bluuebunny/crossref_metadata_2025 huggingface dataset:
The optomotor yaw response of the desert locust, Schistocerca gregaria
Authors: EGGERS A. , PREISS R. , GEWECKE M.
Published: March 2008

Abstract The optomotor yaw response of the desert locust, Schistocerca gregaria (Forsk.), was investigated under open‐ and closed‐loop conditions. When flying tethered in the centre of a vertically striped hollow sphere, the polarity of response of the locust was always the same as the stimulus. The response, therefore, appears suitable to stabilize body posture against passive rotations around the yaw‐axis in free flight. Responses were induced by contrast frequencies up to 150 Hz with a maximum of amplitude at about 20 Hz. The characteristic curve, measured between 0.3 and 160 Hz, is widened up towards higher frequencies as compared with those of bees and flies.

Variability was the most striking feature in the locust's yaw response. The amplitude of modulation not only varied greatly between individuals but also changed with the same visual stimulus in the course of an experiment. We therefore suppose that the locust's turning behaviour is subject to gain control mechanisms and that spontaneous gain modulations are responsible for the observed variability in the stimulus‐response conversion.
Effect of temperature and photoperiod on the calling behaviour of a migratory insect, the oriental armyworm Mythimna separata
Authors: HAN ER‐NING , GATEHOUSE A. GAVIN
Published: March 2008

Abstract The pre‐calling period (PCP), between emergence and first release of pheromone, determines the number of nights over which female Mythimna separata (Walker) (Lepidoptera: Noctuidae) can express their migratory potential. In its seasonal migrations in eastern Asia, this armyworm penetrates to latitudes at which it is unable to over‐winter but at which reliable photoperiodic and temperature cues anticipate the deterioration of conditions. The effect of these environmental factors on PCP was examined in moths descended from samples collected in Nanjing (32oN) during the summer migration. Under LD 14:10h, a reduction in temperature, from 23oC during larval development to 18oC from 24 h after pupation, resulted in a twofold increase in PCP compared with insects held at 23oC. At 23oC, short days (LD 12:12 h) extended PCP but the magnitude of the response was increased under a regime of decreasing photoperiod, from LD 15:9h, to LD 12:12 h through larval, pupal and adult development. Further experiments demonstrated that the response depended on a decrease in photoperiod from pre‐pupal stage to adult emergence (the pupal period is spent below ground). A reduction of 50–60min over the 13–15 day pupal period at 23oC was effective. The significance of decreasing photoperiods, irrespective of absolute levels, as a cue for species whose migrations traverse substantial ranges of latitude is considered and the results are discussed in relation to the genetic determination of PCP in M.separata and to its seasonal migrations in eastern China.
Evidence for a calcium‐dependent outward conductance in endocrine cells of the cockroach, Diploptera punctata
Authors: McQUISTON A. R. , TOBE S. S.
Published: March 2008

Abstract The cell membranes of the corpora allata of the cockroach Diploptera punctata contain voltage‐dependent calcium channels. Depolarizing current injection into cells of the corpora allata in the presence of the calcium channel blockers, cadmium, cobalt or verapamil allows the production of multiple action potentials, as does treatment with the intracellular calcium chelator, BAPTA/AM. These results suggest that calcium currents are involved both in decreasing the excitability and in activating an outward current in cells of the corpora allata. Electrophysiological measurements also suggest a concomitant reduction in outward conductance following the multiple action potentials produced in the presence of the channel blockers or BAPTA/ AM. We hypothesize that the calcium current may play an important role in the regulation of intracellular calcium concentration and Juvenile Hormone biosynthesis.
Adipokinetic hormone of the true armyworm, Pseudaletia unipuncta: immunohistochemistry, amino acid analysis, quantification and bioassay
Authors: ORCHARD IAN , CUSSON MICHEL , McNEIL JEREMY N.
Published: March 2008

Abstract A cluster of five to seven AKH‐like immunoreactive cells lie in each lobe of the paired corpora cardiaca of the true armyworm, Pseudaletia unipuncta. These cells form a mesh work of immunoreactive processes within the corpora cardiaca, and immunoreactive tracts projecting posteriorly over the aorta.

Reversed‐phase high performance liquid chromatography of extracts of the corpora cardiaca of P.unipuncta revealed a single large U.V. absorbent peak with a retention time identical to synthetic Manduca‐AKH. Amino acid analysis of the contents of this peak yielded a composition identical to that of synthetic Manduca‐AKH which was analysed in a parallel manner. Furthermore the material within the peak possessed adipokinetic activity when bioassayed in day 2 adult male P. unipuncta. The corpora cardiaca of similar individuals were found to contain approximately 17.6ng (17.6pmol) of Manduca‐AKH equivalents per pair.

Injection of Manduca‐AKH into 2‐day‐old adult male P.unipuncta resulted in a dose‐dependent elevation in haemolymph lipid levels with a maximum level of 80–90μmg/μl obtained with 5–10 ng of Manduca‐AKH. Continuous flight also elevated haemolymph lipid levels in day 4 adult males with a significant elevation evident in the first samples taken after 15 min of flight and lipid levels plateauing at approximately 100 μg/μl by about 60 min of flight.
Tarsal contact chemoreceptors of the black swallowtail butterfly Papilio polyxenes: responses to phytochemicals from host‐ and non‐host plants
Authors: ROESSINGH PETER , STÄDLER ERICH , SCHÖNI RETO , FEENY PAUL
Published: March 2008

Abstract Tarsal contact chemoreceptors of the black swallowtail butterfly Papilio polyxenes (Lepidoptera: Papilionidae) were stimulated with leaf‐surface extracts and ethanolic extracts of whole leaves of a host‐plant (Daucus carota) and a non‐host (Brassica oleracea). Both leaf extracts evoked large numbers of spikes but stimulated different receptor neurones. It is concluded that a large difference exists between the sensory responses to host and non‐host extracts. Two chemicals, luteolin 7‐0‐(6“‐0‐malonyl)‐β‐D‐glucopyranoside and trans‐chlorogenic acid, known to be present in the host and known oviposi‐tion stimulants for P.polyxenes, were also tested and shown to be active. No responses were found to luteolin 7‐O‐β‐D‐glucoside or to luteolin 7‐O‐β‐D‐glucuronide. These flavonoids occur in D.carota foliage, but do not stimulate oviposition.
Wandering behaviour and pupariation in tsetse larvae
Authors: ŽĎÁREK JAN , DENLINGER DAVID L.
Published: March 2008

Abstract .Following parturition, the third instar larva of Glossina morsitans morsitans West begins a wandering period in which it crawls to the site of pupariation. The duration of wandering can be drastically shortened by pinching or by denying the larva physical contact with the substrate. Contact with water increases the wandering period. Duration of subsequent activities appears to be rigidly fixed. At the end of the wandering period, the larva quickly progresses through a stereotypic sequence of behaviours that include immobilization and excretion of a liquid from the anus, retraction of the anterior segments, cuticular shrinkage, and tanning. Muscular activity and mechanical changes in the cuticle are reflected in changes of haemocoelic pressure. Muscular contractions produce pressure pulses that gradually increase in frequency and intensity, reaching a peak during retraction of the anterior segments. Changes in the mechanical properties of the cuticle cause a more gradual elevation of baseline pressure as the cuticle shrinks and loses its plasticity. As tanning begins, muscular activity ceases and haemocoelic pressure gradually decreases. In spite of its unusual early development within the confines of the female's uterus, the free‐living larva shows the full behavioural repertoire observed in other cyclor‐rhaphous Diptera at pupariation.
The influence of feeding on predatory tactics in a water bug
Authors: CLOAREC ANN
Published: March 2008

Abstract. The tropical belostomatid Diplonychus indicusVenk. & Rao (Heter‐optera: Belostomatidae) forages both actively and from ambush, changing frequently from one predatory mode to the other. Analyses presented here of the influence of feeding and of developmental stage on several locomotory and predatory parameters show that the fact that a bug was eating did not prevent it from reacting to and from seizing prey items, but it did influence the mode of predatory attempts. Feeding bugs were less active and they foraged actively less frequently, but feeding did not affect the frequency of predatory attempts from ambush. No important variations during development were found and first stadium larvae behaved similarly to adults. Capture success rates were higher at all developmental stages during a meal than when a bug was not eating and rejection rates were lower during a meal. These results suggest that, when eating, Diplonychus indicus bugs aim more successfully at prey items they are more likely to capture and to eat.
Single cell recordings from tsetse (Glossina m.morsitans) antennae reveal olfactory, mechano ‐ and cold receptors
Authors: OTTER C. J. DEN , NATERS W. M. VAN DER GOES VAN
Published: March 2008

Abstract. Action potentials from individual cells and receptor potentials were recorded from antennae (funiculi) of living tsetse flies, Glossina m.morsitansWestwood, using a ‘surface‐contact’ recording technique. Stimuli were pressure of the electrode, changes in temperature and the vapours of l‐octen‐3–ol, acetone, 3–methylphenol, dichloromethane and CO2. Two types of mechano‐receptive cells were found. One type only fired action potentials when pressure was increased, the other type continued firing when pressure was maintained. Of the 182 cells tested for their sensitivity to temperature change and the odour stimuli, 19% did not respond to any of the stimuli, suggesting that we are still unaware of cues which may be of import to the flies, and 4% responded to temperature only, increasing and decreasing their activity with a decrement and increment in temperature, respectively. Of the 141 cells which were olfactory receptors, 52% responded to 1‐octen‐3–ol and 40% were exclusively sensitive to this substance. For 3–methylphenol these percentages were 23 and 18, for acetone 13 and 11, for dichloromethane 12 and 7, for CO2 13 and 13. No clustering of cell types in certain areas of the funiculi was found, nor was a difference apparent between the sexes. The majority of the olfactory cells responded by increasing their activities on odour stimulation. Inhibition was found in three cells only, in which spontaneous activity was suppressed on stimulation with 3–methylphenol. Spike responses were phasic‐tonic and varied between two extremes: Cells showing relatively rapid cessation of spike activity after the end of stimulation, and cells which continued firing for several seconds or minutes after stimulation. Possible behavioural effects of the activities of the various cell types are discussed.
The behaviour of queen honeybees and their attendants
Authors: FREE J. B. , FERGUSON A. W. , SIMPKINS J. R.
Published: March 2008

Abstract. The behaviour of queen and worker honeybees (Apis melliferaL.) was observed using small colonies in observation hives. Workers paid more attention to queens which had been mated for 2 months or more than to those which were newly mated; virgin queens received least attention. Queens received most attention when they were stationary and least when they were walking over the comb; virgin queens were most active. Queen cells had as many attendants as virgin queens and queen larvae were inspected almost continuously. The queen pheromone component 9–oxo‐trans‐2–decenoic acid stimulated ‘court’ behaviour when presented on small polyethylene blocks, but workers responded aggressively to complete extracts of queens' heads. Both the heads and abdomens of mated queens received much attention from court workers but the abdomens were palpated by more workers for longer and were licked much more. The queens' thoraces were least attended. Abdominal tergites posterior to tergite glands were licked for longer than those anterior to the glands. Only worker bees very near to the queen reacted to her and joined her ‘court’.

No evidence was found of a diel periodicity in the behaviour of a queen or her ‘court’. During the winter the queen's court was smaller than in summer and she walked less and laid fewer eggs. When colonies were fed with sucrose syrup in winter, their queens laid more eggs and workers reared more brood but there was no change in the attention received by the queens.

The implications of these findings for the secretion and distribution of queen pheromones are discussed.
In‐flight orientation to volatiles from the plant‐host complex in Cotesia rubecula (Hym.: Braconidae): increased sensitivity through olfactory experience
Authors: KAISER L. , CARDE R. T.
Published: March 2008

Abstract. Plasticity in in‐flight orientation to odours from the plant‐host complex (PHC: plant infested by the host) was investigated in Cotesia rubecula, a specialist larval parasitoid of Pieris rapae which feeds almost exclusively upon cruciferous plants. A wind tunnel was used to study effects of both concentration of volatile emissions and females' experience. A low proportion of naive wasps located weak odourant sources, i.e. either a single cabbage leaf or a leaf with two first stadium P.rapae larvae. This rate could be elevated by increasing the odour concentration or by providing the wasps with either a previous oviposition experience on the PHC or an exposure to the PHC odour. Previous oviposition on washed larvae (diet‐fed, starved and then rinsed with distilled water) in an odourless environment had no effect, which suggested that increased sensitivity to the PHC odour resulted from olfactory experience. The number of mature eggs in a female was affected by oviposition on the PHC or washed larvae but not by exposure to the PHC odour. Therefore the number of mature eggs available was not correlated to the observed differences in orientation behaviour. Possible mechanisms of the behavioural changes described are discussed in the light of the host specificities of C.rubecula and P.rapae.
Morphological and physiological differences of the auditory system in three related bushcrickets (Orthoptera: Phaneropteridae, Poecilimon)
Authors: STUMPNER ANDREAS , HELLER KLAUS‐GERHARD
Published: March 2008

Abstract. The auditory system of three closely related bushcrickets was investigated with respect to morphological and physiological differences. The size of the acoustic vesicle in the prothorax cavity and the size of the acoustic spiracle were compared to differences in auditory tuning of the tympanic nerve and differences in the directionality. The results indicate that a small auditory vesicle and auditory spiracle provide reduced sensitivity in the high frequency range (above 10—15 kHz), but increase sensitivity at low frequencies (below 10 kHz). The directionality of the hearing system deteriorates at frequencies between 10 and 25 kHz in species with a small spiracle and trachea. The evolutionary implications of these differences of the auditory systems are discussed. They are considered to be influenced more by ecological factors than bioacoustical ones.
Effects of experience on parasitoid movement in odour plumes
Authors: VET LOUISE E. M. , PAPAJ DANIEL R.
Published: March 2008

Abstract. Insects commonly improve the effectiveness with which they locate biotic resources through learning, but the mechanism by which experience exerts its effects has rarely been studied in detail. The effect of oviposition experience on upwind movement of the eucoilid parasitoid, Leptopilina heterotoma (Thomson) (Hym.: Eucoilidae), in odour plumes of host microhabitats, was quantified with the use of a Kramer‐type locomotion compensator. A 2h exposure to host Drosophila melanogaster larvae in either fermenting apple‐yeast or decaying mushroom substrate (known to affect their preference for these odours in glasshouse and field choice experiments) had a number of effects on movement in plumes of each substrate. Females experienced with a particular substrate walked faster and straighter, made narrower turns and spent more time in upwind movement (i.e. toward the source) in a plume of odour from that substrate than in odour from an alternative substrate. Inexperienced females, by contrast, generally showed little or no significant difference in responses to alternative odours. In addition to affecting the mean values of movement parameters, experience also affected variability around those means. When walking speed or path straightness in an odour plume was increased by experience, variability among individuals was correspondingly decreased. The consequences of odour learning for microhabitat choice is discussed briefly.
Variability of femoral chordotonal organ reflexes in the locust, Locusts miaratoria
Authors: BÚSSLER ULRICH
Published: March 2008

Abstract. The femoral chordotonal organ of a locust front, middle or hind leg was stimulated mechanically under open‐loop conditions and the forces produced by the muscles moving the tibia were measured. In nearly all cases resistance reflexes were elicited in the inactive animal. However, in rare, but reproducible cases, a positive feedback occurred. In an animal performing active movements the responses were very labile: often no response occurred, sometimes a reaction comparable to the active reaction in stick insects was found, and sometimes resistance reflexes were present.
Effect of host diet and preflight experience on the flight responses of Microplitis croceipes (Cresson)
Authors: ELLER F. J. , TUMLINSON J. H. , LEWIS W. J.
Published: March 2008

Abstract. Female Microplitis croceipes without previous exposure to host diet, feeding damage or faeces, and with no oviposition experience (i.e. inexperienced) exhibited flight tunnel responses towards extracts of faeces from several diet–host species combinations, excluding artificial diet. Inexperienced females exhibited the following preference order towards faeces from Heliothis zea larvae fed selected diets: cotton > wild geranium > cowpea > artificial diet, suggesting and adaptation to ‘preferred’ host plants.

Females having a preflight experience with a plant‐host complex (PHC) prior to testing exhibited a higher percentage of oriented flights in the wind tunnel than did inexperienced females. Oviposition Per se had little effect on the flight response of females. The increased flight response after an experience is apparently due to a combination of sensitization and associative learning. In a choice situation, a single experience was insufficient to establish a preference for the PHC experienced; however, repeated experience resulted in preferences, and the degree of preference tended to increase with the number of experiences.
Effect of changes in the thermoperiod on reproductive diapause in Bruchidius atrolineatus Pic (Coleoptera: Bruchidae)
Authors: LENGA A. , HUIGNARD J.
Published: March 2008

Abstract. Bruchidius atrolineatus (Pic) is a tropical bruchid developing in Vigna unguiculata (Walp) pods. Adults are in reproductive diapause during the dry season. In conditions of 40:25d̀C or 35:25d̀C, diapause is induced when larvae develop in thermophases longer than 14 h, in thermophases shorter than 10 h and in continuous darkness. Thermophases of 12 h cause a reduction of the proportion of diapausing beetles. This proportion also depends on the thermoperiod temperatures. Development at low temperatures (23: 16d̀C, 12: 12 h) induces a high percentage of diapausing beetles. However, at low temperatures, the developmental times of the beetles are long and show important interindividual variability. When larvae develop in decreasing temperatures, small changes in thermoperiod temperatures (35:25d̀C to 3O:2Od̀C) have a strong effect on diapause induction. When larvae develop at low temperatures (25:15d̀C) and then at high temperatures (40:25d̀C), the proportion of diapausing beetles depends on the duration of development at low temperatures. Whatever the developmental conditions, both sexually active and diapausing beetles always emerge from the seeds. This interindividual variability is important in this species which has a wide geographical distribution in Africa.
Initial reproductive investment and parental body size in Cryptocercus punctulatus (Dictyoptera: Cryptocercidae)
Authors: NALEPA CHRISTINE A. , MULLINS DONALD E.
Published: March 2008

Abstract. Females of the subsocial woodroach Cryptocercus punctulatus Scudder generally have a single oviposition period during which they produce one to four oöthecae. Monogamous pairs and their recently deposited oöthecae were collected in the field, and measured, weighed and analysed for nitrogen in the laboratory. Females put 9.8 ± 2.4% (mean ± SD) of their dry weight and 11.6 ±0.5% of their body nitrogen into oöthecae. The total nitrogen and dry weight of the brood were positively related to the post‐oviposition total nitrogen and dry weight of the mother. A female's investment, on a per nymph basis, averaged 0.06% of her post‐oviposition dry weight. Females may be able to recover up to 58.7% of the nitrogen invested into a brood by consuming the egg cases after hatch. Overall, there was little variation in the width of head capsules of adults in this species, and this parameter was not significantly different between the sexes. Females were heavier than males (dry weight) (P =0.06). Within pairs, the weights and nitrogen contents of males and females were positively correlated, probably because they feed together in the same log for nearly a year prior to reproduction.
The role of the androconia in the mating behaviour of the European skipper, Thymelicus lineola, and evidence for a male sex pheromone
Authors: PIVNICK KENNETH A. , LAVOIE‐DORNIK JANY , McNEIL JEREMY N.
Published: March 2008

Abstract. Laboratory experiments were carried out to determine the role and characteristics of male scent scales (androconia), located in patches (stigmata) on the forewings of Thymelicus lineola (Ochsenheimer) (Lepidoptera: Hesperiidae).

In behavioural tests, there were 30—40% fewer matings of virgin females by males with the stigmata removed or where females had their antennal sensilla covered with nail polish, when compared to sham‐treated controls. These reductions occurred despite a large increase in male courtship activity. No physical contact was observed between male wings and female antennae during mating.

A scanning electron microscope study of male wings and female antennae showed that: (1) lysis zones form over time on the androconia and pieces (osmo‐phores) distal to these zones break off; (2) while few of these zones are present at emergence they are numerous in‐day‐old males; (3) during a single episode of courtship and mating approximately two‐thirds of the available osmophores break off, yet the commonly observed courtship between males does not appear to result in osmophore release; and (4) osmophores were never observed on the female antennae.

Electroantennogram recordings (EAGs) indicated that: (1) female antennae responded strongly to odours from male forewings but not from other parts of either males or females; (2) female antennae responded more strongly to young field‐collected males than to newly‐emerged or old, field‐collected males; (3) female antennal response to male forewings was reduced if the androconia were scraped off, and was eliminated if the stigmata were removed; (4) male antennae gave weak EAG responses to both male and female forewings.

We conclude that males release pheromone via the breakage of osmophores during courtship. We propose that the frequently observed refusals by females of courting males are at least partially dependent on the quantity or quality of male pheromone released, which are in turn correlated with the male's age and mating status.
Perizin, an acaricide to combat the mite Varroa jacobsoni: its distribution in and influence on the honeybee Apis mellifera
Authors: BUREN NICOLETTE W. M. van , MARIËN ADRIANA G. H. , OUDEJANS ROB C. H. M. , VELTHUIS HAYO H. W.
Published: March 2008

Abstract. The distribution of coumaphos (the active component of perizin), fed to individual honeybees, in the honey stomach, haemolymph, midgut and rectum was studied over time. Concurrently, we investigated changes occurring in the haemolymph volume due to the ingestion of perizin, and we examined the influence of a Nosema apisinfection on the survival of bees that had been fed perizin. The maximum amount of coumaphos in the haemolymph was found 4h after ingestion, but it was only 2–3% of the total amount recovered. After 15 min 55% of the total amount of the coumaphos recovered was in the honey stomach and available for distribution within the colony by trophallaxis, while 45% had already passed the proventriculus. Ultimately the coumaphos accumulated in the rectum. The volume of the haemolymph significantly increased in bees which were fed perizin compared with bees which were fed syrup and with non‐fed bees. The lethal dose of coumaphos to 3‐day‐old bees was three times higher than the lethal dose for 18‐ and 1‐day‐old bees. The number of Nosema apis spores in the alimentary canal was not correlated with the survival of the bees that were fed perizin. It is concluded that coumaphos can act as a systemic agent and can be distributed to other individuals in a colony through trophallaxis, but these effects are limited to a maximum period of 12h after ingestion.
Photoperiodic induction of winged females in the black bean aphid. Aphis fabae
Authors: NUNES MARLIES VAZ , HARDIE JIM
Published: March 2008

Abstract. The Photoperiodic of winged females (alatae) in the black bean aphid, Aphis fabae Scop. (Homopetera: Aphididae), is investigated in detail with emphasis on the interaction of the maternal and embryonic/young larval photoperiodic clocks. Previous work had shown that in uncrowded conditions the induction of gynoparae (winged females that produce sexual females) requires both prenatal and postnatal exposure to long‐night (12 h) Photoperidic cycles: present results show that sole postantal exposure to long nights of any lenght does not induce wing formation in early‐born aphids.

When aphids were exposed to experimental light‐dark cycles postanatally only, their daughters developed as alate in long nights and as apterae in short nights: the critical night lenght (CNL) was 11:1 h. Additional prenatal exposure to experimental regimes resulted in a significantly shorter CNL (10.6 h). This difference could be accounted for by the fact that more experimental light‐dark cycles were experienced in the latter case.

Apterous aphids transferred from LD 16:8 h to LD 12:12 h as either third‐or fourth‐stadium larvae, or young adults, switched for aptera‐production to alata‐production. The transition form aptera‐ to alata‐production was rather abrupt in third‐stadium transfers but more gradual when transfers occurred as fourth‐stadium larvae and adults. Moreover, s the number of days required for 50% of the aphids to become alata‐producers increased from 7–8 in third‐stadium transfers, to 9–10 and 11–12 in the later transfers.
Thermal response and reversibility of diapause in the eggs of Locusta migratoria
Authors: ANDO Y.
Published: March 2008

Abstract. Eggs of a local population of Locusta migratoria L. (Orthoptera: Acrididae) collected near Hirosaki (40.5oN) entered diapause when incubated at temperatures between 20 and 35oC. For diapause development the optimum temperature was 10oC. The lower thermal threshold for post‐diapause development was 14.7oC. After chilling at 10oC for 20 days, the rate of hatching varied with incubation temperature, being 0, 61% and 81% at 20, 25 and 30oC, respectively. After chilling for 40 days or more, however, almost all eggs hatched at 20–30oC. Diapause with a reduced intensity seemed to be eliminated easily by a high temperature of 25 or 30oC.

When eggs chilled at 10oC for 20 days were kept at 20oC for 7 days or more before incubation at 25oC, almost all eggs maintained diapause. Most eggs chilled at 10oC for three 10 day periods separated by 3 days of warming at 25oC failed to terminate diapause. Daily alternations of 10oC (18 h) and 25oC (6h) decreased the diapause‐terminating effect of chilling. These facts suggest that diapause intensity can be restored if eggs chilled insufficiently are exposed to a moderately high temperature. This reversible change in diapause intensity would play an important role in maintaining diapause before winter.
Source of an egg kairomone for Trissolcus basalis, a parasitoid of Nezara viridula
Authors: BIN F. , VINSON S. B. , STRAND M. R. , COLAZZA S. , JONES W. A.
Published: March 2008

Abstract. The eggs of the southern green stink bug, Nezara viridula (L.) (Hemiptera: Pentatomidae), are successfully attacked by Trissolcus basalis (Woll.) (Hymenoptera: Scelionidae) and are recognized as hosts by a secretion applied to the egg chorion. This secretion is produced by the follicular cells in the proximal region of the ovariole of the female pentatomid and functions as an adhesive for attaching the eggs to the oviposition substrate. The adhesive and kairomone activity could be partially removed with water. This water extract elicited host recognition behaviour in T. basalis when applied to glass beads which stuck together as the extract dried. The adhesive and kairomonal activity was removed completely with acetone since acetone‐washed host eggs were not recognized by T. basalis. Application of the acetone extract to glass beads stimulated ovipositional probes by T. basalis. The adhesive appeared to be composed of a mucopolysaccharide–protein complex.
Effects of citrate, heparin and cation supplementation on mortality and egg production of laboratory‐reared horn flies
Authors: GUERRERO FELIX D. , GUILLOT FRANK S. , FISHER WILLIAM F.
Published: March 2008

Abstract. The effects of the blood anticoagulants sodium citrate and sodium heparin on horn fly, Haematobia irritans L., egg production were tested. Sodium citrate was added to freshly collected bovine blood to give final concentrations of 5‐100mM while sodium heparin was used in concentrations of 10–70 USP units/ml blood. Small cages containing five male and ten female newly emerged laboratory‐reared horn flies were maintained for 8–10 days on these blood samples, and mortality and egg production recorded daily. Results showed that as blood citrate concentration was increased, egg production decreased logarithmically. At sodium citrate concentrations of 50 mM and above, severe impacts on egg production and adult horn fly survival occurred. Although no dose‐related response of egg production to increasing heparin concentrations was noted, the 25 USP units heparin/ml blood treatments gave the largest egg production, yielding approximately 28% more eggs than any other treatment. Since citrate is a known chelator of divalent metal cations, the effects of supplemental cation additions to citrated blood were tested for their ability to reverse the egg production decrease seen at 50 mM sodium citrate. Blood samples containing 50mM sodium citrate were supplemented with CaCl2, calcium lactate, CuCl2, cupric acetate, FeCl3, ferric citrate, MgCl2, magnesium acetate, MnCl2, ZnSO4, EGTA or EGTA plus calcium lactate, each at 1 mM except EGTA which was used at 2.5 mM. The magnesium acetate supplement and the combination of calcium lactate plus EGTA resulted in a statistically significant increase in egg production (P< 0.05).
The role of vision in the host plant‐finding behaviour of the Hessian fly
Authors: HARRIS M. O. , ROSE S. , MALSCH P.
Published: March 2008

Abstract. After mating, female Hessian flies, Mayetiola destructor (Say), sit for several hours before taking flight and exhibiting host‐finding behaviours. Observation of these behaviours indicated that females used both chemical and visual cues to find oviposition sites, and that visual cues from plants consisted of both spectral (colour) and spatial information. Females oriented to and were stimulated to land on targets reflecting wavelengths in the region of 530‐560nm (either alone or in combination with UV) but were inhibited by wavelengths from 400 to 500 nm. This spectral discrimination was probably mediated by photoreceptors located in the medio‐frontal zone of the compound eyes. The spatial patterning of targets also influenced orientation during flight; targets with vertical rather than horizontal contour lengths and a higher density of vertical contour lengths were approached and landed on more frequently.
Ultrastructure of honey bee, Apis mellifera, sperm with special emphasis on the acrosomal complex following high‐pressure freezing fixation
Authors: PENG CHRISTINE YING‐SHIN , YIN CHIH‐MING , YIN LUCY R. S.
Published: March 2008

Abstract. The ultrastructure of ejaculated sperm of the honey bee, Apis mellifera L., was studied after sperm were processed by using a high‐pressure freezing fixation and freezing substitution method. The electron micrographs of samples processed by this method clearly revealed previously unobserved or unresolved fine details, particularly those in the acrosomal complex. The present study demonstrates that the acrosomal complex of honey bee sperm consists of an anterior tubular acicular apex, an enlarged spherical region, and the elongated acrosomal proper. Internally, the structures of acrosomal complex confirm the general description of the tri‐layer model; having an extra‐acrosomal layer, an acrosome vesicle, and a central acrosomal rod located in a subacrosomal cavity. The acrosomal rod terminates anteriorly with an electron dense corpuscle in an ensheathing cap at the spherical region. The electron micrographs also show the presence of a centriolar adjunct and a structure possibly of a centriolar or basal body origin. The chemical and functional aspects of these ultrastructures remain unknown.
Specificity of sex pheromones, the role of host plant odour in the olfactory attraction of males, and mate recognition in the aphid Cryptomyzus
Authors: GULDEMOND J. ADRIAAN , DIXON A. F. G. , PICKETT J. A. , WADHAMS L. J. , WOODCOCK C. M.
Published: March 2008

Abstract. Choice tests in an olfactometer showed that males of the aphid Cryptomyzus galeopsidis spent more time in the odour of conspecific females than of a sibling species or a more distantly related Cryptomyzus species, which all co‐occur on red currant. Analysis of the pheromone‐emissions of females showed the presence of a nepetalactol and a nepetalactone, two known aphid sex pheromone components. However, no interspecific difference in the ratio of the components (c. 30:1) was found, and this ratio did not change as the females aged. Males were only slightly attracted by a synthetic 30:1 mixture of these two components, and in a choice test preferreď the odour of conspecific females. The sex pheromone of Cryptomyzus spp. must thus consist of more than two components, the first time this has been reported for aphids. Host plant odour did not attract males or enhance the activity of the pheromone.
The effects of drone age, semen storage and contamination on semen quality in the honey bee (Apis mellifera)
Authors: LOCKE SARAH J. , PENG YING‐SHIN
Published: March 2008

Abstract. The effect of semen storage time, drone age and semen contamination on honey bee semen quality was investigated using assays for motility and viability of semen in vitro. Four age groups (1, 2, 4 and 6 weeks) and five storage times (0, 1, 2, 4 and 6 weeks) were examined. As storage time increased, sperm viability and motility significantly decreased. However, motility patterns of unstored semen samples were significantly lower than those samples that were stored up to 2 weeks. Sperm viability decreased significantly with increasing drone age, but motility patterns did not change. Those semen samples that were found to be contaminated with foreign particles or microorganisms had a significantly lower mean viability than uncontaminated samples.
Cuticular spectra in the slave‐making ant Polyergus rufescens and the slave species Formica rufibarbis
Authors: HABERSETZER C. , BONAVITA‐COUGOURDAN A.
Published: March 2008

Abstract. The relative proportions of cuticular components having the same retention times were compared between the slave‐making ant Polyergus rufescens and the slave ant Formica rufibarbis living in monospecific or mixed colonies. The two species were found to present different spectra. The Formica workers, when enslaved by Polyergus, tend to lose their colony characteristics but they do not seem to adopt the characteristics of Polyergus.
Cuticular spectra and inter‐individual recognition in the slave‐making ant Polyergus rufescens and the slave species Formica rufibarbis
Authors: HABERSETZER C.
Published: March 2008

Abstract. The relationship between behavioural tests and relative proportions of cuticular components were studied in the slave‐making species Polyergus rufescens and the slave and Formica rufibarbis living in either monospecific or mixed colonies. A correlation between the relative proportions of the cuticular products and interindividual recognition exists in each of the two species Polyergus and Formica: Polyergus are fiercely aggressive towards individuals which have different cuticular spectra and originate from a geographically isolated nest. This seems to be true also in the case of Formica living in monospecific colonies. A similar correlation also exists between the two species, which have different cuticular spectra: encounters arranged between them show that free‐living Formica are always fiercely aggressive towards Polyergus. The reason why no such correlation seems to exist, however, between Polyergus and Formica when the latter are enslaved and the two species coexist peacefully at the same nest is discussed.
Flight capacity: genetic determination and physiological constraints in a migratory moth Mythimna separata
Authors: HAN ER‐NING , GATEHOUSE A. GAVIN
Published: March 2008

Abstract. Flight capacity of the oriental armyworn Mythimna separata (Walker) (Lepidoptera: Noctuidae) was estimated by a new tethered flight technique. Samples of a migrant population showed a substantial proportion of ‘long fliers’. Heritability of flight capacity was found to be significant (h2= 0.27). Female moths from a line selected for long pre‐reproductive period (PRP) showed greater flight capacity than those from a short PRP line. This difference was not apparent among males. Onset of calling behaviour inhibited the expression of flight capacity in females showing a clear ‘oogenesis‐flight syndrome’. These results are discussed in relation to seasonal migration in eastern China and the mechanisms involved in the migratory strategy of this species.
Odour‐mediated upwind flight of Culex quinquefasciatus mosquitoes elicited by a synthetic attractant: a reappraisal
Authors: PILE M. M. , SIMMONDS M. S. J. , BLANEY W. M.
Published: March 2008

Abstract. Pile et al. (1991) report that the putative oviposition attractant ace‐toxyhexadecanolide has four effects on gravid females of Culex quinquefasciatus Say: (1) it induces upwind anemotaxis, (2) near to an oviposition site it evokes an orthokinetic slowing of flight speed plus (3) a klinokinetic increase in turning rate, and (4) it causes females to stay longer at oviposition sites. This reappraisal shows that the first two of these conclusions are supported by the evidence provided but the second two are not.
Diel rhythms of adipokinetic hormone, fat body response, and haemolymph lipid and sugar levels in the house cricket
Authors: DAS SUBRATA , MEIER OUIDA W. , WOODRING JOSEPH
Published: March 2008

Abstract. The adipokinetic hormone (Grb‐AKH) content in the corpora car‐diaca of the house cricket, Acheta domesticus, varied during a day with two peaks in the scotophase and one peak in the photophase. There were two distinct peaks of total lipid concentration in the blood, one early in the photophase and the other early in the scotophase. Fat body sensitivity to adipokinetic hormone also varied in close synchrony with the lipid rhythm. It was not possible to attribute the rhythm of blood lipid titre unequivocally to either the rhythm of adipokinetic hormone content in the corpora cardiaca or to the rhythm of sensitivity of the fat body to the hormone. In adult crickets the blood carbohydrate titre had two peaks in adult females, one towards the end of scotophase and another in the late photophase (c. 12h apart), but a single peak at the end of scotophase was apparent in last instar larvae. The blood carbohydrate rhythm persists in DD and is therefore endogenous. Carbohydrates were not mobilized by the Grb‐AKH, therefore could not be involved in the blood carbohydrate rhythm. Exposure to various day lengths caused shifts in the patterns of the carbohydrate rhythms, but imposition of a cyclic temperature regime had no effect on the rhythm.
Hourglass and oscillator expressions of photoperiodic diapause response in the cabbage moth Mamestra brassicae
Authors: KIMURA YUJI , MASAKI SINZO
Published: March 2008

Abstract. Both oscillator and hourglass features are found in the photoperiodic response that controls the pupal winter diapause of Mamestra brassicae. The expression of oscillatory response to extended long‐night cycles is temperature dependent, i.e. circadian resonance appears at 23 and 25oC but not at 20 and 28oC. At 20oC, scanning of extended scotophases by a short light pulse does not reveal any clear circadian rhythmicity. However, a circadian feature of the photoperiodic response is indicated even at 20oC by a bistability phenomenon, i.e. either one of the two dark periods in symmetrical skeleton photoperiods determines the diapause response depending on the phase angle with the preceding (entraining) light‐dark cycles. At 20 and 25oC, the incidence of diapause increases as a function of the number of light–dark cycles regardless of the cycle length (T), if T is 24 h or 2 X 24h (with a 12 h light period). A non‐diel cycle (r=36h) is less effective, suggesting that disturbance of the circadian organization partly impairs the diapause‐inducing function. The inductive effect of a long night is largely affected by temperature, and becomes saturated with eight cycles at 20oC and 14 cycles at 25oC. Presumably, an hourglass mechanism measures the dark time, and a circadian component involved in some later sequence of the photoperiodic response may or may not be expressed depending on the mode of interaction between them.
Distant olfactory response of the cabbage seed weevil, Ceutorhynchus assimilis, to oilseed rape odour in the field
Authors: EVANS K. A. , ALLEN‐WILLIAMS L. J.
Published: March 2008

Abstract. The olfactory orientation of adult cabbage seed weevils (Ceutorhynchus assimilis Payk.) from a distance of 20 m to extracts of oilseed rape (Brassica napus L.) was studied in the field using mark–release–recapture experiments. Male and female weevils dispersed upwind from the centre of a circular array of traps baited with Oilseed rape extracts. In the absence of host‐plant odour, female weevils dispersed randomly, and male weevils downwind. Percentage recapture of weevils was significantly greater in traps baited with rape flower than rape leaf extracts. Significantly fewer weevils were recaptured in unbaited traps compared to traps baited with rape flower or leaf extracts. We suggest that seed weevils can use odour‐mediated upwind anemotaxis to locate their host‐plants from distances of at least 20 m.
Light and temperature entrainment of a locomotor rhythm in honeybees
Authors: MOORE DARRELL , RANKIN MARY ANN
Published: March 2008

Abstract. The circadian locomotor (walking) rhythms of forager honeybees (Apis mellifera ligustica L.) were entrained to eight different 24 h light‐dark cycles. The phases of activity onset, peak activity, and offset were correlated with the lights‐off transition, suggesting lights‐off as the primary zeitgeber for the rhythm. Further support for this hypothesis was provided by LD 1:23 experiments, in which entrainment occurred when the light pulse was situated at the end, but not at the beginning, of the subjective photophase. Steady‐state entrainment of the locomotor rhythm was achieved with square‐wave temperature cycles of 10oC amplitude under constant dark: most of the activity occurred within the early thermophase. Smaller amplitude temperature cycles yielded relative coordination of the rhythm. Interactions of temperature and light‐dark cycles resulted in entrainment patterns different from those elicited in response to either cycle alone or those formed by a simple combination of the two separate responses. Furthermore, temperature cycles having amplitudes insufficient for entrainment of the rhythm nevertheless modified the pattern of entrainment to light ‐ dark cycles, suggesting a synergism of light and temperature effects on the underlying circadian clock system.
Comparative effects of form, colour, and pheromone of twospotted spider mite quiescent deutonymphs on male guarding behaviour
Authors: ROYALTY REED N. , PHELAN P. LARRY , HALL FRANKLIN R.
Published: March 2008

Abstract. Effects of form, colour, and pheromone of twospotted spider mite, Tetranychus urticae (Koch), quiescent deutonymphs on adult male guarding behaviour were tested independently and in combination using no‐choice and sequential‐presentation bioassays. Significantly more males approached yellow stimuli sources than non‐yellow sources in all bioassays, suggesting that males orient visually to yellow carotenoid pigments of quiescent deutonymphs. The form and extract (pheromone) of quiescent deutonymphs did not increase male approach frequency. All three cues elicited male arrestment; contrasts of 2 × 3 factorial bioassay data showed that male tactile and/or visual perception of form increased arrestment frequency more than did contact chemoperception of extract, while extract perception caused more arrestments than did visual perception of colour. All three cues prolonged arrestment duration and increased frequency of intermale conflicts near stimuli sources, but form had greater impact than did other cues on the numbers of conflicts observed during coguarding incidents. Significant interactions among stimuli were observed, indicating that presence of multiple stimuli had a synergistic effect on the duration of male response. Males approached and were arrested by all three stimuli combined as often as by quiescent deutonymphs, but arrestments caused by quiescent deutonymphs were longer than those elicited by artificial stimuli. This difference suggests that either additional cues or differences in pheromone release rates are involved in eliciting and prolonging male T. urticae guarding behaviour.