The dimorphism observed in the honey bee female caste is particularly interesting because workers and queens have the same genotype yet exhibit a 10-fold difference in lifespan. Queens live on average 1–2 years (Page and Peng 2001), although a maximum lifespan of 8 years was reported in one study (Bozina 1961). Queens take the shortest time to develop (16 days) and have the longest lifespan. Workers live on average 15–38 days in the summer (Free and Spencer-Booth 1959 Fukuda and Sekiguchi 1966), 30–60 days in the spring and fall, and 150–200 days in the winter (Anderson 1931 Free and Spencer-Booth 1959 Fukuda and Sekiguchi 1966). Workers develop in 21 days and their lifespans vary depending on season. Drones have a developmental time of 24 days, and they live on average 21–32 days in the spring and summer, the only times when drones are produced (Winston 1987). Queens and drones are both reproductive, whereas workers are non-reproductive and spend their lives performing in-hive tasks or foraging outside the hive for pollen, nectar, and water.Īll castes exhibit different developmental times and lifespans. Queen–worker differentiation is nutritionally determined during the larval stage. Honey bees are social insects with a haplodiploid sex determination system, in which unfertilized eggs laid by the queen develop into drones (male bees) and fertilized eggs develop into either workers or queens (both castes consisting of genetically identical female bees). Life history, caste-specific lifespan and reproductive behavior First, what evolutionary forces have produced these long-lived but highly fertile organisms? Second, what molecular mechanisms allow individuals to have extreme longevity and fecundity? We preface these discussions with a brief overview of honey bee ( Apis mellifera) life history and caste-specific differences in lifespan and reproductive behavior. In this review, we will concentrate on the two we consider most fundamental. These observations raise several interesting questions. Social insect queens are the only animals known that can live for decades while also producing hundreds to thousands of offspring per day (Keller and Genoud 1997). Longevity and fecundity typically are negatively correlated and the extent of this tradeoff varies within and among species. Social insect species are promising subjects for the study of aging, in part because of their caste-specific life-histories and extreme lifespan differences, which provide the opportunity to identify naturally occurring candidate genes involved in aging (Keller and Jemielity 2006).Įven more compelling is the observation that social insect queens live at least an order of magnitude longer than reproductive adults of non-social insects, despite sustaining high rates of reproduction. In these insects, queens and workers exhibit up to a 100-fold difference in lifespan, with reproductive queens outliving non-reproductive workers (Winston 1987 Keller and Genoud 1997 Page and Peng 2001). Advanced insect societies, such as those of ants, bees, wasps, and termites, are characterized by overlapping generations of adult colony members, a system of caste division (reproductive vs non-reproductive individuals), and cooperative care for young colony members (Wilson 1971).
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