Parasites, Floral Resources and Reproduction in Natural Populations of Bumblebees

Abstract

Weekly censures of bee abundance, flower availability, resource use and infestation of bees by parasitic flies (Conopidae, Diptera) were made throughout a seasonal cycle in eight populations each of Bombus pascuorum and B. terrestris―B/ lucorum (pooled as B. terr/luc). Several life history parameters, together with factors describing environmental conditions were used to characterise the populations. Length of the life cycle varied from 47 to 99 d in B. pascuorum and from 43 to 61 d in B. terr/luc. Also, time of appearance of males in relation to life cycle, the temporal delay between worker and male production, duration of male emergence, number of males produced, and number of males emerged per worker varied substantially among populations