This study tests the effects of temperature, water, food and photoperiod on breaking diapause and resumption of activity (emergence from the soil) in Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae) diapausing under natural winter conditions or at constant temperatures in the laboratory. Behavioural and physiological criteria were used to characterize the various phases of diapause. Three successive phases are distinguished during hibernation: 'diapause development' or true diapause, a facultative 'post-diapause quiescence' and, finally, a transient phase of post-diapause development leading to emergence from the soil. Diapause development is completed within 3 months in the field and its duration depends on temperature. Although they are buried in the soil during this phase, beetles remain sensitive to photoperiod when artificially exposed to it. They do not emerge from the soil when exposed to higher temperatures. Thereafter, they stay in a quiescent state maintained by low temperature, low humidity or lack of food. The response to temperature changes during hibernation. In the soil, activity begins when soil temperature reaches 4-5"C, but this temperature is too low to permit postdiapause development. The transient phase has a temperature threshold between 8 and 10°C, whereas emergence from the soil occurs only when the temperature exceeds 11°C. Post-diapause development is influenced strongly by temperature and humidity. After emergence, post-diapause development leads eventually to reproduction. Food is essential for reproduction after diapause whereas photoperiod plays no further role.

Exoneura richardsoni is a common allodapine bee which, in southern montane Victoria, primarily nests in dead fronds of tree ferns. We sampled intact colonies from the Dandenong Ranges from August 1992 through to February 1993. The bee is univoltine, with egg production commencing in later winter and adult eclosion occurring over summer. The majority of colonies in both re-used and newly founded nests contain more than one female. Intra-colony relatedness is very high (r = + s.e., 0.759 k 0.087) in re-used nests and moderately high (0.498 i 0.152) in newly cofounded colonies, indicating maintenance of kin integrity during nest re-use and kin recognition during foundress association. This is only the second time that kin cofounding has been demonstrated in a primitively social bee species. Samples during winter and early summer show that per capifa brood production increases with colony size up to about 3 or 4 females per nest, and this may explain the high degree of social nesting in this species. Whilst eusociality could occur in some nests, the opportunities for older, adult brood members to help rear younger siblings are very limited. It seems likely that in E. richardsoni and at least some other Australian allodapine bees, the selective maintenance of high levels of social nesting and kin recognition does not depend on the existence of eusociality.

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