bluuebunny/crossref_metadata_2025 huggingface dataset:
Arrest, resorption, or maturation of oöcytes in Aedes aegypti: dependence on the quantity of blood and the interval between blood meals
Authors: LEA ARDEN O. , BRIEGEL HANS , LEA HILDA M.
Published: March 2008

ABSTRACT. After emergence, the follicles of A. aegypti double in length and the oöcytes may deposit a small amount of yolk, but within 2 days growth is arrested. Renewed growth and vitellogenesis, as well as the number of eggs finally produced, depends on the quantity of blood ingested. All females, given either a small (1 μl) or large (4 μl) meal of rat blood by enema, began yolk deposition in a nearly equal number of oöcytes, and each oöcyte had about the same amount of yolk 8 h later. Within 48 h, females fed 4 μl had each produced more than 100 eggs, whereas females fed 1 μl either had continued yolk deposition in some oöcytes, while most degenerated, or had all re‐entered oögenic arrest. Consequently, 48 h after the 1 μl meal, a female had either c. 50 or 0 eggs. Even by 14 h after a 1‐μl meal, females were either committed to re‐enter oögenic arrest or to complete maturation of some oöcytes and resorb the yolk of others. This was shown by removing and examining one ovary 14 h after a blood meal and then giving a second blood meal. The second meal stimulated meal maturation in the remaining ovary, but only in those females whose oöcytes had been in oögenic arrest when the first ovary was examined; the second meal had no effect on females whose first ovary had contained both vitellogenic and degenerating oöcytes. Oösorption was not reversed by a second blood meal. Our results do not support the hypothesis that the female ‘evaluates’ the ingested meal and begins vitellogenesis in an ‘appropriate’ number of oöcytes. The results demonstrate that the ovary is an unreliable indicator of the frequency of blood‐feeding, when females take a small meal.
Mechanism of secretion of the contents of the mandibular glands of Plodia interpunctella larvae
Authors: MOSSADEGH M. S.
Published: March 2008

ABSTRACT. Larvae of Plodia interpunctella deposit droplets of mandibular gland secretion onto silk filaments connecting particles within the substrate they inhabit, and on to the substrate itself. Active participation of the mouthparts is necessary for both the formation and deposition of these droplets along the filaments and occurs as the silk is spun. Deposition of secretion directly on the substratum does not involve the mouthparts and appears to result from contact between the lower surface of the head and the substratum. Larvae from which the mandibular glands have been removed by excision neither produce droplets on silk nor deposit them on the substratum. Those which are incapable of spinning silk due to cauterization of the spinneret are still able to deposit secretion on the substratum, however. Deposition of secretion on silk webbing does not occur when the setae which regulate formation of droplets on filaments are removed by shaving. Droplets are not characteristic of a particular larval instar but are produced by larvae of all instars as a normal function which does not depend upon intraspecific encounters. Four other Lepidopteran pests, Ephestia elutella, Ephestia cautella, Anagasta kuehniella and Antigasta catolaunalis, were also found to produce droplets of mandibular gland secretion in a similar manner to larvae of P. interpunctella.
A simple field cryoscope‐osmometer for freezing‐point determination with small fluid samples
Authors: UNWIN D. M. , WILLMER P. G.
Published: March 2008

ABSTRACT. This paper describes a portable battery‐powered freezing‐point apparatus which uses readily available aerosol cans of refrigerant to cool the specimens. The instrument is directly calibrated and can be used to estimate osmolalities in nanolitre volumes over a wide concentration range.
Multicomponent alarm pheromones in the mandibular glands of major workers of the African weaver ant, Oecophylla longinoda
Authors: BRADSHAW J. W. S. , BAKER R. , HOWSE P. E.
Published: March 2008

ABSTRACT. The complex system of alarm communication in Oecophylla longinoda is described. The mandibular gland secretion of major workers releases in other major workers a complex pattern of behaviour, which includes components of alerting, attraction and biting. The main constituents of the secretion are hexanal and 1‐hexanol, which release alerting and attraction respectively. Of the thirty or so trace components, at least two, 2‐butyl‐2‐octenal and 3‐undecanone, act as markers for attack. In combination, these components produce a sequential message in space and time, dependent on their relative proportions, volatilities and threshold concentrations for behavioural reponses.
Chemical composition of the poison apparatus secretions of the African weaver ant, Oecophylla longinoda, and their role in behaviour
Authors: BRADSHAW J. W. S. , BAKER R. , HOWSE P. E.
Published: March 2008

ABSTRACT. Major workers of Oecophylla longinoda emit venom from the tip of the abdomen, as it is brought immediately above the head. The sources of the venom are (a) the poison gland, which contains formic acid, and (b) Dufour's gland, which contains hydrocarbons, including n‐undecane and other n‐alkanes, 4‐tridecene, 8‐heptadecene and 4, 7‐heptadecadiene. The venom elicits a ‘mass attack’ response in other major workers. Formic acid and n‐undecane presented together experimentally also evoke this response, the mixture being considerably more effective than either compound tested separately. These compounds act in combination with the mandibular gland secretions to form a complex alarm/defence system.
Experimental studies on parasitization by Apanteles glomeratus.
Authors: SATO YOSHIBUMI
Published: March 2008

ABSTRACT. The host‐finding sequence of Apanteles glomeratus females and the factors involved in it were analysed. A female wasp is attracted by the leaf odour of the food plant of the host (Pieris rapae crucivord). She then walks slowly with the tips of her antennae rubbing the leaf surface. When she comes across damage produced by the host's feeding, her antennae are raised and she turns towards the damage. She often then erects her wings and/or bends her abdomen forward in response to a chemical produced from the leaf by the host's saliva. Long‐lasting searching elicited by this odour normally leads to an encounter with a host caterpillar, whereupon odour from the host itself releases opposition. Host saliva, faeces and silk are also involved in these responses, but the response to fresh leaf damage has the most specific function in the overall strategy of host‐finding.
Genetic manipulation of the circadian clock's timing of sexual behaviour in the Queensland fruit flies, Dacus tryoni and Dacus neohumeralis
Authors: SMITH PETER H.
Published: March 2008

ABSTRACT. Mating in Dacus tryoni is restricted to dusk, whereas that of a sibling species, Dacus neohumeralis, occurs in the middle of the day. The timing of sexual behaviour in both species is determined by an interaction between a circadian clock and light intensity. In D. tryoni peak mating responsiveness is at the time of dusk, and the optimal light intensity for mating is approximately 91x. In D.neohumeralis peak responsiveness is in the middle of the day, and the optimal light intensity for mating is greater than 10 000 lx. The two species were crossed and the time of mating and response to light intensity of F1, F2 and backcross progeny determined. The circadian clock set a mating phase (‘gate’) as narrow in F1 flies as in their parents, suggesting the circadian timing mechanism to be common between the two species. The results indicate that the genetic mechanism controlling timing is independent of that controlling response to light intensity, and that both genetic mechanisms are complex.
A radar‐Doppler autocorrelation analysis of insect activity
Authors: BUCHAN P. B. , SATTELLE D. B.
Published: March 2008

ABSTRACT. A novel actograph is described which utilizes radar‐Doppler methods to monitor continuously the activity of one or a group of insects. By means of autocorrelation analysis of the output of the radar‐Doppler detector changes in the rate of movement can be followed. Components of the activity of an individual insect such as flight and walking can also be distinguished using radar‐Doppler autocorrelation. Some applications of this method are illustrated in experiments on the following species: Periplaneta americana L., Musca domestica L., Calliphora erythrocephala Mg., Drosophila melanogaster Mg.
An ultrasonic insect movement detector
Authors: LUFF M. , MOLYNEUX L. , BALL S.
Published: March 2008

ABSTRACT. An ultrasonic insect movement detector is described. Insect movement in an experimental chamber causes changes in an ultrasonic standing wave pattern: these changes are amplified and recorded, either as a continuous signal or as pulses. Results are presented from ground beetles, earwigs and a braconid parasite, showing that behaviour of these insects in the apparatus is similar to that assessed by other methods.
Interaction of central and peripheral mechanisms during walking in first instar stick insects, Extatosoma tiaratum
Authors: BÄSSLER ULRICH
Published: March 2008

ABSTRACT. Individual stick insects were studied walking on a tread‐wheel. When a leg caught hold of a small fixed rod beside the wheel it: (a) applied a rhythmically modulated backward directed force (with the modulation frequency identical to the stepping frequency of the other legs); or (b) regularly lifted off the stick during the phase of minimum force, and then returned to the stick; or (c) it stepped onto the wheel. If the wheel was stopped, the applied force increased. It is deduced that this behaviour is driven by central rhythmicity of unknown origin. All the known sensory inputs to this behaviour are superimposed on this central oscillation. A hypothesis is discussed which qualitatively fits all the experimental results on the effect of these sensory influences on the timing of an individual leg's movements in stick insects.
Effect of exogenous juvenile hormones on mating behaviour and yellow colour in allatectomized adult male desert locusts
Authors: PENER M. P. , LAZAROVICI P.
Published: March 2008

ABSTRACT. A comprehensive dose–response study of exogenous juvenile hormones, JHI and JHIII, on mating behaviour and on yellowing was carried out in allatectomized, crowded adult Schistocerca americana gregaria males. Injections of either hormone induced mating behaviour, but topical applications were almost completely ineffective. In contrast, topical applications were at least as effective as injections for inducing yellow colour. Induction and/or intensity of mating behaviour was dependent on the number of (repeated) administrations (from one to eight) and on the cumulative dose (80 or 160/μg) of the hormone, but these factors, within the above ranges, showed no distinct dose‐response relationship to yellowing. Even 160/μg of cumulative dose, given in the relatively most effective way (eight repeated injections of 20 /μg each), did not fully restore mating behaviour; the level of maximum intensity reached about half of that obtained for non‐allatectomized controls. JHI and JHIII did not differ markedly in this respect, but a 1:1 mixture of the two hormones improved the effect, revealing a mild synergy. JHI induced maximum or near maximum yellowing, but JHIII, under any conditions tested, was unable to induce full yellowing. The effect was always temporary; after cessation of JH administrations mating behaviour rapidly declined and the yellow colour slowly faded. The results indicate that the response of the two physiological systems (male mating behaviour and yellowing) to exogenous JH is completely independent. Although, depending on conditions of administration and on the kind of hormone, exogenous JHs were able to restore mating behaviour and yellowing, effective doses were extremely high. These conclusions are further discussed.
The circadian eclosion rhythm in Sarcophaga argyrostoma: delineation of the responsive period for entrainment
Authors: SAUNDERS D. S.
Published: March 2008

ABSTRACT. The circadian rhythm of pupal eclosion in Sarcophaga argyrostoma shows a declining responsiveness to the phase‐shifting effects of single light pulses as development proceeds, the intrapuparial stages becoming largely ‘insensitive’. Maximum responses occur in the intra‐uterine embryos and first‐instar larvae. Pharate adults, however, are responsive to single high temperature pulses. Pupae, pharate adults, and females carrying ovarian eggs, also respond to single stepwise transfers from light to dark, or vice versa, but the peaks of eclosion show a phase angle to the light which differs from that produced by transfers of embryos or larvae. The results are consistent with the view that separate ‘larval’ and ‘adult’ clocks occur at different stages of development.
The innervation of the wind‐sensitive head hairs of the locust, Schistocerca gregaria
Authors: BACON JON , TYRER MARK
Published: March 2008

ABSTRACT. The innervation of the locust head hairs was investigated by filling the sub‐cuticular neurones with cobalt and by recording antidromic spikes at individual hairs when the circumoesophageal and cervical connectives were stimulated. The central projections from most head hairs (c. 80%) terminate in the suboesophageal ganglion, whereas about 20% extend into the thoracic ganglia. Sensilla with projections to the thoracic ganglia are structurally no different from those whose fibres terminate in the suboesophageal ganglion and they are scattered throughout the hair fields with no consistent positions in different individuals. We have re‐investigated the ‘accessory response’ (Camhi, 1969) and conclude that it is not indicative of a separate afferent or efferent system but is simply cross‐talk from adjacent axons. We relate our findings to the fibre composition of the dorsal tegumentary nerve.
Modification of female circadian flight‐activity by a male accessory gland pheromone in the mosquito, Culex pipiens quinquefasciatus
Authors: JONES M. D. R. , GUBBINS S. J.
Published: March 2008

ABSTRACT. The pattern of circadian flight activity in female Culex pipiens quinquefasciatus was modified after insemination or injection with an extract of male accessory glands. The changes were linked with an apparent alteration in the timing of one of the major components of the rhythm. In LD 12:12, virgin females were highly active at ‘dusk’ and ‘dawn’ and in the latter part of the dark phase; inseminated females were less active at ‘dusk’ and ‘dawn’ and were active in the first half of the dark phase. In DD, there were two peaks in each cycle, the initial (evening) peak occurring at the same time after all treatments; the peaks were approximately 12 h apart in virgin females, but only 6–7 h apart in females which had been inseminated or injected with accessory gland extract. The accessory gland substance (pheromone) also appeared to cause a progressive increase in activity. These induced changes are consistent with a switch to host‐seeking behaviour, which, under natural conditions, leads to a peak of biting in the middle of the night.
Responses of carrot fly larvae, Psila rosae, to the odorous and contact‐chemostimulatory metabolites of host and non‐host plants
Authors: JONES O. T. , COAKER T. H.
Published: March 2008

ABSTRACT. The responses of third instar carrot fly larvae, Psila rosae, to plant metabolites were studied in a moving air olfactometer. Directed responses over distances greater than 7.5 cm were obtained to both host and non‐host plant odours, to CO2 and methyl eugenol, a volatile secondary metabolite of carrot roots. Larvae also oriented to gradients of contact‐chemostimuli. The role of both olfactory and contact‐chemostimuli in the host plant finding behaviour of P. rosae larvae is discussed, and observational evidence for the behavioural mechanisms involved presented.
A possible sensory function for the stop—go patterns of running in phorid flies
Authors: MILLER P. L.
Published: March 2008

ABSTRACT. Running activity was filmed at high speed in two species of phorid fly, Megaselia scalaris and Puliciphora borinquenensis, which differ in weight by about one order of magnitude. Under all experimental conditions, activity consisted of brief runs regularly interrupted by short halts when the insect was completely immobile. Runs and halts were approximately equal in duration and occurred five to eight times a second. In crowded conditions the flies made longer stops and usually also shorter runs. Maximum instantaneous velocities during running were 0.2 m s‐1 in M. scalaris and 0.09 m s‐1 in male P. borinquenensis. Maximum relative velocities were 80 and 112 fly‐lengths s‐1 respectively. In M. scalaris, step frequencies reached at least 57 Hz and this rate can probably be exceeded. Fast running was accompanied by small side‐to‐side oscillations of the body at the step frequency. Fast turns were normally made at the start of runs and only rarely at other times. Painting the compound eyes or removing the antennae did not disrupt the stop—go pattern of running, although flies so treated were reluctant to run. Possible visual and chemosensory functions for stop—go running are discussed.
Central control of tarsal thresholds for proboscis extension in the blowfly
Authors: HALL MARTIN J. R.
Published: March 2008

ABSTRACT. The literature contains contrary reports with respect to the control of the proboscis extension of blowflies in response to stimulatory solutions. Control could be effected centrally, peripherally or by a combination of both. In this report a comparison of (i) behavioural responsiveness to sucrose (measured by tarsal thresholds for proboscis extension) and (ii) sensitivity of tarsal sugar receptors (measured from 0.1 to 1.1 s after stimulus onset) both before and 1 h after feeding of male Protophormia terraenovae suggests that the observed decrease in behavioural responsiveness after feeding is due to central inhibition rather than to a decline in peripheral sensitivity.
The imaginal ecdysis of the desert locust, Schistocerca gregaria.
Authors: HUGHES T. D.
Published: March 2008

ABSTRACT. Endogenously‐generated motor programmes were found to underlie the repetitive patterns of muscular activity that perform specific tasks prior to and during adult emergence in locusts. Several of these motor programmes are described. Emergence is brought about by the action of waves of longitudinal segmental contraction that pass anteriorly along the abdomen, working the animal forward out of its old cuticle. Additional motor programmes assist in the extrication of the legs and mouthparts. During ‘Stage 3’ (Hughes, 1980a) emergence behaviour is organized into repeating units, defined as bouts. The metathoracic ganglion times the expression of concurrently‐active motor programmes so that they bear definite phase relationships one to another within a bout. Each bout is functionally divisible into three phases, each of which contributes differently to the emergence of the animal. Bout period and the duration of ‘Stage 3’ are both under sensory control in relation to the progress of emergence.
Electroantennogram responses of the carrot fly,Psila rosae, to volatile plant components
Authors: GUERIN P. M. , VISSER J. H.
Published: March 2008

ABSTRACT.Electroantennogram (EAG) responses of male and female carrot flies,Psila rosaeF. (Diptera: Psilidae), were recorded to thirty‐six volatile plant constituents. The most distinct EAG responses were obtained to: (1) the general green leaf volatiles 1‐hexanol, trans‐2‐hexen‐1‐ol and cis‐3‐hexen‐1‐ol, their isomers cis‐2‐hexen‐1‐ol and trans‐3‐hexen‐1‐ol, the alcohol 1‐heptanol, the ester cis‐3‐hexenyl acetate and the leaf aldehydes hexanal and trans‐2‐hexenal, and (2) from four compounds associated with the umbelliferous host plants of this insect, namely trans‐methyl‐iso‐eugenol, β‐caryophyllene, linalool and trans‐2‐nonenal. Higher responses were elicited by the leaf aldehydes than by the corresponding alcohols. Although the absolute amplitude of the female response was over twice that of the male, there were no differences between the relative responses to the compounds tested in both sexes, with the exception of a much higher response to the leaf aldehydes in the male. The shape of the EAG evoked by the various compounds was consistently different, with the slowest recovery being recorded for trans‐methyl‐iso‐eugenol. While the antennal olfactory receptors of the carrot fly are sensitive to the closely related general green leaf volatiles, they are most specifically tuned to the aldehyde component of this green odour complex. In addition, the ability of this insect to discriminate between different plants may be augmented by the perception of a group of more host specific volatiles. The conformity of the responses of males and females to the compounds tested may indicate that host plant volatiles plays an additional role as an aggregation cue for both sexes.
The imaginal ecdysis of the desert locust, Schistocerca gregaria.
Authors: HUGHES T. D.
Published: March 2008

ABSTRACT. The newly‐emerged adult locust stretches its soft new cuticle into its adult shape and size, and at the same time caters for its ventilatory demands, by means of a pattern of behaviour, the ‘expansional motor programme’. This programme begins after emergence and persists until about an hour after wing‐folding, during which time its period changes in a predictable manner. In the post‐expansional period, abdominal dorsoventral movements occur that may serve to deflate the gut and to fill the air‐sacs, and the mandibles are periodically ad ducted.
Inter‐and intra‐specific effects of the mandibular gland secretion of larvae of the Indian‐meal moth, Plodia interpunctella
Authors: MOSSADEGH M. S.
Published: March 2008

ABSTRACT. The effects of the mandibular gland secretion of larvae of Plodia interpunctella (Hübner) on the behaviour of conspecific larvae and on its parasitoid, Nemeritis canescens (Gravenhorst) were studied in open chambers and in an olfactometer. The secretion is deposited in the form of droplets on the silk while it is being spun, and as irregular patches on the substratum. Plodia larvae presented with a choice between fresh food and food contaminated with mandibular gland secretion chose fresh food. Those provided with contaminated food only, chose this in preference to starvation. The secretion also caused ‘attraction’ and stimulation of oviposition movements in female Nemeritis, leading to increased parasitization. The stimulatory effect of the droplets was remarkably persistent and could be detected after storage for at least 5 years at room temperature as well as at 4°C or ‐7°C. Chemical analysis indicated the presence of two components, the major with an Rf value of 0.6 (empirical formula C24H40O4), and the other with an Rf value of 0.8 (empirical formula C22H38O3).
Light versus pheromone‐bearing wind in the control of flight direction by bark beetles, Scolytus multistriatus
Authors: CHOUDHURY J. H. , KENNEDY J. S.
Published: March 2008

ABSTRACT. A wind tunnel lit from above was used to measure the relative effectiveness of light as opposed to pheromone‐bearing wind in directing the flight of male S.multistriatus. Upward flight in the tunnel was overridingly phototactic not geotactic, while horizontally upwind flight toward the pheromone source was anemotactic not chemotactic, since the pheromone concentration was uniform in the tunnel. The flight tracks of newly‐emerged unfed and previously unflown beetles were preponderantly upwards and downwind; the longer the beetles had spent in flight activity beforehand, the more of them flew upwind.
Sound production and endothermy in the horse botfly, Gasterophilus intestinalis
Authors: HUMPHREYS W. F. , REYNOLDS S. E.
Published: March 2008

ABSTRACT. Adult Gasterophilus intestinalis (De Geer) frequently produce a ‘buzzing’ sound while stationary. This buzzing was always associated with heat production in the fly's thorax, although sometimes heat production occurred without audible buzzing. Thoracic temperature (Tth) could be elevated by as much as 12°C. As buzzing continued, the Tth rose, the pitch of the buzzing sound increased, the frequency being directly proportion to Tth. Periods of buzzing were usually, but not always, terminated by attempted flight. Often, flies showed long episodes of cycling, when periods of continuous buzzing were interspersed with periods of rest. Such cycling maintained Tth above ambient temperature for long periods. During sustained tethered flight, flies were able to maintain Tth at high, steady values for long periods. Heat loss from the thorax is restricted by a dense covering of hair, and also by active control over heat transfer between thorax and abdomen.
Methanol tolerances and the effects of methanol on longevity and oviposition behaviour in Drosophila pachea
Authors: JEFFERSON MARGARET C. , AGUIRRE MARGARITA
Published: March 2008

ABSTRACT. Tests on two laboratory strains of Drosophila pachea (Patterson & Wheeler) showed that adults can tolerate concentrations up to 1% methanol vapour in air. Greater concentrations resulted in markedly decreased longevity. When exposed to low concentrations of methanol (0.25% and 0.5%), adults showed increased longevity, however. The populations showed no variability for the ten enzyme systems that were examined. Females retained mature ovarioles at all concentrations of methanol except 4% and 8%, and showed a preference to oviposit on media containing 0% and 0.5% methanol.
Circadian rhythmicity in cockroaches: effects of early post‐embryonic development and ageing
Authors: PAGE TERRY L. , BLOCK GENE D.
Published: March 2008

ABSTRACT. Effects of early post‐embryonic development and ageing on the circadian rhythm of locomotor activity in the cockroach, Leucophaea maderae, were investigated. Cockroach nymphs (first to fourth instars) were found to exhibit a circadian rhythm of activity generally similar to that of adults, but there appeared to be a significant change in pacemaker period (τ) early in nymphal development, and nymphs exhibited regular fluctuations in activity level which may be related to the moulting cycle. Mean τ of adults was remarkably stable with age – no significant change was found in either males or females throughout the life span of the adult. There was, however, a small but significant difference between the average period (τ) of adult males (τ= 23.72 ± 0.12h) and adult females (τ= 23.84 ± 0.13 h). Lighting conditions during post‐embryonic development were found to have major effects on τ of adults. Males raised in constant darkness had a significantly shorter period (τ= 23.52 ± 0.11 h) than males raised in LD 12:12, and adult males and females which had been raised in non‐24‐h light cycles (T = 22 h or 26 h) exhibited major differences in τ from animals raised in LD 12:12 which persisted for several months. Animals exposed as adults to non‐24‐h light cycles also showed ‘after‐effects’ on τ, but the magnitude of the effect was much less than that exhibited by animals exposed as nymphs.
Post‐mating changes in the behaviour and activity of the female anobiid bread beetle, Stegobium paniceum
Authors: WARD J. P.
Published: March 2008

ABSTRACT. In an investigation of the effect of mating on the behaviour and activity of female Stegobium paniceum (L.) the following factors were examined: initiation of oviposition, amount of walking activity, refractory behaviour, and tendency to fly. 2–3 min in copula were sufficient to induce initiation of oviposition, increase the amount of walking activity and produce refractory behaviour. Mating was also shown to increase the occurrence of female flight behaviour. The number of females flying increased after oviposition had started and decreased when oviposition was complete. The greatest behavioural changes were found in females allowed to separate from males in their own time after a mean period in copula of 63 min. The significance of these changes and possible causative stimuli are discussed.
Mating in the mosquito, Anopheles gambiae s.l.
Authors: CHARLWOOD J. D. , JONES M. D. R.
Published: March 2008

ABSTRACT. Swarming behaviour in the Anopheles gambiae complex was observed in the field, in the Gambia, West Africa, and in the laboratory. Naturally occurring swarms of A.melas were seen in a clearing at the edge of mangrove swamps close to their breeding sites. Males could be induced to swarm over artificial ‘markers’ within this ‘arena’ but not outside it. Females were observed entering the swarm and mating. In the laboratory, in an artificial ‘dusk’, male A.gambiae s.str. swarmed over a black marker on the floor of their 1.2‐m cube cage. In contrast to the males, females made only short flights over the marker, performing brief turning movements at its edge. It is proposed that swarming brings about the aggregation necessary before short‐range attraction can take place, and that, in nature, anopheline mosquitoes orientate visually first to an arena and then to a marker within the arena. Female behaviour can be interpreted as a process of scanning possible swarm sites until mating is achieved.
Food‐aversion learning in two polyphagous caterpillars, Diacrisia virginica and Estigmene congrua
Authors: DETHIER V. G.
Published: March 2008

ABSTRACT. Two species of woolly bear caterpillars, Diacrisia virginica and Estigmene congrua, were shown by behavioural tests to prefer Petunia hybrida to five of nine common food‐plants. Ingestion of Petunia causes acute illness from which most individuals recover. After recovery larvae no longer prefer Petunia. The potential value of food‐aversion learning to polyphagous insects is discussed.
The importance of illumination level in the daily onset of flight activity in nocturnal moths
Authors: DREISIG HANS
Published: March 2008

ABSTRACT. The daily onset of flight activity in nocturnal moths from Denmark and Florida was investigated in natural and experimental reductions of illumination. The daily cycle of illumination is described, especially the variation of the rate of change during the evening. Different species commence activity (‘onset’) at different mean light intensities. These means occur around the termination of twilight, at between 0 and –2.50 log lux. In a given species the illumination at mean onset is constant, and the dispersion of onsets in the population is constant with respect to the illumination. As a consequence, the dispersion with respect to time increases, the longer the duration of twilight. The temporal dispersion, therefore, depends upon season and latitude. A model describing the number of onsets in relation to the decrease of illumination is presented. At the physiological level it is proposed that a preparatory process precedes the actual onset of activity. This is observed as a latency between the light change and the activity onset. It is presumed to represent a change, from an inhibiting to a disinhibiting output from a controlling CNS centre, brought about by the reduction in illumination increasing the sensitivity of the centre to a ‘sensitizer’. This might represent the Zeitgeber effect of illumination reduction. The results indicate that during a gradual decrease of illumination, the latency process is initiated by a certain low illumination and that it proceeds further, the lower the illumination. The faster the rate of decrease, the faster is the rate of the process, so that it is completed at about the same time as a threshold illumination for overt activity is reached, irrespective of the rate of decrease. However, at very fast reductions of illumination, the physiological process cannot keep pace with the reduction, and activity onset occurs at a lower illumination than normal.
Queen pheromone transfer within honeybee colonies
Authors: FERGUSON A. W. , FREE J. B.
Published: March 2008

ABSTRACT. The observations provided strong circumstantial evidence that workers in a queen's court obtain queen pheromone on their antennae, and that queen pheromone is distributed through the colony during antennal contact between workers. Workers that had just left the court of a mated or virgin queen had an increased tendency to make reciprocated antennal contacts with other workers. This tendency was reinforced when the workers concerned licked the queen in addition to palpating her with their antennae, probably because they spent longer in the court. The first workers contacted by those leaving the court also had an increased tendency to make reciprocated antennal contacts. Antennal contacts were more likely to be initiated by bees other than those from the queen's court. Workers from the court and those they first contacted, participated in food transfer more than did workers selected at random. Workers that licked a virgin queen subsequently participated in food transfer more than those that palpated her with their antennae only. Within about 5 min of leaving the court, a worker's participation in reciprocated antennal contacts and in food transfer diminished to the level of non‐court workers. Workers chosen at random made more transient and non‐reciprocated antennal contacts when in a colony with a mated queen than when in a colony with a virgin queen.
Physical and biochemical factors affecting diapause in insects; especially in the European corn borer, Ostrinia nubilalis: a review
Authors: GELMAN DALE B. , HAYES D. K.
Published: March 2008

ABSTRACT. Ostrinia nubilalis Hübner is characterized according to the type of diapause exhibited and the structural and physiological changes associated with the diapausing state. Effects of physical factors such as photoperiod, temperature, and relative humidity, as well as physiological and biochemical aspects such as the neurosecretory system and cyclic AMP involvement in diapause induction, maintenance, and break are reviewed. The possible roles of circadian oscillator and hourglass mechanisms associated with photoperiodism and the functioning of the biological clock of the insect are discussed.
The influence of juvenile hormone analogue on soldier differentiation in the higher termite, Macrotermes michaelseni*
Authors: OKOT‐KOTBER B. M.
Published: March 2008

ABSTRACT. The influence of topically‐applied or vapour‐administered juvenile hormone analogue (ZR‐515, methoprene (JHA)), on soldier differentiation in a higher termite species, Macrotermes michaelseni (Sjostedt) (Isoptera; Macro‐termitinae) was examined. It was found that even male third larvae, which under natural conditions develop exclusively into major workers, could be induced by JHA to differentiate into presoldiers. Intermediate forms between workers and soldiers were produced from some of the treated individuals. Administered in vapour form, JHA induced a higher proportion of presoldiers and a lower proportion of intermediate forms than it did when administered topically. The rate of presoldier formation was found to be JHA‐dose‐dependent. Biometric analysis showed that male presoldiers have the largest head capsule size, but the smallest mandibular index. The possible mechanism of soldier induction is discussed.
The responses of central acoustic and vibratory interneurones in bushcrickets and locusts to ultrasonic stimulation
Authors: SILVER SUSAN , KALMRING KLAUS , KÜHNE ROLAND
Published: March 2008

ABSTRACT. Analysis of the ultrasonic content of the calling songs of two tettigoniids, Decticus verrucivorus L. and Tettigonia cantans Fuessly, showed that the major secondary energy peaks in the ultrasonic range are only about 15–20 dB below the main audible frequency peaks. The song of the acridid, Locusta migratoria L., contains no appreciable secondary peaks at ultrasonic frequencies, Bifunctional acoustic‐vibratory interneurones are present in the ventral nerve cord of all three species. They are divided into three categories, according to their response characteristics: VS (vibration and sound), S (sound) and V (vibration) neurones. All the unit‐types capable of coding sound signals in the ventral cord (VS and S neurones) are sensitive to frequencies of up to 100 kHz, with one exception (S3). In tettigoniids, three of these unit‐types are more sensitive at ultrasonic frequencies than they are at the audible frequencies of their conspecific songs. Among the vibratory neurones (V), one unit‐type receives inhibitory inputs from ultrasonic acoustic primary receptors. The possible importance of ultrasonic perception in the natural environment is briefly discussed.
Factors determining the release of Nasonov pheromone by honeybees at the hive entrance
Authors: FERGUSON A. W. , FREE J. B.
Published: March 2008

ABSTRACT. Worker bees recently denied access to their colony expose their Nasonov glands, thereby releasing pheromone, at the entrance to their hive. Odours of the following induced this response: empty comb, purified beeswax, honey, pollen, propolis, a live queen, the (E)‐9‐hydroxy‐2‐decenoic acid component of a queen's mandibular glands, live drones and workers, inert material on which workers had walked inside the hive, and synthetic Nasonov pheromone. The total odour of a foreign colony also induced worker bees to expose their Nasonov glands but was less effective than the odour of their own colony. Odours of the following were not effective: the (E)‐9‐oxo‐2‐decenoic acid component of a queen's mandibular glands, recently killed drones and workers, worker brood (eggs, larvae, pupae).
Some effects of photoperiod on larviposition and fresh weight‐gain in Myzus persicae
Authors: HODGSON C. J. , LANE I. R.
Published: March 2008

ABSTRACT. The larviposition of adult apterous Myzus persicae previously entrained to LD 18:6 showed a marked rhythm both under LD 12:12 (on plants reared in LD 18:6) and under LL (on plants reared in LL). No rhythm was detectable in larviposition by adults reared in LL. Larviposition peaked towards the end of the photophase in LD 12:12. Fresh‐weight gain also showed a circadian rhythm with the greatest weight increases during the photophase. Re‐entrainment from LD 12:12 to DL 12:12 was not complete after 10 days. It is concluded that the changes in the light cycle did not affect the aphids through the plant.
Functional exploration of the visual field of the wood‐cricket, Nemobius sylvestris
Authors: JEANROT NICOLE , CAMPAN RAYMOND , LAMBIN MICHEL
Published: March 2008

ABSTRACT. Orientation towards a rectangular black visual target was measured with tethered crickets, Nemobius sylvestris (Bosc). The orientation reaction was induced only if the target was located in a visual field within 100° of the sagittal plane, 60° above and 40° below the horizontal plane. The motor response was maximum when the target was presented between 30° and 40° of the sagittal plane, and between 0° and 20° above the horizontal one. The orientation reaction was induced optimally by an area of the eye which is lateral and slightly dorsal, whose ommatidia are not included in the binocular field. The ability to move the head enlarged the visual field by about 20° laterally, improving the exploration of the visual space.
Temperature‐dependent changes in circadian patterns of cricket premating behaviour
Authors: LOHER WERNER , WIEDENMANN GOTTFRIED
Published: March 2008

ABSTRACT. Male‐calling and female‐walking in Teleogryllus commodus (Walker) is mainly performed during the night (in LD 12:12 at constant temperature). Cold nights of 1–7°C switched both activities from night to daytime. After cold exposure it took several transient cycles until the original phase angle difference to lights‐out was re‐established. The involvement of a circadian clock in these processes was revealed by observing the free‐running rhythm in constant light after a cold night. The rhythm was delayed, evidently due to the resetting of the biological clock by the cold exposure. This temporal alteration of premating behaviour in males and females is discussed in relation to intraspecific consequences, its adaptive value in natural conditions, and with respect to the potential parallel effects in parasites and predators.
Control of the alary muscles of locust dorsal diaphragm
Authors: MILLER T. A. , S.‐RÓZSA K.
Published: March 2008

ABSTRACT. The heartbeat in whole, intact, adult Locusta migratoria R.F. was characterized by a regular rate but apparently irregular amplitude. Cutting segmental nerves often eliminated apparent amplitude fluctuations, and electrically shocking a segmental nerve in the whole animal evoked apparent amplitude changes corresponding to the shocks. Saline‐perfused tissue preparations showed that the apparent amplitude fluctuations could be duplicated by segmental nerve stimulation, and that the fluctuations were due largely to contractions of the alary muscles of the dorsal diaphragm which shifted the position of the heart chamber without a change in volume. The alary muscles are each multi‐terminally innervated by one motor axon. Neurally‐evoked postsynaptic potentials facilitated and summated, and the diaphragm muscles began visibly contracting at stimulation rates as low as 2 Hz. Stimulation at higher frequencies caused greater depolarization of the muscle fibres with no indication of electrically‐excited responses. The alary muscles were insensitive to perfusion with acetylcholine, l‐glutamate, l‐aspartate, dopamine, octopamine, noradrenaline, proctolin, 5‐hydroxytryptamine, or gamma aminobutyric‐acid in saline at concentrations up to 10‐3M. Larval or adult brain extracts of Locusta at 10 μg/μl and diluted 1:5 in saline caused uniform contractions of the alary muscle preparation, while perfusion of skeletal muscle extracts produced no response.
The influence of light cycle and circadian rhythm on oviposition in five pyralid moth pests of stored products
Authors: BELL C. H.
Published: March 2008

ABSTRACT. When batches of about 100 moths of mixed age and sex were kept at 25°C, 65±5%r.h., few eggs were laid by Ephestia cautella, E.kuehniella, E.elutella and Corcyra cephalonica while they were exposed to light of 400‐1000lx for up to 12h. Large numbers were laid soon after the light was switched off, however, and the yield during the first hour of darkness increased as the period previously spent in light increased from 1 to 18h. Plodia interpunctella, on the other hand, laid many eggs in light and the numbers laid subsequently during the first hour of darkness in the Slough stock were not influenced by the duration of the light exposure. In LD 12:12, the first four species laid most of their eggs during the scotophase, with E.cautella laying the largest number and E.elutella the smallest. E.cautella transferred from LD 12:12 to constant darkness showed a free‐running circadian rhythm for at least three cycles, with most eggs laid near the time that was previously the first hour of darkness, but those transferred to constant light free‐ran for only one cycle.
Evaluation of the various components of the Nasonov pheromone used by clustering honeybees
Authors: FREE J. B. , FERGUSON A. W. , PICKETT J. A.
Published: March 2008

ABSTRACT. Of the various components of the Nasonov pheromone, geraniol, (E)‐citral and nerolic acid were the most important for inducing clustering. The presence of (Z)‐citral with (E)‐citral, or in a mixture of components including (E)‐citral, did not diminish clustering and sometimes increased it. Geranic acid alone encouraged clustering, but was less effective with nerolic acid or the citrals. Nerol and (E, E)‐farnesol had little obvious influence on clustering. A 1:1:1 mixture of geraniol + nerolic acid + (E)‐ and (Z)‐citrals was as effective as a mixture of all the seven components in equal proportions, which was in turn as effective as a mixture containing the components in the proportions present naturally in the Nasonov gland.
The control of receptivity and ovulation in the tsetse fly, Glossina morsitans
Authors: GILLOTT C. , LANGLEY P. A.
Published: March 2008

ABSTRACT. A rapid decline in receptivity of mated female Glossina morsitans morsitans Westwood is shown to depend on both physical and chemical stimuli associated with copulation. Radiolabelling revealed the transfer of substances from the male to the haemolymph of the female during copulation. Implantation of male tissues or their injection as homogenates into virgin females showed the chemical stimulus to come from the male accessory glands. Receptivity decreased in females mated to males with ejaculatory ducts severed or testes removed and also in females which had a glass bead inserted into their uterus and/or the tip of their abdomen covered with wax, suggesting that a physical stimulus inducing refractoriness is provided by distension of the uterus and/or stimulation of their terminalial setae. Exposing virgin females to daily short matings in which no male materials were transferred, confirmed this. Receptivity also declined slowly with age in unexposed virgin females. Transfusion of haemolymph from mated females (up to 11 days old) into virgins did not indicate the existence of a haemolymph‐borne ovulation‐inducing factor; apparently only physical stimuli from mating are involved in the induction of ovulation, and somehow prime the ovarian tissue so that it responds appropriately later when the egg has matured. Whether the stimulus is transmitted to the ovary neurally or hormonally is unknown.
The programming of circadian flight‐activity in relation to mating and the gonotrophic cycle in the mosquito, Aedes aegypti
Authors: JONES M. D. R.
Published: March 2008

ABSTRACT. The circadian flight activity of female Aedes aegypti (L.) changes after insemination and during the course of the gonotrophic cycle. Virgin females attain a high level of spontaneous activity within 3–4 days of adult emergence; in LD 12:12 there are peaks of activity at the beginning and end of the light phase. Inseminated females are less than 20% as active as virgins, but exhibit a similar daily pattern. After blood‐feeding, inseminated females become almost totally inactive for about 48h and then show a unimodal pattern of activity which is consistent with oviposition behaviour; after oviposition they revert to the basic inseminated pattern and level of activity. Blood‐fed virgin females continue to show a high level of spontaneous activity. It is suggested that insemination has the general effect of raising the threshold for activity and that it is necessary before blood‐fed females can switch to the gravid behaviour programme. Blood‐fed uninseminated females thus continue with behaviour which will maximize the probability of insemination.
Long‐term effects of diet on the neuroendocrine system of the sheep blowfly, Lucilia sericata
Authors: APPLIN D. G.
Published: March 2008

ABSTRACT. The medial neurosecretory cells (MNC), corpus allatum (CA) and ovaries of Lucilia sericata Mg. are quiescent in mature flies fed on a diet of sugar and water, but these tissues rapidly respond to the ingestion of a protein meal. The present study revealed that after oogenesis, virgin flies synthesized and stored neurosecretory material, but this activity declined as they grew older. At the same time, the CA, following a decrease in size during the latter stages of oogenesis, became enlarged again. This is interpreted as denoting synthesis but not release of CA hormone. In meat‐fed mated flies, cycles of oviposition and oogenesis were reflected in the rise and fall in activity of the MNC and CA. The MNC and CA of male flies also responded to the ingestion of a protein meal, and the activity of these tissues persisted for several days before it declined. The similar response of the MNC and CA in both males and females demonstrates the importance of a meat meal to reproduction in this species: in females it is required for oogenesis, but its ingestion by both sexes is necessary for overall reproductive success.