Contrasting eusociality with casteless organization: ecology, genetics and historical demography in Australian xylocopine bees

Author: Rebecca Dew

Dew, Rebecca, 2017 Contrasting eusociality with casteless organization: ecology, genetics and historical demography in Australian xylocopine bees, Flinders University, School of Biological Sciences

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Abstract

The xylocopine bees have a diverse range of behaviours, ranging from solitary, to facultatively social to eusocial organization, but with only one origin of true queen and worker castes. I clarify definitions of sociality to include casteless behavior, and show that this lack of hierarchical organization occurs in two species that are closely related to Exoneurella tridentata, a species which shows the most extreme morphological divergence between queens and workers among all bees. I then take a comparative approach to explore how the evolution of these contrasting social behaviours may be influenced by ecological niches, particularly by constraints to independent nesting and the benefits of cooperation. I revise the systematics of these important bees, to bring their taxonomy into line with their phylogenetic relationships. Lastly, I explore how these bees were influenced by past climate change events, and show that these responses differ strongly between species which means that predicting the response of bee faunas to future climate change will be a complex challenge.

Keywords: social behaviour, eusocial, casteless, nest-site limitations, climate change, coalescent analyses, biogeography, historical demography
Subject: Biological Sciences thesis

Thesis type: Doctor of Philosophy
Completed: 2017
School: School of Biological Sciences
Supervisor: Michael Schwarz