bluuebunny/crossref_metadata_2025 huggingface dataset:
Upwind flight by the cabbage root fly, Delia radicum
Authors: FINCH S. , SKINNER G.
Published: March 2008

ABSTRACT. In fourteen releases, most female D.radicum (L.) (Diptera, Anthomyiidae) flew upwind or at an angle to it of less than 77° regardless of the presence of host‐plant odour. Females ready to lay eggs flew upwind without prior stimulation by odours from either a host crop or a trap releasing up to 3 ml/day of the attractant allylisothiocyanate. Upwind flight was more pronounced in flies from a diapause than from a continuous, non‐diapause culture. Males from the non‐diapause culture dispersed upwind and downwind in more or less equal numbers; old males flew mainly downwind. But, like the females, most males from the diapause culture flew upwind. Long‐distance, odour‐modulated anemotaxis did not appear to be used to locate distant host crops by either sex. It is concluded that the distances of insect orientation to plant odours recorded to date are only of intermediate range, and that long‐range orientation to the odours of a host‐plant still has to be proven. It is suggested that host‐plant volatiles are involved not only in the final stage of host location but also in the first, and probably most important stage of host selection whilst the insect is still in flight.
The analysis of flight paths of male Egyptian cotton leafworm moths, Spodoptera littoralis, to a sex pheromone source in the field
Authors: MURLIS J. , BETTANY B. W. , KELLEY J. , MARTIN L.
Published: March 2008

ABSTRACT. The flight of male Spodoptera littoralis (Boisd.) (Noctuidae) towards a pheromone source was recorded during the early part of the night using a cine camera and an image intensifier. The cine films were analysed frame by frame to produce flight tracks from which it was possible to calculate the mean advance rate of moths towards the pheromone source and their projected ground speed, for a series of positions downwind of the source. As wind speed was measured the moth's air speed was also estimated. The moths compensated for changes in wind speed by varying their air speed, hence maintaining a ground speed independent of wind speed. The ground speed itself was found to decrease as moths flew closer to the pheromone source.
Gustatory discrimination of sugars, amino acids, and selected allelochemicals by the tarnished plant bug, Lygus lineolaris
Authors: HATFIELD L. D. , FRAZIER J. L. , FERREIRA J.
Published: March 2008

ABSTRACT. Selected sugars, amino acids and allelochemicals were tested over a range of concentrations to determine their effect on the ingestion rates of adult tarnished plant bugs. Experiments were performed with a two‐choice bioassay technique utilizing artificial membranes. Sucrose was the most effective feeding stimulant of all the compounds tested. Glucose was an effective stimulant but was 8 times less potent than sucrose. Fructose was 50 times less potent than sucrose. Methionine and phenylalanine were the only amino acids of seven tested which stimulated feeding. Leucine produced a deterrent effect. Cotton tannin was the most effective deterrent of all allelochemicals tested and was 10 times more potent than gossypol. The quinone, 1, 4‐napthoquinone, and the alkaloid, tomatine, were also effective feeding deterrents. Sinigrin and its aglycone, ethyl isothiocyanate, were among the weakest deterrents of all the allelochemicals tested. Hydroquinone was the least potent deterrent of all compounds tested. The results indicate a strong chemosensory component regulating the feeding response of the tarnished plant bug. It is suggested that this response is mediated by epipharyngeal chemosensitive sensilla.
Comparison of the behavioural and physiological responses to humidity of five species of dry‐wood termites, Cryptotermes species
Authors: STEWARD R. C.
Published: March 2008

ABSTRACT. A circular humidity gradient apparatus with a porous cellulose substrate was used to compare the humidity responses of pseudoworkers (immature wood‐feeding forms) of five species of dry‐wood termites. Four of these species are widely distributed pests of buildings: Cryptotermes brevis (Walker), C. cynocephalus Light, C. dudleyi Banks and C. havilandi (Sjöstedt). The fifth species, C. naudei Coaton, has not been recorded from buildings. C. havilandi, C. cynocephalus and C. naudei were found to tend to group and feed at humidites above 90% r.h., while C. dudleyi pseudoworkers avoided humidities above 90% r.h. and below 70% r.h. These results accord with the results of studies on the effects of relative humidity on feeding and reproduction of these species. The behaviour of the most widespread species, C. brevis, seems to be closely associated with its ability to undergo acclimatization and to feed efficiently at either medium (c. 60%) or high (c. 90%) relative humidity. C. brevis kept at 89% r.h. showed an increased tendency to group at humidities above 90%, with a lower temperature preference, changes in faecal pellet formation and, for one population at least, an increased tolerance of exposure to saturated air. The humidity preferences at constant temperature were compared with the temperature preferences of the same individuals examined in uniform humidity. The value of behavioural responses as indicators of physiological differences between species and populations is considered.
Spectral sensitivity and flicker fusion frequencies of the compound eye of salmon and wild‐type tsetse flies, Glossina morsitans
Authors: DAVIS J. C. , GOODING R. H.
Published: March 2008

ABSTRACT. The spectral sensitivity and flicker fusion frequency (FFF) of wild‐type and salmon Glossina morsitans morsitans Westwood (Diptera, Glossinidae) were compared electroretinographically (ERG). Spectral sensitivity curves were similar in shape for dark‐adapted wild‐type and salmon flies, but salmon flies were over 100 times as sensitive as wild‐type flies over much of their sensitivity range. Estimation of the spectral absorption curve (from the differences in ERG sensitivities) for the pigment absent from (or present in low concentration in) the salmon eye suggests that the pigment is an ommochrome. FFF at threshold light intensities was similar in wild‐type and salmon flies, but at higher light intensity (1.3 °W/cm2) the FFF of salmon flies increased c. 200–300%, due to the capacity of the salmon eye to adapt rapidly to the flicker stimulus. Body weight had little effect upon spectral sensitivity and FFF. Wild‐type males were more sensitive to yellow‐green light and had higher FFF than did wild‐type females. Salmon males and females did not differ in spectral sensitivity, but females had higher FFF (when tested with 520‐nm light) than did males. Old wild‐type females did not differ from young females in either spectral sensitivity or FFF. However, old salmon females were more sensitive but had lower FFF than young salmon females. Food deprivation reduced spectral sensitivity and FFF in wild‐type males but not in salmon males. Irradiation (10.5 krad) reduced spectral sensitivity (c. 75–375%) and FFF (c. 30%) in wild‐type males. The greatly increased spectral sensitivity and FFF in salmon flies indicate that these flies may behave differently from wild‐type flies in the field. Differences in the way spectral sensitivity and flicker discrimination are affected by dark and light adaptation, and by such factors as age and sex, indicate that these measurements are of two independent phenomena.
Pupation site preference and body orientation of the potato tuber moth, Phthorimaea operculella
Authors: ONO TOMOHIRO
Published: March 2008

ABSTRACT. Pupation site preference and body orientation of potato tuber moth larvae, Phthorimaea operculella Zeller (Geleehiidae), were examined in the laboratory. The larvae preferred a dry, enclosed, dark place as their pupation site. Dryness was the strongest of the three categories of stimulus; the second was stimuli evoking thigmotaxis; the third was darkness. Having selected a pupation site, a larva oriented its head to the open side of the site. If two or more openings were present, final orientation was influenced by light and gravity. These preferences and orientation habits enhance pupal protection, and the ultimate successful exit of the adult pupation crevices.
A photographic account of pollen digestion by adult hoverflies
Authors: HASLETT JOHN R.
Published: March 2008

ABSTRACT. The method of pollen digestion by adults of the hoverfly Cheilosia albitarsis Mg. (Diptera: Syrphidae) was investigated by observing pollen grains at different stages in their progression along the gut. No form of mechanical ‘grinding’ to break up the grains was observed, as suggested by some previous authors. Instead, there was an exudation of the pollen grain contents through one of the pores in the pollen exine. This exudation may start as a growing pollen tube. The exact conditions which cause the pollen grains to give up their contents in this way are unknown, but it is suggested that nectar sugar within the gut may provide the necessary stimulus.
Differences between single cell responses to different components of the sex pheromone in males of the lightbrown apple moth (Epiphyas postvittana)
Authors: CSIRO E. R. RUMBO
Published: March 2008

ABSTRACT. Single cell responses, elicited by each of three components of the pheromone blend of the lightbrown apple moth, Epiphyas postvittana (Walker) (Lepidoptera, Tortricidae), exhibit significant differences in disadaptation rates and effect of stimulation on the spontaneous generation of spikes upon removal of the stimulus. The major component has a disadaptation rate of a few seconds and a sustained effect on the rate of spontaneous spike generation upon removal of the stimulus. Faster disadaptation rates and sharp reduction in the spike rate upon removal of stimulus, were observed for one minor component, 12: Ac, and suggests a likely role in close‐range orientation to the female. The second minor component produces two types of response, one of which resembles the major component. The other, more common response, exhibits a very slow rate of disadaptation, of the order of minutes. This characteristic also may have some bearing on search strategies.
Control of ventilatory movements in the aquatic insect Corydalus comutus: central effect of hypoxia
Authors: KINNAMON SUE C. , KAMMER ANN E. , KIORPES ANTHONY L.
Published: March 2008

ABSTRACT. The influence of hypoxia and hypercapnia on the ventilatory rhythm of the hellgrammite Corydalus cornutus L. (Megaloptera) was studied. In intact animals the frequency of rhythmic retractions and protractions of abdominal gills is increased by hypoxia (10% O2, 90% N2) but no ventilatory response is elicited by hypercapnia (1–5% CO2, 20% O2, 75–79% N2).

The ventilatory motor pattern was examined by recording extracellularly from the gill retractor muscle or its efferent nerve. In response to hypoxia (8% 02, 92% N2), there are decreases in the cycle‐time, the interspike interval, and the burst length of the gill retractor motorneuron. In addition, previously quiescent motorneurons associated with gill protraction are recruited.

Individual ganglia or small groups of abdominal ganglia can be isolated both from the central ganglionic chain and from the periphery by selective cutting of roots and connectives. When exposed to hypoxia, preparations that include the first abdominal ganglion show characteristic changes in the ventilatory motor pattern similar to those in intact animals. Thus sensitivity to oxygen appears to be located centrally and not peripherally. In small animals (head width < 7 mm), abdominal ganglia 2–3 and 2–7 respond characteristically to hypoxia, but in larger animals (head width > 9 mm), chains of ganglia lacking abdominal ganglion 1 fail to respond. In larger animals oxygen sensitivity may thus be concentrated in abdominal ganglion 1, whereas in smaller animals the ability to initiate a ventilatory response to hypoxia is distributed among the abdominal ganglia.
Retinal scanning and visual inputs in freely walking crickets
Authors: LAMBIN MICHEL
Published: March 2008

ABSTRACT. Freely walking crickets were filmed from above during their visual orientation towards a black stripe. A frame‐by‐frame analysis enabled head and body movements to be recorded. The animals walk in 200ms bouts (runs) separated by pauses of similar duration. During each run, rotations of the body axis are observed and some corrections of the course direction occur between successive runs. Generally, the crickets do not walk straight ahead but slightly sideways. Because no lateral head movements were observed during visually orientated locomotion, retinal scanning results from both rotations of the body axis and translation of the head. While walking, one of the target edges is maintained by the cricket on a relatively limited area of the retina, generally between 10d̀ and 25d̀ laterally. Thus, the cricket often records three pieces of information about each edge: one in the monocular visual field, and two in the binocular visual field. Nevertheless, between two pauses, the images of each edge shift asymmetrically on the retinae. Such movement could prevent receptor adaptation by modulation of the ommatidial excitation, or by stimulation of the neighbouring ommatidia. It is also suggested that antennal movements are influenced by the positions of the visually fixated target edges.
Pupal colour dimorphism in swallowtail butterflies: timing of the sensitive period and environmental control
Authors: WEST DAVID A. , HAZEL WADE N.
Published: March 2008

ABSTRACT. Two North American swallowtail butterflies with pupal colour dimorphism, Eurytides marcellus (Cramer) and Papilio troilus L., use chiefly the colour of the pupation substrate to determine pupal colour, and are affected hardly (P.troilus) or not at all (E.marcellus) by substrate texture. The use of colour cues in these species is in contrast to the greater importance of texture in two other sympatric swallowtails (Hazel & West, 1979). E.marcellus larvae evacuate the gut and start prepupal wandering around mid‐day. If they have not reached the sensitive period for pupal colour determination by nightfall they will delay the sensitive period until the next day. Among other North American swallowtails with pupal colour dimorphism there is no tendency for those species that use textural cues for pupal colour determination to evacuate the gut later in the day than those using pupation site colour.
Influence of temperature changes on larviposition rhythm in the tsetse fly, Glossina morsitans
Authors: ROBINSON M. W. , BAKER P. S. , FINLAYSON L. H.
Published: March 2008

ABSTRACT. The hourly and quarter‐hourly distribution of larval deposition by female Glossina morsitans Westw. was studied at various temperatures. At constant temperature and humidity, peak larviposition occurred 8–9 h after lights on. The effect of confining the flies to daily (LD 12:12 h) regimes of at least twenty‐five consecutive cycles that included a sudden increase in temperature of c. 6°C for 2 h was a significant reduction in depositions during each period of increased temperature, and a significant increase before the heat impulse. When the temperature was allowed to fall rapidly, larviposition rate doubled in the following 15 min.
Gating of ventilatory activity in the cave‐cricket, Troglophilus cavicola
Authors: KASTBERGER GERALD
Published: March 2008

ABSTRACT. The rhythm of ‘abdominal respiratory movements’ (ARMs) in partly tethered cave‐crickets was recorded via correlated hindleg movements associated with abdominal ventilation, and analysed with respect to postural changes (cricket placed horizontally or vertically) under the following stimulus regimes: touch stimuli of constant duration but varying rates were presented to the hind legs independently of the ARM rhythm; touch stimuli with constant delays were triggered by the previous ARM; and light stimuli were presented, preceding the touch stimuli. With constantly spaced touch stimuli, on‐ and off‐effects are visible in the number of ARMs per time unit and this is more pronounced in the horizontal than in the vertical position. Continuous modulations of ARMs patterning (tonic effects) are revealed in free run cycles which are intercalated in rhythmic driving series: at intertouch lengths of 20 s such free run cycling is faster under vertical than under horizontal conditions. With the vertical stance it is delayed by additional light. Even the kind of vertical orientation causes tonic effects. Thus crickets that face downward exhibit a slower ARM rhythm than those facing upward. Under entrainment to constantly delayed touches, two parameters of ARM rhythm (‘basic period’ and ‘consecutive period’) were studied to elucidate the hypothetical cycling of the pacemaker under different stances. Under horizontal conditions the ‘basic periods’ are shortened if the delay of touch does not exceed 0.2 periods of free run cycling. However, in the vertical position, the ‘basic periods’ are prolonged. With delay times exceeding 0.5 periods of free run cycle, the ‘consecutive periods’ are lengthened if the cricket is oriented vertically, but remain unaffected under horizontal conditions. On the basis of these results, a model for resetting and sensory modulation of ARM control is presented.
Intra‐ and interspecific sex‐pheromone communication in the genus Yponomeuta
Authors: HENDRIKSE ANS
Published: March 2008

ABSTRACT. Male behaviour in pheromone attraction was observed in a wind tunnel for eight species of the genus Yponomeuta Latreille. Interspecific responses and the effect of some combinations of female pheromones were also investigated. The results show that the species Yponomeuta cagnagellus (Hübner), Y. malinellus Zeller, Y. rorellus (Hübner) and Y. plumbellus (Den. & Schiff.) are isolated by the specificity of their female pheromones. The other four species, Y. evonymellus (L.), Y. padellus (L.), Y. irrorellus (Hübner) and Y. vigintipunctatus (Retz.), exhibited interspecific pheromone attraction.
Uptake and loss of water in diapause and non‐diapause eggs of crickets
Authors: TANAKA SEIJI
Published: March 2008

ABSTRACT. In laboratory‐laid eggs of the striped ground cricket, Allonemobius fasciatus DeGeer (Gryllidae), water absorption occurs at an early stage of embryogenesis (stage II) at 30°C but is delayed until later stages at lower temperatures. This is related to the variation in diapause stage at different temperatures. No egg developed beyond stage VII (the end of anatrepsis) without water absorption.

A. fasciatus shows seasonal variation in the stage of water absorption. At 30°C, eggs collected in August absorb water at the early stage while many of those collected in September avert diapause and absorb water at a later stage.

Diapause also influenced the water absorption of eggs in A. socius Scudder. Eggs of short‐day females enter diapause and absorb water at stage II, while those of long‐day females develop without diapause and absorb water at a later stage (around stage IV).

The susceptibility to desiccation (r.h. 50%) was examined at 20°C with A. fasciatus eggs. The percentage water loss and mortality of eggs varied with the time and duration of exposure to desiccation. Eggs are most sensitive to desiccation during the first several days after being laid and during the period of water absorption.
Effects of photoperiod on the timing of larval wandering in Drosophila melanogaster
Authors: ROBERTS BRIAN , HENRICH VINCENT , GILBERT LAWRENCE I.
Published: March 2008

ABSTRACT. A rearing method is described that will allow the use of well‐timed larvae of Drosophila melanogaster (Canton S) in physiological investigations. Using a LD 16:8 h cycle and uncrowded rearing conditions, it was shown that photoperiod influences the departure of third instar larvae from the food (i.e. post‐feeding larvae or wandering behaviour). Larval wandering occurs during the scotophase, suggesting a gated event, and does not occur in larvae raised under constant light or in overcrowded cultures reared in a LD 1623 h cycle. Although the data suggest, but do not prove, the existence of circadian gating, the rearing regimen described will provide well‐timed post‐feeding larvae for future studies.
Food intake, conversion efficiency, and feeding behaviour of tobacco hornworm caterpillars given artificial diet of varying nutrient and water content
Authors: TIMMINS W. A. , BELLWARD K. , STAMP A. J. , REYNOLDS S. E.
Published: March 2008

ABSTRACT Fifth stadium tobacco hornworm caterpillars, Manduca sexta (L.), given artificial diet diluted to varying extents with either cellulose or water compensated for the food's reduced nutrient content by eating more of it. This compensation was, however, in most cases not sufficient to maintain normal growth rates. When the water content of the diet was reduced, the insects ate less than the usual fresh weight of food but maintained their intake of nutrients. Nevertheless, growth rate was impaired. The insects were better able to compensate for dilution of their food with water than with cellulose.

The efficiency of conversion of ingested food (ECI) was decreased when the diet was adulterated with cellulose. At moderate dilution (50% nutrient) this was due mostly to decreased approximate digestibility (AD), but at greater dilution (25% and 10% nutrient content) the efficiency of conversion of digested food (ECD) was decreased. ECI was maintained when the water content of the diet was increased to give 50% nutrient concentration, but was decreased when water content was changed more radically (200%, 25% and 10% nutrient diets). This was due mostly to increased metabolic costs (decreased ECD) in all cases.

The retention time of food in the gut was progressively decreased (i.e. speed of passage was increased) as nutrients were replaced by cellulose. By contrast, dilution of the diet with water resulted in only slight changes in retention time, except at extreme dilution (10% nutrient content) when retention time was reduced.

Compensation of food intake was achieved by spending more (or less) time eating. Video analysis of feeding behaviour showed that there were significant changes in the length of feeding bouts and of interfeed gaps when caterpillars fed on diets of altered composition. For diets diluted with cellulose, changes in bout length and bout frequency contributed substantially to the increased time spent feeding on the adulterated food. For diets diluted with water, however, almost all of the compensatory change in behaviour was due to increased bout length, with bout frequency affected only slightly. This suggests that volumetric feedback contributes principally to the termination of feeding bouts in caterpillars, while nutrient flow may affect both the initiation and termination of feeding.
Biomechanics of the release of sex pheromone in moths: effects of body posture on local airflow
Authors: CONNER WILLIAM E. , BEST BARBARA A.
Published: March 2008

ABSTRACT. The calling posture of Spilosoma congrua Walker (Lepidoptera: Arctiidae) affects local airflow in ways that may impact on the release of chemical signals. Dried specimens of S. congrua imitating resting moths, calling moths, and moths with intermediate postures were placed in a wind tunnel. The wind speed was measured near the abdomenal tip where sex pheromone emission occurs. The calling posture, wings‐up, gave significantly greater mean wind speeds near the surface of the sex pheromone gland, effectively eliminating the dead air space that surrounds a non‐calling moth. The calling posture also decreased the relative intensity of turbulence near the pheromone gland surface.
Tsetse mating behaviour: effects of age and hunger in Glossina morsitans morsitans and G.pallidipes
Authors: WALL RICHARD
Published: March 2008

ABSTRACT. The effects of age and hunger on the responses of male Glossina morsitans morsitans Westwood and G.pallidipes Austen to freeze‐killed female decoys, were examined in the laboratory. In both species, activity, estimated as the total number of interactions between males and decoys, increased with both age and hunger. Interactions were divided into short‐stay (<60 s) and long‐stay, full copulatory responses. In both species, young, unfed males were significantly less likely to attempt to copulate with a decoy after encounter than were fed males. Among fed males the proportion of interactions that proceeded to full copulatory attempts did not change with increasing age, but decreased consistently with increasing hunger. At all ages and hunger levels, G.pallidipes were more active than G.m.morsitans. However, after encountering a decoy, G.pallidipes were less likely to attempt to copulate than G.m.morsitans. In both species the duration of copulatory attempts did not change with age, but declined with increasing hunger. Copulatory attempts by G.pallidipes were significantly shorter than those of G.m.morsitans. The results are discussed in relation to the behaviour of tsetse in response to control devices such as traps and targets.
Changes in the circadian flight activity of the mosquito Anopheles stephensi associated with insemination, blood‐feeding, oviposition and nocturnal light intensity
Authors: ROWLAND MARK
Published: March 2008

Abstract. The circadian activity patterns of Anopheles stephensi Liston were examined before and after mating and throughout the gonotrophic cycle. In LD 12:12h, males and virgin females are active at dusk. After insemination, females are active at dusk and also for short bursts during much of the night. After blood‐feeding, inseminated females are inactive for two nights. On becoming gravid, these females become highly active at dusk and, to a lesser extent, are also active later in the night. In contrast, blood‐feeding and egg maturation have minimal effects on the activity pattern of virgin females, who continue to fly only during dusk periods, i.e. virgins continue with the activity pattern which would most likely lead to mating encounters. After oviposition, parous females resume the activity pattern characteristic of inseminated nulliparous females. In a light regime which simulates moonlit nights and normal days, inseminated females are more active overall and flight‐burst durations are much longer than in LD 12:12h.
The host‐orientated behaviour of tsetse flies (Glossina): the interaction of visual and olfactory stimuli
Authors: TORR S. J.
Published: March 2008

ABSTRACT. Studies were made in Zimbabwe of the propensity of Glossina pallidipes Austen and G. morsitans morsitans Westwood to divert from flying upwind in plumes of host odour to various visual features (termed targets). Using various arrangements of electrocuting nets with targets placed downwind of an odour source it was found that 45% diverted to a square target, c. 30% diverted to a black vertical oblong and there was no significant diversion to a bark‐coloured vertical oblong that simulated the bole of a tree. The relative propensity of tsetse to divert to variously coloured targets decreased in the order: black = blue > red > yellow; for different shapes it decreased in the order: circle > square > horizontal oblong = vertical oblong. Changes in the composition or concentration of the odour, or loss of contact with it, did not markedly affect the percentage that diverted. Tsetse that diverted to a target and subsequently flew away from it showed an upwind bias in the presence of odour. In the absence of odour there was a slight crosswind bias. If these crosswind fliers then flew into a plume of host odour they turned c. 50d̀ upwind.
Trade‐off between flight and reproduction in the African armyworm moth, Spodoptera exempta
Authors: GUNN A. , GATEHOUSE A. G. , WOODROW K. P.
Published: March 2008

ABSTRACT. The existence of a trade‐off between flight and reproduction in the migratory noctuid, Spodoptera exempta (Wlk.), was examined in experiments in which female moths were flown on flight balances and then provided with distilled water or sucrose solution. For individuals flight‐tested from the night of eclosion (night 0) through night 1 and fed only distilled water, there was a linear, negative relationship between weight‐related fecundity and flight duration. When flight was recorded through night 2, a curvilinear relationship was obtained suggesting that highly active moths suffer a smaller decrease in fecundity than predicted from its rate of decline with increasing flight duration in less persistent fliers. The hypothesis that this reflects an energetically expensive, initial phase of each flight, followed by a less costly, cruising phase is examined. Fecundity was independent of flight duration in females provided with sucrose after flight but was related to moth weight, as it was in all unflown moths. Effects of flight and feeding on longevity and mating frequency are also reported.

There is a clear trade‐off between flight and fecundity in S.exempta which is only evident in moths denied access to a source of carbohydrate after flight. The results indicate the importance of nectar sources in the field in allowing restoration of lipid reserves depleted during migratory flight. An important implication of this conclusion is that lipid is the resource limiting to fecundity in this species and not protein as is generally supposed for leaf‐feeding insects. This might be expected in highly active species as lipid is the resource for which the energetically expensive functions of flight and reproduction must compete.
The distribution and relative potency of diuretic peptides in the house cricket, Acheta domesticus
Authors: COAST G. M. , WHEELER C. H.
Published: March 2008

ABSTRACT Dose‐response curves are presented for the diuretic activity in aqueous extracts of brain, retrocerebral complex, and ventral nerve cord ganglia from Acheta domesticus. Diuretic activity is highest in extracts of brain and corpora cardiaca. In comparison with such extracts, those of the suboesophageal ganglia and thoracic ganglia I‐III produce truncated responses, whilst abdominal ganglia 1–4 show evidence of an inhibition of the diuretic response at high doses. ED50 values, obtained from Hill plots, are similar for extracts of brain, corpora cardiaca, corpora allata, and abdominal ganglia, but are 3–4 times higher for extracts of suboesophageal and thoracic ganglia.

Separation of aqueous extracts of corpora cardiaca by reversed‐phase HPLC yields a number of fractions which stimulate fluid secretion in isolated tubules. Diuretic activity in these fractions is destroyed by treatment with Pronase E, and on this basis is identified as peptidic. In general, diuretic activity is found in the same RP‐HPLC fractions prepared from aqueous extracts of brain, suboesophageal ganglia, thoracic ganglia I‐III, and abdominal ganglia 1–4.
Cold shock and heat shock: a comparison of the protection generated by brief pretreatment at less severe temperatures
Authors: CHEN CHENG‐PING , LEE RICHARD E. , DENLINGER DAVID L.
Published: March 2008

Abstract Brief exposure to low (0oC) or high (40oC) temperature elicits a protective response that prevents injury when the flesh fly, Sarcophaga crassipalpis Macquart, is subjected to more severe cold (‐10oC) or heat (45oC). Both the low and high temperature responses were found in all developmental stages of the fly, but were most pronounced in the pupal and pharate adult stages. The protective responses generated by brief exposure to 0 or 40oC appear similar in that both result in a rapid acquisition of cold or heat tolerance and a loss of protection after the flies are returned to 25oC. The protection generated by chilling is obvious within 10 min of exposure to 0oC while a 30 min exposure to 40oC is required to induce the high temperature protection. High temperature protects against cold shock injury within a narrow range (around 36oC) but we have no evidence that low temperature can protect against heat injury. We previously demonstrated that the rapid increase in cold tolerance correlates with concomitant increases in glycerol concentration, but in this study we found no significant elevation in glycerol in heat‐shocked flies. Thus the physiological and biochemical bases for the rapid responses to cold and heat appear to be different.
Host Search behaviour by Rhagoletis pomonella files: inter‐tree movement patterns in response to wind‐borne fruit volatiles under filed conditions
Authors: ALUJA MARTIN , PROKOPY RONALD J.
Published: March 2008

Abstract. Responses of Rhagoletis pomonella (Wash) (Diptera: Tephritidae) to synthetic host fruit violates were studied in the field. Individually marked females were released in the centre of a 25 m2 patch containing twenty‐five host trees (Crataegus mollis var, toba) and followed as they moved within and between trees. Fly response to three experimental conditions was studied: (1) ‘clean’ air; (2) synthetic host fruit violates (apple) permeating the patch; and (3) a single point source of odour placed c 1m away from the edge of the patch. Files in a patch permeated with host odour moved faster, exhibited more straightened‐out moves, and reached the edges of the patch more quickly than those exposed to clean air. Flies exposed to a point source of odour exhibited clear orientation responses, arriving consistently at the tree harbouring the source of odour. Odour exposure was intermittent and usually brief (c. 20s‐1 exposure) with intervals between exposure periods averaging 103s. Wind speed and direction were highly variable. Flies moved during wind ranging in speed form 0.5 to 4.4 m s‐1, with their activity being greatest at winds below 2m s‐1. Strong winds (>3.5 ms‐1) either arrested movement or enhanced downwind displacement. Our observations tend to support the ‘series‐of‐steps’ hypothesis reviewed by Gibson & Brandy (1985) as a mechanism of close‐range host location (1‐5m from odour source). Our findings are discussed with respect to theoretical and practical implications of insect orientation mechanisms to odours, dispersal, and control strategies.
Effect of rapid freezing and thawing on cellular integrity of honey bee sperm
Authors: PENG CHRISTINE YING‐SHIN , YIN CHIH‐MING , YIN LUCY R. S.
Published: March 2008

Abstract. Direct observations on the effect of rapid freezing and thawing on honey bee (Apis melliferaL.) sperm were made by light, scanning and transmission electron microscopy. Rapid freezing of honey bee ejaculated sperm, suspended in freezing diluent, in liquid nitrogen followed by rapid thawing can cause cellular injuries which lead to the death of the sperm. The frozen‐thawed sperm, supravitally stained, showed a significant decrease in cell viability compared with that of the control fresh sperm (P<0.001). Significant uptake of the stain in the dead sperm resulted from damage in the cell membrane. The scanning electron micrographs of frozen‐thawed sperm further demonstrated that the injury of cell membrane can lead to the splitting of mitochondrial derivatives from the flagellar axoneme. More cellular injuries including the release of acrosomal content and membrane damage at the acrosome, nucleus and the tail regions were further revealed by transmission electron microscopy. The impact of cellular injuries on the quality of honey bee sperm cryopreserved for artificial insemination of honey bee queens is discussed.
Does the tsetse parturition rhythm have a circadian basis?
Authors: ŽĎĂREK JAN , DENLINGER DAVID L. , OTIENO LEONARD H.
Published: March 2008

Abstract. Under an LD 12:12h photoregime at constant temperature, parturition in Glossina morsitans centralis is a gated event occurring late in the afternoon. When flies are switched to continuous light the rhythm quickly dampens, but its persistence for at least two 24‐h cycles beyond the final scotophase suggests the rhythm has a circadian basis. A weak rhythm appears after 7 days of continuous light, perhaps in response to the daily disturbance caused by feeding. Return of the flies to LD 12:12h restores the rhythm after exposure to a single scotophase.
Periodic muscular activity and its possible functions in pupae of Tenebrio molitor
Authors: TARTES URMAS , KUUSIK AARE
Published: March 2008

Abstract. During pupal development, Tenebrio molitor L. show regular periods of rhythmic muscular contractions and associated body movements. These periods of activity last 2.5‐5.8 min and are more frequent in newly ecdysed pupae (c. 3h‐1). They become less frequent (c. 1.5 h‐1) when the basal metabolism reaches its lowest level. In the pharate adult stage the clear pattern of muscular activity disappears.

Muscular activity is temperature‐dependent and is commonly absent below 20d̀C. Muscular activity did not disturb the cyclic output of CO2, which is characteristic of metamorphosis. The heart shows characteristic periods (1–3 min) of activity during pupal development. The frequency of these heart pulsation periods depends on metabolic rate. Heart pumping was correlated mostly with muscular contractions. Therefore we suggest that the main physiological function of muscular activity is to support circulation.
Feeding behaviour of female Aedes aegypti: effects of diet temperature, bicarbonate and feeding technique on the response to ATP
Authors: MOSKALYK L. A. , FRIEND W. G.
Published: March 2008

Abstract. The effects of variation in diet temperature, mouthpart deployment and the addition of bicarbonate to a saline‐ATP diet were investigated for their effects on amount ingested and diet destination in female Aedes aegypti (L.). Mouthpart deployment was achieved by having the insects feed through a membrane, or from a free‐liquid surface with mouthparts intact, or with the fascicle separated from the labial groove.

Under the ‘feeding through membrane’ protocol, a 6‐fold increase in the percentage of Aedes feeding on ATP‐diets was recorded at 37d̀C compared with 21d̀C. Bicarbonate (9.5 or 19 mM) induced a 3‐fold increase in numbers feeding at both 21d̀C and 37d̀C. Neither diet temperature nor bicarbonate content appeared to affect meal size. The pH of all diets was adjusted to 7.0. Diet was directed primarily to the midgut for all diets tested under this regimen, with the exception of the saline‐ATP‐19 mM NaHC03 at 37d̀C which caused the diet to be directed primarily to the crop.

Under the ‘feeding without membrane through feeding tube’ protocol, females showed little control over diet destination. Female Aedes aegypti exhibited no strong response to ATP when the mouthparts were immersed in 21d̀C diets in feeding tubes and few of these insects ingested large meals. The addition of bicarbonate to the ATP diets did not enhance feeding under these test conditions.
Antennal glands in Psylliodes chrysocephala, and their possible role in reproductive behaviour
Authors: BARTLET ELSPETH , ISIDORO NUNZIO , WILLIAMS INGRID H.
Published: March 2008

Abstract. The antennal morphology of Psylliodes chrysocephala L. (Coleoptera: Chrysomelidae), an important pest of oilseed rape (Brassica napus), was studied. Two types of tricellular, integumentary glands were found. The common antennal glands are distributed under all sensilla‐bearing parts of male and female antennae. The male‐specific antennal glands are only located under a glabrous area found on antennomeres 6–10 of male beetles. The common antennal glands are synthetically active in both pre‐ and post‐diapause adults, but the male specific antennal glands are only active in post‐diapause (reproductively active) males. During studies of mating behaviour, the antennae of the males were highly active at the beginning and end of copulation, and in response to increased female activity. The male specific antennal glands may secrete a sex pheromone, and the glabrous area on the male antennae could be the release site for such a pheromone.
Compensatory feeding in response to variable food quality by Melanoplus differentialis
Authors: YANG YUELONG , JOERN ANTHONY
Published: March 2008

Abstract. The behavioural mechanisms driving compensatory food consumption in response to dietary dilution as well as the relationship between feeding time and food residence time (i.e. digesta retention time in the gut) were studied using the non‐diapausing strain of the grasshopper Melanoplus differentialis (Thomas) (Orthoptera: Acrididae). 3‐day‐old, sixth‐instar nymphs and 3‐day‐old adults were fed artificial diets containing 1%, 3% and 5% total nitrogen (N) at 30d̀C, LD 14:10h; the feeding behaviour was recorded using electronic monitoring devices connected to microcomputers for 24 h. The percentage of time spent feeding increased linearly as diets were diluted using non‐digestible cellulose from 5% to 1% N. This response was due to an increase in the number of meals while the meal duration of a feeding bout was unaltered. Sixth‐instar nymphs spent about 40% more time feeding than the larger adults. The increased feeding time in nymphs resulted from both more frequent feeding bouts and longer meal duration. Feeding time and food residence time were highly negatively related.
Fungal hyphae as a source of nutrients for the leaf‐cutting ant Atta sexdens
Authors: BASS M. , CHERRETT J. M.
Published: March 2008

Abstract. The mutualistic fungus of leaf‐cutting ants produces both ordinary hyphae and specialized ant rewards: the staphylae. Workers of Atta sexdens (L.) lived longer on diets which included nutritive staphylae than on those which provided only hyphae. However, hyphae were a better diet than sucrose solution or water alone. Small workers lived longer than large workers when receiving fungus garden, whether or not staphylae were available, probably because they are specialized to care for the garden and can exploit it. Large workers lived longer than small ones when only water was available. This may be a consequence of scale, larger workers containing proportionately more nutritional reserves in their bodies.

When starved workers were exposed to fungus for 3h, they gained weight. This weight gain represented the amount of food ingested during the test period. Workers gained 7.3 times more weight on natural fungus garden bearing staphylae than on garden with only hyphae. They gained only 1.5 times as much weight when the fungus was artificially cultured on agar. The results suggested that workers found hyphae attractive, but difficult to obtain in natural fungus gardens.

Material from hyphae and staphylae stained with a fluorescent dye was detected in worker crop contents using fluorescence microscopy. The crop contents of workers fed on staphylae fluoresced 1.14 times more than those of workers fed on hyphae.

Hyphae may provide a small source of food for workers, and the fungus as a whole may provide up to 9.0% of the respiratory energy requirements of workers, the remainder presumably being provided by plant sap.
Changes in learning ability and mechanism during development of grasshopper nymphs, Melanoplus bivittatus
Authors: HOLLIDAY J. L. , HOLLIDAY N. J.
Published: March 2008

Abstract. In an experimental arena, Melanoplus bivittatus (Say) (Orthoptera: Acrididae) nymphs of four stadia were observed to determine whether they learn to associate food with positional or light‐related cues. Nymphs were observed for 4 h in the arena containing one yellow box and one green box, then they were trained by placing food in the green box overnight. Following training, the responses of nymphs to green and yellow boxes were observed for a second 4 h period.

Before training, nymphs of all stadia visited the yellow box more frequently than the green box. Training did not affect the behaviour of second‐stadium nymphs, but training increased the relative frequency of visits to the green box by third, fourth and fifth instars. Effects of training on duration of visits to boxes were not evident. Investigations of the mechanism of learning showed that positional cues were used by third‐stadium nymphs, but that fourth and fifth instars responded to light‐related cues. The progression from no learning in second instars, through use of positional cues by third instars, to use of light‐related cues by fourth and fifth instars is probably associated with the greater mobility, greater food consumption, and more varied diet of older nymphs.
Influence of plume structure and pheromone concentration on upwind flight of Cadra cautella males
Authors: MAFRA‐NETO A. , CARDÉ R. T.
Published: March 2008

Abstract. The effects of pheromone plume structure and its concentration on the pheromone‐mediated flight of male Cadra cautella (Lepidoptera: Phycitinae) were investigated in a laminar‐flow wind tunnel. When two C. caurella males flew simultaneously along a ribbon plume of mixed smoke and pheromone, their inflight behaviour was dependent on the instantaneous structure of the plume they encountered. When a male intercepted an intact ribbon filament, he sustained a crosswind course, whereas when he intercepted a turbulent filament (created by an upwind male fragmenting the ribbon plume), he adopted a flight course more due upwind. These results indicate that C. cautella males altered their in‐flight manoeuvres in response to instantaneous changes in the fine structure of the pheromone plume. We also demonstrated that differences in the fine structure of the plume had more influence on the flight pattern of C. cautella males than a 1000‐fold range in pheromone dose. The size of the plume was increased by adding wind deflectors upwind of the pheromone source, independent of source dosage, males following ribbon plumes flew slow zigzag tracks, whereas males following large, turbulent plumes flew directly to the source in fast, straight tracks with less counterturning.
Contact chemoreception of oviposition‐stimulating glucosinolates and an oviposition‐deterrent cardenolide in two subspecies of Pieris napi
Authors: DU Y.‐J. , LOON J. J. A. VAN , RENWICK J. A. A.
Published: March 2008

Abstract. Electrophysiological responses to ten glucosinolates, oviposition stimulants isolated from their cruciferous host plants, were recorded from tarsal taste neurones of two subspecies of Pieris napi: P. napi napi L. and P. napi olerucea (Harris) (Lepidoptera: Pieridae). In the cluster of fourteen medial B‐sensilla on the fifth tarsomere, strong responses to glucosinolates were recorded. Three receptors cells, identified on the basis of spike amplitude and shape, were typically active in these responses, with the cell producing the smallest spike predominating. The response intensity of the latter cell to a particular glucosinolate at 1 mm concentration depended both on the chemical structure of the stimulus and on the subspecies of insect. In P. napi napi, aromatic glucosinolates were just as effective as aliphatic glucosinolates, whereas in P. napi oleracea the long‐chain aliphatic glucosinolates gluconapin and progoitrin were stronger stimuli. At 10 and 100 pg/ml concentrations, significant differences between the subspecies were found in the absolute response intensity to seven compounds. A second cell in P. napi olerucea, producing a medium‐sized spike, was excited most by sinalbin, whereas in Pnupi nupi three aliphatic glucosinolates were equally effective stimulants for a similar cell. In both subspecies the cell producing the medium‐sized spikes in response to glucosinolates was also highly sensitive to erychroside, an oviposition deterring cardenolide occurring in a host of P. napi olerncea. The evolutionary divergence between the two geographically separated subspecies is reflected by differences in chemosensory recognition mechanisms.