| Abstrakt: |
Abstract: Eggs of two species of camel cricket Atachycines apicalis (Brunner, 1888) (=Aa) and Tachycines asynamorus Adelung, 1902 (=Ta) enter diapause soon after deposition. When exposed to various constant temperatures, they hatched at 15-25°C and the hatchability at 20 and 25°C was higher in Aa than in Ta but the reverse was the case at 15°C. Exposure to temperatures of 4-20°C for various periods followed by incubation at 25°C resulted in three groups of eggs: (a) hatched in = 7 weeks, (b) hatched in >7 and <30 weeks and (c) unhatched for >=30 weeks. The proportion of "a" eggs was increased by previous exposure to 10-20°C in Aa and to 7-15°C in Ta. Nymphs of various sizes (and sometimes adults) were caught occasionally (Aa) or by traps (Ta) shortly before and after winter. From these data, both species are inferred to have biennial life cycles, passing the first winter as eggs and the second winter as larvae of even adults. The different thermal requirements in the egg stage of the two species cannot as yet be related to their different habitat preferences. |
