bluuebunny/crossref_metadata_2025_split huggingface dataset:
Search orientation of Musca domestica in patches of sucrose drops
Authors: FROMM JEFFREY E. , BELL WILLIAM J. 
Published: March 2008

ABSTRACT. The searching tactics of the housefly, Musca dormestica L. (Diptera: Muscidae), have been delineated from digitized pathways of flies walking in patches of sucrose drops arranged in linear (ROW) and hexagonal (HEX) arrays.The areas covered by flies in ROW and HEX patches are distinctly different, but flies seem not to employ different tactics for the two types of resource arrays. The number of drops located, if at least one drop is found, does not differ between ROW and HEX.Most quantitative measures of local search remain constant after the first interdrop interval, although feeding time decreases as flies sample successive drops. Local search intensifies after each drop is ingested, with locomotory rate decreasing and turning rate increasing, followed by decay of both measures toward ranging levels.Searching can be characterized by two movement tendencies resulting from specific, definable, locomotory functions: a forward‐moving tendency is expressed by the fly as it leaves a resource in approximately the same direction as it arrives; and local search is characterized by looping, rather than straight walking, with a variable turning rate that generates a rough ‘zigzag’ superimposed on looping. The two movement tendencies, combined, allow flies to locate resources in a linear arrangement, because of the forward‐moving tendency, and to locate resources not arranged in a linear array because of the ‘noisy’ loop.M. domestica does not appear to retain and use information gained from one patch of drops in another, so the search tactic of the fly seems therefore to be a compromise between straight movement and circular movement that may be adaptive for an environment subject to frequent changes in the spatial distribution of resources.Giving‐up‐time, the period between ingesting the last drop and leaving the patch, is a function of the rate of change in the transition from local search to ranging, which is constant in our experiments. If a fly does not encounter another drop while ranging, during which it walks relatively straight, the fly moves out of and away from the patch.
Monitoring the effects of juvenile hormones and 20‐hydroxyecdysone on yolk polypeptide production of Drosophila melanogaster with enzyme immunossay
Authors: WU SHUENN‐JUE , ZHANG JIAN‐ZHONG , MA MICHAEL 
Published: March 2008

ABSTRACT. A double antibody sandwich enzyme‐linked immunosorbent assay (ELISA) was developed for detecting and quantifying small amounts of yolk polypeptides (YP) in studies on the hormonal control of vitellogenesis in Drosophila melanogaster Meigen. Monoclonal antibodies were incorporated as primary antibodies in the ELISA procedure to ensure selectivity in YP detection. The fact that YP concentration increases immediately after adult eclosion presents some difficulties in designing hormonal regulation experiments. Female adults decapitated immediately after eclosion remain alive for several days and virtually no YP is detected in the haemolymph 24 h after decapitation. The surgical procedure does not interfere with the competence of the fat bodies to respond to exogenous source of hormones. The effect of juvenile hormone (JH) on vitellogenesis can be studied by topical application of test material to these decapitated adults. A juvenile hormone analogue. Methoprene applied at 0.2 μg/fly or greater, restores YP production. The relative potencies of JH I2 II3 III and ZR 515 are compared at the same dose of 0.25 μg/fly. Their ranking in terms of re‐initiating vitellogenesis is ZR‐515 < JH II<JH III=JH I.Fat bodies which are left attached to the body wall, are successfully maintained in culture. With this in vitro system, synthetic hormone can be administered precisely to the organ culture. After a short incubation period, aliquots of medium are removed for the quantification of YP. Incubation of fat bodies with a physiological dose of the 20‐hydroxyecdysone (20‐HE) stimulates the production and release of YP into the medium. This represents the first direct experimental evidence for 20‐HE stimulation of Drosophila fat bodies for YP production in the absence of other endogenous factors that might either promote or interfere with vitellogenesis
Differentiation of roles of chemosensory organs in food discrimination among host and non‐host plants by larvae of the tobacco hornworm, Manduca sexta
Authors: BOER GERRIT DE , HANSON FRANK E. 
Published: March 2008

ABSTRACT. The contributions of olfactory and gustatory organs in food plant discrimination were examined in larvae of Manduca sexta (Johan.) (Lepidoptera, Sphingidae). Larvae, from which various chemosensory organs had been removed surgically, were tested for feeding preferences for a host, tomato (Lycopersicon esculentum); a weakly acceptable non‐host, rape (Brassica napus); and an unacceptable non‐host canna (Canna generalis), using a two‐choice disc bioassay.Removal of all known chemosensory organs resulted in failure to show discriminatory behaviour in a strictly chemosensory bioassay, indicating that all external chemosensory organs have been accounted for. The involvement of non‐chemosensory organs results in residual discrimination for leaves by individuals with total chemosensory ablations.Larvae possessing either olfactory or gustatory organs still exhibit normal preferences for tomato over rape. Gustatory (but not olfactory) organs are required for larvae to show normal preferences for tomato over canna; in fact, olfactory organs do not appear to participate in this decision.To examine which if any of the plant species is being selected in two‐choice tests, larvae were given a choice between each leaf species and a ‘neutral’ substance (wet filter paper). Both olfactory and gustatory organs are required for normal preferences for tomato, but either alone will suffice for rape. Only gustation is needed to select canna, and participation of either the epipharyngeal sensilla or a single medial sensillum styloconicum is sufficient to elicit complete rejection behaviour.We conclude that, in larvae of M. sexta, the complement of chemosensory organs needed for food plant discrimination varies with the plant species sampled. Evidence is presented exposing a potential artefact of ablation experiments; extirpation of one sensory organ may affect the functioning of others nearby, even though they may appear normal by visual inspection.
The inhibition of lipid synthesis in vitro in the locust, Schistocerca gregaria, by factors from the corpora cardiaca
Authors: GOKULDAS M. , HUNT P. A. , CANDY D. J. 
Published: March 2008

ABSTRACT. The rate of lipid synthesis from [14C]acetate in fat body from Schistocerca americana gregaria has been studied in vitro. Maximum incorporation is found on days 6–10 in adults and day 4 of the fifth stadium. The label appeared in the fatty acid components of triacyl‐glycerol, diacylglycerol and phospholipid.Lipid synthesis in vitro was inhibited by extracts of corpora cardiaca, and such inhibition was most marked (up to 85%) in fat bodies from insects at stages where fatty acid synthesis was greatest. HPLC separation of corpora cardiaca extracts gave several active fractions of which the most active was adipokinetic hormone 1 (AKH‐1).
Fluid secretion by single isolated Malpighian tubules of the house cricket, Acheta domesticus, and their response to diuretic hormone
Authors: COAST G. M. 
Published: March 2008

ABSTRACT. A simple modification of the Ramsay method is described for the isolation in vitro of Malpighian tubules from Acheta domesticus. Isolated tubules continue to secrete for many hours in a simple Ringer solution. The rate of secretion is linearly related to the length of tubule within the bathing fluid.Secretion rates during the immediate post‐equilibration period relate to the physiological state of the donor insect. Highest rates are recorded in tubules removed from animals during the scotophase when the crickets are most actively feeding. Starvation reduces the rate of secretion and when previously starved insects are given access to food the rate increases. These results are consistent with variations in the haemolymph titre of DH that are induced by feeding.Tubule fluid secretion is stimulated by either CC extract (1 gland pair/50 μ1) or dibutyryl cAMP (10‐3M). CC extracts increase the rate of fluid secretion by c. 200 pl/mm/min for up to 6 h after the tubules have been isolated. The response varies little with the age or physiological state of the donor insect. However, tubules from newly moulted insects secrete at very low rates and respond poorly to CC extract, although they are stimulated by cAMP. The significance of these results is discussed with particular reference to the use of Acheta tubules as a bioassay preparation for DH.
Effects of egg availability and egg maturity on the ovipositional activity of the parasitic wasp, Coccophagus atratus
Authors: DONALDSON J. S. , WALTER G. H. 
Published: March 2008

ABSTRACT. Effects of egg availability on daily ovipositional activity were determined for Coccophagus atratus Compere (Hymenoptera: Aphelinidae). Females were observed for 6 h per day for their entire adult lives. Observed ovipositional activity was analysed in relation to egg maturation before and after emergence, egg depletion during oviposition and egg replenishment after oviposition. Ovipositional activity, including oviposition, inconsequential probes and searching for hosts, occurred predominantly in the first 30 min of exposure to hosts on the 2nd, 4th, 7th, 10th and 13th days after emergence. The remaining time was spent on non‐ovipositional activities (preening, drinking honeydew and sitting on the glass of the experimental arena). Peaks of ovipositional activity were associated with high numbers of mature eggs in the ovaries. Eggs that remained in the ovaries after a bout of oviposition were apparently not mature even though they had attained their maximum size. Non‐ovipositional activity continued until females had built up a reserve of about eighteen mature eggs. After each successive bout of oviposition, the rate of oogenesis slowed down. Consequently females took longer to accumulate a supply of eggs and periods of non‐ovipositional activity increased.We conclude that (1) the availability of eggs and the tendency of females to store mature eggs influences ovipositional activity, (2) full‐sized eggs are not necessarily mature, (3) future experiments with C.atratus could be restricted to days of high ovipositional activity, and (4) the terms syn‐ and pro‐ovigenic formulated by Flanders (1950) to describe apparent differences in oogenesis between various parasitic Hymenoptera do not apply to C. atratus and are therefore not universally applicable.
Morphogenetic and gonadotrophic effects of a juvenile hormone analogue ((7S)‐hydroprene) in last instar female larvae of Diploptera punctata
Authors: KIKUKAWA S. , SMITH C.L. , TOBE S.S. 
Published: March 2008

ABSTRACT. The effect of treatment of last instar female larvae of Diploptera punctata with a Juvenile Hormone (JH) analogue, (7S)‐hydroprene, has been determined with respect to the ability of the analogue to alter the duration of the stadium and the nature of the ensuing ecdysis. We have also investigated the effects of the analogue on JH release, the growth of the basal oocytes, as well as ecdysteroid titres during the fourth stadium. Analogue treatment prior to day 10 of the stadium results in prolongation of the stadium and desynchronization of ecdysteroid release. Thereafter, treatment with the analogue has little effect. Analogue treatment results also in the formation of supernumerary larvae and intermediates, in a dose‐dependent fashion, provided that animals are treated on day 10 or earlier. Thus, the ‘critical’ period for metamorphosis in last instar D. punctata is between days 0 and 10.Treatment with (7S)‐hydroprene produces profound effects also on both JH release, and basal oocyte growth. At a dose of 500μg administered on day 1, JH release is stimulated significantly at a time when JH release is normally undetectable. Significant growth of basal oocytes is observed in such treated animals, and appears to precede the peak in JH release. We suggest that the growth of the basal oocytes, as a result of analogue treatment, stimulates the production of JH by CA in these last instar larvae.
Electrophysiological investigations of sex pheromone reception and release in Bruchidius atrolineatus
Authors: POUZAT J. , IBEAS D. NAMMOUR 
Published: March 2008

ABSTRACT. Male antennal sensitivity to female sex pheromone in Bruchidius atrolineatus was investigated electrophysiologically (EAG). The existence of receptors for this pheromone was shown in the antennae of males. (No such receptors exist in the antennae of females.) Young (age < 24h) males gave an EAG of amplitude 25–30% of the response of older males. Diapausing males several days old gave a much smaller response than active males of the same age.EAGs were used to test the production/release of pheromone by groups of twenty females. Before they are 24 h old, active females do not produce/release the pheromone; older females release it at an almost constant rate. Sexually diapausing females do not produce and/or release the sex pheromone.In sexually active females, mating inhibits pheromone release almost immediately. There is a correlation between reproductive status of the females (development of ovaries, oogenesis) and the production or release of the pheromone. A corresponding correlation also exists in the males whose antennae show a very low sensitivity when they are young or when they are in reproductive diapause.
Factors affecting the antennal and behavioural responses of the saw‐toothed grain beetle Oryzaephilus surinamensis to food odour and aggregation pheromone
Authors: WHITE PETER R. 
Published: March 2008

ABSTRACT. The effects of insect age, sex, mated state and culture density on the attraction of adult saw‐toothed grain beetles, Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae), to sources of food odour and synthetic aggregation pheromone were investigated. In single‐insect behavioural assays, insect age affected the attraction to the food odour, but not to the synthetic aggregation pheromone. Conversely, there were sexual differences in the attraction to the aggregation pheromone, but not to the food odour. The effects of the same factors on the antennal response to food odour and synthetic pheromone were also investigated, using the electroantennogram (EAG) technique. Insect age affected the EAG response to food odour, but not to the synthetic pheromone. There were no sexual differences in the EAG responses to either food odour or synthetic pheromone.The correlation of factors affecting both behavioural and antennal responses, and the possible role of changes in peripheral olfactory receptor sensitivity in the modulation of behaviour are discussed.
Post‐eclosion diuresis in adult Heliothis zea
Authors: BUSHMAN DAVID W. , RAINA ASHOK K. , NELSON JUDD O. 
Published: March 2008

ABSTRACT. The marked weight loss that follows adult eclosion in Heliothis zea (Boddie) (Lepidoptera: Noctuidae) was found to be the result of diuresis. This diuretic weight loss amounted to 18.2% of the emergence weight in females and 22.5% in males. Ligation between head and thorax immediately following emergence resulted in a significant reduction in this weight loss. Injection of homogenates of brain (BR) or suboesophageal ganglion (SOG) partially restored the weight loss in ligated insects, indicating potential neurohormonal regulation of this phenomenon.Because injection of homogenates of nervous and neuroendocrine tissues other than BR and SOG did not result in increased weight loss over controls, the activity present in BR and SOG was probably a tissue‐specific phenomenon. We speculate that a factor at least partially responsible for the enhanced diuretic weight loss is present in the fused BR/SOG.
The effect of larval temperature and photoperiod on the incidence of larval diapause in the blowfly, Calliphora vicina
Authors: NUNES M. VAZ , SAUNDERS D. S. 
Published: March 2008

ABSTRACT. The blowfly, Calliphora vicina Meigen (Diptera: Calliphoridae), displays a maternally induced larval diapause. Progeny of adults exposed to short days enter diapause if the larval temperature is 15d̀C or below; exposing adults to long days, or larvae to temperatures above 15d̀C, results in non‐diapause. By keeping progeny from short‐day parents at the parental temperature of 23.5d̀C for various lengths of time before transfer to 11d̀C, it could be shown that the diapause‐averting effect of high temperature operates in the late wandering stage of larva, possibly at the moment of the decision for the brain‐ring gland complex to release PTTH/ecdysone at the diapause/non‐diapause stage.Although photoperiodic induction in the blowfly is maternal, previous work had shown that the larvae were also slightly sensitive to photoperiod. From the present study it is evident that also the eggs are photo‐sensitive.
Desiccation resistance in arboreal and terrestrial ants
Authors: HOOD W. GREGORY , TSCHINKEL WALTER R. 
Published: March 2008

ABSTRACT Arboreal and terrestrial ants were exposed to 0, 25, 50, 75 and 100 (control)% r.h., at 30oC. Desiccation resistance increased with body size (as dry weight0.55), but not as quickly as expected from the consequences of the surface area and volume relationship (as dry weight0.67). Arboreal ants took 8 times longer to die than terrestrial ants of comparable size. Even after size effects were removed, desiccation resistance differed between various terrestrial species and showed a correlation with foraging patterns.Arboreal and terrestrial ants whose waterproofing epicuticular lipids were removed by chloroform: methanol extraction had equally high water loss rates at 0% r.h. Unextracted arboreal ants had water loss rates half those of unextracted terrestrial ants, suggesting that differences between them were based on differences in epicuticular lipids. The lower water loss rates of arboreal ants contributed significantly to their longer survival under desiccation. Arboreal ants also had greater total rectal pad area than terrestrial ants, suggesting that they may be able to reclaim faecal water more effectively. There were no differences in the minimum viable water content between the two groups of ants. Both had water loss tolerances comparable with those of arthropods adapted to xeric environments. Initial water loss rates could not account for all of the differences in desiccation resistance between arboreal and terrestrial ants. Other adaptations to desiccation stress by arboreal ants are likely.Comparisons of water loss rates and desiccation resistance between arboreal and desert ants suggest that the arboreal habitat is at least as stressful as the desert habitat.
The ocelli control the flight course in honeybees
Authors: KASTBERGER GERALD 
Published: March 2008

Abstract Fully‐sighted honeybees and bees with all ocelli occluded were trained to fly through an arena to arrive at a feeding place. After training, the bees were exposed to side‐light flashes during their feeding flights. The flight paths were recorded on video and analysed frame by frame at 40 ms intervals with reference to the main parameters, the coordinates of the thorax and the yaw angle of the bee. Course angles, translational course velocities and accelerations were calculated, and the responses to side light flashes evaluated with respect to ‘on’ and 'off.Immediately after light on, fully‐sighted bees respond slightly positively by yawing and flying toward the side light. Bees in which all ocelli are occluded are greatly disturbed and respond with negative yawing and flight path directions.The ocelli apparently help to control phototactic alertness in the bee. They determine whether phototactic orienting or pattern‐induced orienting behaviour is more important in a particular state of motivation. They help to minimize the level of disturbance in flight course control, obviously by activating a neuronal circuit with comparator attributes. It is assumed that this kind of compensation or suppression of phototactically guided reflexes occurs only for a few 100 ms. Consequently, the biological significance of light flashes shorter than 400 ms is very slight.Fully‐sighted bees decelerate strongly when a side light is switched on. Bees in which the ocelli are occluded behave less cautiously: they generally fly faster and need more reaction time. Thus, the ocelli help the bee to react photokinetically to photic stimuli in a much shorter time than do the compound eyes alone.
Fixation and optomotor response of walking colorado beetles: interaction with spontaneous turning tendencies
Authors: LÖNNENDONKER U. , SCHARSTEIN H. 
Published: March 2008

Abstract The paths of Colorado beetles (Leptinotarsa decemlineata Say) in a featureless environment are circular, like those of other species studied. The turning velocity may reach 35o/s and is due to an internal asymmetry, which may change spontaneously. Normally, all control loops of the insect, like fixation or optomotor responses, must work against this asymmetry to stabilize the insect's path. Stationary vertical patterns damp this turning tendency, but their effect is not strong enough to induce a straight path. Only 70% of the turning tendency can be so eliminated. This reaction is termed optomotor response because it can be adequately described with the parameter turning velocity alone. The insect's path was stabilized more effectively when pattern wavelengths were greater than 60o. The insects seemed to fixate these wider stripes. This reaction is termed fixation because the correlation between pattern components and insect's course becomes prominent.A comparison was made between these reactions to stationary patterns and to turning patterns. No differences could be found in the behavioural reactions to the different situations. This suggests that the insect does not use an internal representation of its spontaneous turning tendency to discriminate between the type of turning of the optical environment. These results can be explained by a simple feedback control loop with an additive interaction between the internal turning command and feedback signals from the eyes.
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.