摘要:

Abstract.Fifth stadium larvae of the tobacco hornworm,Manduca sexta(L.), ate larger meals than usual when they had been deprived of food for periods of time longer than the usual intermeal interval (c. 45 min). Meal size increased with time since the last meal until 180 min, when it was about 3 times normal. There was no evidence of a role for volumetric feedback from the gut in controlling meal size. Injections of a paraffin oil/wax mixture, or of petroleum jelly (Vaseline) into the foregut, midgut or rectum failed to decrease meal size. Cutting the recurrent nerve failed to alter meal size compared to sham‐operated controls (although both groups took smaller meals than unoperated controls). By contrast, injections of an extract of soluble nutrients from the diet into the midgut inhibited feeding in some insects and reduced subsequent meal size in others. Appropriate controls showed that these effects were not due to the volumetric or osmotic effects of the injections. These results imply that nutrient feedback plays an important role in controlling meal size inManducacaterpillars, while volumetric feedback is probably unimportan

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb00993.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

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

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb00994.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract.This study is the first to demonstrate the capacity of an arthropod egg, that of a tropical walking stickExtatosoma tiaratum(Macleuy), to absorb water vapour from the air. This species diapauses both as an early embryo and then again as a pharate first instar larva, and both stages are capable of absorbing water vapour. Water vapour absorption occurs at lower humidities and at a lower rate for an egg in early embryonic diapause (c. av0.30, 0.516 mg h‐1δv‐1) than in the diapausing pharate first instar (c. av0.60, 0.725 mgh‐1δav‐1) at 25d̀C. In addition to having the capacity to gain water at very low vapour activities, water is efficiently conserved as indicated by the low rate of water loss (0.015% h‐1in the early embryo and 0.046% h‐1in the pharate larva at 25d̀C). Eggs that have been killed lose water when held at a hydrating vapour activity, thus implying that active uptake contributes to net absorption. Wax block experiments suggest that water is absorbed over the entire chorionic surface. Eggs of five other insect species that were examined[Lymantria dispar(L.),Bombyx mori(L.),Antheraea polyphemus(Cram.),Oncopeltus fasciatus(Dallas) andDiaferomera femorata(Say)] lacked the ability to absorb at

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb00995.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Book reviewed in this article:REPRODUCTIVE BEHAVIOUR OF INSECTS. Edited by W. J. Bailey and J. Ridsdill‐SmithTHE ACARI: REPRODUCTION, DEVELOPMENT AND LIFE‐HISTORY STRATEGIES. Edited by Reinhart Schuster and Paul W. Mu

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1992.tb00996.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY