bluuebunny/crossref_metadata_2025 huggingface dataset:
Innate control of local search behaviour in the house fly, Musca domestica
Authors: COLLINS R. D. , GARGESH R. N. , MALTBY A. D. , ROGGERO R. J. , TOURTELLOT M. K. , BELL W. J.
Published: March 2008

Abstract. The genetic basis of variation in local searching behaviour in the house fly, Musca domestica L., was examined by estimating the heritability of locomotory parameters using parent—offspring regressions. Pathways of adult flies were videotaped for 3 min after ingestion of a 1 μl drop of 0.25 M sucrose in a 75 cm diameter circular arena with minimal external cues. Locomotory variables computed from digitized walking pathways, including locomotory rate, turning rates per unit of distance and time, turn bias, number of stops, and stop duration, were significantly heritable, but heritabilities (additive genetic variance ÷ total phenotypic variance) was generally low (<0.25). Phenotypic variance in search parameters increased with time since ingestion of the sucrose drop, but heritabilities were highest when only the first 30 s of the searching bout were examined, and declined as longer periods were considered. Significant genetic correlations among search parameters suggest that many of these characters are influenced pleiotropically by the same genes or closely linked genes. However, some aspects of local search were inherited independently (e.g. stop duration and locomotory rate). The independence of controlling mechanisms was supported by observed differences between genetic and environmental correlations. This genetic independence could enhance the likelihood of appropriate population responses to temporally or spatially changing selective forces.
Interactions of allelochemicals with dietary constituents: effects on deterrency
Authors: GLENDINNING JOHN I. , Jr FRANK SLANSKY
Published: March 2008

Abstract. That variation in the water and nutrient content of plant tissues affects allelochemical toxicity to insects is well established. However, little is known about how these dietary constituents influence allelochemical deterrency. In vertebrates, deterrency of particular allelochemicals increases with dietary water, and decreases with an increase in dietary nutrients. We determined if these findings were relevant to phytophagous insects through an experimental design that allowed us to vary independently the content of water (70–90% fresh mass, fm, with nutrient level at 10% fm) and nutrients (10–30% fm with water level at 70% or 80% fm) in an artificial diet through use of alphacel, a non‐nutritive cellulose fibre. We examined the effect of these dietary manipulations on allelochemical deterrency by comparing larval feeding responses of two noctuid species, the oligophagous Anticarsia gemmatalis Hübner and the polyphagous Spodoptera frugiperda (J. E. Smith), to a control diet and an allelochemical‐treated diet in two consecutive, no‐choice tests. These tests were restricted to 3 min to minimize post‐ingestive influences. From an initial twelve compounds tested, all but two were excluded for the following reasons: (i) failure to elicit an intermediate level of deterrency at <1% fm (i.e. albizziin, amygdalin, hordenine, ouabain, pipecolic acid, salicin, sinigrin and umbelliferone); (ii) an apparently rapid toxic effect (nicotine hydrogen tartrate); and (iii) adsorption to alphacel (quinine hydrochloride), which may have reduced deterrency. The deterrency of caffeine and linamarin increased with dietary water but was unaffected by nutrient content for both species. The similar results for an alkaloid and a cyanogenic glycoside, with two species differing considerably in feeding habits, suggest that dietary water is likely to influence the defensive efficacy of a broader range of deterrent allelochemicals to a variety of plant‐feeding insects.
Function of the spermathecal muscle in Chelymorpha alternans Boheman (Coleoptera: Chrysomelidae: Cassidinae)
Authors: RODRÍGUEZ VITERBO
Published: March 2008

Abstract. When the spermathecal muscle of a virgin female Chelymorpha alternans Boheman (Coleoptera: Chrysomelidae) was cut, the number of spermatozoa transferred in a single mating to the spermatheca and the spermathecal duct was not affected, but their distribution differed. Cutting the spermathecal muscle also reduced egg fertility. Eggs from females with a cut muscle showed a lower average percentage fertilization. Longer delays in oviposition after removal of the spermathecal muscle were associated with higher proportions of infertile eggs.
Field and laboratory evidence for a volatile pheromone produced by parous females of the Scottish biting midge, Culicoides impunctatus
Authors: BLACKWELL A. , DYER C. , LUNTZ A. J. MORDUE , WADHAMS L. J. , MORDUE W.
Published: March 2008

Abstract. Electrophysiological, behavioural and field evidence is presented for a volatile attractant produced by host‐seeking, parous female Culicoides impunctatus Goetghebuer. Attraction of host‐seeking females to other live parous females or to extracts of parous females was demonstrated in Y‐tube bioassays, as well as in field trials using baited sticky traps. Threshold numbers were 100–200 females, both in the laboratory and field. Antennal receptors to this pheromone were revealed by recording electroantennograms (EAGs) in response to odour from live parous females and to the extracts of female midges. The female‐produced attractant did not alter field catches of male C. impunctatus.
Neural activation of the sex‐pheromone gland in the moth Manduca sexta: real‐time measurement of pheromone release
Authors: CHRISTENSEN THOMAS A. , LASHBROOK JASON M. , HILDEBRAND JOHN G.
Published: March 2008

Abstract. Investigations of various species of moths have suggested that the biosynthesis of sex pheromone in the abdominal pheromone glands of females may be at least partly regulated by neuroendocrine mechanisms. Few studies, however, have explored the mechanisms underlying the release of sex pheromone. In experiments on the sphinx moth Manduca sexta (L.) (Lepidoptera: Sphingidae), we have monitored the time course of sex‐pheromone release in scotophase females with the aid of an electroantennogram bioassay based on the highly sensitive and selective sex‐pheromone receptor neurones of the male antenna. Pheromone release was evoked by orthodromic stimulation of the ventral nerve cord. Neurally stimulated release occurred with a subsecond latency and did not depend on bioactive factors in the haemolymph or on movement of the abdomen or the ovipositor. Severing the most medial pair of nerves posterior to the terminal abdominal ganglion (the terminal nerves) eliminated pheromone release, but not abdominal contractions. Release was also inhibited reversibly if the descending Ca2+‐dependent synaptic input to the terminal ganglion was blocked by exposure to elevated concentrations of Mg2+. These findings indicate that the release of sex pheromone from the pheromone gland in female M. sexta is a true neuroeffector response and that the gland appears to be controlled by neurones that project to it from the terminal abdominal ganglion.
Effects of constant light on the rhythm of adult locomotor activity in the blowfly, Calliphora vicina
Authors: HONG SEAU‐FENG , SAUNDERS D. S.
Published: March 2008

Abstract. Females of the blowfly, Calliphora vicina, showed an increase in the free‐running period (γ) of their locomotor activity rhythm when transferred from continuous darkness (DD) to continuous ‘dim’ light (LL) at an irradiance below about 0.03 Wm‐2. Transfer to LL of this intensity also caused a reduction in the duration of the active phase (α) of the cycle. Transfer to ‘bright’ light (>0.03 Wm2), however, lead to arrhythmicity. Data suggest that constant light of this intensity does not ‘stop’ the circadian pacemaker but imposes behavioural arrhythmicity at a more superficial level.
Search strategies of fruit flies in steady and shifting winds in the absence of food odours
Authors: ZANEN P. OLIVIER , SABELIS MAURICE W. , BUONACCORSI JOHN P. , CARDE RING T.
Published: March 2008

Abstract. Flight behaviour by females of two species of fruit flies, Drosophila funebris and Drosophila immigrans, was videorecorded in a wind tunnel in still air and in wind with a constant or shifting direction. Flies which were deprived of food overnight took flight in the absence of food odours. Both species responded to the presented winds in agreement with two models that predict the shortest distance to an odour plume. According to these models, the shortest distance to an odour plume is travelled when insects fly at right angles to the wind with a steady direction. In winds shifting over more than 60d̀, the shortest distance to an odour plume is achieved when insects fly parallel to the time‐averaged wind direction. We propose a behavioural mechanism which accomplishes the observed flight directions taken by the two species of fruit flies in response to the tested wind regimes.
Host location by a parasitoid using leafminer vibrations: characterizing the vibrational signals produced by the leafmining host
Authors: MEYHÖFER R. , CASAS J. , DORN S.
Published: March 2008

Abstract.The aim of this study was to characterize the vibrations produced by the apple tentiform leafminerPhyllonorycter malella(Ger.) (Lepidoptera, Gracillariidae). Host location using vibrations by one of its parasitoidsSympiesis sericeicornisNees (Hymenoptera, Eulophidae) was postulated by Casas (1989) on the basis of detailed quantitative behavioural observations and has also been suggested by other authors on similar systems. Both host and parasitoid send and may receive vibratory signals; consequently we first attempted to characterize and classify the signals, one of the first steps required in the design of an adequate vibrational biotest. In this respect, our approach differs fundamentally from the familiar setting of host location via semiochemicals and is best framed within the context of vibratory communication.

Vibrational signals produced by a moving larva and pupa were measured on several spots on the leaf using a laser vibrometer. The emitted signals were characterized by their temporal patterns of change in amplitude and frequency spectra. The vibrational patterns released by a moving larva were different from those released by a wriggling larva and a wriggling pupa in the time as well as in the frequency domains. Wriggling larvae and wriggling pupae triggered vibrations that were similar in frequency, but differed in their temporal pattern.

Frequencies up to 15 kHz could be identified. The amplitudes and frequencies of the signals both decreased significantly from the tip to the base of the leaf. A wriggling pupa and a wriggling larva produced stronger signals than a foraging larva. All calculated parameters (displacement, velocity, acceleration, and duration of the signal components) of the vibrational signals were found to be in a range comparable with others used for well‐known arthropod communication systems.

The vibrations produced by the host displayed distinct characteristics: they could usually be distinguished easily from background noise; could be perceived anywhere on the leaf; and were specific for a certain host stage and activity. Our findings support the hypothesis that vibration signals represent a reliable source of information to foraging parasitoids and, therefore, explain certain behavioural patterns observed in a population ofS. sericeicornisfemales foraging in the field.
The ultrasonic mating signal of the male lesser wax moth
Authors: SNEDDEN W. ANDY , TOSH COLIN R. , RITCHIE MICHAEL G.
Published: March 2008

Abstract. Male lesser wax moths, Achroia grisella (Fabricius) (Lepidoptera: Pyralidae: Galleriinae), produce both a pheromone and an ultrasonic acoustic signal that function in mate attraction. We describe the structure of the acoustic signal, in particular the interpulse intervals and the spectral properties of the pulses. The song consists of a train of ultrasonic pulses. The interpulse interval is usually bimodally distributed, but can sometimes be unimodal. This reflects variation in the duration of the up and down wing strokes. The pulses are also usually paired which can produce multimodality of the interpulse intervals. These paired pulses probably reflect wingbeat asynchrony because they are not found in males in which the signalling capability of one wing's sound producing structure is abolished.

The song's frequency spectrum has peaks at around 80 and 100 kHz. The first peak varies significantly with male size, with larger males producing a lower frequency peak. The second peak is associated with male age, with 1‐day‐old males producing songs with a lower frequency second peak. Thus the ultrasonic song of lesser wax moths is more complex in structure than previously reported and could provide potentially important cues to females. However, the ability of females to discriminate such detail is not known.
Dynamics of sperm storage in the grasshopper Eyprepocnemis plorans
Authors: LÓPEZ‐LEÓN M. D. , PARDO M. C. , CABRERO J. , CAMACHO J. P. M.
Published: March 2008

Abstract. Sperm storage duration in the grasshopper Eyprepocnemis plorans Charpentier (Orthoptera, Acrididae) was found to be 58.5 days but with a wide between‐female variation (from 26 to 113 days). One copulation was enough to fertilize two to eight egg‐pods and to produce 130 eggs (28–313) and 119 embryos (28–290), on average. Sperm availability, however, decreased progressively with time, so that the majority of females spent a long final period of their lives without laying any pod. Finally, sperm storage duration was positively correlated with clutch size and total production of eggs and embryos.
Behaviour of flying oriental fruit moth males during approach to sex pheromone sources
Authors: WILLIS M. A. , BAKER T. C.
Published: March 2008

Abstract. The pheromone‐modulated upwind flight tracks of Grapholita molesta (Busck) males were video recorded as they approached a point‐source of pheromone in a wind tunnel. The field of view of the video recording was divided longitudinally into 33 cm sections and the flight behaviour of the males in these sections was measured and compared as they approached from 233 cm to 50 cm downwind of the pheromone source. As the males approached the source, their mean ground speeds decreased. The mean values of their track angles increased with respect to due upwind (0d̀), indicating movement more across the wind. These changes resulted mainly from the males decreasing their air speeds as they progressed up the plume toward the source. They did not change the average direction of their steering (course angle). Thus, the increase in track angles resulted from the males allowing themselves to drift more in the wind as they approached the odour source. The males also increased their average rate of counterturning as they approached the source. The net result of all these behavioural changes was a track that slowed and grew narrower, giving the impression that the males were ‘homing‐in’ on the pheromone source as they approached. Causes of these systematic changes in behaviour are considered with respect to the known systematic changes in pheromone plume structure as the distance to the source decreases.
Vitellogenin sequestration by Simulium oocytes: the effect of Onchocerca infection
Authors: RENSHAW M. , HURD H.
Published: March 2008

Abstract. The effects of Onchocerca infection on Simulium ornatum Meigen vitellogenesis were investigated. Vitellogenesis is triggered by ingestion of blood and is therefore linked to disease transmission. Vitellin subunits were described for the first time in the Simuliidae. In the British blackfiy S.ornatum, vitellin in the ovaries consists of two subunits, with a large subunit of molecular weight 200 kDa and a small subunit of 68 kDa. Simulium ornatum vitellin was recognized by polyclonal antibodies produced from Aedes aegypti (L.) vitellin. When blackflies were injected with Onchocerca lienalis (Stiles) microfilariae, there was a significant reduction in the amount of vitellin in the ovaries at 24, 34 and 50 h post blood‐feeding.
Puparial wax restricts passive movement of water during diapause in the flesh fly
Authors: YODER JAY A. , MOREAU MELISSA J.
Published: March 2008

Abstract. To determine whether the capacity of diapausing pupae of the flesh fly (Sarcophaga crassipalpis Macquart) to absorb water from drier air than non‐diapausing pupae is due to a simple passive process, we examined water flux in empty puparia. Empty puparia from both types of fly absorb and lose water passively, but those from diapause pupae do so to a lesser degree. The impervious nature of such puparia is attributed to an extra layer of cuticular wax not found in the non‐diapause group.
Moisture relationships of the high arctic collembolan Onychiurus arcticus
Authors: HODKINSON I. D. , HEALEY V. , COULSON S.
Published: March 2008

Abstract. Rates of desiccation, rehydration and survival, under conditions of 0 and 100% relative humidity, were investigated in the high arctic collembolan Onychiurus arcticus (Tullberg) over a range of temperatures from ‐3 to 10d̀C. Desiccation, measured over 4h in a dry environment, was rapid and highly significantly correlated with saturated vapour pressure deficit (SVPD). At 10d̀C animals lost over 60% of body moisture in under 1h. Under moist conditions body weight remained constant. Survival, measured over 4h under dry conditions, showed a highly significant negative correlation with SVPD across the range of temperatures. Survival in moist controls was 100%. Partially desiccated animals were able to rehydrate using free water or moisture from a saturated atmosphere, but uptake of the former was faster. Rates of water uptake were around 30 times slower than rates of loss through desiccation. Animals given free water regained initial weights in 24‐144h, dependent on temperature. Uptake rates of free water, measured over the time necessary fully to rehydrate, were highly significantly correlated with temperature, whereas those for atmospheric moisture were not. Over the time scales used in the experiments, three linear regression equations accurately predict rates of desiccation, rehydration and survival from SVPD or temperature. Ecological adaptation by O.arcticus to the highly contrasting climatic environments of the arctic summer and winter seasons is discussed in the context of climate change.
On the similarity of the Dufour gland secretion and the cuticular hydrocarbons of some bumblebees
Authors: OLDHAM NEIL J. , BILLEN JOHAN , MORGAN E. DAVID
Published: March 2008

Abstract. There is a close correspondence in composition between the hydrocarbons of the Dufour gland and the cuticular hydrocarbons of workers of some bumblebee species. This correspondence is characteristic of the species, and independent of the place and time of collection.
Effects of egg load on finding and acceptance of host fruit in Ceratitis capitata flies
Authors: PROKOPY R. J. , ROITBERG B. D. , VARGAS R. I.
Published: March 2008

Abstract. In studies conducted on potted host trees in field cages and in the laboratory, we examined the influence of egg load on the finding and acceptance of high‐ranking (kumquat) and lower‐ranking (grapefruit) hosts for oviposition by wild‐origin Mediterranean fruit fly females, Ceratitis capitata (Wiedemann). By prescribing the periods during which females had access to protein prior to testing, we generated four classes of females having progressively increasing egg loads but not differing in population origin, age, degree of protein hunger at testing, or amount of prior experience with host fruit (none). Egg load had no discernible effect on behaviour associated with finding either type of fruit but did have a significant effect on several behaviours associated with oviposition after alighting on fruit. Increasing egg load led to increasing propensity to engage in ovipositional‐type behaviour on both kumquats and grapefruits. There was no evidence, however, to support a hypothesis that medflies would become less discriminating against grapefruits relative to kumquats as egg load increased. Relative to kumquats, grapefruits were accepted for oviposition by intermediate and high egg load females to a substantially greater degree in laboratory cages than on trees, suggesting that results of laboratory cage experiments on host discrimination by tephritid flies may poorly reflect differences in behavioural responses expressed under less constrained conditions.
An analysis of the behavioural effects of crowding and re‐isolation on solitary‐reared adult desert locusts (Schistocerca gregaria) and their offspring
Authors: BOUAÏCHI ABDELGHANI , ROESSINGH PETER , SIMPSON STEPHEN J.
Published: March 2008

Abstract. The time‐course of behavioural change in response to crowding and re‐isolation was investigated in adults of Schistocerca gregaria Forskål (Orthoptera, Acrididae) using logistic regression analysis. Crowding solitary‐reared adults for a period of 4 h caused them to behave similarly to crowd‐reared insects, with their becoming much more active and moving towards rather than away from a stimulus group of locusts. Responsiveness to crowding was greatest in young adults. The behaviour acquired after 48 h of crowding was lost within 1 day of re‐isolation. Although experience by solitary‐reared adults of crowding for 48 h had only transitory effects on their own behaviour, there was also a long‐term influence on the behaviour of their offspring. The strength of this effect was dependent on the age at which adults experienced crowding, increasing in a graded manner with adult age, and hence the recency of crowding before oviposition. Parents crowded at a late stage in the reproductive cycle yielded hatchlings which behaved indistinguishably from those from crowd‐reared adults. Such an effect is consistent with the idea that females, through their previous experience of crowding, are effectively predicting the probability that their offspring will emerge into a high‐density population, and predisposing their hatchlings' behaviour accordingly.
A behavioural test of the sensitivity of a nocturnal mosquito, Anopheles gambiae, to dim white, red and infra‐red light
Authors: GIBSON GABRIELLA
Published: March 2008

Abstract. A behavioural test was used to determine the light sensitivity of the nocturnal mosquito Anopheles gambiae Giles s.s. to low intensities of ‘white’ light (tungsten filament), ‘red’ light (white light filtered by a darkroom safelight filter) and ‘infra‐red’ light) of two types (white light filtered by a λ>700 nm filter, and light‐emitting diodes with λ>900 nm). Mosquitoes were placed in a 20 cm diameter flight‐tunnel and their ‘optomotor’ response to a pattern of stripes moving across their visual field (at 14.5 cm s‐1) was recorded with infra‐red‐sensitive video. In free‐flight, with ample light, the mosquitoes controlled their flight speed and direction in relation to the stripe movement, so that the stripes always appeared to move across their visual field from front to back. They did this by flying either with the moving stripes fast enough to overtake them (19.5 ± 0.7 cm s‐1), or against them more slowly (10.3 ± 0.7 cm s‐1)‐ The net ground speed of the mosquitoes was thus c. 4–5 cm s‐1. This response was significant down to 10‐5 W m‐2 in ‘white’ light, and 10‐3 W m‐2 in ‘red’ light. At light intensities below threshold and in infra‐red light, however, they appeared to fly at random with respect to the stripe movement. The assumption commonly made, that mosquitoes do not ‘see’ in red light, may thus have to be revised.
Effect of the fine‐scale structure of pheromone plumes: pulse frequency modulates activation and upwind flight of almond moth males
Authors: MAFRA‐NETO A. , CARDÉ R. T.
Published: March 2008

Abstract. The effects of plume intermittency and volume on behavioural and flight responses to pheromone of male Cadra cautella (Walker) (Lepidoptera: Phycitinae) were investigated in a pulling wind tunnel. The fine‐scale structure of turbulent pheromone plumes was mimicked and manipulated using a pulser device that generated continuous ribbon plumes or intermittent plumes with defined pulse frequency and volume. As pulse frequency increased from 0.6 to 5 Hz and injected volume increased from 0.5 to 5 mls‐1, males flew progressively higher air and ground speeds, turned less frequently, and steered smaller course angles, resulting in straighter flight tracks. The faster the frequency of pulses and the greater the volume of the plume, the higher the proportion of males responding, the shorter their latencies, and the less time spent in the behaviour. Flight tracks of male C.cautella to point sources of pheromone depend on the frequency of filaments encountered.
A genetic analysis of photoperiodic reproductive diapause in Drosophila triauraria
Authors: KIMURA MASAHITO T. , YOSHIDA TAKAO
Published: March 2008

Abstract. Recombinant inbred lines were produced from hybrids between diapausing and non‐diapausing strains of Drosophila triauraria Bock & Wheeler by twenty generations of full‐sib mating. The analysis of these inbred lines suggests that the difference in the photoperiodic response between the original diapausing and non‐diapausing strains is due to genes at three or four loci and at least one of these loci is located on the X chromosome. The original diapausing strain and two inbred lines exhibited circadian peaks when subjected to the Nanda‐Hamner protocol, although they had different critical daylengths. This suggests that critical daylength is modified independently of the circadian oscillation system in this species. On the other hand, diapause duration was correlated with critical daylength among the inbred lines and the original diapausing strain, suggesting that these two traits are under the control of the same genetic system.
Electroantennogram responses of the stable fly, Stomoxys calcitrans, to components of host odour
Authors: SCHOFIELD STEVEN , CORK ALAN , BRADY JOHN
Published: March 2008

Abstract. Electroantennograms (EAGs) were recorded from laboratory‐reared male and female Stomoxys calcitrans (L.) in response to a range of synthetic chemicals known to be electrophysiologically‐active for other biting flies. Of the eight compounds initially tested, only two ‐ 1‐octen‐3‐ol and 3‐methylphenol ‐ consistently elicited larger electroantennograms (EAGs) than did control treatments; 1‐octen‐3‐ol was the most potent. EAG recovery time was inversely correlated with EAG amplitude. EAGs recorded with primary C2‐C12 carbon chain‐length primary aliphatic alcohols peaked at octan‐1–ol with pentan‐1‐ol, hexan‐1‐ol and heptan‐1‐ol also eliciting EAG responses significantly larger than the controls. When different C8 carbon chain compounds and nonane were tested: 1‐octen‐3‐ol elicited the largest EAGs followed by, in decreasing activity, octan‐1‐ol, 1‐bromooctane, octan‐3‐ol, octanal, 2‐octanone, octanoic acid and nonane. The EAG response of 1‐octen‐3‐ol increased sigmoidally with dose, with the threshold at between 2 and 20 ng, and the peak response at 200 μg on filter paper. EAGs larger than control were also elicited by entrained ox odour and ox breath. The behavioural implications are discussed.
Diapause induction and coloration in the Senegalese grasshopper, Oedaleus senegalensis
Authors: COLVIN JOHN , COOTER RICHARD J.
Published: March 2008

Abstract. Embryonic diapause induction in the Senegalese grasshopper, Oedaleus senegalensis Krauss (Orthoptera: Acrididae), is influenced both by the photoperiod and the temperature experienced by females. High temperatures (40°C) and long photoperiods (LD 14:10h), which characterize the beginning of the rainy season in the Sahel, cause non‐diapausing eggs to be laid. Lower temperatures (25°C) and shorter photoperiods (LD 12:12h), which occur at the end of the rains, result in the production of diapausing eggs. At 30°C and constant photoperiods, O. senegalensis exhibited a long‐day‐short‐day response with critical photoperiods of c. 13 h and c. 20 h, only the former value being of ecological significance. The photoperiodically sensitive stages to diapause induction in females occurred from the fifth stadium onwards. Temperature also affected the coloration of both nymphs and adults. Dark‐black and pale‐white individuals were produced by low (25°C) and high (40°C) temperatures respectively, whereas an intermediate temperature (30°C) produced individuals which were greyish brown. These results are discussed in relation to the ecology of O. senegalensis.
Identification of oviposition attractants for the sandfly Lutzomyia longipalpis (Diptera: Psychodidae) in volatiles of faeces from vertebrates
Authors: DOUGHERTY M. J. , GUERIN P. M. , WARD R. D.
Published: March 2008

Abstract. Extracts of volatiles from rabbit and chicken faeces preferentially attracted gravid sandflies, Lutzomyia longipalpis (Lutz and Neiva), in an oviposition bioassay. In electrophysiology experiments, the same extracts selectively stimulated two olfactory cells while inhibiting another in ascoid sensilla on the antennae of these flies. Analysis of faeces volatiles by gas chromatography linked to ascoid sensillum recording revealed two early eluting electrophysiologically active components of rabbit faeces. These active compounds were identified in both rabbit and chicken faeces volatile extracts by gas chromatography ‐mass spectrometry as hexanal and 2‐methyl‐2‐butanol. Hexanal stimulated one cell type and inhibited another, whereas 2‐methyl‐2‐butanol stimulated a third cell type. A 1:l mixture of synthetic hexanal and 2‐methyl‐2‐butanol elicited the same targeted oviposition response from gravid females on the treatment septum of the bioassay as did the total volatile extract of rabbit or chicken faeces.

The monoterpenes α(+)‐pinene (plus some optical and positional isomers) and a‐terpinene activated a separate cell type, whereas benzaldehyde stimulated the same receptor as hexanal, but with a higher threshold. Furthermore, an olfactory cell selectively tuned to the perception of the male sex pheromone of this species was also found in the ascoid sensillum.
Isolation and identification of AKH/RPCH family peptides in blister beetles (Meloidae)
Authors: GÄDE GERD
Published: March 2008

Abstract. Two peptides were isolated from methanolic extracts of corpora cardiaca of the blister beetle, Decupotoma lunata, by a single‐step purification procedure, utilizing C‐18 reversed‐phase high‐performance liquid chromatography (RP‐HPLC) for separation, and the increase of haemolymph lipids in Locusta migratoria for bioassay. The native peptides were analysed by matrix‐assisted laser‐desorption ionization mass spectrometry revealing main ions at m/z 1180 and 1009 respectively which were attributed to the [M + Na]+ form of the respective peptides. After deblocking of the N‐terminal pyroglutamate residue of each peptide, the structures of the deblocked peptides were determined by pulsed‐liquid phase sequencing employing Edman chemistry. The sequences of the two peptides, (1) pGlu‐Leu‐Asn‐Phe‐Ser‐Pro‐Am‐Trp‐Gly‐AsnNH2 and (2) pGlu‐Leu‐Asn‐Phe‐Ser‐Pro‐Asn‐TrpNH2, characterize them as deca‐ and octapeptide members of the AKH/RPCH family. Whereas the decapeptide is a novel member of this family and is given the acronym Del‐CC (Decupotoma lunata corpus cardiacum peptide), the octapeptide has previously been found in tenebrionid beetles and has the acronym Tem‐HrTH. The corpora cardiaca of two other species of blister beetles (Cyaneolytta pectoralis and Mylabris coeca) contain the same two peptides as D. lunata, as judged by RP‐HPLC and biological activity. Neither a corpus cardiacum extract of Decupotoma lunata nor the synthetic peptides Del‐CC and Tem‐HrTH were active in mobilizing carbohydrates or lipids in the blister beetle.
Disruption of male spruce budworm orientation to female moths by pheromone and pheromone analogues in a wind tunnel
Authors: SANDERS C. J.
Published: March 2008

Abstract. The ability of male spruce budworm moths, Choristoneura fumiferana (Clem.), to orientate to and locate virgin female moths was investigated in a laboratory wind tunnel. When presented with two caged ‘target female’ moths, more than 99% of the male moths locked on and flew directly to the females. When confined for 3 h before release, downwind of a three‐dimensional array of thirty‐five evenly distributed female moths (a density of 40/m3), over 90% of the males still successfully oriented to one or another of the females, although not always to the target females. With an array of thirty‐five septa containing either E‐11‐tetradecenyl acetate on E‐11‐tetradecenol there was no visible change in behaviour; >90% of the males flew directly to the two target females, which indicates that neither the acetate nor the alcohol has potential for mating disruption. An array of thirty‐five septa containing a 955 blend of E‐ and Z‐11‐tetradecenal, the main components of the spruce budworm sex pheromone, significantly reduced the numbers of male moths able to locate the target females, and effects were concentration‐dependent. The highest concentration, which gave a release rate similar to that of a calling female, produced the same level of disruption as the thirty‐five females, but sensory fatigue became a factor in addition to ‘false trail following’. Lower concentrations were significantly less effective, with no evidence of sensory fatigue. At all concentrations significant numbers of males flew to the septa (false trail following), but when male moths were left uncaged in the tunnel for a further 3h, most eventually located the females. This suggests that false trail following alone will not prevent mating. The level of disruption was not improved by the addition of 2% tetradecanal to the 955 blend. Similar levels of disruption to the 955 blend were obtained with an 80:20 blend. A 5050 blend still caused a significant amount of false trail following, but less than the other blends. The ability of male spruce budworm to orientate to off‐blend trails was enhanced if the males were first exposed to the natural, female‐produced pheromone.
Electrophysiological and behavioural evidence for a fourth sex pheromone component in the turnip moth, Agrotis segetum
Authors: WU W.‐Q. , HANSSON B. S. , LOFSTEDT C.
Published: March 2008

Abstract. In addition to the pheromone components (Z)‐5‐decenyl, (Z)‐7‐dodecenyl and (Z)‐9‐tetradecenyl acetate (Z5‐10:OAc, Z7‐12:OAc and Z9‐14:OAc), it has previously been shown that the sex pheromone gland of the turnip moth, Agrotis segetum (Lepidoptera: Noctuidae Schiff) contains 10:OAc, 12:OAc, Z5‐12:OAc, Z9‐12:OAc, 11–12:OAc, Z5‐14:OAc, Z7‐14:OAc and Z11‐16:OAc. To find out whether any of these additional compounds is involved in the sex pheromone communication in A. segetum, a comprehensive electro‐physiological and behavioural investigation was conducted. Single‐sensillum recordings on male antennae revealed three subtypes of sensilla among the previously so‐called Z5‐10:OAc sensilla. One subtype was identified having one receptor neurone (A) that responded to Z5‐10:OAc with a large spike amplitude and another neurone (B) that responded to (Z)‐5‐decenol (Z5‐10:OH) with a small spike amplitude. In another subtype the B neurone responded to Z5‐12:OAc and sometimes also to 27‐12:OAc and 10:OAc, in addition to responding to Z5‐10:OH. In a third subtype the A neurone responded to all acetates identified from the female pheromone gland, whereas the small spike amplitude neurone was tuned to Z5‐10:OH. A flight tunnel assay showed that blends composed of nine, eight or seven compounds were equivalent to the previously identified three‐component pheromone blend in eliciting male behavioural responses. In field trapping tests, blends of eleven, nine or seven compounds did, however, catch significantly more moths than the three‐component blend. Further assays showed that only 25‐ 12:OAc could significantly increase the catch numbers when added to the three‐component blend, and thus qualified as a fourth pheromone component in A. segerum. The behavioural significance of additional female‐produced acetates — for which males possess antennal receptors — is suggested, but may be impossible to confirm because of ‘diminishing returns’ when trying to refine a multicomponent pheromone further.
Behavioural and sensory responses to some neem compounds by Pieris brassicae larvae
Authors: LIN‐ER LUO , LOON J. J. A. VAN , SCHOONHOVEN L. M.
Published: March 2008

Abstract.The efficacy of a commercial product (Margosan‐O) to inhibit feeding inPieris brassicaeL. (Lepidoptera: Pieridae) larvae was compared to that of three pure triterpenoids of botanical origin: azadirachtin and salannin (occurring inMelia azedurach), and toosendanin (occurring inM. toosendan). In dual‐choice behaviour tests the order of antifeedant efficacy was: Margosan‐O > toosendanin > salannin > azadirachtin. The ranking order of their capacity to stimulate the deterrent receptor located in the medial sensillum styloconicum appears to be: Margosan‐O = toosendanin > salannin > azadirachtin. In addition to stimulating the medial deterrent cell, toosendanin inhibits the sugar receptor and the glucosinolate receptor, both located in the lateral sensillum styloconicum. The amino acid receptor in this sensillum, however, is not affected. In contrast, neither azadirachtin nor salannin influences the sensitivity of any of the receptor cells in this sensillum.

The adaptation rate of the deterrent receptor is low in comparison to that of the two sugar receptors.

A significant correlation is found between the antifeedant indices of the four neem compounds tested at three different concentrations, and the responses of the deterrent receptor to these compounds at similar concentrations. It is concluded that when this insect species feeds on its natural foodplant (i.e. cabbage), the deterrent effect of neem compounds is mediated solely via the medial deterrent receptor, whereas inhibitory effects on the sugar and glucosinolate receptors do not play a significant role.
Wind structure in relation to odour plumes in tsetse fly habitats
Authors: GRIFFITHS NIGEL , BRADY JOHN
Published: March 2008

Abstract. Key characteristics of airflow were measured in the African bush in a study of host odour plume structure. Wind speed, speed variance, direction, and directional variance were measured by conventional cup anemometers plus wind‐vanes and by a solid state ultrasonic anemometer, on time scales from seconds to minutes. The two technologies gave opposite relationships between wind speed and turbulence measured as rate of angular direction change in the wind (° s‐1). A positive correlation between turbulence and wind speed was observed with mechanical anemometers and wind‐vanes, evidently caused by their inherent hysteresis (stalling in weak wind, overswinging after gusts). The same correlation was negative with the solid‐state anemometer which, being hysteresis free, should have measured the true directional turbulence more accurately. Such fine‐scale turbulence at a fixed point in space (on a scale of about ∼15 cm diam.) decreased with wind speed up to ∼1.5 m s‐1, as does large‐scale (∼1m diam.) turbulence of air moving through space (Brady et al., 1989). This decrease occurred both within vegetation and out in the open, but the slope and intercepts of the relationship depended on vegetation and topography. Variables for describing wind speed and turbulence are considered in the context of odour plume structure.
Pheromone release by the two forms of Callosobruchus maculatus females: effects of age, temperature and host plant
Authors: LEXTRAIT PATRICIA , BIÉMONT JEAN‐CLAUDE , POUZAT JEAN
Published: March 2008

Abstract. The influence of age, temperature and host plant on pheromone release was investigated in females of two forms of Callosobruchus maculatus (Coleoptera: Bruchidae), referred to as the flightless form and the flight form. The emission of pheromone seemed to be correlated with reproductive status: the flightless‐form females which were sexually mature at emergence began to release pheromone on the first day following emergence. The flight‐form females which exhibited no reproductive activity at emergence also showed a delayed emission of pheromone. The temperature conditions and the availability of host plant seeds had no apparent effect on pheromone release by the flightless form. In flight‐form females pheromone release was stimulated by the presence of host plant seeds. Temperature seemed to affect the age at which females initiated pheromone release for the first time after emergence, pheromonal emission being brought forward slightly by higher temperature. All these results are discussed relative to the specific environment of each form.
Structural and chemical ontogeny of the postpharyngeal gland in the desert ant Cataglyphis niger
Authors: SOROKER V. , HEFETZ A. , COJOCARU M. , BILLEN J. , FRANKE S. , FRANCKE W.
Published: March 2008

Abstract. The postpharyngeal gland of Cataglyphis niger (André, 1881) workers is characterized, at the ultrastructural level, by a well‐developed smooth endoplasmic reticulum, Golgi apparatus, and numerous mitochondria and lamellar inclusions suggesting an involvement in lipid metabolism. In addition, the microvillar differentiation of the apical membrane and basal invaginations of the cell imply a transportation process.

The gland shows a clear structural as well as chemical age‐dependent development. Epithelial thickness increases with age, reaching its maximum within the first week after emergence. Concurrently there is a progressive development of microvilli and appearance of the lamellar inclusions. The gland's secretion consists mainly of hydrocarbons, with a predominance of monomethyl and dimethyl alkanes. Congruency was found between the hydrocarbon composition of glandular exudates and those of the epicuticular washes. An age‐dependent increase in the total amount of hydrocarbons was found to correlate with the ultrastructural development and gross morphology (thickness of epicuticular lining) of the gland.
The influence of the development rates of immature stages of Eristalis arbustorum (Diptera; Syrphidae) on adult abdominal colour pattern
Authors: OTTENHEIM MART M. , WALLER G. ESMEE , HOLLOWAY GRAHAM J.
Published: March 2008

Abstract. The abdominal colour pattern of Eristalis arbustorum (L.) shows seasonal variation, with animals emerging in spring being darker than those emerging during summer. One of the most important environmental cues influencing the abdominal colour pattern is developmental temperature. An experiment was carried out to establish which period during the immature stages was important in determining final adult colour pattern. The results indicate a good relationship between the length of the pupal period and both the extent of the paler markings on the abdomen and the grey score of these markings. The length of the larval period did not have any effect on adult colour pattern.
Changes in temperature, not photoperiod, control the pattern of adult eclosion in the tsetse, Glossina morsitans
Authors: ŽĎÁREK JAN , DENLINGER DAVID L.
Published: March 2008

Abstract. The timing of adult eclosion in tsetse, an event that normally occurs in mid‐afternoon, is regulated by the daily cycle of temperature elevation. If a temperature cycle is maintained, the rhythm of eclosion persists under continuous light or continuous darkness. Artificially shifting the temperature peak to the scotophase results in a concomitant shift in the eclosion pattern. Daily temperature variations as small as 0.4°C are sufficient to establish the rhythm. Eclosion activity tracks the temperature peak, even if the pulses are of short duration (4 h) or with irregular frequencies of 12 or 36 h. The temperature‐induced rhythm offers a simple mechanism for separating females and males. Individuals that pupariate on the same day eclose as adults over a 4–5 day period at 25°C, and in such collections, females are the first to eclose. This distinction makes it possible to collect samples of predominately one sex, a feature that may facilitate the collecting of males for use in the sterile‐male technique.
Flight fuel related differences between solitary and gregarious locusts (Locusta migratoria migratorioides)
Authors: AYALI AMIR , GOLENSER E. , PENER M.P.
Published: March 2008

Abstract. Flight fuel relations of crowded and isolated Locusta migratoria migratorioides were investigated in younger (12–16 days after fledging) and older (27–30 or 27–32 days after fledging) adult males.No phase polymorphism dependent differences were found in resting haemolymph carbohydrate levels of the younger locusts.In the older age group, resting haemolymph carbohydrate levels were slightly though significantly higher in the isolated than in the crowded locusts.Injection of various doses of synthetic adipokinetic hormones (AKHs) did not induce marked changes in haemolymph carbohydrate levels and no differences were found between crowded and isolated locusts.A 30 min flight led to the same decrease in haemolymph carbohydrate levels of isolated and crowded locusts, 43.3% and 44.6% of the resting levels, respectively.We concluded, therefore, that the results do not seem to indicate that isolated locusts rely more heavily on carbohydrates as flight fuel than crowded locusts.Hyperlipaemic responses to flight were less intense in isolated than in crowded locusts, but phase polymorphism dependent differences in flight‐induced increase of haemolymph lipid levels were not parallel in 12–16‐day‐old and 27–32‐day‐old males.In the younger age group the difference was mainly in the duration of flight needed to induce full response which appeared already after 20 min of flight in the crowded locusts, but only after 45 or 60 min of flight in the isolated ones.In contrast, the older isolated locusts showed markedly lower haemolymph lipid elevations than the crowded locusts even after 30, 45 or 60 min of flight.The hypothesis is forwarded that isolated locusts have a rather coarse adipokinetic strategy focused on a single long‐distance migratory flight, whereas gregarious locusts possess a fine adipokinetic balance for reiterative migratory flights and saving fuel reserves for unpredictable long‐distance migrations.
Effects of ingestion of dung containing ivermectin on aspects of behaviour in the fly Neomyia cornicina
Authors: GOVER JANE , STRONG LES
Published: March 2008

Abstract. Adults of the dung fly Neomyia cornicina (Fabricius) were fed continuously on either dung containing no ivermectin (control dung) or dung containing 0.125 μg g‐1or 0.25 μ g‐1ivermectin (wet weight).Comparisons were made between the behaviour of flies during the first 24 h of dung feeding and that observed after 96 h of feeding.Subsequent experiments investigated the effects of ivermectin ingestion on three measures of locomotory ability: escape time, time to re‐right, and capture time.

Analysis of behavioural data showed a significant reduction in the activity of ivermectin‐fed flies compared to that of the controls.After 96 h of feeding on dung containing ivermectin, there was a significant increase in the duration of time spent standing and a reduction in duration and frequency of walking and grooming behaviours compared to controls.

Seventy‐two hours after the onset of dung feeding, flies fed dung containing ivermectin took significantly longer to escape from a glass tube and to re‐right themselves after overturning than flies fed control dung.The time taken to capture flies that had fed on dung containing ivermectin at 0.25 μg g‐1was significantly shorter than that required to catch control flies when flies from the different treatment groups were presented blind and randomly.