Wege der Mikroevolution und Artbildung bei Bienen (Apoidea, Hymenoptera): Populationsgenetische und empirische Aspekte

Mazzucco K & Mazzucco R (2007). Wege der Mikroevolution und Artbildung bei Bienen (Apoidea, Hymenoptera): Populationsgenetische und empirische Aspekte. IIASA Interim Report. IIASA, Laxenburg, Austria: IR-07-049

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Abstract

Bees are haplodiploid organisms: haploid males develop from unfertilized eggs, diploid females from fertilized eggs. Under haplodiploidy, deleterious mutations are effectively purged by purifying selection on haploid males. Therefore, genetic load and inbreeding depression are low in bees, which allow them to exist in very small populations, and facilitate the colonization of new areas and habitats by single fertilized females. Exceptions caused by distinct modes of genetic sex-determination are discussed. Owing to the purifying selection and the higher rate of genetic drift in small populations, the genetic variation of bees is only one third of the variation of diploid insects. As a consequence, bees have less genetic adaptability to environmental change, for which they compensate by exhibiting higher learning ability and greater behavioural plasticity than many other insect taxa.

Most bee species need specific microclimatic conditions to perform the proper flight behaviour to provision their nests with larval food. Energy flow and metabolic rates in flight muscles of bees are among the highest ever measured in animal tissue. The temperature dependence of the enzymes which drive the flight muscle metabolism is therefore of critical importance for the functioning of the system. Mutations which change the thermal tolerance range of one of those enzymes might lead to changing habitat requirements, and parapatric or allochronous population divergence. The fact that bees choose their nesting site very carefully already hints at the critical role, temperature and humidity ranges play for bee development. Experiments show a remarkable dependence of learning ability and behaviour on developmental temperatures.

Evolutionary and ecological aspects of social behaviour, social and cleptoparasitism, and flower choice in bees are discussed. Possible paths of population divergence and speciation are pointed out. The reproduction rate of bees is closer to the rates of primates than to that of other insects. Compared to other insects, bees evolve only slowly.

Item Type: Monograph (IIASA Interim Report)
Research Programs: Evolution and Ecology (EEP)
Postdoctoral Scholars (PDS)
Depositing User: IIASA Import
Date Deposited: 15 Jan 2016 08:40
Last Modified: 25 Oct 2016 14:27
URI: http://pure.iiasa.ac.at/8409

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