ABSTRACT. The duration of diapause in larvae of Plodia interpunctella (Hübner) (Lepidoptera, Pyralidae) was assessed at 20°C in LD 11:13. Mean times from hatch to pupation for diapausing larvae from different populations ranged from 88 to 236 days. Most non‐diapausing larvae pupated within 70 days at this temperature. Transferring diapausing larvae to 25°C and LD 9:15, or to 20°C and LD 15:9, 70 days after hatch reduced the subsequent mean time to pupation by 18–82% and 9–63% respectively. Only two population samples terminated diapause faster under LD 15:9 at 20°C than under LD 9:15 at 25°C. The mortality of diapausing larvae caused by 6‐ or 10‐week exposures at 5, 7.5 or 10°C was generally less than 25%. Hybrids produced from a reciprocal cross between a temperate and a tropical African stock survived well. For other stocks there was some correlation between survival and diapause intensity. The low temperature regime which resulted in the greatest shortening of pupation time after return to the conditions used to induce diapause, did not always coincide with the temperature permitting the best survival. Results, however, indicate that some individuals of all stocks but one from the tropics are likely to survive in the U.K.
Ecdysteroids and adult diapause in the Colorado potato beetle, Leptinotarsa decemlineata
Authors: BRIERS T. , PEFEROEN M. , LOOF A. DE
Published: March 2008

ABSTRACT. The difference in ecdysteroid activity in short‐day (10‐h photo‐phase) and long‐day (16‐h photophase) Leptinotarsa decemlineata Say adults was characterized by high performance liquid chromatography, which revealed that for short‐day beetles ecdysterone and ecdysone are the major constituents of the free ecdysteroids, whereas in long‐day beetles products co‐migrating with 2‐deoxyecdysone and 2‐deoxyecdysterone are just as abundant. Ecdysteroids were detected (15 ng/ml) only in the haemolymph of females. Ligation experiments showed that the induction of the diapause syndrome by inactivation of the corpora allata or the brain not only resulted in the formation of the typical diapause proteins but also in an increase of the ecdysteroid activity. It is suggested that adult diapause in L.decemlineata is regulated by a multifactorial system.
Anatomy and physiology of trochanteral campaniform sensilla in the stick insect, Cuniculina impigra
Authors: HOFMANN T. , BÄSSLER U.
Published: March 2008

ABSTRACT. Four groups of campaniform sensilla are found on the trochanter of Cuniculina impigra Tedtenbacher (Phasmidae). One of these groups can be divided into two sub‐groups. The sensilla are approximately parallel within each group or sub‐group. As sensilla with parallel orientation will respond to the same direction of shear force, each group or sub‐group of campaniform sensilla should act as one unit. When the coxa is fixed, activity in the nerve supplying the campaniform sensilla can be released by bending the femur forwards and backwards. The sensilla are sensitive to movement only in one direction. The investigated sensilla react to the stimulus with phasic‐tonic discharge patterns. The dependence of the phasic component upon the velocity of the stimulus can be described by a power function. The tonic component depends on the amplitude of the stimulus. By mechanical stimulation of individual groups of sensilla it can be shown that at least two groups of campaniform sensilla contain units which respond to bending the femur backwards. The activity of some motor neurones can be influenced by slightly bending the leg in the horizontal plane. The levator trochanteris muscle is activated when the femur is bent forwards, and the frequency of the slow extensor tibiae motor neurone is increased when the femur is bent backwards. The reaction of both muscles is phasic. There is no detectable reaction in the protractor or the retractor of the coxa or the depressor trochanteris.
Renewal of sexual receptivity in mated female mosquitoes, Aedes aegypti
Authors: YOUNG A. D. M. , DOWNE A. E. R.
Published: March 2008

ABSTRACT. Females of Aedes aegypti (L.) (Diptera, Culicidae) were not receptive to mating 1 h after the initial insemination or at later times throughout the first gonotrophic cycle. A significant proportion of these females (75–90%) were inseminated again prior to the second gonotrophic cycle. Insemination was determined by the detection in females of sperm labelled with 3 H(G)‐adenine or 32PO4 after matings with radiolabeled males. Females deprived of males after the first insemination displayed an abnormal reduction in fertility throughout successive gonotrophic cycles.
The circadian locomotor rhythm of Hemideina thoracica (Orthoptera; Stenopelmatidae): the circadian clock as a population of interacting oscillators
Authors: CHRISTENSEN N. D. , LEWIS R. D.
Published: March 2008

ABSTRACT. The behaviour of the circadian locomotor rhythm of the New Zealand weta, Hemideina thoracica (White), supports the model that the underlying pacemaker consists of a population of weakly coupled oscillators. Certain patterns of locomotor activity, previously demonstrated almost exclusively in vertebrates, are presented here as evidence for the above hypothesis. They include after‐effects of various pre‐treatments, rhythm‐splitting and spontaneous changes in the rhythm. After‐effects, which describe the unstable behaviour of free‐running circadian rhythms following particular experimental perturbations, have been observed in Hemideina following single light pulses, constant dim light, and laboratory and natural entrainment. Period changes occurred in the activity rhythm after single light pulses of 8‐h and 12‐h duration (25 lx). Constant dim light (0.1 lx) increased the free‐running period (τ) of the activity rhythm, but the after‐effect of constant dim light was either an increase or a decrease in τ. After‐effects upon both τ and the active phase length of the activity rhythm were found following non‐24‐h light entrainment cycles with 8‐h and 12‐h light phases of 25 lx. Qualitative measurements of these after‐effects upon τ are presented which reveal a relationship between both the direction and amount of change in τ, and the difference between entrainment cycle length (T) and pre‐entrainment free‐running period. The after‐effect of natural entrainment was an initial short‐period free‐run (τ < 24h) lasting 5–10 days, generally followed by a rapid period lengthening to τ= 25–26 h. Support for the population model was provided by spontaneous dampening, recovery, and period changes of the rhythm, together with the disruption of the active phase following critical light perturbations, and rhythm‐splitting. These Hemideina results are compared with the simulations of the Coupled Stochastic System of Enright (1980).
The auditory system in larvae of the migratory locust
Authors: PETERSEN MARLEN , KALMRING KLAUS , COKL ANDREJ
Published: March 2008

ABSTRACT. The course and projection areas of the tympanal receptor fibres in the thoracic ventral cord were revealed by iontophoresis in the last three larval instars. There were no significant differences between the arrangement in larvae and that in adults. The threshold curves of the auditory organ of the last three instars were measured by recording summed potentials in the tympanal nerve. In the frequency range tested (1–20 kHz), larvae and adults differed only in sensitivity. More detailed information was obtained by single‐cell recordings from receptor neurones in the tympanal nerve of last instar larvae. No differences could be shown between the threshold curves, or the suprathreshold activity, of low frequency receptors of last instars and adults. However, the high frequency receptors of the last instars are far less sensitive in the frequency range above 12 kHz. This seems to depend on the different mechanical properties of the tympanum in larvae. The response patterns of some typical ventralcord neurones (G‐, K‐, B‐type) were identified by extracellular single‐cell recordings in last instar larvae. Convergence of auditory and vibratory inputs onto the G‐neurone and the B‐neurone (as is known to exist in the adult) was found in larvae in the final and penultimate instars to be causing similar response patterns.
Source and characterization of an egg recognition kairomone of Telenomus heliothidis, a parasitoid of Heliothis virescens
Authors: STRAND M. R. , VINSON S. B.
Published: March 2008

ABSTRACT. The ability of Telenomus heliothidis Ashmead (Hymenoptera; Scelionidae) to recognize its host, the eggs of Heliothis virescens (F.) (Lepidoptera; Noctuidae), was determined in laboratory studies. The material present in the accessory gland of female H. virescens adults acted as an egg recognition kairomone for T. heliothidis. Host eggs which lacked the kairomone were not attacked, while glass beads the size of H. virescens eggs and coated with the accessory gland material were. The parasitoid failed to respond to the kairomone unless it was associated with a target the size and shape of normal hosts. The kairomone is heat stable, but was deactivated by proteolytic enzymes. The accessory gland contained 200 mg/ml protein which suggests that the kairomone is proteinaceous.
The use of a microcomputer to collect activity data
Authors: SYMONDS R. J. , UNWIN D. M.
Published: March 2008

ABSTRACT. Use of small microcomputers to collect and record from the outputs of activity detectors is described in simple terms for the uninitiated. Provided simple external latches are used, the microcomputer may be programmed in a high level language, such as BASIC, and the system can be used to control light or temperature cycles. Data are acquired and control effected through an 8‐bit parallel ‘user’ port, as fitted to most microcomputers, and details are given of the installation of such a port.
Influence of group size and composition on soldier differentiation in female final larval instars of a higher termite, Macrotermes michaelseni
Authors: OKOT‐KOTBER B. M.
Published: March 2008

ABSTRACT. Experiments with Macrotermes michaelseni (Sjöstedt), involving artificial groups of different sizes of final larval instar females, showed that the proportion of presoldiers produced in each group decreased exponentially with increase in the size of the colonies. This relationship was not smooth, however, but stepwise. Increasing the number of workers in a group with larvae improved the chance of the larvae differentiating into presoldiers, although the normal proportion of soldiers for the species was not achieved under these conditions, even at maximum crowding. The inhibitory effect of soldiers in stopping larvae differentiating into more soldiers was established, and evidence obtained for a non‐volatile or low volatility pheromone. It is postulated that dominance by larvae which have acquired ‘competence’ over others, allows them to suppress these others from differentiating into presoldiers through the pheromone acting on specific behavioural elements.
Stabilization of altitude and speed in tethered flying gypsy moth males: influence of (+) and (‐)‐disparlure
Authors: PREISS R. , KRAMER E.
Published: March 2008

ABSTRACT. Changes in lift and thrust were elicited in tethered male gypsy moths, Lymantria dispar L. (Lepidoptera, Lymantriidae), by visual pattern elements moving radially either towards or from the point directly beneath their body, if the sex‐pheromone, (+)‐disparlure, was present. The sign of these changes was such as to counteract the pattern movements, which were generated by a rotating spiral beneath the moth. By restricting the area of spiral visible to the moth to either transverse or longitudinal sectors, flight altitude was affected by the centrifugal/centripetal movements in the lateral sectors, whereas flight speed was affected by those in the frontal sector. It is deduced that in free flight these compensatory reactions are responsible for the stabilization of flight altitude and speed, respectively. Surprisingly, without pheromone present these responses were usually not detectable: a wide range of flight altitude and speed was then observed. In the presence of (+)‐disparlure, however, these responses were always strongly pronounced, the animal keeping within a narrow range of speed and altitude. These compensatory reactions were blocked by the attraction‐inhibiting (‐)‐disparlure if presented in racemic mixture with the (+) form: the range of speed and altitude shown by the moth was then the same as without any pheromone. Under closed‐loop conditions, the mean flight speed was reduced by the racemic mixture as well as by (+)‐disparlure alone, however.
Behaviour of worker subcastes in the fire ant, Solenopsis invicta, in response to proteinaceous food
Authors: SORENSEN A. ANN , BUSCH TANA M. , VINSON S. BRADLEIGH
Published: March 2008

ABSTRACT. The effects of division of labour on response behaviour to food in the red imported fire ant, Solenopsis invicta Buren, were examined to determine if caste members differ in amount of food taken, in rate of food transfer, or in internal distribution of food; and to see if food availability, time, or temporal subcaste pairing affect feeding behaviour. To measure differences in behaviour we fed radioiodinated albumin mixed with egg yolk to colonies containing larvae, queens, and (a) foragers and nurses, or (b) foragers and reserves, or (c) nurses and reserves. Samples were taken over a 72‐h period and radioactivity in the head, thorax and abdomen of each worker was determined. There were significant differences between nurses, foragers and reserves in quantity of food consumed, rate of transfer, and internal distribution of radioactivity. These differences were related to their respective roles of foraging, food storage and transfer, and brood tending. The quantity of food taken per subcaste was dependent on the total amount of food in the colony, with transfer rates differing between subcastes as the quantity of food in the colony increased. The rate at which protein was transferred between subcastes was slower in the reserves than that in either foragers or nurses. Therefore, reserves may serve as a temporary store of protein for the colony.
Heart structure and beat in the stable fly, Stomoxys calcitrans
Authors: COOK BENJAMIN J. , MEOLA SHIRLEE
Published: March 2008

ABSTRACT. The heart of the adult stable fly, Stomoxys calcitrans (L.), is suspended from the dorsal sclerites of the abdomen by strands of connective tissue, and supported from below by alary muscles that insert into a central band of longitudinal muscle just beneath the aorta. Valved openings occur in three of the heart segments. The central band of muscle beneath the heart is innervated but there is no well‐defined lateral cardiac nervous system. The myocardium consists of a single layer of circular muscle composed of a series of muscle fibres that are joined dorsally and ventrally by intercalated discs in the midline of the insect. T‐system tubules are closely associated with the sarcoplasmic reticulum, forming dyads. The heart rate of intact stable flies varied from short intervals of almost no activity to periods with a very rapid beat (126–294 pulses/min), and when the connections to the central nervous system were severed the heart beat became very regular (258 pulses/min). Slight pressure applied to the dorsal septum stopped myocardial contractions in that segment. The myocardium was insensitive to perfusion with 10‐3M acetylcholine, l‐aspartic acid, l‐glutamic acid, Λ‐aminobutyric acid, 5‐hydroxytryptamine, octopamine, tyramine and proctolin 10‐5m. However, Mn++ caused either an intermittent beat at lower concentrations (0.5 min) or near arrest at higher concentrations (2 mM).
Defensive potential of components of the larval osmeterial secretion of papilionid butterflies against ants
Authors: HONDA KEIICHI
Published: March 2008

ABSTRACT. Toxicity and repellency of components of larval osmeterial secretions of the Papilionidae to the ants Lasius niger and Crematogaster matsumurai were evaluated in the laboratory and in the field. The test chemicals comprised five aliphatic acids, five esters, three monoterpene hydrocarbons and four sesquiterpenes.

The majority of aliphatic acids and esters exhibited weak to potent toxicity, but exposure to acetic, isobutyric, 2‐methylbutyric and isovaleric acids, ethyl 2‐methylbutyrate and methyl 3‐hydroxy‐n‐butyrate proved fatal to both ant species. Monoterpene hydrocarbons also had considerable toxicity, whereas sesquiterpenes were only slightly or not toxic. Of the terpenic compounds tested, α‐pinene was found to be the most toxic. L. niger ejected formic acid in response to d‐limonene.

Field experiments revealed that all the compounds examined except 3‐hydroxy‐n‐butyric acid were significantly repellent to worker ants of both species. Acetic, isobutyric and 2‐methylbutyric acids especially showed pronounced repellency, while the esters were less deterrent.

Among terpenic compounds, the repellency of caryophyllene oxide was noticeable. d‐Limonene elicited no particular response, other than rapid evasion, by L. niger.
Geographic variation and genetic aspects of reproductive diapause in Drosophila triauraria and D. quadraria
Authors: KIMURA MASAHITO T.
Published: March 2008

ABSTRACT. Geographic variation and genetic aspect of reproductive diapause were studied in Drosophila triauraria Bock & Wheeler and D. quadraria Bock & Wheeler, in relation to their quantitative response to photoperiods. D. quadraria from the subtropical region had no photoperiodic diapause. In D. triauraria strains, diapause was induced under LD 10:14 or 12:12, but not under LD 14:10 or longer photoperiods. Their diapause was induced more effectively and maintained longer by LD 10:14 than by LD 12:12. The duration of diapause was longer in a northern strain, but the diapause inducing process varied little among different geographical strains. Diapause incidence was 50% or lower in F1 hybrids between D. triauraria and D. quadraria and backcross progenies between F1 and D. quadraria, and about 70% in backcross progenies between F1 and D. triauraria under LD 10:14, but very low under LD 12:12. The lower incidence of diapause in these F; and backcross progenies is assumed to be due to the less efficient induction of diapause, since once diapause was induced in them, it was maintained for a long time, especially in the backcross progenies between F1 and D. triauraria. These experiments suggest that diapause induction and maintenance are different physiological processes controlled by different genetic systems.
Continuous single sensillum recording as a detection method for moth pheromone components in the effluent of a gas chromatograph
Authors: PERS J. N. C. VAN DER , LÖFSTEDT C.
Published: March 2008

ABSTRACT. Single sensillum recordings were made from male antennal pheromone receptors of Agrotis segetum (Schiff.) (Noctuidae) and Adoxophyes orana (F.v.R.) (Tortricidae). A gas chromatograph (GC) was used to prepare and to deliver the odour stimuli. Samples of female abdominal gland extracts were injected into the column of the GC and the responses of the receptor cells to the effluent were recorded continuously. The receptor cells responded with an increase of their action potential frequency during elution of the major pheromone components. The pheromone receptors of Agrotis showed a much higher sensitivity than those of Adoxophyes. In the extract of female glands from Agrotis, compounds were detected which have not been identified in previous studies of the sex pheromone of this species. It is suggested that the combination of GC techniques with direct single sensillum recording may serve as a valuable supplement to electro‐antennographic techniques.
Influence of mating on sexual receptivity and oviposition in the mosquito, Culex tarsalis
Authors: YOUNG A. D. M. , DOWNE A. E. R.
Published: March 2008

ABSTRACT. Mated females of Culex tarsalis Coq. (Diptera, Culicidae) were receptive to additional insemination after gonotrophic activity. Sexual receptivity was not renewed in mated, aged nulliparous females. Insemination was determined by the detection in females of sperm labelled with adenine‐3H(G) after matings with radio‐labelled males. When females were deprived of males after their first insemination, the production of fertile eggs was reduced and oviposition activity was altered throughout successive gonotrophic cycles.
Effect of dietary ecdysterone on protein ingestion and copulatory behaviour of the blowfly, Sarcophaga bullata
Authors: CLERCK D. DE , LOOF A. DE
Published: March 2008

ABSTRACT. In Sarcophaga bullata and other blowflies, the low haemolymph ecdysteroid titre is responsible for the inability of males to synthesize vitellogenin, although they have the genes coding for this protein. The high moulting hormone titre in females is of crucial importance for vitellogenesis. In this context we investigated whether the difference in protein ingestion between the sexes might also be related to differences in ecdysteroid titre. Using a two‐choice system, we observed that upon addition of ecdysterone to the food, protein ingestion increased in males. Topical application of methoprene also had a stimulating effect. Prolonged treatment with ecdysterone reduced the copulatory behaviour of males.
Sensitivity to juvenile hormone is not reduced in clustering monarch butterflies, Danaus plexippus, in Australia
Authors: JAMES DAVID G. , HALES DINAH F.
Published: March 2008

ABSTRACT. Female monarch butterflies, Danaus plexippus (L.) were collected from clusters in the Sydney region at weekly intervals after cluster formation. They were neck‐ligated and injected with juvenile hormone (JH) in order to test for any period of lowered JH sensitivity during the non‐reproductive clustering phase. Response was assessed by production of mature oocytes. In all weekly samples, the mean response was equal to or greater than that of newly emerged females reared and maintained in optimal conditions, and was substantially higher than that reported for diapausing monarchs in North American clusters. The result is further evidence for the absence of a true reproductive diapause in New South Wales populations.
A non‐anemotactic mechanism used in pheromone source location by flying moths
Authors: KUENEN L. P. S. , BAKER T. C.
Published: March 2008

ABSTRACT. Male oriental fruit moths, Grapholitha molesta (Busck) (Tortricidae), continue to zigzag along a pheromone plume to the source in zero wind, if they have started flight with wind on. If the pheromone source is removed and the plume is hence truncated, moths flying in zero wind out of the end of the plume into clean air increase the width of their reversals and the angles of the straight legs of the tracks so they are more directly across the former wind line. Such moths reach the source less often than do those flying along a continuous plume. The males continue to zigzag up a plume in zero wind, apparently by a combination of sequential sampling of concentration along their path and the performance of an internal, self‐steered programme of track reversals (zigzags) whose frequency increases with concentration. Visual feedback may aid in the still‐air performance of the zigzags. We propose that both the sequential sampling (longitudinal klinotaxis) and self‐steered counter‐turning programme also are used in wind as well; anemotaxis apparently polarizes the direction of the zigzags to result in upwind displacement, and the narrow zigzags caused by the higher concentration in the plume keep the male ‘locked on’ to the odour.
Effect of varying proportions of the alcohol component on sex pheromone blend discrimination in male Oriental fruit moths
Authors: LINN C. E. , ROELOFS W. L.
Published: March 2008

ABSTRACT. The flight response of individual male Oriental fruit moths, Grapholitha molesta (Busck), was observed in a sustained‐flight tunnel to 100 blend–dosage combinations of the three sex pheromone components: (Z)‐ and (E)‐8‐dodecenyl acetate and (Z)‐8‐dodecen‐l‐ol (1, 3, 10, 30 and 100 μg of Z8‐12: AC with, 2, 6, 10, 20% E and, 0, 3, 10, 30 or100% OH alcohol added). Complete flights to the source were observed only to blend combinations containing all three components. Males exhibited highest response levels to two dosages (3 and 10μg) of the natural 6% E blend and these levels were relatively unaffected by changes in the proportion of Z8‐12: OH. Certain treatments surrounding the peak area also elicited high response levels compared to the 6% E treatments, but these were strongly dependent on the proportion of OH in the blend. Hierarchical cluster analysis was utilized to compare and group treatments that elicited similar levels of response over the entire flight sequence and to derive an area of blend‐dosage combinations within the matrix tested that elicited peak levels of attraction. Analysis of the response patterns for suboptimal treatments adjacent to the area of optimal attraction showed that response specificity was controlled by two major effects on flight behaviour, one occurring early in the flight sequence affecting male orientation to the odour plume, and the other occurring later in the sequence as an arrestment of upwind flight. These effects were strongly influenced by changes in the OH component and the E isomer, with the latter playing the critical role in effecting flight behaviour. Temporal analysis of the flight response to treatments within the optimal area showed that whereas the % OH did not significantly affect the magnitude of response, increasing the level of Z8‐12: OH in the blend did significantly increase the duration of each phase of the behavioural sequence. Considering both the magnitude and temporal aspects of male response, optimal attraction in male OFM was best characterized by a small area of treatments around the peak 6% E blends that contained 10% OH. Finally, field tests showed a high degree of correlation between trends in response with changing proportion of Z8‐12: OH as observed in the flight tunnel. Peak dosages were generally higher in the field, however, compared to those in the flight tunnel.
Activity patterns in pregnant tsetse flies, Glossina morsitans
Authors: BRADY JOHN , GIBSON GABRIELLA
Published: March 2008

ABSTRACT. Actograph measurements of the spontaneous flight activity of isolated female Glossina morsitans morsitans Westw. were made through their first two pregnancy cycles in constant conditions under LD 12:12. Activity fell from a mean of c. 20 units/day to near zero during the 24 h preceding the day on which larvipositionoccurred. Activity on the day of larviposition rose significantly, to c. 35 units/day, then fell back to the baseline 20 units on subsequent days. The circadian pattern of activity was changed markedly by larviposition: 48 h before it, activity in the morning peak of the usual V‐shaped diel pattern was twice normal; over 70% of the flies then fed, and the evening arm of their V disappeared; 24 h before larviposition, most flies were totally inactive, the few that did fly performing only 1 or 2 units/day, and only in the first and last hours of the photophase; on the day of larviposition, the morning peak of the V was reduced by c. 70%, and activity peaked instead during the post‐noon 2–3 h, before and during the act of parturition. Almost all larvipositions occurred between noon and lights‐out. It is suggested that the c. 48 h of pre‐larviposition quiescence may play a role in the fact that pregnant G. morsitans females often survive non‐residual aerosol insecticide campaigns.