bluuebunny/crossref_metadata_2025 huggingface dataset:
The activation of resting tsetse flies (Glossina) in response to visual and olfactory stimuli in the field
Authors: TORR S.J.
Published: March 2008

ABSTRACT Studies were conducted in Zimbabwe of the responses of Glossina morsitans morsitans Westwood and Glossina pallidipes Austen resting in a refuge to various host stimuli. Tsetse took off in response to 100% ox odour, 0.08% carbon dioxide or a visual stimulus consisting of a 0.75 × 0.75 m black target placed c. 5 m from the refuge moving at 4o s‐1, but the level of response was low with only 35%, 19% and 29% responding, respectively. Tsetse did not take off in response to any one of 25% ox odour, 0.8% carbon dioxide, acetone (3 μg 1‐1) or octenol (0.03 μg 1‐1). In the absence of any host stimuli, flies emerged from the refuge later on hotter days (35–37oC) than on cooler days (32–34.5oC). Male G.pallidipes emerging later in the afternoon contained significantly more haematin than those emerging relatively earlier. There were no significant differences between the responses of G.m. morsitans and G.pallidipes. It is suggested that the initial activation of resting flies is primarily mediated through endogenous, rather than host, stimuli.
Social control of egg‐laying rate in queens of the fire ant, Solenopsis invicta*
Authors: TSCHINKEL WALTER R.
Published: March 2008

ABSTRACT Social control of egg‐laying rate in queens of the fire ant (Solenopsis invicta Buren) was studied by experimental manipulation of the number of larvae, pupae and workers in colonies, and the age and size of larvae and workers. Workers and pupae do not stimulate oviposition by queens. The number of fourth instar larvae, on the other hand, bears a positive log‐log relationship to the queen's egg‐laying rate. Such larvae are needed both to stimulate and maintain oviposition. Their withdrawal results, within 48 h, in a decline in queen oviposition almost to zero. Their addition to broodless nests results in peak laying in about 4 days. Larvae in the first three stadia and early in the fourth stadium have a much lower effect upon queen fecundity. Sexual larvae are only c. 5% as stimulating on a weight basis, but equivalent on an individual basis. Several associated measures are positively correlated to egg‐laying rate: weight of the queen, the number of her vitellogenic follicles per ovariole, total vitellogenic follicles, the time she spends feeding and (usually) the number of workers in the retinue that cares for her. The egg volume is negatively correlated with laying rate, so that queens lay more eggs for the same expenditure of material as laying rate increases. As body size of workers increases, they become less effective in transmitting the larval stimulation to the queen, but worker age has no effect on this ability. For a given number of larvae, queens in small, naturally growing colonies lay fewer, larger eggs than do queens in experimental colonies, but their fecundity increases more rapidly in relation to number of larvae. When larvae are fed vital‐dyed food in one experimental colony, and then transferred to an undyed colony, the dye is rapidly transferred to worker crops, and into the queen's eggs, indicating bulk movement of material from larvae to workers to the queen and eggs. Large larvae are more effective at this than small larvae. Fourth instar larvae may be a digestive and metabolic caste that processes protein for egg production by the queen. If that is the case, the queen and fourth instar larvae are linked in a positive feedback loop. Either the logarithmic relation of fecundity to larval numbers or physical limits of the queen may set the maximum egg‐laying rate, and thus determine maximum colony size. The data do not allow a clear choice between these alternatives.
On the mechanism of speed and altitude control in Drosophila melanogaster
Authors: ZANKER J. M.
Published: March 2008

ABSTRACT The total power output of tethered flying Drosophila melanogaster in still air depends on translational velocity components of image flow on the eye, whereas the orientation of the average flight force in the midsagittal plane of the fly is widely independent of visual input (Götz, 1968). The fly does not seem to control the vertical and the horizontal force component independently. Freely flying flies nevertheless generate different ratios between lift and thrust, simply by changing the inclination of their body. By the combined adjustment of the body angle and the total power output a fly appears to be able to stabilize height and speed (David, 1985). Here a possible mechanism is proposed by which the appropriate torque about the transverse body axis could be generated. Translational pattern motion influences the posture of the abdomen and the plane of wing oscillation. Thus the position of the centre of gravity relative to the flight force vector is changed. When abdomen and stroke plane deviate from an equilibrium state, a lever is generated by which the force vector will rotate the fly about its transverse axis.
The control of Myrmica rubra workers by queens of their own and other Myrmica species and the interaction between queenless groups of workers
Authors: BRIAN M. V.
Published: March 2008

ABSTRACT. Queens of two species of the ant genus Myrmica bonded to workers of the species M. rubra L. as the latter emerge from the pupal skin can use these workers nearly 6 months later to arrest gyne formation in sex‐competent larvae of the same species. Queens of M. ruginodis Nylander var. microgyria (Brian & Brian, 1949) are as good at this as the natural M. rubra, but those of M. sabuleti Meinert (of a race close to M. scabrinodis) are not. Though the M. sabuleti queens induce normal aggression against sexualizing larvae, they are unable to prevent some or all of the workers feeding larvae as though they were queenless. However, queens from different colonies of M. rubra adopted by queenless populations of workers in spring, control their brood‐rearing behaviour perfectly. M. rubra workers from different colonies bring gynes to maturity from female sexual larvae at different average sizes. When workers from two such sources are mixed in equal proportions, the size of gyne larva produced after a week's culture corresponds with that of one of the worker populations; it is not intermediate in size. Also, large workers can rear larger gyne‐larvae than small workers of the same age. This is only true if the workers have been living with queens all the time from emergence as an imago to the moment the experiment was set. Size mixtures only achieve the same size larvae as a pure culture of small workers would. A possible reason for this is that small workers exclude the larger ones from the nursery areas of the nest.
Flight behaviour of tsetse flies in host odour plumes: the initial response to leaving or entering odour
Authors: GIBSON GABRIELLA , BRADY JOHN
Published: March 2008

ABSTRACT. Free‐flying, wild male and female Glossina pallidipes Aust. and G. m. morsitans Westw. were video‐recorded in the field in Zimbabwe as they entered or left the side of a host‐odour plume in cross‐wind flight, or as they overshot a source of host odour in upwind flight (camera 2.5 m up looking down at a 3 times 2.5 m field of view at ground level). 80% of cross‐wind odour leavers turned sharply (x̄ turns 95o), but without regard to wind direction (overshooters behaved essentially the same except that nearly 100% turned). Many fewer flies entering a plume cross wind turned (c. 60%), and when they did they made much smaller turns (x̄ 58o); these turns were, however, significantly biassed upwind (c. 70%). All three classes of fly had similar groundspeeds (x̄ 5.5–6.5 m s_1) and angular velocities (x̄ 350–400o s‐1). Clear evidence was obtained of in‐flight sensitivity to wind direction: significantly more flies entering odour turned upwind than downwind, and odour losers turning upwind made significantly larger turns than average. The main basis for the different sizes of turn was the different durations of the turning flight, rather than changes in angular velocity or speed. No evidence was found of flies landing after losing contact with odour.
Characterization of the sexual responses of male tsetse flies, Glossina morsitans morsitans, to pheromone‐baited decoy ‘females' in the field
Authors: HALL MARTIN J. R.
Published: March 2008

ABSTRACT. The sexual behaviour of male Glossina morsitans morsitans Westwood (Diptera: Glossinidae) towards decoys dosed with sex phero‐mone (15,19,23‐trimethylheptatriacontane) is described quantitatively from field observations. The flies responded with a standard behavioural pattern after landing. This involved: first, the perception of pheromone; second, orientation on the decoy and genitalia engagement; and third, a lengthy quiescence corresponding to natural copulation. The probability of a fly leaving a decoy decreased during the sequence and was least in the final ‘copulatory’ phase, when it remained constant under constant conditions. The initial, rapid rates at which flies left decoys were affected mostly by pheromone dose: the lower the dose, the higher the rate. The final, slow rate of leaving was unaffected by pheromone dose, being most affected by environmental stimuli, especially interference from other flies: at high fly densities, final rates of leaving were high. The results are discussed in the context of improving the potential for using pheromone and chemo‐sterilant‐dosed decoys for tsetse autosterilization.
Temperature modulation of behavioural thresholds controlling male moth sex pheromone response specificity
Authors: LINN C. E. , CAMPBELL M. G. , ROELOFS W. L.
Published: March 2008

ABSTRACT. The response specificity of male Oriental fruit moths, Grapholita molesta (Busck) and pink bollworm moths, Pectinophora gossypiella (Saunders), to different blends and doses of pheromone is altered dramatically by temperature. When acclimated and tested in a flight tunnel at 20oC males of both species exhibit a high degree of specificity, with peak response levels occurring to a narrow range of blend‐dose combinations close to the natural blend. When tested at 26oC, however, males exhibit a significantly lower degree of specificity, with peak response occurring to a broader range of treatments. The change in response specificity results from shifts in behavioural threshold effects influencing plume orientation and initiation of upwind flight, as well as from arrestment of upwind flight, occurring later in the flight sequence. The observed changes in male behaviour suggest that the effect of temperature is directly on neural pathways involved in the perception of odour, and not simply the result of an increase in motor activity or a significant change in the release rate of the pheromone. The results support the threshold hypothesis for pheromone perception (Roelofs, 1978) as a general principle in the Lepidoptera, but also show that the degree of response specificity can be significantly affected by temperature.
Conditions for estimation of corpus allatum activity in the blowfly, Phormia regina, in vitro
Authors: LIU M.‐A. , JONES G. L. , STOFFOLANO J. G. , YIN C.‐M.
Published: March 2008

ABSTRACT. Incubation conditions have been established for the corpus cardiacum‐corpus allatum (CC‐CA) complex of female Phormia regina (Meigen), which will support CC‐CA biosynthetic activities in vitro as measured by the incorporation of a labelled methyl group with L‐[methyl‐3H]methionine as the methyl donor. After incubation, radioactivity in the organic extract of the medium was determined by scintillation counting. Analysis of the organic extract with reverse phase high‐performance liquid chromatography (HPLC) revealed that a compound which has similar retention time (UV absorbance) with synthetic JH III was synthesized by the CC‐CA complexes of liver‐fed females. By using this short‐term, in vitro, radiochemical assay for CA activity, it was shown that a protein diet significantly increases the activity of the CA compared with females fed only a sugar‐water diet. Furthermore, use of HPLC separation, in conjunction with scintillation counting of time‐collected fractions, demonstrated the existence of a moiety containing incorporated radiolabeled methyl group (from the methionine) which did not co‐elute with JH I or JH III standards. These results suggest that in P. regina use of the incorporation of a radiolabeled methyl group to measure JH biosynthesis (CA activity) can be misleading if the compounds which do not co‐elute with JHs are not considered.
Photoperiodic induction of diapause in the silkworm, Bombyx mori: location of the photoreceptor using a chemiluminescent paint
Authors: SHIMIZU ISAMU , HASEGAWA KOU
Published: March 2008

ABSTRACT.To locate the photoreceptor involved in the photoperiodic induction of diapause inBombyx moriL., covering of larval head with black paint or local illumination using chemiluminescent paint was carried out. A silkworm race showing a response of long‐day type during the larval stage was employed. The results demonstrated that the photoreceptor is located in the head but is extraocular. The optical properties of the larval body suggest that during the first and second stadia light is admitted through the translucent clypeus of the head, but during later stadia enters over the entire larval body including the head, and that it reaches the cerebral lobe where a photoreceptor is possibly located.
Processing of calling songs by an L‐shaped neuron in the prothoracic ganglion of the female cricket, Acheta domesticus
Authors: STOUT J. F. , DEHAAN C. H. , HALL J. C. , RHODES M.
Published: March 2008

ABSTRACT. An L‐shaped auditory intemeuron (LI) has been recorded from extracellularly and intracellularly, and identified morphologically (by Lucifer yellow or cobalt injection) in the prothoracic ganglion of mature female Acheta domesticus.

The morphology of the LI is very similar to ascending, prothoracic acoustic interneurons that are most sensitive to higher carrier frequencies in both A. domesticus and other gryllid species. Its terminations in the brain are similar to ascending acoustic interneurons found in other gryllids. The LI neuron is most sensitive to 4–5 kHz model calling songs (CSs), the main carrier frequency of the natural call. Thresholds to high frequencies (8–15 kHz) are 15–20 dB higher.

Increasing CS intensities of up to 15 dB above threshold at 4–5 kHz result in increased firing rates by the LI. More than 15 dB increase in intensity causes saturation with little increase in spiking rate until the intensity surpasses 80 dB. In response to 70 dB or higher stimulus intensities, the LI responds to the second and third CS syllables with one or two spikes, pauses, and then produces a burst of nerve impulses with the same or greater latency than for lower intensity stimuli. In response to CS syllables of changing duration (10–30 ms) this neuron responds with a rather constant duration burst of impulses. Syllable periods of the CS stimuli were accurately encoded by the LI.

Progressively stronger injection of hyperpolarizing current reduces, and ultimately stops spiking of the LI in response to CS stimuli. More intense stimulation with reduced hyperpolarization shows an initial spike, pause and burst of spikes. Intracellular recording from axonal regions of the neuron shows large spikes, small EPSPs and a developing hyperpolarization through the response to a CS chirp. Inhibitory input to the LI is demonstrated at 4.5, 8 and 16 kHz. This probably explains the specialized response characteristics of the LI which enhanced its encoding of CS syllable period.
Survival of parent and brood adult bark beetles, Ips typographus, in relation to size, lipid content and re‐emergence or emergence day
Authors: ANDERBRANT OLLE
Published: March 2008

ABSTRACT. This study investigated a possible trade‐off between bark beetle reproductive effort and future survival. Parent adult Ips typographus (L.) (Coleoptera: Scolytidae) were collected when they re‐emerged from a laboratory culture after completing their first brood and held at constant temperatures of 4 or 25oC. As a comparison, emerging brood adults were collected and held at 25oC. The longevity of the beetles was related to when they re‐emerged or emerged (measured in days since parent introduction) and to their size (pronotal width), fresh weight and lipid content at collection, by multiple regression analysis. The expression (fresh weight x pronotal width ‐2.6), used as an estimate of lipid content of the living beetles, was significantly correlated (r=0.67, P<0.001) with the actual (extracted) lipid content. At 25oC, fat content was the variable most strongly correlated with survival time in all beetle groups except parent females. In both parent and brood females, re‐emergence or emergence day, respectively, contributed significantly to the explanation of survival time, whereas pronotal width and fresh weight never contributed significantly to the regression equation. At 4oC, fat content was not estimated but, re‐emergence day was negatively correlated with survival time. In conclusion, beetles with high fat content and re‐emerging or emerging early have longer expected survival than beetles leaving the log later or containing less fat. This means that females laying a large first brood might suffer a somewhat higher mortality than females laying a smaller brood.
The role of ocelli in circadian singing rhythms of crickets
Authors: RENCE BRADFORD G. , LISY MARK T. , GARVES BRIAN R. , QUINLAN BRIAN J.
Published: March 2008

ABSTRACT. . There is a direct quantitative relationship between the free‐running period (r) of the circadian stridulation rhythm of male Australian field crickets, Teleogryllus commodus (Walker), and the intensity of the constant light conditions. Both T. commodus and the house cricket, Acheta domesticus (L.), show free‐running periods of the singing rhythm of c. 24 h when the light intensity is 0.00025 lux. In both species the severance of the three ocellar nerves significantly slows the circadian period which is indicative of a reduced perception of the available light intensity. To test whether this period reduction is a peripheral or a central effect, electro‐retinograms (ERGs) were recorded from compound eyes of male T. commodus with the ocelli fully functional, then occluded, and then uncovered. The size of the compound eye ERG is reduced by 20% with ocellar occlusion and can subsequently be fully restored to the intact level, which indicates that the ocellar effect is a peripheral one. Intensified CoCl2 fills reveal one neurone in A. domesticus and two in T. commodus which travel from the lateral ocellar nerve out into the ipsilateral optic lobe of the compound eye. These neurones all terminate in or distal to the lobular neuropile. The data are interpreted to indicate a role for ocelli in modulating the light intensity perception of the compound eye. The final effect of the ocellar afferents is at a peripheral level prior to the input of the visual information to the optic lobe circadian pacemaker. Hence ocelli play an indirect role in circadian rhythmicity, augmenting the sensitivity of the primary photoreceptors to better perceive photic entrainment signals.
The repellent effect of two pyrethroid insecticides on the honey bee*
Authors: RIETH JOSEPH P. , LEVIN MARSHALL D.
Published: March 2008

ABSTRACT. . An improved model for the repellent effect of pyrethroid insecticides on insects was developed using small colonies of honey bees, Apis mellifera L., in flight cages. Conditioning to scented feeders allowed the separation of foraging bees from a single colony into paired treatment and control groups. The repellent response was characterized as a sublethal toxic effect resulting in transitory inhibition of activity. Permethrin and cypermethrin were shown to be contact repellents to honey bees; exposure was primarily to the tarsi and abdominal venter. Repellency was fully reversible within 24 h. No permanent effects on either memory function or foraging efficiency were observed following acute exposure.
The sensory basis of trail following in some lepidopterous larvae: contact chemoreception
Authors: ROESSINGH PETER , PETERSON STEVEN C. , FITZGERALD T. D.
Published: March 2008

ABSTRACT. . Caterpillars of the genus Malacosoma follow trails of the chemical 5‐beta‐cholestane‐3,24‐dione, but nothing is known of how they perceive this compound, or more generally about the sensory basis of trail following in caterpillars. By selective ablations of chemosensory organs we show that, in Malacosoma, the trail chemical is perceived by the maxillary palpi. In another lepidopteran species, Yponomeuta cagnagellus, the palpi are needed to discriminate their own trails from a trail of Malacosoma. Malacosoma larvae also lose their specificity for conspecific trails when their palpi are ablated. Volatile cues evidently do not play a role in trail‐following behaviour, since neither Malacosoma nor Yponomeuta can orient on a trail covered with fine nylon mesh. These data indicate that for Malacosoma, and probably also for Yponomeuta, contact chemoreception mediated by the maxillary palpi is the primary mode of pheromone perception. The evolution of receptor sensitivity to trail chemicals in caterpillars is discussed.
A comparison of dietary selection behaviour in larval Locusta migratoria and Spodoptera littoralis
Authors: SIMPSON S. J. , SIMMONDS M. S. J. , BLANEY W. M.
Published: March 2008

ABSTRACT. . Final instar nymphs of the oligophagous acridid Locusta migratoria (L.) and larvae of the polyphagous noctuid Spodoptera littoralis (Boisduval) were fed for 4, 8 or 12 h, the conditioning period, on one of four artificial diets. Of these, diet PC contained 20% protein and 10% digestible carbohydrate; another, P, contained 20% protein but with the digestible carbohydrate component replaced by cellulose; a third, C, had the protein component substituted by cellulose, and the fourth, O, had both protein and digestible carbohydrate replaced. After this conditioning period, insects were given a choice of two diets, P and C, and hence an opportunity to select for the nutrients, if any, which were lacking in their previous food. Amounts eaten and selection behaviour were then recorded in detail for a total of 9 h. This paper deals with total amounts of diet eaten during the conditioning and choice periods. Spodoptera larvae were more sensitive than the locusts to being fed a nutritionally inadequate conditioning diet, and ate only small quantities of the P, C and O diets as compared with the PC diet, irrespective of the duration of conditioning. Locusts, on the other hand, when restricted to the P diet continued to eat relatively large amounts of it throughout a 12 h conditioning period. Those nymphs fed the C diet ingested large quantities (more than of the PC diet) up until 8 h, after which intake fell. When offered a choice, both species selected for the nutrients missing from the conditioning diet, even if the conditioning period had been as short as 4 h. During the first hour of choice locusts selected the P diet if they had been previously fed C and the C diet if previously fed P. Those deprived of both nutrients increased consumption of both P and C diets. Spodoptera larvae were more sensitive to prior deprivation of digestible carbohydrate than of protein. During the first hour of choice they selected the C diet if previously fed P or O but did not choose the P diet if previously fed C. In the subsequent 8 h of choice, however, a strong selection for the P diet after previous deprivation became apparent. In the locust, the selection for nutrients missing from the conditioning diet continued for the following 8 h of choice but became masked by a tendency, shown by all nymphs, to select C over P. The functional significance and possible physiological basis of all these responses is discussed.
The flight and landing of tsetse (Glossina) in response to components of host odour in the field
Authors: TORR S. J.
Published: March 2008

ABSTRACT. Studies were conducted in Zimbabwe of the responses of Glossina morsitans morsitans Westwood and Glossina pallidipes Austen to various host odours using either arrangements of electrocuting nets or visual observations. Tsetse flying upwind in a plume of carbon dioxide, acetone and octenol turned downwind upon flying into a plume of acetone or octenol, but did not turn upon flying into a plume of carbon dioxide. They also turned in response to a transient decline in odour concentration. Tsetse landed on the ground in the vicinity of a source of natural odour or artificial odour containing carbon dioxide but not at sources of acetone or octenol only. The proportion of female G.pallidipes caught at a source of natural odour (37%) was significantly different from that caught at a source of synthetic odour (17%). Resting tsetse stimulated by natural odour took off sooner than non‐stimulated flies and had a strong upwind bias in the direction of take off. Tsetse stimulated with artificial odour did not take off sooner than non‐stimulated flies. It is suggested that there is an unidentified components) of ox odour that activates resting tsetse.
Behaviour of tsetse flies (Glossina) in host odour plumes in the field
Authors: TORR S.J.
Published: March 2008

ABSTRACT. In Zimbabwe, studies were made of the responses of Glossina pallidipes Austen and G.morsitans morsitans Westwood to artificial host odour using an incomplete ring of electrocuting nets. In a plume of synthetic host odour tsetse flew generally upwind, with 50–60% flying within 35o of due upwind. More than 80% of tsetse flew at < 50 cm above ground level. Upon losing contact with odour they executed a reverse turn within about 2 m, and upon regaining contact they turned upwind. There were no clear differences in the responses of G.m.morsitans and G.pallidipes. Using electrocuting nets lying horizontally on the ground it was found that tsetse landed in the vicinity of the odour source, the propensity to land being greater for G.pallidipes than for G.m, morsitans, greater for immature than mature flies, and greater for males than females.
Stimulation of fluid secretion by single isolated Malpighian tubules of the house cricket, Acheta domesticus
Authors: COAST G. M.
Published: March 2008

Abstract. Fluid secretion by single isolated Malpighian tubules of Acheta domesticus(L.) is stimulated by aqueous extracts of nervous and neuroendocrine tissues from the cricket. Diuretic activity, expressed as the increase in rate of secretion per microgram tissue protein (pl/mm/min/ug protein), is highest in the CA and CC.

The response to aqueous CC extracts is dose‐dependent. The maximum increase in secretion rate is 300–350 pl/mm/min and the EDmax and ED50 are 0.1–0.2 and 0.02–0.03 gland pairs respectively.

The diuretic activity in the CC is retained after 5min at 95C, and is freely soluble in 80% methanol. Diuretic activity is, however, greatly reduced after prolonged heating or after treatment with either pronase or chymotrypsin. It is conluded that the diuretic factor(s) is a low molecular weight peptide. A loss of activity after incubation with pyroglutamate amino peptidase suggests that some active peptides present are N‐terminally blocked.

The diuretic activity of crude aqueous CC extracts is rapidly lost on standing at room temperature. This is partly prevented by precipitation of protein enzymes by either heat treatment or extraction in methanol.

Synthetic vertebrate and insect neuropeptides are generally low in activity increasing fluid secretion by no more than 60pl/mm/min. However, extracts of neuroendocrine tissues from a wide range of insect species are potent stimulants of tubule secretion. Various biogenic amines were tested and have little effect on fluid secretion; thus they cannot contribute greatly to the response of cricket tubules to aqueous tissue extracts.
Visual responses of flying aphids and their chemical modification
Authors: HARDIE JIM , POPPY GUY M. , DAVID C. T.
Published: March 2008

Abstract. Five winged forms of the black bean aphid, Aphis fabae, were subjected to 30 min of free flight in a recently designed, automated wind tunnel (David & Hardie, 1988). A circular green target, on the side of the chamber, was illuminated for 2.5 s of each minute of flight. Half of the fundatrigeniae (‘spring migrants’) and all of the virginoparous ‘summer migrants’ responded by flying towards the illuminated target while gynoparae (‘autumn migrants’) induced by short days over two generations in uncrowded conditions were unresponsive. 27% of generation 1 gynoparae, induced by crowded conditions and short days over one generation, responded to the target as did 50% of males.

Anaesthetization of adult gynoparae with nitrogen and carbon dioxide, but not ether, induced targeted flights. However, the effect of carbon dioxide was transient over the first 10 min whereas the effect of nitrogen continued throughout the 30‐min experimental period. In addition, treatment of late fourth instar larvae, but not young adults, with Juvenile Hormone I provoked target responses. The results are discussed with reference to settling behaviour and the endocrine control of polyphenism.
Behavioural study of plasticity in host preferences of Trichogramma maidis (Hym.: Trichogrammatidae)
Authors: KAISER L. , PHAM‐DELEGUE M. H. , MASSON C.
Published: March 2008

Abstract. To test the relative importance of genetic and environmental factors in host preferences of Trichogramma maidis Pint. & Voeg., a polyphagous parasitoid, the oviposition behaviour was analysed on two host species: Anagasta kuehniella used for mass rearing) and Ostrinia nubilalis a target pest). Females were compared according to the species on which they had been reared, and to that on which they had an oviposition experience. To quantify an oviposition sequence, the most frequent behavioural succession was established for each experimental situation, individual sequences were then compared with this standard one to count the number of additional behaviours. An affinity coefficient positively related to host acceptance was then calculated from these additional behaviours. A preference for O.nubilalis versus A kuehniella appeared, but rearing on A. kuehniella enhanced the level of spontaneous affinity for this unnatural host. These initial preferences were modified by an oviposition experience: the affinity for a given host was higher after an oviposition on the same species, which suggests a female's ability to learn. This learning ability was higher on the non‐preferred host, which led to an equivalent final parasitic performance on both hosts. Moreover, the learning ability was specific to a given host, since the oviposition on a given species did not provide any improvement in the level of affinity for the other species.
Hypertrehalosaemic activity in corpus cardiacum‐corpus allatum‐aorta complex and adipokinetic response of Glossina morsitans
Authors: MWANGI R. W. , AWITI L. R. S.
Published: March 2008

Abstract. Extracts from the corpus cardiacum‐corpus allatum‐aorta (CC‐CA‐A) complex of Glossina morsitans morsitans Westwood contain a hypertrehalosaemic factor when assayed in Periplaneta americana L. and in G.morsitans. A slight though significant decrease, followed by an increase, in haemolymph total carbohydrate occurs when tsetse are flown for 1 h. When assayed in Locusta migratoria L., the extracts have no adipokinetic activity, but L.migratoria corpus cardiacum extract produces an adipokinetic response in the female tsetse. It is suggested that the neurosecretions contained in the tsetse CC‐CA‐A complex contain a hypertrehalosaemic factor whose role is to mobilize glycogen.
Development of imaginal competence to adipokinetic hormone in Locusta: lipid and carbohydrate levels, and glycogen phosphorylase activity in precocene‐induced adultiforms
Authors: PENER M. P. , BROEK A. Th. M. Van den , MARREWIJK W. J. A. Van , DOORN J. M. Van , HORST D. J. Van der , BEENAKKERS A. M. TH.
Published: March 2008

Abstract. Adipokinetic responses to injection of synthetic adipokinetic hormone I (sAKH) were investigated in precocene‐induced fifth‐instar adultiforms and in chemically allatectomized but morphogenetically normal adults of Locusta migratoria(L.). The results were compared with data on normal fifth (=last)‐instar nymphs and normal adults. Chemical allatectomy did not affect the resting level of lipid in the haemolymph, nor the slight decrease of haemolymph carbohydrate concentration induced by sAKH. The effects of chemical allatectomy on sAKH‐induced hyperlipaemia, the resting level of haemolymph carbohydrate, total glycogen phosphorylase specific activity, as well as sAKH‐induced phosphorylase activation in the fat body, were mostly minor and probably indirect. The concentrations of lipid and carbohydrate in the haemolymph, and sAKH‐induced activation of fat body glycogen phosphorylase were more or less similar in normal fifth‐instar nymphs, normal adults and fifth‐instar adultiforms. Thus, precocious metamorphosis did not affect markedly those parameters which show no or slight changes during normal metamorphosis. In contrast, parameters which change substantially during normal metamorphosis (sAKH‐induced hyperlipaemia, sAKH‐induced changes in haemolymph carbohydrate level and total glycogen phosphorylase activity) showed similar changes in the course of precocious metamorphosis; the values for fifth‐instar adultiforms were similar to those obtained for normal adults, but differed markedly from those found in normal fifth‐instar nymphs. Thus, accelerated (precocious) morphological adult development is strongly correlated with accelerated imaginal target competence to AKH and with relevant physiological development.
Antennal responses of tsetse to analogues of the attractant 1‐octen‐3‐ol
Authors: SAINI R. K. , HASSANALI A. , DRANSFIELD R. D.
Published: March 2008

Abstract. Antennal movement responses of male Glossina morsitans morsitans Westwood to twelve analogues of the tsetse olfactory attractant 1‐octen‐3‐ol were investigated to determine their structure‐activity relationships. The results indicate that the chemoreceptors which perceive this set of kairomones may not be highly specific. Activity is dependent on the length of the alkyl chain; also homologues with odd alkyl chains such as 3‐buten‐2‐ol, 1‐hexen‐3‐ol and 1‐octen‐3‐ol evoked higher antennal responses than homologues with even alkyl chains such as l‐nonen‐3‐ol, 1‐hepten‐3‐ol and 1‐penten‐3‐ol. Comparison of the activities of eight carbon structural variants of 1‐octen‐3‐ol showed that the structural requirements for activity of the functional end of the molecule may not be rigid; thus, 1‐octyn‐3‐ol elicited relatively high responses. However, low responses to 1‐octene and 3‐octanol showed that both the π electron system as well as the oxygen function are important for activity. Laboratory bioassay findings indicate that compounds such as 1‐octyn‐3‐ol, 3‐buten‐2‐ol, allyl alcohol and 1‐octen‐3‐one which evoke antennal responses 2–3 times greater than the control have attractive properties and preliminary field investigations show that 3‐buten‐2‐ol and allyl alcohol significantly increase trap catches.
The patterning of compensatory sugar feeding in the Australian sheep blowfly
Authors: SIMPSON S. J. , BROWNE L. BARTON , GERWEN A. C. M. van
Published: March 2008

Abstract. The pattern of feeding is described for males of the Australian sheep blowfly, Lucilia cuprina, with ad libitum access to either 0.1 M or 1.0 M glucose solution. Flies given the 0.1 M solution ingested nearly 3 times the volume taken by flies given the 1.0 M solution by eating meals of, on average, twice the size about 1.5 times as frequently. Flies were usually relatively inactive following a meal, with the extent of this post‐prandial quiescence being a function both of meal size and concentration of sugar. Quiescence lasted only about 20% of the average intermeal interval, however, and there was no correlation between meal size and time to the next meal. The crop emptied more slowly when it contained 1.0 M rather than 0.1 M glucose solution and the crop was, on average, fuller at the beginning of a meal on the higher concentration. The volume of solution imbibed during a meal was positively correlated with time since the end of the preceding meal. The average crop volume at the end of a meal was similar in flies feeding on 0.1 M and 1.0 M solutions. The results are considered in relation to published information on control of feeding and compensation in the blowfly Phormia regina.
Ingestion and diet destination in Culiseta inornata: responses to water, sucrose and cellobiose
Authors: FRIEND W. G. , SMITH J. J. B. , SCHMIDT J. M. , TANNER R. J.
Published: March 2008

ABSTRACT. At ambient temperature, contact with free liquids containing sugar induces Culiseta inornata Williston (Diptera: Culicidae) females to adopt the nectar‐feeding mode of behaviour. While in this mode, two distinct control mechanisms appear to operate: one controlling the amount of ingestion, the other diet destination. Mosquitoes were exposed to water and various concentrations of sucrose and cellobiose in water. Only small or taste amounts of water were imbibed, and it was directed to the midgut. Cellobiose solutions of less than 0.1M were treated as water. Cellobiose was phagostimulatory; as the concentration increased from 0.1 to 0.5 M the percentage of insects ingesting large amounts rose from 11% to 68%. Cellobiose diets were directed primarily to the midgut. Sucrose was also phagostimulatory. As the concentration increased from 0.025 to 0.2 M, the percentage of insects ingesting large amounts increased from 20 to 92. At lower sucrose levels, insects ingesting large amounts put it mainly into the crop, while insects ingesting smaller amounts put the diet into the midgut or both the crop and midgut. At sucrose concentrations of 0.4 M or more, most insects took large amounts and directed it to the crop. Different combinations of sucrose and cellobiose with a total concentration of 0.5 M all caused insects to take mainly large meals. At sucrose concentrations of 0.2M and above, the insects responded as they would to sucrose alone, directing the diet to the crop. At sucrose concentrations of 0.1M or less, diet destination patterns were more complex, with individual animals depositing the diet in the crop, the midgut, or in both. A behavioural model is presented which postulates different receptors for sucrose and cellobiose, control of diet destination via differential control of midgut and crop valves, and variation of threshold values according to endogenous factors.
Queen execution in the Argentine ant, Iridomyrmex humilis
Authors: KELLER LAURENT , PASSERA LUC , SUZZONI JEAN‐PIERRE
Published: March 2008

ABSTRACT. Field censuses and laboratory experiments show that in the Argentine ant, Iridomyrmex humilis (Mayr), c. 90% of the queens are executed by workers in May, at the beginning of the reproductive season. The reduction in the number of queens probably decreases the inhibition exerted by queens on the differentiation of sexuals and thus allows the production of new queens and males shortly thereafter. In the laboratory, there was no correlation between the percentage of queens executed and their weight or fecundity. At the time of execution of queens, nearly all queens were of the same age; less than 1 year. Therefore it is not likely that the age of queens plays any role in the choice that workers make in the queens they executed. Execution of these queens results in a heavy energetic cost for the colony which amounts c. 8% of the total biomass. This behaviour of workers executing nestmate queens is discussed with regard to possible evolutionary significance at the queen and worker level.
Response to nigh interruption in photoperiodic determination of wing form of the ground cricket Dianemobius fascipes
Authors: MASAKI SINZO , WATARI YASUHIKO
Published: March 2008

ABSTRACT. In the ground cricket Dianemobius fascipes (Walker), the occurrence of long‐ or short‐winged form is determined by photoperiod during larval development. The pattern of this response is similar to that of diapause induction in other insects with a clearly defined critical nightlength (11.5 h). In symmetric skeleton regimes formed by a pair of 1 h light pulses, the critical nightlength is about 2 h longer than in the complete photoperiod. The long‐night (short‐wing) effect is eliminated by an interrupting light pulse. This response to night interruption shows only one peak in scotophases of various lengths and can be related to the critical nightlength before or after interruption. The light‐reaction time required for the interruption effect changes during the night. In the early scotophase, 1 h of light is enough but 15 min fails to reverse the long‐night effect, while a light pulse of only 1 min is effective about 1 h before the critical nightlength is reached. Several possible interpretations of this change are discussed.
Instrumental measurement of the gypsy moth pre‐flight behavioural response to pheromone
Authors: OBRIECHT CHRISTINE , HANSON FRANK E.
Published: March 2008

ABSTRACT. Vibrations of the thorax and electrical activity (EMG) of gypsy moth flight muscles were recorded during wing fanning following pheromone stimulation. The percentage of positive responses and durations of bursts of flight muscle activity increased with the logarithm of pheromone dose, whereas latency decreased. The results correlated well with wing fanning responses of freely moving gypsy moths exposed to nearly identical stimulus conditions. Typical dose‐response curves in the range of 0.04‐400ng disparlure were obtained in both types of experiments. These methods provide an electrical analogue of wing fanning behaviour.
Factors influencing dominance behaviour in queenless bumblebee workers (Bombus terrestris)
Authors: DOORN ADRIAAN VAN
Published: March 2008

ABSTRACT. The establishment of a dominance order within seventy eight groups of four callow workers was investigated. The dominant worker establishes its position by means of overt aggression. Aggression starts 20—40 h after confinement. Dominance order becomes established within 2 days of removal from the colony. Once established, the dominance order is maintained by dominant‐subordinate interactions.

The dominant worker starts ovipositing at an age of about 6 days. Subordinates rarely lay eggs. In 25% of the groups the dominant worker is superseded by another worker before any oviposition occurs. Once the dominance order is established, the dominant worker inhibits endocrine activity in subordinates.

Differences in body size and in endocrine activity are thought to be responsible for the ranking of workers in the dominance hierarchy. Ranking seems to depend more on the activity of the corpora allata (CA) than on the activity of the ovaries. Ovariectomized workers do not differ from control workers in the performance of dominance behaviour. Dominant ovariectomized workers do not construct egg cells, but they do defend these if they are present.
Juvenile Hormone biosynthesis and release during oocyte development in Phormia regina Meigen
Authors: ZOU B.‐X. , YIN C.‐M. , Jr J. G. STOFFOLANO , TOBE S. S.
Published: March 2008

A radiochemical assay for Juvenile Hormone (JH) biosynthesis and release by the corpus allatum (CA) was used to assess the effects of diet on CA activity of adult female Phormia regina (Meigen) fed either sugar‐water or sugar‐water‐liver. CC‐CA complexes were incubated in L‐methionine‐free medium 199 supplemented with 3H‐L‐methionine.

The rate of JH release by the CC‐CA complexes is linear for 3 h and declines slightly thereafter. JH III appears to be one of the major components of the isooctane‐extractable product from incubated CC‐CA. High pressure liquid chromatographic analysis indicates that 10% of the released radiolabelled product is JH III. Rates of JH release show a strict dependence on L‐methionine concentration in the incubation medium, with optimal rates occurring between 100 and 150 μM L‐methionine. JH release is at a low level (<0.02pmolh‐1 per pair of CC‐CA) in flies fed only sugar‐water, but increases dramatically in flies fed sugar‐water‐liver (average release rate of 0.2pmolh‐1 per pair of CA, 24h after a liver meal). The rate of JH release increases steadily to more than 1.2pmolh‐1 per pair at 128h of age (i.e. 56h after a liver meal) at which time oocytes are mature. Elevated rates of JH release in vitro appear to be correlated in vivo with the appearance of vitellogenin in the haemolymph and its uptake by the developing oocytes.
The electrical and mechanical properties of the proleg retractor muscle of the Chinese oak silkmoth larva
Authors: COX SALLY C.
Published: March 2008

ABSTRACT. The main proleg retractor muscle (y) of Antheraea pernyi Guer. (Lepidoptera, Saturniidae) larvae consists of three layers of fibres. The innermost layer of fibres is dually innervated. Cobalt backfills of the two motor neurones, in nerve 2d, showed the somata to be situated ventrally and anteriorly in the same segmental ganglion, ipsilateral to the filled nerve. Intramuscular microelectrode recordings showed excitatory junction potentials (EJPs) of two distinct amplitudes, both of which were relatively slow. However, 26% of the larger amplitude EJPs had an active membrane response. The EJPs and mechanical responses both summated at low stimulation frequencies. Large EJPs resulted in a much greater development of tension than small ones. Extracellular stimulation of nerve lbiii modulated peak tension and peak rate of relaxation.
An analysis of anemotactic flight in female moths stimulated by host odour and comparison with the males' response to sex pheromone
Authors: HAYNES K. F. , BAKER T. C.
Published: March 2008

ABSTRACT. The flight pattern of mated female navel orangeworm moths, Amyelois transitella (Walker), responding to odour from potential larval hosts is zigzagging upwind flight. However, at times these moths are capable of flying nearly directly upwind towards the odour source (track angles near 0d̀). This response indicates that these females are capable of very accurate anemotactic control of their heading or course angle, since small angular errors in this measure would translate into larger deviations from direct upwind flight. Males of this species exhibit flight patterns similar to those of females, including track angles clustered about 0d̀ when flying upwind to a source of the female‐produced pheromone, but under these experimental conditions they flew with a higher average airspeed than the females. When females lose contact with an odour plume they initiate a well‐defined programme of cross‐wind counterturning or casting, which may normally increase their chances of retrieving contact with that plume when the wind direction shifts. The resultant track angles of females increase significantly by 0.8 s after plume loss, indicating that the female has initiated changes in both her course angle and airspeed. By 1 s after plume loss the females' track angles are no longer unimodally distributed about 0d̀, but are bimodally distributed about ‐90d̀ and +90d̀. Males responded more rapidly to the loss of a pheromone plume, demonstrating a significant change in track angle 0.4 s after plume loss. Overall, female and male A.transitella exhibited remarkably similar anemotactic flight manoeuvres during upwind flight to odour sources as well as after plume loss.