bluuebunny/crossref_metadata_2025 huggingface dataset:
Different seasonal rearing conditions do not affect pheromone‐sensitive receptor neurons of the adult cabbage looper moth, Trichoplusia ni
Authors: GRANT ALAN J. , BORRONI PAOLA F. , O'CONNELL ROBERT J.
Published: March 2008

Abstract. In southern parts of the United States the cabbage looper moth, Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae), is multivoltine, and therefore successive generations experience different environmental conditions during development from larvae to adults.Since environmental conditions are thought to influence pheromone communication, we tested the effects of two different temperature and light regimes (selected to mimic those occurring in the spring and summer growing seasons in the south) during rearing on the response characteristics of the adult male olfactory receptor neurons responsible for detecting the major component of the female pheromone.The dose‐response functions of receptor neurons from the warm‐ and cold‐reared insects were similar in both their slopes and thresholds to stimulation with the major component of the female‐emitted pheromone, (Z)‐7, dodecen‐1‐ol acetate and (Z)‐7, dodecen‐1‐ol, a behavioural inhibitor.In double pulse experiments, designed to emulate the temporal dispersion of pheromone in nature, neurons were stimulated with short pulses (200 ms) of (Z)‐7, dodecen‐1‐ol acetate separated by varying intervals.Intervals as short as 30 ms reduced the response to a second pulse by over 50%.When the intervals between pulses were longer than 2 s, significant differences were not seen between the responses to the first and to the second pulse.These temporal response patterns were similar in both warm‐ and cold‐reared animals.
Sex pheromone and visual trap interactions in mate location strategies and aggregation by host‐alternating aphids in the field
Authors: HARDIE JIM , STORER J.ROBERT , COOK FRASER J. , CAMPBELL COLIN A.M. , WADHAMS LESTER J. , LILLEY RICHARD , PEACE LYNN
Published: March 2008

Abstract. Field observations were made on the responses of males and gynoparae of three host‐alternating aphid species, the blackberry‐cereal aphid, Sitobion fragariae (Walker), the bird cherry‐oat aphid, Rhopalosiphum padi (L.) and the damson‐hop aphid, Phorodon humuli (Schrank) to species‐specific sex pheromones released from transparent and coloured water traps.Pheromone traps caught significantly more males than did control traps without pheromone, whereas transparent, light green, yellow and orange traps caught most insects.Measurements of the distance over which sex pheromones function indicated that male P.humuli detect the pheromone 2–6 m from the source and can fly upwind to a source in wind speeds of 0.7 m s‐1.In all three species significantly more gynoparae were caught in pheromone traps than in control traps, suggesting that pheromone released by adult sexual females may assist late‐flying gynoparae to locate a suitable host plant on which to deposit their progeny.The response is relatively stronger for males than gynoparae, but the pheromones appear to act as both sex and aggregation pheromones.
Low oviposition stimuli reduce egg production in the pollen beetle Meligethes aeneus
Authors: HOPKINS RICHARD J. , EKBOM BARBARA
Published: March 2008

Abstract. Gravid female pollen beetles, Meligethes aeneus (F.) (Coleoptera: Nitidulidae), were exposed at different intervals to oviposition sites that varied in acceptability.The egg load of dissected individuals which had been deprived of oviposition sites was not greater than individuals which had been frequently exposed to oviposition sites.However, the egg load of individuals which had been exposed to highly acceptable host plants was greater than those exposed to a host plant of low acceptability.Over the experimental period the total number of eggs which an individual produced was lower for those that were either deprived of an oviposition site or frequently exposed to a low‐quality host plant.There was no evidence of either increased oviposition probability or clutch size as the period since the last oviposition increased.It is concluded that low host quality and low host encounter rate reduce the egg production of M.aeneus. It is further concluded that the suppressed egg production reduces the accumulation of eggs, so that physiological motivation for the insect to oviposit is not increased.If low oviposition site quality acts to reduce oogenesis, as found here, then the probability of egg deposition on low‐quality species may not increase over time and the effect of antixenotic resistance may be enhanced.
Preference of the cabbage root fly, Delia radicum (L.), for coloured traps: influence of sex and physiological status of the flies, trap background and experimental design
Authors: KOŠŤÁL VLADIMÍR , FINCH STANLEY
Published: March 2008

Abstract. Catches of Delia rudicum (L.) (Diptera: Anthomyiidae) were compared in water traps that reflected predominantly wavelengths shorter (violet and blue traps) and longer (green and yellow traps) than 500 nm.Traps were positioned in choice and no‐choice situations against backgrounds of bare soil and weeds in the field and against backgrounds of brown and green paper in the laboratory.The physiological status of the flies was modified in the laboratory by denying them access to food sources and oviposition sites.

Males discriminated significantly more clearly than females between yellow and blue traps.The discrimination between yellow and blue traps was significantly more pronounced when the traps were presented in the choice than in the no‐choice situation in both sexes.Green background (weeds and green paper) was highly preferred for landing and thus competed with the traps to such an extent that few flies were caught when non‐preferred violet and blue traps were sited on green backgrounds.Flies seldom landed on the brown background (soil and brown paper) which resulted in the relative increase of catches in the non‐preferred violet and blue traps.The preference for yellow traps was innate even in young flies with immature egg‐follicles.Females that were ready to lay eggs, even those deprived of an oviposition site till the age of 8 days, also preferred yellow traps.In the no‐choice situation, flies deprived of food landed with the same frequency in yellow and blue traps.Food deprivation, however, did not affect preference for yellow traps over the blue traps presented in a choice situation.
Diapause duration, survival in relation to desiccation and egg‐pod morphology of the Senegalese grasshopper, Oedaleus senegalensis
Authors: COLVIN JOHN
Published: March 2008

Abstract. The Senegalese grasshopper, Oedaleus senegalensis (Krauss) (Orthoptera: Acrididae), is periodically a devastating pest of subsistence crops in the sahelian zone of West Africa.Egg diapause has been suggested as an important component of the mechanism acting to generate outbreaks and therefore diapause duration, egg survival in relation to desiccation and egg‐pod morphology were investigated in this study.

Three months after oviposition, 50% of initially diapausing egg pods maintained in the laboratory exhibited ‘partial emergence’ and produced hoppers.No difference in diapause duration was evident between egg pods maintained at a constant 30 ± 1°C and those maintained under alternating temperature conditions of 23 ± 1°C and 35 ± 1°C.Laboratory maintained eggs showed significant variation in diapause duration with diapause lasting between 2 months and 4 years.Diapause duration was shorter in the field with only c. 1.4% of eggs remaining in diapause after a single dry season (6–7 months).Survival of eggs in relation to desiccation was high in the field and low in the laboratory, and field eggs lost only c. 20% of their body weight over the dry season.Survival of diapausing and non‐diapausing egg pods in the laboratory was similar, indicating that diapause in this species is primarily a mechanism for preventing emergence at an inappropriate time of year, rather than conferring any additional resistance to desiccation.Egg pods oviposited under diapause‐inducing conditions (LD 14:10 h, 25°C) were significantly shorter than those laid under non‐diapausing conditions (LD 10:14 h, 40°C).These results are discussed both in relation to possible O.senegalensis‘bet‐hedging’ strategies and to the probable mechanism operating behind major outbreaks of this species.
Factors influencing response of flying Prostephanus truncatus to its male‐produced aggregation pheromone
Authors: FADAMIRO HENRY Y. , WYATT TRISTRAM D.
Published: March 2008

Abstract. The effects of age, sex, mating status, pre‐exposure to pheromone, resource (diet) quality, and starvation on the response of Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) to its male‐produced aggregation pheromone were investigated.Age was an important factor determining the level of response to pheromone: young adults were more responsive than older adults.The suitability of the resource in which P.truncatus is present affected its dispersal tendency, but not its sensitivity to pheromone per se. Sex, mating status, brief prior exposure to pheromone, and starvation did not influence the response of the larger grain borer to pheromone.The orientation behaviour of the beetle is described, and it is proposed that the pheromone primarily functions as a ‘suitable resource location and colonization signal’.
Involvement of vitamin A in the photoperiodic induction of diapause in the spider mite Tetranychus urticae is demonstrated by rearing an albino mutant on a semi‐synthetic diet with and without p‐carotene or vitamin A
Authors: BOSSE Th.C. , VEERMAN A.
Published: March 2008

Abstract.Data are presented on the development from egg to adult of a wild‐type and an albino strain of the spider miteTetranychus urticaeon a semi‐synthetic liquid diet.The diet is a modification of the diet developed by Van der Geestet al.(1983).Apart from the standard diet without added carotenoids, diets supplemented with either β‐carotene or vitamin A were tested.A high incidence of diapause was found in the wild‐type strain under short‐day conditions on all three diets.No diapause was found in the albino mutant under short days on the standard diet.Partial restoration of the photoperiodic response was obtained after addition of β‐carotene to the diet, and full restoration was found after the addition of vitamin A.Diapause could be terminated in diet‐reared diapausing females of both strains after a cold rest of 3 weeks at 4°C.The results lead to the conclusion that vitamin A or a derivative of vitamin A probably functions as the photoreceptor pigment for the photoperiodic induction of diapause in the spider mite.
Host odour composition affects host location efficiency of tsetse (Diptera, Glossinidae)
Authors: GROENENDIJK C.A. , TAKKEN W.
Published: March 2008

Abstract. Marked Glossina pallidipes Austen were released downwind of an odour source in the field in Zimbabwe and the percentage recaptured at the source on the same day was measured.In the absence of odour, 1.3% of the marked tsetse released from a box or refuge were recaptured, independent of the distance between release point and odour source.The distance was varied from 10 to 100 m.When natural ox odour or a blend of carbon dioxide, acetone, octenol and phenols was dispensed, untransformed recapture percentages of box‐released tsetse decreased from 18% for tsetse released at 10 m to 2% for tsetse released at 100 m.Recapture percentages were significantly higher than in the absence of odour at all release distances for ox odour and for release distances up to 75 m downwind for the artificial odour.When a combination of acetone, octenol and phenols or carbon dioxide on its own was dispensed, recapture percentages decreased from 6% for tsetse released at 10 m to 0% for tsetse released at 100 m.With these odours, recapture percentages were higher than in the absence of odour when tsetse were released at 20 m from the source, but were lower than recaptures in the presence of ox odour or the artificial mixture with carbon dioxide.Recapture percentages of flies spontaneously leaving refuges were higher than those of box‐released tsetse.Proximity of source had no effect on the recapture percentage of refuge‐leaving tsetse and host‐location efficiency was close to 100% when host odour was detected at 30 m or less.The results are discussed in relation to the host location strategy of tsetse.
Elevation of pheromone response threshold in almond moth males pre‐exposed to pheromone spray
Authors: MAFRA‐NETO A. , BAKER T.C.
Published: March 2008

Abstract. High percentages of naive Cadra cautella (Walker) (Lepidoptera: Pyralidae) males not pre‐exposed to pheromone flew upwind to sources containing 50 ng (83%) and 500 ng (97%) of pheromone, but not to sources containing 5 μg (23%) and 50 μg (4%).Of the naive males that flew upwind in response to 50 ng sources, 67% located and landed on the source, whereas fewer than 19% of the naive males that flew upwind in response to higher doses located and landed on the sources.A 2‐minute pre‐exposure of C.cautella males to a spray cloud containing 50 ng, 500 ng, 5 μg or 50 μg of pheromone, induced shifts in response levels such that in wind‐tunnel bioassays performed 1 h later, there was an increase in the doses that optimally elicited upwind flight and landing on the source that was proportional to the pre‐exposure dose.Few of the pre‐exposed males flew upwind to (10–43%) and landed on (0–33%) 50 ng sources, whereas they now perferentially flew upwind to(58–81% and 52–73%) and landed on (33–68% and 55–60%) pheromone sources of doses of 500 ng and 5 μg, respectively.Therefore pre‐exposure to pheromone promoted a shift of threshold for response, and not an overall reduction in responsiveness to pheromone.
Development‐activity relationships in nymphal corpora allata of the cockroach, Diploptera punctata
Authors: CHIANG ANN‐SHYN , HOLBROOK GLENN L. , SCHAL COBY
Published: March 2008

Abstract. In females of Diploptera punctata the corpora allata undergo a gradual increase in volume during most of the second nymphal stadium. In the first half of the stadium, steady growth of the glands results from a progressive increase in the size of constituent cells. Late in the stadium, cell size declines but the volume of the glands continues to rise due to an increase in cell number. Changes in cell size during the stadium displayed a distinct pattern in relation to Juvenile Hormone (JH) synthesis. Both cell size and activity increased during the first two‐thirds of the stadium, peaked early in the last third of the stadium, and decreased before the moult. The rise in cell numbers late in the stadium corresponded to a wave of cellular mitosis and occurred after a steep decline in the rate of JH biosynthesis. Exposure of late second instars to fenoxycarb. a JH analogue, depressed mitosis significantly, suggesting autocrine regulation of cell proliferation in the corpora allata. Possible mechanisms modulating sequential cycles of growth and atrophy of cells and cell proliferation in these glands are discussed in relation to temporal patterns of JH and ecdysteroid titres in nymphs.
Cold shock and rapid cold‐hardening of pharate adult flesh flies (Sarcophaga crassipalpis): effects on behaviour and neuromuscular function following eclosion
Authors: KELTY JONATHAN D. , KILLIAN KATHLEEN A. , LEE RICHARD E.
Published: March 2008

Abstract. Little is known about the nature of injury due to cold shock, or its prevention by rapid cold‐hardening, in insects. To understand these phenomena better at the system level, physiological and behavioural comparisons were made between control, cold shock injured, and rapidly cold‐hardened flesh flies, Sarcophaga crassipalpis Macquart (Diptera, Sarcophagidae). Cold shock impaired the proboscis extension reflex in response to 0.125,0.5 and 1.0 M sucrose solutions. Cold shock‐injured flies were unable to groom effectively and spent only 12.5% of the first 5 min following general dust application producing ineffectual leg movements. In contrast, control and rapidly cold‐hardened flies exhibited normal grooming behaviour spending 92.4% and 94.1% of the first 5 min following generalized dust application grooming. Cold shock also decreased the mean resting membrane potential of tergotrochanteral muscle fibres from ‐65.9 mV in control flies to ‐41.6 m V. Conduction velocities of the three motor neurone populations innervating the tergotrochanteral muscle were all significantly lower in cold‐shocked flies than in control or rapidly cold‐hardened flies. Finally, cold shock impaired neuromuscular transmission as evidenced by a lack of evoked end plate potentials.
Inheritance of photoperiodic response in the bird cherry aphid, Rhopalosiphum padi
Authors: LUSHAI GUGS , HARRINGTON RICHARD
Published: March 2008

Abstract. The photoperiodic induction of presexual females (gynoparae) and males of the aphid Rhopalosiphum padi (L.) was examined in single clones collected from different latitudes (N clone from Blair Atholl, 56.5d̀N 3.1d̀W; C clone from Leeds, 53.5d̀N 1.4d̀W and S clone from Exeter, 50.4d̀N 3.3d̀W). Critical night lengths (CNLs) for gynopara and male production (CNLs: 50% of maximum production) and inter‐clonal differences, defined by the different forms of progeny produced at a single discriminating night length (12 h 30 min), were measured at 16 ± 1d̀C. The aphid clones differed in CNL and in the morphs produced at the discriminating night length. These differences were used to investigate the inheritance of the photoperiodic response. In crosses between clones the photoperiodic response showed considerable overall variation. The variation in CNLs indicated that the photoperiodic response was unlikely to affect the overwintering success after long‐distance movement of clones from one latitude to another.
Cereal aphid responses to sex pheromones and host‐plant odours in the laboratory
Authors: LILLEY RICHARD , HARDIE JIM
Published: March 2008

Abstract. The movement of Sitobion fragariae (Wlk.) (Homoptera: Aphididae) males towards odours from conspecific sexual females (oviparae) and the aphid sex pheromone component (4aS,7S,7aR)‐nepetalactone were demonstrated in a linear‐track olfactometer. Males of the closely related Sitobion avenae (Fab.) were attracted to odours from conspecific oviparae and also oviparae of S. fragariae. These results were consistent with the recent identification of this nepetalactone isomer as the major component of the sex pheromone in these species. Males of S.fragariae were not significantly attracted to oviparae of S.avenae. indicating some qualitative or quantitative difference in the pheromones of the two species. Males did not respond to the related (1R,4aS,7S,7aR)‐nepetalactol or to host‐plant odours. Gynoparae of these species moved towards the nepetalactone and also to host‐plant odours. A combination of both stimuli was more attractive than plant odour alone. Gynoparae of S.fragariae also responded significantly to the combined treatment when this was tested against the nepetalactone.
Hopkins' ‘host selection principle’, another nail in its coffin
Authors: EMDEN H. F. VAN , SPONAGL BARBARA , WAGNER EVELYN , BAKER T. , GANGULY S. , DOULOUMPAKA SOFIA
Published: March 2008

Abstract. Adult female parasitoids (Aphidius rhopalosiphi De Stef.) (Hymenoptera: Aphidiidae) reared on the aphid Metopolophium dirhodum (Walk.) (Homoptera: Aphididae) changed their responses to odours of two wheat cultivars (‘Maris Huntsman’ and ‘Rapier’) when the parasitized aphids had been moved from the former to the latter cultivar at various times after parasitization. If the aphids were moved after less than 6 days, the female parasitoids emerging from mummies by then formed on ‘Rapier’ responded positively to that cultivar, whereas parasitoids emerging from mummies transferred as still living aphids after 8 days on ‘Maris Huntsman’, responded positively to that cultivar rather than to ‘Rapier’ on which they had emerged. This appeared to be evidence for Hopkins' ‘host selection principle’, which states that chemical experience acquired by the larva of an endopterygote insect can be transferred through the pupal stage to the adult. However, discrimination in favour of either cultivar disappeared when the parasitoids were reared in aphids on both cultivars, and the emerging females were tested following excision of the pupae from the aphid mummies. The previous discrimination shown by adult parasitoids emerging from aphid mummies must therefore be determined by the chemicals contacted by a parasitoid on the skin of the mummy or while biting its way out of the dead aphid.
Behavioural and gustatory responses of female Neobellieria (=Sarcophaga) bullata to sucrose and amino acids
Authors: ALBERT P. J. , BANGA N. , DOLZAN E.
Published: March 2008

Abstract. Unmated female Neobellieria (=Sarcophaga) bullata (Parker) (Diptera: Sarcophagidae) of different ages ranging from 1 to 24 days consistently preferred a solution of 100 mM/1 sucrose to one containing a mixture of six amino acids at a total concentration of 10 mM/1. When these solutions were used to stimulate the gustatory sensilla on the proboscis of 2‐ and 5‐day‐old flies, sucrose elicited a greater response from cells 1 and 2 in large and cell 1 in medium‐length hairs, which could account for the feeding preference of the flies for this chemical.
Expression and activity of 3‐hydroxy‐3‐methylglutaryl‐CoA synthase and reductase in the fat body of ovariectomized and allatectomized Blattella germanica
Authors: CASALS NURIA , MARTÍN DAVID , BUESA CARLOS , PIULACHS MARIA‐DOLORS , HEGARDT FAUSTO G. , BELLÉS XAVIER
Published: March 2008

Abstract. . 3‐Hydroxy‐3‐methylglutaryl‐CoA (HMG‐CoA) synthase and HMG‐CoA reductase show coordinated regulation in the fat body of Blattella germanica females. Since the profile of activity is parallel to the cycle of vitellogenin production, we postulated a link between the mevalonate pathway and vitellogenesis. Here we have studied both enzymes in females of B.germanica modified by ovariectomy (which leads to a saturable accumulation of vitellogenin) and allatectomy (which supresses vitellogenesis). Protein levels and enzymatic activity for both enzymes in ovariectomized specimens rose early in the first days of imaginal life and remained high until the end of the period studied, whereas controls showed cyclic profiles. In allatectomized specimens the same parameters were measured on day 4 of adult life and values were much lower with respect to controls. The parallelism between the patterns of HMG‐CoA synthase and reductase, and that of vitellogenin, suggests a functional relationship between the mevalonate pathway and the glycosylation of vitellogenin through dolichol intermediates.
Effects of treatments for electrical penetration graph recordings on behaviour and biology of Aphis craccivora (Aphididae)
Authors: ANNAN I. BILLy , SCHAEFERS GEORGE A. , TINGEy WARD M. , TJALLINGII W. FREDDY
Published: March 2008

Abstract. Two laboratory studies were conducted to investigate effects of treatments for direct “current electrical penetration graph (DC‐EPG) recordings or ‘tether effect’, on behaviour and reproductive performance of cowpea aphid Aphis craccivora Koch. The experiments constituted a control study in application of DC‐EPGs to analyse cowpea aphid feeding behaviour and host plant resistance mechanisms. Resistant (ICV‐12) and susceptible (ICV‐1) cultivars of cowpea Vigna unguiculata (L.) Walp were used. EPG treatments included two groups of aphids: tethered aphids that were exposed to DC electricity via an attachment of a thin, flexible gold wire on their dorsum using a droplet of adhesive silver paint, and ‘free’ (untethered) aphids with a dorsal spot of silver paint only. EPGs of the tethered aphids were recorded continuously for c.! h, whereas from the ‘free’ aphids recordings were done only for brief periods of 2–5 min, by temporarily contacting a gold wire to the spot of silver paint. Waveform signals generated from resistance fluctuations and electromotive forces, and representing aphid stylet penetration behaviour were recorded. A separate experiment was conducted to investigate effects of EPG treatments on aphid survivorship and population growth. Overall, EPG treatments did not significantly affect aphid stylet penetration behaviour or life‐table parameters. However, effects of crop cultivar on those characteristics were significant. Waveform E2, which denotes aphid ingestion in phloem sieve elements, and non‐penetration behaviour were important indicators of aphid resistance in ICV‐12. Also, apart from the number of aphid generations, other life‐table parameters were useful indicators of ICV‐12 resistance. Thus, DC‐EPGs provided a reliable technique for studying aphid stylet behaviour, and investigation of aphid resistance in cowpeas.
Aphid flight‐track analysis in three dimensions using video techniques
Authors: HARDIE JIM , YOUNG STEPHEN
Published: March 2008

Abstract. A technique is described for the three‐dimensional analysis of the flight paths of small insects using two video cameras placed alongside each other with the optical axes coincident at a point some distance beyond the area of interest. The video signals were mixed and a time base introduced before recording the superimposed images from both cameras on a single VCR. With suitable lighting and a black background, flying aphids appeared on the monitor as double, bright images on a dark background. The distance between the two images was inversely proportional to the distance of the aphid from the camera lenses. A calibration grid was used to insert the correct parameters into software designed to provide the x (vertical), y (horizontal) and z (distance from the cameras) Cartesian co‐ordinates for a flying insect and to calculate the distances flown, flight speed and turning parameters. The advantages of the system are that it is designed for a single VCR and monitor, provides automatic synchrony between camera signals and can examine a larger visual arena than screen‐splitting methods. It operates with insects as small as aphids, and wind‐tunnel studies on the black bean aphid, Aphis fabae Scop., showed that some flight parameters (for the final one‐second approach to a visually attractive landing platform) differed according to whether wind was present or not. Thus, ground speed and distance moved differed significantly but turning parameters were unchanged. In addition, flight trajectory on the approach to landing depended upon initial direction of flight and the presence of wind.
Pulsed pheromone stimuli affect the temporal response of antennal receptor neurones of the adult cabbage looper moth
Authors: GRANT ALAN J. , BORRONI PAOLA F. , O'CONNELL ROBERT J.
Published: March 2008

Abstract. Male cabbage looper moths, Trichoplusia ni (Hiibner) (Lepidoptera: Noctuidae), fly upwind in response to pheromone blends produced and released by calling conspecific females. Specialized sensilla on the male antenna contain sensitive, highly specific olfactory receptor neurones which respond to constant olfactory signals, with a phasic‐tonic pattern of action potential discharge. Olfactory stimuli in nature are not uniform. They are thought to consist of pulses of odours whose distribution is shaped by wind and local environmental features. We begin to evaluate this natural situation by stimulating pheromone‐sensitive sensilla with short (200 ms) paired pulses of the major component of the female's pheromone blend, (Z)‐7‐dodecen‐l‐ol acetate (Z‐7,12:AC). Different stimulus protocols in which the pulses were separated from each other by varying intervals were evaluated. The interval between pulses had a large effect on the phasic component of the response. Intervals between pulses as short as 30 ms reduced the response to a second pulse by > 50%. When the intervals between pulses were longer than 3 s, significant differences were not seen between the responses to the first and second pulse. Implications for male orientation in natural, female‐produced, pheromone plumes are discussed.
Response of body temperature to solar radiation in restrained nymphal migratory grasshoppers (Orthoptera: Acrididae): influences of orientation and body size
Authors: LACTIN DEREK J. , JOHNSON DAN L.
Published: March 2008

Abstract. .We restrained forty‐nine nymphal migratory grasshoppers (Melanoplus sanguinipes) in a series of orientations to the sun and measured rate of temperature change due to radiation intercepted, compensating for temperature loss by convection and greybody reradiation. Direct solar radiation affected body temperature significantly, but diffuse radiation did not. The coefficient of direct solar heating (Hdir), varied from 0.603 to 0.690 depending on how radiation interception was estimated, and on whether insect size was expressed as mass or as a function of length. H is the rate of temperature change as a proportion of the maximum rate assuming complete conversion of all incident radiation to heat. None of the Hdir estimates was significantly different from visible‐spectrum absorbance to (0.722), suggesting that the latter is a reasonable approximation of Hdir

In simulations, equilibrium body temperature elevation decreased with body size where energy influx was expressed as the amount intercepted (W), but increased with body size when expressed as insolation as (W m‐2) because at a specified insolation, the amount of energy intercepted increases with body size. Expressing energy influx as the amount intercepted reveals the underlying biophysical mechanisms which determine body temperature.

This paper presents a model of body temperature elevation in which fundamental physical processes are assembled to provide good estimates. This basis in physics implies that the model can can be applied with confidence to conditions other than those in which it was derived.
Feeding, drinking and digestive enzyme activities in long‐ and short‐day females of Pyrrhocoris apterus (Heteroptera)
Authors: SOCHA R. , ŠULA J. , ZEMEK R.
Published: March 2008

Abstract. .Reproducing females of the firebug, Pyrrhocoris apterus (Linnaeus) (Heteroptera: Pyrrhocoridae), reared under long‐day (LD 18:6h) photocycle (long‐day females), and diapausing females reared under short‐day (LD 12:12h) conditions (short‐day females) were analysed for temporal patterns of feeding, drinking and gut digestive enzyme activities. In long‐day females the highest activities of feeding and drinking were found at the beginning of each reproductive cycle. Significant correlation between feeding and drinking activities in both reproducing long‐day females and short‐day females during pre‐diapause state was found. In pre‐diapausing short‐day females the cyclical pattern of feeding and drinking was maintained despite the inhibition of reproduction. After entering the diapause their feeding activity became very low. Analysis of five gut enzymes revealed that short‐day females differ significantly from long‐day females in higher protease, amylase and esterase activities, in case of lipase only at certain times of their adult life; no significant difference was found in the aminopeptidase activity. Positive correlations between intensity of feeding and gut enzyme activities were observed in short‐day females. Using several protease inhibitors most protease activity in the gut of P.apterus was identified as cysteine and aspartyl proteases, and only a small part of the activity could be caused by some serine proteases.
Effects of photoperiod and low temperature on diapause termination in the yellow‐spotted longicorn beetle (Psacothea hilaris)
Authors: SHINTANI YOSHINORI , ISHIKAWA YUKIO
Published: March 2008

Abstract. .The effects of photoperiod and low temperature on diapause termination in the yellow‐spotted longicorn beetle, Psacothea hilaris (Pascoe) (Coleoptera: Cerambycidae), were examined using a population from Ino, Japan. Diapausing insects obtained by rearing larvae under short daylength (12 or 13 h) at 25oC were subjected to various treatments. When the photoperiod was changed at the same temperature, diapausing larvae showed a long‐day response with a critical daylength between 13.5 and 14h. The diapause was terminated and consequently pupation occurred if the daylength was longer than 13.5 h. Chilling the diapausing larvae at 10oC for 30 or more days also terminated diapause in most larvae irrespective of the photoperiods during and after chilling treatment. In contrast, the post‐chilling photoperiod had a critical effect on development of diapausing larvae chilled for only 15 days.
Specificity of accessory gland extracts. in three Delia fly species (Diptera: Anthomyiidae)
Authors: SPENCER D.J L. , CANDOLFI M. P. , KELLER . E. , MILLER J. R.
Published: March 2008

Abstract. Extracts of testes and male accessory (paragonial) glands made from three species of Delia (onion fly {D.antiqua), seedcorn fly (D.platura), and cabbage fly (D.radicum)) were injected into conspecific virgin females. Extracts of paragonial glands, but not testes, from onion, seedcorn and cabbage fly males stimulated oviposition and suppressed mating when injected into conspecific virgin females. When extracts of paragonial glands from males of these species were injected into heterospecific virgin females, the extracts of D.antiqua and D.platura were fully cross‐reactive with respect to oviposition; interspecific injection stimulated oviposition at the level of the conspecific mated controls. Injection of D.radicum extract fully activated the D.antiqua and D.platura ovipositional response. D.antiqua extract caused mating inhibition and partial oviposition in D.radicum; that of D.platura had no effect on either oviposition or mating inhibition in D.radicum. These results suggest that D.antiqua and D.platura are more closely related to one another than either is to D.radicum, and agree with published anatomically‐based phylogenies and a genetic distance calculation based on eight enzyme loci. The occurrence of sex peptide cross‐reactivity, though asymmetrical, between D.radicum versus D.antiqua and D.platura indicates that, functionally, sex peptides have changed little during the evolution of this genus. An emerging pattern of broad cross‐reactivity within genera suggests that sex peptides are not an initiator of reproductive isolation.
Orientation of flying male Anobium punctatum (Coleoptera: Anobiidae) to sex pheromone: separating effects of visual stimuli and physical barriers to wind
Authors: WyATT TRISTRAM D. , VASTIAU KATIA , BIRCH MARTIN C.
Published: March 2008

Abstract. Flying male woodworm, Anobium punctatum, are able to locate a source of female pheromone offered as a point source but land more quickly if the same odour source is presented on a model ‘tree’ (cylinder). We tested the response to a two‐dimensional black ‘tree’ marked as a silhouette on the upwind screen of the wind tunnel, with or without a hidden upwind barrier to the wind. The beetles responded equally to pheromone presented on a visual silhouette with wind barrier and to the hidden upwind wind‐barrier alone, suggesting that the wind‐barrier itself has a significant effect on insect orientation and landing: visual stimuli do not add to the landing response if the barrier is present. However, without the barrier upwind, landing was faster when the visual stimulus was present than without. This is the third forest‐living species to be shown to respond in this way, which suggests this phenomenon may be more widespread. The possibility that this phenomenon is present in other, non‐forest, phytophagous insects, their predators and parasitoids is discussed.
The selection of nutritionally balanced foods by Locusts migratoria: the interaction between food nutrients and added flavours
Authors: CHAMBERS P. G. , RAUBENHEIMER D. , SIMPSON S. J.
Published: March 2008

Abstract. To investigate the ability of insects to discriminate between nutritionally balanced and unbalanced foods, fifth‐instar nymphs of Locusta migratoria L. (Orthoptera: Acrididae) were given one of thirteen pairings of artificial foods differing only in their concentration of protein and carbohydrate. One food, containing a previously estimated optimum balance of these nutrients, was common to each pairing. The relative intake of this ‘target’ food increased on the more extreme pairings, i.e. the insects demonstrated increasingly strong preference for the balanced food when it was paired with unbalanced alternative foods. When distinctive non‐nutritional flavours (tannic acid and amygdalin) were added to one or both of the foods, the insects' intake of the unbalanced foods increased, particularly on high‐protein foods. It is suggested that learned associations were not involved in the observed patterns of selection and that the added flavours disrupted the chemosensory responses to nutrients used by the insects to differentiate foods in this context.
Thief ants have reduced quantities of cuticular compounds in a ponerine ant, Ectatomma ruidum
Authors: JERAL JOSEPH M. , BREED MICHAEL D. , HIBBARD BRUCE E.
Published: March 2008

Abstract. Workers of a tropical ponerine ant, Ectatomma ruidum (Roger), exhibit a system of intercolonial thievery for food; thief ants enter conspecific colonies, intercept food, and carry it to their own colony. We analysed thief ants, ants from the thief's colony, and ants from the colony being robbed to determine if changes in cuticular profiles could facilitate entry by thieves into a target colony. Thief ants have significantly lower total quantities of dichloromethane‐soluble cuticular compounds than non‐thieves. The reduction in cuticular compounds on thieves suggests that thievery is facilitated by inhibition of either synthesis or acquisition of its home colony's recognition cues. Five of the fifteen compounds differed significantly in their relative proportion among colonies. Principal components analysis lends support to the hypothesis that both inhibition of a thief's home colony cues and acquisition of its target colony's cues play a role in successful thievery.
Oviposition pheromone in the Simulium damnosum complex: biological activity of chemical fractions from gravid ovaries
Authors: McCALL P. J. , HEATH R. R. , DUEBEN B. D. , WILSON M. D.
Published: March 2008

Abstract. Communal oviposition in the Afrotropical blackfly species complex Simulium damnosum Theobald (Diptera: Simuliidae) is mediated by a pheromone emitted by freshly laid eggs. Previously, two compounds (designated peaks A and B) emanating from fresh eggs were shown to be associated with attractiveness to gravid blackflies in bioassay. The present study investigated the role of these compounds by testing the responses of wild‐caught Simulium yahense in Ghana to fractionated hexane extracts of gravid ovaries prepared by gas chromatography (GC). Although the fractions were prepared from Sierra Leonean Simulium leonense, GC analysis of the emissions from fresh S.yahense eggs showed that the volatile blends of both species were similar. When tested in a two‐choice bioassay, 66% of ovipositing blackflies chose the substrate baited with a mixture of the four fractions recombined. In a series of bioassays testing responses to the four individual fractions presented with a control in a multiple‐choice arrangement, only fraction 3 (containing peaks A and B) attracted significantly more ovipositions than the other fractions and control. However, fraction 3 failed to elicit a significant response when presented as the sole attractant with a control in a two‐choice bioassay. It was concluded that fraction3, though mainly responsible for mediating aggregated oviposition by S.yahense, was acting in tandem with additional cues, probably further chemicals, which remain to be isolated and characterized.
Under‐sized larvae from short‐day adults of the blow fly, Calliphora vicina, side‐step the diapause programme
Authors: SAUNDERS D. S.
Published: March 2008

Abstract. Larvae of Calliphora vicina R.‐D. (Diptera: Calliphoridae) hatching from eggs laid by adult females exposed to short day length, and then raised in darkness at 11oC, normally enter diapause rather than undergoing prompt pupariation. However, if the feeding stage is curtailed by premature extraction of larvae from their food, or if the larvae are subjected to severe overcrowding, smaller larvae side‐step the diapause programme to become miniature puparia, whereas larger larvae proceed to diapause as fully‐fed ones. In addition, smaller diapausing larvae show a shorter (or less intense) diapause than full‐sized larvae. Apart from the smallest individuals, flies can emerge from these miniature puparia and in some cases are capable of laying eggs; this suggests that avoidance of diapause may allow undersized individuals an opportunity to reproduce before winter sets in. Fat determinations performed on larvae and pupae of various sizes, however, showed that short‐day (diapause‐destined) individuals lay down the same proportion of fat as long‐day (non‐diapause) individuals, and the same proportion of fat across all size classes. The possible functional significance of this phenomenon is discussed.
Regulation of vitellogenin synthesis and uptake in the boll weevil, Anthonomus grandis
Authors: TAUB‐MONTEMAyOR TINA E. , RANKIN MARy ANN
Published: March 2008

Abstract. Hormonal factors influencing reproductive development were examined in adult boll weevils, Anthonomus grandis (Boheman) (Coleoptera: Curculionidae). Long‐day, high‐temperature rearing conditions promote reproduction whereas short‐day, low‐temperature conditions do not. Implants of corpora allata (CA), brains, or brains plus retrocerebral complexes taken from long‐day donors, or hormone analogue treatments were used to examine onset of vitellogenin synthesis and uptake in decapitated bodies of adult weevils reared in short‐day, low‐temperature conditions. Weevils decapitated within 2 days after eclosion and reared in short‐day, low‐temperature conditions never initiated vitellogenin production or ovarian development. Females and males decapitated on day 2 showed haemolymph vitellogenin within 5 days following treatment with Juvenile Hormone (JH) analogue or implantation of CA, but not after implantation of brain alone or implantation of muscle (sham). Uptake of vitellogenin into the oocytes did not occur unless both JH analogue and brain were given as replacement therapy. These experiments indicated that JH is necessary and sufficient to stimulate vitellogenin synthesis in this species but that a brain factor must be present for vitellogenin uptake.
Flight of Heliothis virescens males in the field in response to sex pheromone
Authors: VICKERS NEIL J. , BAKER THOMAS C.
Published: March 2008

Abstract. The behaviour of Heliothis virescens males flying upwind in the field in a sex pheromone plume was videorecorded and analysed. Males flew faster and straighter, with less counterturning, and heading more directly into the wind when they were 9‐11m away from the odour source than when they were 1–3 m away. Regardless of their distance from the source or the windspeed, they maintained an average groundspeed of c. 200 cm s_1, except when they arrived within 1 m of the source, when their groundspeed slowed significantly. Two or more males flying in the plume at the same instant often exhibited either extremely straight and directly upwind tracks or else zigzagging tracks with significant counterturning (as did males flying through the field of view of the cameras at slighdy different times). The males' position, either in the centre of the plume's axis or along one side, might explain these differences in track straightness, which previous studies with H.virescens have shown to be caused by higher frequencies of contact with plume filaments. When a significant shift in wind direction occurred, males tended to make an initial movement in the direction of the shift, perhaps due to latencies of response in both the olfactory and visual systems associated with flying into clean air. The males' behaviour in the field overall was similar to that observed in the wind tunnel, except that their airspeeds and groundspeeds were significantly higher than those observed in the laboratory. The fact that they flew faster in the field can be explained both by the significandy higher windspeeds that males need to compensate for in the field to attain a preferred velocity of image motion, as well as by a higher height of flight over the ground in die field causing a slower apparent motion of images at a given groundspeed compared with the laboratory.
The effects of mass and age on standard metabolic rate in house crickets
Authors: HACK MACE A.
Published: March 2008

Abstract. This study employed flow‐through respirometry to measure the oxygen consumption rates (VO2) of inactive male house crickets, Acheta domesticus L. (Orthoptera: Gryllidae), and to quantify the effects of body mass and adult age on standard metabolic rate (SMR). The Vo2 increased with male body mass at a rate similar to that found in other studies of insect aerobic metabolism. The data reported in this study are combined with published data from other species of Orthoptera to generate a consensus allometric relationship between SMR and body mass for the Order. In general, the Orthoptera expend 2–3 times the energy per unit of body mass when inactive as compared to other arthropods, such as tenebrionid beetles, ants and spiders. Possible explanations for this substantial difference are discussed. By contrast to body mass, mass‐specific Vo2 decreased with increasing male age. This age effect has previously been reported for mammals but is not well established for insects, and its implications for the preference of cricket females for older mates is discussed. As energy expended for metabolic maintenance comprises 78% of a male cricket's daily energy budget, changes in SMR may have a substantial effect on the energy available for reproduction.
Manoeuvres of female Brachymeria intermedia flying towards host‐related odours in a wind tunnel
Authors: KERGUELEN V. , CARDÉ R. T.
Published: March 2008

Abstract. Mature female Brachymeria intermedia (Hymenoptera: Chalcididae) were conditioned to fly towards vanilla odour in a wind tunnel. We analysed the tracks of wasps flying along turbulent plumes of either host odour (pupae of the gypsy moth, Lymantria dispar) or vanilla odour, along either a ribbon plume or a turbulent plume of vanilla odour, and before and after plume removal. Wasps flew in similar shallow zigzagging tracks along the turbulent plume of host and vanilla odours. When the plume was removed while wasps were flying upwind along a turbulent plume of vanilla odour, wasps either maintained an upwind course or drifted sideways, alternating upwind and downwind courses before turning around and flying downwind. No wasp casted upon loss of the plume.