摘要:

ABSTRACT.Queens of two species of the ant genusMyrmicabonded to workers of the speciesM. rubraL. 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 ofM. ruginodisNylander var.microgyria(Brian&Brian, 1949) are as good at this as the naturalM. rubra, but those ofM. sabuletiMeinert (of a race close toM. scabrinodis)are not. Though theM. sabuletiqueens 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 ofM. rubraadopted by queenless populations of workers in spring, control their brood‐rearing behaviour perfectly.M. rubraworkers 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

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1988.tb00902.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

ABSTRACT.The auditory characteristics of two populations (laboratory reared and wild) of North American gypsy moths (Lymantriidae:Lymantria disparL.) 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 maleL. disparpossess 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 evolutiona

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1988.tb00903.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

ABSTRACT.The calling posture ofSpilosoma congruaWalker (Lepidoptera: Arctiidae) affects local airflow in ways that may impact on the release of chemical signals. Dried specimens ofS. congruaimitating resting moths, calling moths, and moths with intermediate postures were placed in a wind tunnel. The wind speed was measured near the abdomenal tip where sex pheromone emission occurs. The calling posture, wings‐up, gave significantly greater mean wind speeds near the surface of the sex pheromone gland, effectively eliminating the dead air space that surrounds a non‐calling moth. The calling posture also decreased the relative intensity of turbulence near the pheromone gland surf

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1988.tb00904.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

ABSTRACT.Incubation of corpora allata (CA) from adult females ofLocusta migratoria(L.)in vitroin 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 potassiu

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1988.tb00905.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

ABSTRACT.Free‐flying, wild male and femaleGlossina pallidipesAust. andG. m. morsitansWestw. 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 fliesenteringa 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 350–400os‐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 losi

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1988.tb00906.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

ABSTRACT.The rate of lipid synthesis from [14C]acetate in fat body fromSchistocerca americana gregariahas been studiedin 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 synthesisin vitrowas 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

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1988.tb00907.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

ABSTRACT.The sexual behaviour of maleGlossina morsitans morsitansWestwood (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 autost

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1988.tb00908.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

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 temperatur

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1988.tb00909.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

ABSTRACT.Incubation conditions have been established for the corpus cardiacum‐corpus allatum (CC‐CA) complex of femalePhormia regina(Meigen), which will support CC‐CA biosynthetic activitiesin vitroas 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 inP. reginause 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 wi

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1988.tb00910.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

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 locate

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1988.tb00911.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY