bluuebunny/crossref_metadata_2025 huggingface dataset:
Age‐dependent responses of last instar larvae of Spodoptera mauritia to precocene II
Authors: SANTHA P. C. , NAIR V. S. K.
Published: March 2008

ABSTRACT. Last instar larvae of Spodoptera mauritia Boisd. (Lepidoptera: Noctuidae) of various ages were treated with a single dose of 80 μg or 160 μg of precocene II (PII) and the effects of larval—pupal transformation were studied. Final instar (sixth) larvae treated on day 0, 1 or 2 with 80 μg P II showed a high mortality; P II treatment during subsequent days of this stadium showed a diminishing tendency for mortality. P II prolonged the larval—pupal period in all larvae but the effect was somewhat reduced in the mid‐stadium.

Treatments of 160μg P II to 0‐day‐old, 1‐day‐old, 2‐day‐old and 3‐day‐old larvae were highly toxic. Treatments of 4‐day‐old and 5‐day‐old larvae with 160 μg P II delayed pupation by 1 day, but in addition the larvae often moulted into larval—pupal intermediates. Co‐application of 50μg juvenile hormone analogue (ZR 512) with 160 μg P II restored both normal morphogenesis and a normally‐timed moult.
Aggregation pheromones in five taxa of the Drosophila virilis species group
Authors: BARTELT ROBERT J. , SCHANER ANGELA M. , JACKSON LARRY L.
Published: March 2008

ABSTRACT. Aggregation pheromones have been demonstrated in the closely related taxa: Drosophila americana americana Spencer, D. a. texana Patterson, D. novamexicana Patterson, and D. lummei Hackman. These pheromones function much as has been reported previously for D. virilis Sturtevant. The compounds are produced by sexually mature males, but both sexes respond in a wind‐tunnel olfactometer. In all species except D. lummei, a 21‐carbon alkene is an important pheromone component. In D. virilis the hydrocarbon is (Z)‐10‐heneicosene (Z10–21), but in D. a. americana, D. a. texana and D. novamexicana it is (Z)‐9‐heneicosene (Z9‐21). All these taxa respond best to the heneicosene which they produce. D. lummei possesses no heneicosenes but, curiously, responds well to both Z9‐21 and Z10‐21. All species possess five male‐specific esters which were previously discovered in D. virilis: methyl tiglate, ethyl tiglate, isopropyl tiglate, methyl hexanoate and ethyl hexanoate. Ethyl tiglate is the most abundant in each case. Responses to the esters vary among the taxa, ranging from highly significant in D. lummei, particularly to ethyl tiglate, to not demonstrable in D. a. americana. Variability in ester response has also been demonstrated between two strains of D. virilis. In all cases the crude male‐derived pheromone is synergistic with an extract of fermented willow bark, on which oviposition is said to occur.
The dynamic nature of the activities of the wood ant Formica aquilonia foraging to static food resources within a laboratory habitat
Authors: COSENS DEREK , TOUSSAINT NEIL
Published: March 2008

ABSTRACT. A laboratory colony of the wood ant Formica aquilonia (Yarrow) was maintained under strictly controlled feeding regimens. The number of foragers at a particular site is related to the previous provisioning of the colony and the familiarity and accessibility of the resource to foragers. Under a standard regimen a predictable number of ants forage to a known site and display a typical pattern of daily activity. This pattern is examined under stable and changing circumstances. Following food‐deprivation individuals increase their foray‐frequency and carry larger volumes of sugar solution per foray. On days of critical food‐deficit supernumerary workers are recruited. How foragers are directed to a novel food source in unfamiliar territory is examined. Following‐behaviour is not involved, neither it appears are pheromones.
The effect of adult feeding on lipid and protein reserves in African armyworm, Spodoptera exempta, moths before and during reproduction
Authors: GUNN A. , GATEHOUSE A. G.
Published: March 2008

ABSTRACT. Newly‐emerged Spodoptera exempta (Walker) (Lepidoptera: Noctuidae) moths contain high levels of lipid held largely in the abdominal fat body, the quantity depending on the larval feeding conditions. There is a positive relationship between weight‐related lipid content and moth weight, which is consistent for female but not for male moths, suggesting that larval feeding conditions producing large individuals allow the accumulation of quantitatively disproportionate lipid reserves. Male and female moths have comparable levels of abdominal protein.

Changes in the water content in starved moths or ones provided with distilled water or sucrose solution show that while starved individuals die rapidly from desiccation, water‐fed moths regulate their water contents between narrow limits which are higher for females than for males. Sucrose‐fed moths maintain higher, more variable water contents probably due to the phagostimulatory effect of the sugar.

Reproducing and unmated moths are able to supplement their lipid and, to a lesser extent, their protein reserves following carbohydrate uptake.

During both larval and early adult stages, the capacity to accumulate lipid reserves in excess of those apparently required for reproduction, suggests that these reserves also provide the main fuel for the prolonged flights of which migratory individuals are known to be capable.
Endocrine manipulations and ontogenesis of male sexual behaviour in Locusta: studies on precocene‐induced early adultiforms
Authors: SHALOM U. , PENER M. P.
Published: March 2008

ABSTRACT. Fourth‐ and third‐instar permanent adultiforms of Locusta migratoria migratorioides (R.&F.) were produced by applying 7‐ethoxy‐precocene II (precocene III) to hoppers in earlier stages. The mating behaviour of male adultiforms and the effects of injected exogenous juvenile hormone III (JH) on this behaviour were investigated quantitatively and the results were compared to those obtained for normal adult males and for adult males chemically allatectomized by precocene III. Fourth‐ and third‐instar adultiform males exhibited sexual behaviour and injections of JH intensified this behaviour in a dose‐dependent manner, though the number of repeated injections in which a cumulative dose is administered was found to be not less important than the amount of the cumulative dose itself. Huge repeated doses (6×144=864 μg) of JH temporarily induced normal intensity of mating behaviour in fourth‐instar male adultiforms. The same doses of JH intensified mating behaviour also in third‐instar adultiform males, but less markedly so than in fourth‐instar ones. For restoring temporarily normal intensity of mating behaviour in chemically allatectomized but morphogenetically normal adult males, much smaller doses (2×36=72, or 2×72=144μg) of JH were sufficient. In contrast, even huge doses of JH were unable to induce mating behaviour in normal (no precocene‐treated) male hoppers. Thus, the ethological ontogenesis (=‘ethogenesis’) of the male's mating behaviour, including the response of the system to JH, is clearly accelerated by precocious metamorphosis. However, this is not a simple ‘all or none’ effect, because adultiforms in earlier stadia exhibit less intense male mating behaviour and more limited response to JH than adultiforms in later stadia or adults.
Electroantennogram responses of the stable fly, Stomoxys calcitrans, to carbon dioxide and other odours
Authors: WARNES M. L. , FINLAYSON L. H.
Published: March 2008

ABSTRACT. Electroantennograms (EAGs) were recorded from Stomoxys calcitrans (L.) in response to increasing concentrations of carbon dioxide in an airstream. The magnitude of the EAG increases logarithmically from +0.023% carbon dioxide up to approximately +2.0% where a maximum is reached. Flies deprived of food for 48–50 h are more responsive to small increases in the carbon dioxide concentration than those deprived of food for only 20–23 h. It is concluded that the sensitivity of carbon dioxide receptors on the antennae of S. calcitrans increases as hunger develops. EAGs were also recorded in response to cattle odour, odour from fresh cattle faeces, expired human breath, acetone, and l‐octen‐3‐ol. Acetic acid vapour causes a reversal of the usual EAG response indicating inhibition.
Behavioural evidence for polarization vision in crickets
Authors: BRUNNER DANIEL , LABHART THOMAS
Published: March 2008

ABSTRACT. Tethered field crickets, Gryllus campestris L., walking on an air‐suspended bail exhibit a spontaneous response to the e‐vector of polarized light presented from above: E‐vector orientation controls strength and direction of turning tendency. Experiments in which different eye regions are covered with paint suggest that this response is mediated by the anatomically and physiologically specialized dorsal rim area of the compound eye. We conclude that crickets have polarization vision and that the dorsal rim area of the eye plays a key role in this sensory capacity.
Effects of infection with a granulosis virus on larval growth, development and ecdysteroid production in the cabbage looper, Trichoplusia ni
Authors: DOUGHERTY E. M. , KELLY T. J. , ROCHFORD R. , FORNEY J. A. , ADAMS J. R.
Published: March 2008

ABSTRACT. Granulosis virus‐infected Trichoplusia ni (Hûbner) larvae exhibited an increased larval life span with no supernumerary moult and no pupation. Weight gain was not affected. Insects infected shortly after hatching were slower in reaching the fourth and fifth stadia than were control insects. Haemolymph ecdysteroid titres were lower in virus‐infected insects than control insects, but these differences were only significant (P<0.05) in the fifth stadium. Electron microscopic examination of the pro thoracic glands revealed extensive granulosis virus infection, and glands from virus‐infected insects produced no RIA‐detectable ecdysteroids in vitro. Injection of 20‐OII‐ecdysone into virus‐infected larvae at various concentrations and times did not induce pupation.
Caste regulation in the pharaoh's ant Monomorium pharaonis: the influence of queens on the production of new sexual forms
Authors: EDWARDS J. P.
Published: March 2008

ABSTRACT. In colonies of Monomorium pharaonis (L.), the presence of fertile queens normally prevents the production of new queens and males (sexuals). The inhibitory effect of the presence of fertile queens is not shared by virgin queens or by freshly killed dead queens, but can be substituted by the artificial introduction of eggs. Moreover, fertile queens made sterile by exposure to a Juvenile Hormone analogue lose their ability to prevent the rearing of new sexuals. Thus, the inhibitory action of queens is mediated via the eggs that they lay, such that the rearing of new sexuals is limited to the times when either the number or fecundity of extant queens is reduced. Workers appear able to detect changes in the number of eggs present in the colony. When eggs are plentiful (i.e. when queens are laying at maximum rates), only worker brood is reared, but if egg numbers decline, workers will respond by rearing a new batch of males and queens. This method of caste regulation is highly efficient, and the inhibitory action of eggs on the production of sexuals is comparable to the action of ‘queen substances’ reported in some other social insects.
Sensillar types of the ovipositor of Dasineura brassicae: structure and relation to oviposition behaviour
Authors: HALLBERG ERIC , AHMAN INGER
Published: March 2008

ABSTRACT. The distal part of the ovipositor of Dasineura brassicae Winn. (Diptera; Cecidomyiidae) possesses forty to forty‐five sensilla of three morphological types. Most are provided with a cuticular bristle, which projects from the surface of the ovipositor; fifteen have a taste/tactile function based on fine structural characteristics; about twenty‐five are innervated by a single sensory cell, specialized for mechanoreception. Scolopidial sensory receptors are anchored to the cuticle inside the distal part of the ovipositor, they probably respond to changes in length of the ovipositor. Different sensory systems are involved in the choice of oviposition site; compound eyes and antennae are probably active in the earlier stages, whereas the receptors of the ovipositor appear well suited to govern the last steps in this behaviour.
Effects of optic lobe ablation on circadian activity in the mosquito, Culex pipiens pallens
Authors: KASAI MASANORI , CHIBA YOSHIHIKO
Published: March 2008

ABSTRACT. Surgical manipulation was used to show that in the mosquito, Culex pipiens pallens, the circadian pacemaker is probably not located in the optic lobes. Mosquitoes deprived of the greater part of their optic lobes still maintained a circadian activity rhythm: in DD with τ=c. 20–23 h, in LL with τ=c. 14–15 h. The operated mosquitoes showed diphasic activity which entrained to LD 16:8 h (at 200 lux), implying the existence of an extraocular photoreceptive pathway.
The effect of visual input on calling song attractiveness for female Acheta domesticus
Authors: STOUT JOHN F. , ATKINS GORDON , WEBER THEO , HUBER FRANZ
Published: March 2008

ABSTRACT. Of twelve mature phonotactically‐responsive female Acheta domesticus L., ten responded phonotactically to a wider range (30 or SO to 100 ms) of model calling song (CS) syllable periods (SP) on the Kramer treadmill in the dark than in a lighted visually structured arena (50–70 ms). When given a choice between the visually attractive target and the invisible loudspeaker, seven of the ten females that tracked a visually attractive target (black square) when presented alone in the light reduced the range of SPs they tracked phonotactically to 50–70 ms. Three of the ten females that were not strongly attracted to the visual target when presented alone, continued to respond to model calling songs with a wide range of SPs (30–100 ms) when given a choice between visual and acoustical targets under the same conditions. Two of the twelve females responded only to model calling songs with a 50–70 ms SP on the Kramer treadmill in the dark. These females did not change their choice for model calling song SPs when presented with the visually attractive target.
The combined effect of photoperiod and temperature on the calling behaviour of the true army worm,Pseudaletia unipuncta
Authors: DELISLE JOHANNE , McNEIL JEREMY N.
Published: March 2008

ABSTRACT.Pseudaletia unipuncta(Haw.) (Lepidoptera: Noctuidae) virgin females, maintained at either 10 or 25d̀C under LD 12:12 or 16:8 h, started calling at different ages. For a given photoperiod, calling was initiated 11 days later at 10d̀C than at 25d̀C, while for a given temperature, calling at LD 12:12 h was 3–4 days later than at LD 16:8 h. At 10d̀C 50.8% of females did not call within 35 days at LD 12:12 h compared with 30.8% at LD 16:8 h. Calling started earlier in the scotophase at 10d̀C than at 25d̀C and at LD 16:8 h than at LD 12:12 h. Under all treatments calling generally advanced on successive nights. The time elapsed between the mean onset time of calling and the mid‐scotophase was relatively constant under both photoperiod conditions at 25d̀C, but at 10d̀C was more variable. The mean time spent calling increased significantly with calling age but did not differ significantly between the four experimental conditions tested.

Older (15 days) females transferred from 10d̀C, LD 16:8 h to 25d̀C at either LD 163 or 12:12 h, required less time to initiate calling than younger (5 days) ones. Those transferred from 10d̀C, LD 12:12 h took the same time, regardless of their age at the time of the transfer. Females experiencing either a decrease or increase in daylength as well as a temperature increase, required respectively more or less time to initiate calling, compared with individuals that only experienced an increase in temperature.

If temperature was the only parameter changed females that initiated calling soon after the transfer immediately adjusted their calling periodicity to prevailing conditions. When both temperature and photoperiod were altered, it took several days before calling periodicity adjusted to the new regime. The ecological implications of temperature and photoperiodic conditions on the possible autumn migration ofP. unipunctaare discussed.
Behavioural sequence in the attraction of the bark beetle Ips typographus to pheromone sources
Authors: SCHLYTER FREDRIK , LÖFQVIST JAN , BYERS JOHN A.
Published: March 2008

ABSTRACT. The functions of the two synergistic pheromone components, (4S)‐cis‐verbenol (cV) and 2‐methyl‐3‐buten‐2‐01 (MB), and the role of ipsdienol in the attraction of Ips typographus (L.) (Scolytidae) to pheromone sources were studied in the field. Absolute and relative beetle catches were compared between several traps placed at and nearby a central pheromone source: a pipe trap containing the source, a surrounding sticky trap, a nearby window trap, and four distant window traps. A higher catch in the outer down‐wind distant traps indicated an up‐wind anemotaxis to the source. Increased MB release, with cV constant, increased the proportion caught in the central pipe trap, indicating MB as a landing stimulus. Release of MB alone gave a very small catch. Ipsdienol could not substitute for cV in the synergism with MB. An increase of cV, with MB constant, increased the number of beetles caught, but not the proportion caught in the pipe trap. The sex ratio was equal in the window traps, but fell to 30% males in both sticky and pipe traps, showing that a large proportion of the males attracted to the source did not land. The proportion of males in the pipe trap was reduced at the highest cV dose. The results support the idea of each pheromone component having a different relative importance in releasing different steps in the behavioural chain.
Diving behaviour and respiration in Blethisa multipunctata in comparison with two other ground beetles
Authors: ARENS WERNER , BAUER THOMAS
Published: March 2008

ABSTRACT. The diving behaviour of Blethisa multipunctata (L.), a carabid species living on shores, is compared with that of two other hygrophilous carabid species. B. multipunctata enters the water spontaneously and is able to stay more than 1 h beneath the surface without renewing its respiratory air, In flooding experiments, c. 50% of submerged beetles do not leave the water after 2h. These animals emerge from time to time for a few seconds and then descend beneath the water again. Measurements of oxygen consumption and the volume of the respiratory air show that the underwater air‐supply is sufficient for only a few minutes. B. multipunctata achieves maximum diving times of up to 97 min by using its air storage as a physical gill. In comparison with other Carabidae it shows neither morphological nor physiological adaptations, but only behavioural adaptations for its amphibious mode of life.
Temporal learning in the giant tropical ant, Paraponera clavata
Authors: HARRISON JON M. , BREED MICHAEL D.
Published: March 2008

ABSTRACT. Our findings suggest that the capacity for temporal learning in ants may be associated with nectivory. We tested for the existence of time and location learning in the nectivorous tropical ant, Paraponera clavata (F.). Artificial nectar sources were provided at fixed times and locations to P. clavata workers for 5 days. Ants appeared at the feeding location at the appropriate time on the first day that no reward was provided. By the third day without reward there was no difference in visitation between the feeding site and a control site equidistant from the colony. Most ants arrived at the feeding sites within 30 min of the training time, indicating that the precision of ant time sense is similar to that previously documented for honeybees.
Relative air humidity influences the function of the tarsal chemoreceptor cells of the cherry fruit fly (Rhagoletis cerasi)
Authors: STÄDLER ERICH , SCHÖNI RETO , KOZLOWSKI MAREK W.
Published: March 2008

ABSTRACT. Electrophysiological recordings from the tarsal D‐sensilla of mature, 5–7‐day‐old female European cherry fruit fly (Rhagoletis cerasi L.) revealed that a large proportion of sensilla showed no sensory activity in response to stimulation with the oviposition deterring pheromone (‘ODP’) or sucrose. In contrast, good recordings were obtained from almost all sensilla in freshly emerged, 1‐day‐old flies. Ageing, nutritional state and contamination were excluded as possible major factors influencing the responsiveness of the D‐sensilla. The study of the variability in responsiveness of the sensilla of 1‐day‐old flies among different tarsomers, among tarsi of the same individual and among individuals, revealed that the major source of variability was among individuals.

Individual flies were also affected by the humidity in the holding cages: relative air humidity of less then 75% for 4–6 days was shown to reduce the number of D‐sensilla giving recordings with a good signal‐to‐noise ratio. The D‐sensilla on the most distal tarsomers were affected most by the reduced (30–55% r. h.) air humidity. Flies which had contact with plant leaves showed less reduction in responsiveness at low air humidity (40% r. h.) then flies without leaf contact.
Role of photoperiod and temperature in seasonal morph determination of the butterfly Eurema hecabe
Authors: KATO Y. , SANO M.
Published: March 2008

ABSTRACT. Environmental cues affecting seasonal morph determination of the pierid butterfly Eurema hecabe L. were examined in laboratory experiments and in the field. A sexual difference exists in the photoperiodic response for seasonal morph determination: in short days at 25d̀C the proportion of the autumn morph is higher in females than in males, and as the rearing temperature is decreased the proportion of autumn morphs increases in both sexes. A 5d̀C drop in temperature during the final larval stadium induces 100% autumn morph production in short‐day animals. This increase in autumn morph production induced by temperature decrease explains the seasonal morph change of this butterfly occurring in early autumn in the field. The role of this sex‐linked photoperiodic response is discussed as a seasonal strategy of reproduction.
Circadian rhythm of locomotor activity in individual workers of the wood ant Formica rufa
Authors: NORTH R. D.
Published: March 2008

ABSTRACT. Individual worker ants isolated in an actograph exhibit circadian rhythms of locomotor activity. Entrainment occurs more readily in LD 18:6 h than in LD 12:12 h. The ants are either light‐active or dark‐active. Phase angle and duration of activity is influenced by photoperiod.
Puddling in butterflies: sodium affects reproductive success in Thymelicus lineola*
Authors: PIVNICK KENNETH A. , McNEIL JEREMY N.
Published: March 2008

ABSTRACT. Adults of many species of Lepidoptera, principally the males, frequent mud puddles, edges of streams, carrion and animal excreta where they imbibe moisture, an activity referred to as ‘puddling’ Sodium ions are the only known stimulus present which cause males of at least two lepidopteran species to drink for extended periods. In the European skipper Thymelicus lineola (Ochsenheimer) (Lepidoptera: Hesperiidae), only males puddle, even though they have concentrations of abdominal sodium 2–3 times that of females at emergence. During their first mating, males transfer 32% of their abdominal sodium to females. This could be of considerable importance given that an average egg complement contains >50% of the total body sodium of females at emergence. Virgin females, as well as having reduced fecundity, have reduced longevity. This is attributed to virgins not obtaining important nutrients which males transfer to females during mating. Access to sodium ions increases the total number of matings by c. 50% for males living >15 days. Access to sodium ions by once‐mated males increases the percentage of males which re‐mate on the day following first mating; the percentage of females, mated to the twice‐mated males, which lay >50% fertile eggs; and the drought resistance of eggs laid by those females.
The visual responses of free‐flying summer and autumn forms of the black bean aphid, Aphis fabae, in an automated flight chamber
Authors: DAVID C. T. , HARDIE JIM
Published: March 2008

ABSTRACT Summer (virginoparae) and autumn (gynoparae) winged forms of Aphis fabae were flown in an automated flight chamber for up to 100 min, while being exposed to a small green target at their own level for 5 s of each minute. Virginoparae climbed more slowly than gynoparae and responded to the target by turning towards it throughout experimental flights. Gynoparae, on the other hand, were almost completely unresponsive to the target, although some individuals began to respond after an hour or more of flight. The differences between the two migratory forms are discussed with reference to previous work on aphid flight behaviour in the field and the laboratory.
Auditory characteristics and sexual dimorphism in the gypsy moth
Authors: CARDONE BEATRICE , FULLARD JAMES H.
Published: March 2008

ABSTRACT. The auditory characteristics of two populations (laboratory reared and wild) of North American gypsy moths (Lymantriidae: Lymantria dispar L.) were sampled and the neurally derived thresholds of wild males and females to frequencies from 5 to 150 kHz compared. The noctuoid auditory receptors, Al and A2‐cell, and putative proprioceptor, B‐cell, were identified. Both sexes possess neurally responsive ears but females exhibit median best frequencies significantly lower than those of males. Audiogram comparisons reveal significantly different thresholds at 5–15 kHz, 30–120 kHz and 130–140 kHz, with females less sensitive to all but the lowest frequencies. Wild male populations reveal less audiogram variability than laboratory‐reared individuals, while females' tuning curves appear more similar. The high variability present in colony moths warrants caution in the use of laboratory‐reared insects for studies that assume natural levels of selection pressure. We suggest that male L. dispar possess adaptively functional ears tuned to the frequencies in the echo‐location signals of bats but that the flightless females of this species are not exposed to bat predation and therefore possess ears in a state of evolutionary degeneration.
Effect of high potassium concentrations on juvenile hormone release in vitro from corpora allata of Locusta migratoria
Authors: DALE J. F. , TOBE S. S.
Published: March 2008

ABSTRACT. Incubation of corpora allata (CA) from adult females of Locusta migratoria (L.) in vitro in medium with a potassium concentration of 50 mM results in an elevation of the rate of juvenile hormone (JH) release. This elevation is however delayed, becoming apparent after the glands have been returned to low concentration of potassium but it is also prolonged, lasting up to 270 min. The elevation is initially modest but becomes more marked with time. The response of glands to high concentration of potassium is heterogeneous and appears to some extent to be a function of the initial rate of JH release of the glands. Glands starting with low rates of JH release are stimulated strongly by potassium, those with high rates of JH release much less so. Co‐incubation of glands with high concentration of potassium and with calcium channel blockers (both organic and ionic) prevents the elevation of release rates otherwise consequent on high concentrations of potassium.
Circadian timing of cricket calling song: a clock persisting from nymphs to adults
Authors: WIEDENMANN GOTTFRIED
Published: March 2008

ABSTRACT. Male Australian field crickets (Teleogryllus commodus, Walker) reared in LD 12:12 h were transferred to LL at different developmental stages and the timing of their circadian calling song rhythm was analysed in regard to the previous zeitgeber. The phase settings for the onset and end of activity were similar in crickets experiencing the LD/LL transition: (i) 3–52 days after the final moult, (ii) within 24 h before the final moult, or (iii) 1–10 days before the final moult. For all groups the results reveal entrainment of the circadian mechanism at the last LD, thus excluding age‐related differences. The rhythms of crickets, transferred from LD to LL as larval instars and also exposed to a reduced temperature (5–8oC) during their last night, were delayed by about 11 h, an effect similar to that in adult crickets after a comparable cold exposure (Loher & Wiedenmann, 1981).

The results are interpreted showing that the circadian control of (the adult's) calling song already functions in the previous (non‐singing) larval stages. Since the rhythmicity continued through moults and sexual maturation, it is concluded that the control centres regulating those physiological processes (e.g. pars intercerebralis, corpora allata) are not essential to the basic circadian mechanism.
Insect electroantennogram responses to semiochemicals recorded with an inexpensive personal computer
Authors: BJOSTAD LOUIS B.
Published: March 2008

ABSTRACT. . A circuit and accompanying program that allow an inexpensive personal computer to replace an expensive storage oscilloscope in displaying electroantennogram (EAG) recording is described. The maximum amplitude of the EAG is calculated automatically by the computer and appears as an alphanumeric display on the monitor screen. Because the entire EAG trace is stored by the computer, parameters of the EAG trace other than the maximum amplitude are also available for analysis, such as voltages at specified times after antennal stimulation.
Dispersion and spatial orientation ofGerris remigisin response to water current: a comparison of pre‐ and post‐diapause adults
Authors: FAIRBAIRN D. J. , BRASSARD J.
Published: March 2008

ABSTRACT.The movements and orientation of adultGerris remigisSay (Hemiptera; Gerridae) were examined in an artificial stream to determine the mechanisms by which these stream‐dwelling waterstriders compensate for and/or avoid downstream drift, and to compare the movement tendency of pre‐ and post‐diapause adults.G. remigisrespond to current by turning to face directly into the current (rotational orientation), intermittently rowing against the current (translational orientation), and moving onto land to avoid the current. These rotational and translational responses enableG. remigisto maintain their positions in currents =S10 cm s‐1. However, avoidance increases with current speed, and few animals are found where currents exceed 10 cm s‐1. These observations correlate well with the observed distribution of adultG. remigisin a natural stream.

Comparisons between life stages reveal that post‐diapause adults move more, and are more susceptible to drift than pre‐diapause adults. Post‐diapause adults also avoid even slight currents (<5 cm s_1) by seeking land, while pre‐diapause adults do not show a significant preference for land until currents exceed 10 cm s‐1. These data suggest that previously reported differences in the movement tendency of pre‐ and post‐diapause adults in the field may reflect physiologically‐based behavioural differences between these two life stages rather than merely direct responses to environmental cues.
Mating refusal and its significance in females of the ladybird beetle, Harmonia axyridis
Authors: OBATA SHOHKO
Published: March 2008

ABSTRACT. . Mating receptivity in females of the ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae), was studied with reference to internal and environmental conditions. Females sometimes reject copulation: they run away, or shake off the male and bend the abdomen upwards. Newly emerged females show a greater likelihood of accepting copulation with an advance in the stage of ovarian development, this being related to age. Females usually mate repeatedly, but frequently show refusal behaviour under unfavourable food conditions. Dissections reveal that females which accept copulation have a greater number of mature eggs in the ovary than do rejectors. Results also suggest that the food conditions are a major environmental factor, directly controlling mating receptivity.
Using fractal dimensions for characterizing tortuosity of animal trails
Authors: DICKE MARCEL , BURROUGH PETER A.
Published: March 2008

ABSTRACT. The tortuosity of mite trails was characterized by their fractal dimension, which is the non‐Euclidean dimension varying between 1 (completely straight) and 2 (so tortuous that the complete two‐dimensional space is used). This index was shown to be a good, discriminative index for mite trails, which is a completely new use of the fractal dimension. The value of this index is compared with other tortuosity indices.
Hearing in tiger beetles (Cicindelidae)
Authors: SPANGLER HAYWARD G.
Published: March 2008

ABSTRACT.Tympanic hearing organs (ears) are reported for several tiger beetle (Cicindelidae) species. The paired ears are positioned bilaterally on the first abdominal tergum and consist of cavities covered by thin tympana. When the beetle is not flying the elytra covers its ears and reduces their sensitivity to sound. However, when the beetle is flying, its exposed ears are capable of detecting ultrasonic pulses. Under a microscope, beetles with their elytra artificially raised contract their abdomens in response to ultrasound. Ultrasonic emissions directed toward flying beetles induce them immediately to fly downward and land, a response which probably aids escape from predators, particularly echolocating bats. Other possible uses for the ears are the avoidance of diurnal insect predators and intraspecific communication.
Visually‐guided, upwind turning behaviour of free‐flying tsetse flies in odour‐laden wind: a wind‐tunnel study
Authors: COLVIN JOHN , BRADY JOHN , GIBSON GABRIELLA
Published: March 2008

Abstract. To test the hypothesis that tsetse flies use visual input from the apparent movement of the ground to assess wind direction while in flight, Glossina morsitans morsitansWestwood females were video‐ recorded in a wind‐tunnel as they entered, in cross‐wind flight, a broad plume of simulated host odour (C02 at c. 0.05%). The tunnel (2.3 times 1.2 m wide) generated winds up to 0.25 m s‐1 and had a strongly patterned floor that could be moved upwind or downwind to increase or decrease the visual input due to wind drift. Flight tracks were analysed for speed, direction relative to the wind, and angle of turn. Mean groundspeeds were c.1.8 m s‐1. In control measurements in still air (with or without odour) flies turned 50:50 ‘upwind’: ‘downwind’. With a 0.25 m s‐1 odour‐perme‐ ated wind, 79% turned upwind, and c.70% left view flying upwind. When the floor was moved at 0.25 m s‐1 upwind (to mimic the visual input from the ground due to a 0.5 m s_‐1 wind), the strength of this response increased. If instead the floor was moved downwind, faster than the wind speed (to mimic the visual input due to a wind from the opposite direction), 59% turned downwind and c.70% left view flying downwind, and thus away from the source (though progressing ‘upwind’ in terms of the visual input from apparent ground pattern movement). Upwind turns were on average significantly larger than downwind turns. It is concluded that tsetse navigate up host odour plumes in flight by responding to the visual flow fields due to their movement over the ground (optomotor anemotaxis), even in weak winds blowing at a fraction of their groundspeed.
‘Bistability’ experiments and photoperiodic morph determination in the aphid Aphis fabae
Authors: NUNES MARLIES VAZ , HARDIE JIM
Published: March 2008

Abstract. Newly born larvae (presumptive gynoparae) of the aphid Aphis fabae were exposed to ‘symmetrical skeleton’ photoperiods, consisting of two equal pulses of light per 24 h. The general form of the photoperiods tested was LDLD 1:10:1:12 h. This regime is open to two ‘interpretations’, LDLD 1:10:1:12 h (PPs12) and LDLD 1:12:1:10 h (PPs14). As both light pulses are close to 12 h apart, it is expected that the interpretations result in two distinct steady state phase relationships, i.e. this regime would show bistability. If this is true and both interpretations could be adopted, PPs12 is expected to result in a low and PPs14 in a high percentage of ‘apterized’ insects.

Experiments undertaken with the aphid showed that bistability did not occur either at 15d̀C or 20d̀C, and the results could be entirely explained on the basis of an ‘instantly’ damping circadian oscillator clock.
Comparison of male and female olfactory cell response to pheromone compounds and plant volatiles in the turnip moth, Agrotis segetum
Authors: HANSSON BILL S. , PERS JAN N.C. VAN DER , LÖFQVIST JAN
Published: March 2008

ABSTRACT. Pheromone and plant volatile perception was studied with electroantennogram and single sensillum techniques in male and female turnip moths, Agrotis segetum Schiff. Lepidoptera, Noctuidae. The female is insensitive to the pheromone components and her receptors are specialized for plant volatile reception. The specific pheromone receptors on the male antenna are also sensitive to plant volatiles. The male was in addition found to have specialized plant volatile receptors. The biological significance of the different response profiles in males and females, and a possible hypothesis for the evolutionary specialization of olfactory receptors are discussed.
Long hyaline gland discharge and multiple spermatophore formation by the male grasshopper, Melanoplus sanguinipes
Authors: CHEESEMAN M. T. , GILLOTT C.
Published: March 2008

ABSTRACT. Discharge from the male accessory reproductive gland (ARG) by the male grasshopper, Melanoplus sanguinipes (Fabr.), has been studied by assay of a characterized product, a glycoprotein LHPI, and the rate of formation of spermatophores. LHPI is an exclusive long hyaline gland (a prominent ARG tubule type) product whose discharge is symmetrical from the bilaterally paired glands. LHPI forms 65% of a viscous secretion that is discharged concomitantly with the spermatophores. Though low ARG reserves in 5‐day‐old males limit both the number of spermatophores formed and LHPI discharged in copulations ≤6 h, this appears to be the result of shorter copulations. The number of spermarophores formed in 1 h was not impaired by general depletion of ARG protein (by repeated copulations) or by selective depletion of long hyaline gland protein (by unilateral and bilateral long hyaline gland removal), though these manipulations reduced LHPI discharge by 22%, 44% and 100%, respectively. However, 56% of spermatophores formed by males with the long hyaline gland bilaterally ablated failed to uncoil properly. These results indicate LHPI and/or other long hyaline gland proteins may act as lubricants. Unlike spermatophore formation and LHPI discharge, which increased steadily up to 90–120 min then levelled off, transfer of radiolabelled male ejaculate to the spermatheca was very variable. In 90 min copulations, only 1% of the total radioactivity (representing c. 5 μg protein) lost from the ARG complex was transferred to the spermatheca. The importance of male‐derived protein in vitellogenesis is discussed.
Social factors affecting queen fecundity in the ant Myrmica rubra
Authors: BRIAN M. V.
Published: March 2008

ABSTRACT. At the end of winter, normal populations of the polygyne ant Myrmica rubra L. consist of queens, workers and larvae; the latter are dormant and all in the third stadium. During experimental culture in artificial nests in the laboratory, the starting number of all three of these categories was varied and in some, food supply was restricted too. In a population of workers and larvae, queens do not interfere with each other sufficiently to reduce their fecundity; they avoid congestion by dispersing under the canopy of workers. Queens suffer if food is withheld; they probably feed themselves and are thus largely independent of the number of workers. Even in favourable conditions with full food, the distribution of egg‐batch sizes is not normal but follows a hollow curve that is well described by the negative binomial series. A poor food supply accentuates the hollow shape by increasing the number of non‐laying queens and reducing the number that are able to lay large batches. Larvae also suppress fecundity but only if they have sufficient food to grow actively; as their number increases, egg production by queens decreases exponentially.
Chemoreception of amino acids in larvae of two species of Pieris
Authors: VANLOON J.J.A. , VAN EEUWIJK F.A.
Published: March 2008

ABSTRACT. Specificity and sensitivity of gustatory neurones in response to twenty‐two amino acids were studied in larvae of Pieris brassicae L. and Pieris rapae L. (Lepidoptera: Pieridae) using electrophysiological methods. Twelve amino acids stimulated a specific amino acid receptor cell in the lateral styloconic sensillum on the maxillary galea of both species, and a further two evoked single unit responses in the same sensillum of P.brassicae only. Histidine, phenylalanine and tryptophane were the weakest stimulants for P.brassicae, but were among the four best stimulants for P.rapae. In both species, eight amino acids were ineffective. Significant differences in stimulatory effectiveness were found between amino acids. Nutritionally essential amino acids were more effective in both species, as in five other lepidopterous species. Similarities with postulated sites for amino acid recognition in the dipteran Boettcherisca peregrina were found.

Concentration‐response (C/R) relations were studied for five amino acids. Significant differences were found in saturated response levels. Parameters characterizing C/R relations were estimated using a logistic model. Comparing C/R parameters with phytochemical data on concentrations of free amino acids in a common host plant, Brassica oleracea L., shows that amino acids are effective stimuli at their natural concentrations. The amino acid chemoreceptor seems able to transmit information about concentration differences of amino acids in the plant tissue.
Differential responses of galeal gustatory sensilla of the adult Colorado potato beetle, Leptinotarsa decemlineata (Say), to leaf saps from host and non‐host plants
Authors: MITCHELL B. K. , ROLSETH B. M. , McCASHIN B. G.
Published: March 2008

ABSTRACT Responses of galeal sensilla of the Colorado potato beetle, Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae), to leaf sap from Solanum tuberosum and a number of other solanaceous and non‐solanaceous plants are described. A single cell responds vigorously to expressed sap from S.tuberosum, ‐and even to ten‐fold dilutions of expressed sap. The response is characterized by a high spike frequency, low phasic activity and a tonic phase which can last for tens of seconds. At 8 s following stimulus application the primary response is typically 50% of its original activity, indicating slow adaptation to the sap stimulus. The primary response varies little among multiple stimulations of single sensilla and among sensilla on the same animal. There is a secondary response to potato leaf sap from one or more cells which have low spike amplitudes. This is usually of much lower frequency than the response from the primary cell, and it is highly variable.

The prominent and reproducible single cell response to potato sap may be an important component in signalling the presence of a host plant. This hypothesis is tested using saps from two other species of Solanum which are hosts, and several solanaceous and non‐solanaceous non‐hosts. Responses of galeal sensilla to the three host‐plants tested were qualitatively similar and reproducible while responses to the non‐hosts were highly variable and qualitatively different from responses to host saps. These results are interpreted and discussed in the context of a possible mechanism for chemosensory coding of complex stimuli in the insect/plant relationship.

Analysis of the raw electrophysiological data required extensive use of a microcomputer and several programs were developed during the course of this study. The computer analyses are briefly described in the paper and additional information and copies of the programs are available from the authors.
Tarsal chemoreception in the polyphagous grasshopper Schistocerca americana: behavioural assays, sensilla distributions and electrophysiology
Authors: WHITE PETER R. , CHAPMAN REGINALD F.
Published: March 2008

ABSTRACT Behavioural and electrophysiological responses of Schistocerca americana (Drury) (Orthoptera: Acrididae) to chemical stimulation of the tarsi were investigated. Using restrained insects, differences in leg‐waving behaviour were observed following stimulation by sucrose and nicotine hydrogen tartrate (NHT), compared to control stimulations by water. Furthermore, free‐walking insects were able to detect NHT on leaf surfaces, resulting in leg‐raising to avoid tarsal contact.

SEM studies showed the presence of numerous peg chemoreceptor sensilla on the ventral surface of the tarsus. Tip recordings from such pegs showed activity from up to three chemosensitive neurones, plus a mechanoreceptor neurone. Stimulation by NaCl and KC1 elicited similar responses from two or three neurones in all sensilla tested, with increased firing rates at higher concentrations. Sucrose caused an increase in firing rate in few sensilla. In such cases several neurones were stimulated, and there was no evidence of a specific neurone sensitive to sucrose. In contrast, NHT elicited rapid firing in a single neurone, which was not sensitive to NaCl. Stimulation by NHT also inhibited the activity of the NaCl‐sensitive neurones.

Possible mechanisms for chemical discrimination in S. americana tarsi are compared with those previously proposed for grasshopper mouthpart sensilla, and the significance of a NHT‐sensitive neurone in tarsal sensilla is discussed.
Vitellogenins and v itellins of the Mediterranean field cricket, Gryllus bimaculatus: isolation, characterization and quantification
Authors: KEMPA‐TOMM S. , HOFFMANN K. H. , ENGELMANN F.
Published: March 2008

ABSTRACT In the Mediterranean field cricket, Gryllus bimaculatus de Geer, two immunochemically distinct female specific proteins were identified in haemolymph (Vg I and II) and in vitellogenic oocytes (Vn I and II). The corresponding Vgs and Vns seem to be immunochemically identical. On polyacrylamide gels Vg I and II as well as Vn I and II could not be clearly separated because Vg I and Vn I produced broad bands. The Mrs of both Vgs and Vns are approximately 525 kD. Upon dissociation by sodium dodecyl sulphate the Vgs and Vns each yielded at least nine polypeptides in the range of 50–215 kD. Haemolymph Vg titres were determined by rocket immunoelectrophoresis. The time of first appearance of Vg is temperature‐dependent and correlates with the onset of Juvenile Hormone synthesis by the corpora allata. Peak values of Vg were 17 μg μl‐1 haemolymph in normal vitellogenic females. After ovariectomy, Vg appeared at the normal time, but then increased to about 55 μg μl‐1 haemolymph. Ovariectomy also resulted in an accumulation of Vg in the fat bodies. Enforced virginity did not affect the haemolymph Vg titre. In allatectomized or head‐ligated females no Vg/Vn was detectable. Topical application of 100 μg Methoprene onto head‐ligated females induced Vg synthesis, whereas injection of 20‐hydroxyecdysone did not induce Vg synthesis.
Periodicity of pheromone release from female white peach scale
Authors: MCLAUGHLIN J. R. , HEATH R. R. , ASHLEY T. R.
Published: March 2008

ABSTRACT The sex pheromone of the female white peach scale, Pseudaulacaspis pentagona (Targioni‐Tozzetti), is released by newly‐mature females to correspond with the daily eclosion rhythm of males. As with male eclosion, pheromone release commences relative to the onset of light and is suppressed by increasing temperature. Once pheromone release begins it is maintained until the initiation of the scotophase. Pheromone release does not occur during the scotophase. When sexually mature females remain unmated for 5 days, the release of pheromone begins earlier in the day than it does with newly mature females.