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Sexual dimorphism as a facilitator of worker caste evolution in ants
  • Chris Smith
Chris Smith
Earlham College

Corresponding Author:[email protected]

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Ant societies are primarily composed of females, whereby labor is divided into reproductive and non-reproductive, worker, castes. Workers and reproductive queens can differ greatly in behavior, longevity, physiology, and morphology, but their differences are usually modest relative to the differences relative to males. Males are short-lived, typically do not provide the colony with labor, often look like a different species, and only occur seasonally. It is these differences that have historically led to their neglect in social insect research, but also why they may facilitate novel phenotypic variation – by increasing the phenotypic variability that is available for selection. In this study, worker variation along a size-shape axis corresponded with variation in male-queen size and shape. As worker variation increased within species, so did sexual variation. Across species in two independent genera, sexual size dimorphism correlated with worker polymorphism regardless of whether the ancestral condition was large or small worker/sexual dimorphism. These results, along with mounting molecular data showing that process of queen-worker caste determination has co-opted many genes/pathways from sex determination, lead to the hypothesis that sexual selection and selection on colony-level traits are non-independent and that sexual dimorphism may even have facilitated the evolution of the distinct worker caste.
30 Nov 2022Submitted to Ecology and Evolution
01 Dec 2022Submission Checks Completed
01 Dec 2022Assigned to Editor
06 Dec 2022Reviewer(s) Assigned
16 Dec 2022Review(s) Completed, Editorial Evaluation Pending
22 Dec 2022Editorial Decision: Revise Minor
19 Jan 20231st Revision Received
21 Jan 2023Submission Checks Completed
21 Jan 2023Assigned to Editor
21 Jan 2023Review(s) Completed, Editorial Evaluation Pending
27 Jan 2023Editorial Decision: Accept