摘要:

ABSTRACT.The incidence and intensity of embryonic diapause in the striped ground cricket, Allonemobius fasciatus DeGeer (Gryllidae), is influenced by the date of oviposition and the incubation temperature. At 20d̀C, embryos develop normally until the end of the appendage‐formation stage when diapause occurs. The intensity of ‘winter’ diapause at this stage is greatest in eggs laid early in the season. Incubation at higher temperature induces a different and earlier ‘summer’ diapause. The higher the temperature the earlier the stage at which this developmental suppression is imposed. At 27 and 30d̀C, some individuals develop without any interruption and hatch within 20 days. The proportion of these fast‐developing eggs is low in summer but increases towards the end of the laying season. In nature, this species is univoltine and precocious hatching before winter is unlikely.When embryos diapausing at an early stage at 27d̀C are transferred to low temperatures, they resume development and enter winter diapause. The time required to reach the winter‐diapause stage after transfer is inversely related to the temperature (30‐30d̀C). At 30d̀C, sunmer diapause is neither in

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1984.tb00685.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACT.The propagation of sound in the frequency band (2–12 kHz) used by the Corixidae was measured in two shallow natural ponds. At distances of more than 1 m from the shore the water was at least O.4 m deep. The first pond was eutrophic and contained no plants. The spread of sound into the open water obeyed approximately the geometric attenuation of the sound pressure level (SPL); a loss of 6dB for each doubling of the distance from the point sound source. Near the shore the attenuation was considerably greater, especially for low frequencies; for a 2 kHz signal the damping of the SPL was c. 40–50 dB/m.The second pond had dense plant growth, and the sound attenuation depended strongly on the photosynthetic activity of the waterplants. Measurements in winter, with an overcast sky, revealed only a slight damping effect of the plants for a 10kHz test signal. During intense sunlight in summer, however, in addition to the geometric attenuation the damping effect of the plants over a distance of O.5 m was 50 dB for a 2 kHz signal and 80 dB for 10 kHz. This effect was due to gas bubbles produced during intense photosynthesis.Song A of Corixa dentipes Thms. (Heteroptera) males elicits usually a response by male conspecifics. The threshold SPL for this response was measured to be c. 40 dB lower than the SPL at a distance of O.1 m from a stridulating animal. From the measurements of sound propagation it follows, therefore, that the effective range of Song A in the most favourable case is at least 10m, though in a pond overgrown with plants it can be less than O.

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1984.tb00686.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACT.This paper describes the relationship between ambient temperature and wingbeat frequency in bees and flies of different sizes, and presents new data from insects in free fight. The slope of the relationship changes with the size of the insect, and was different for insects in hovering flight compared with individuals of the same species in forward flight.

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1984.tb00687.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Book reviewed in this article:SOCIAL INSECTS: ECOLOGY AND BEHAVIOURAL BIOLOGY. By M. V. Brian.ANIMAL BEHAVIOUR. Edited by T. R. Halliday and P. J. B. Slater.

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1984.tb00688.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

ISSN:0307-6962    

DOI:10.1111/j.1365-3032.1984.tb00689.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY