Geographically distinct but non-monophyletic morphs: Reexamining the evolution of color in Florida burrowing beetles (Coleoptera: Geotrupidae: Peltotrupes)

Abstract

The genus Peltotrupes Blanchard 1888 (Coleoptera: Geotrupidae) is restricted to scrub and sandhill habitats on peninsular Florida’s ridge system. Commonly called Florida Deep Digger Scarabs, individuals excavate burrows as deep as 2-3 m and were traditionally considered to be flightless. The recognized diversity within the genus (P. profundus profundus Howden 1952, P. p. dubius Howden 1955, and P. youngi Howden 1955) is based mostly on structural color differences corresponding to distinct geographic regions (i.e., dune ridges). Herein, we provide the first molecular phylogeny of the genus Peltotrupes and highlight the lack of monophyly of the currently recognized species (i.e., color morphs). We also analyze the color of four dorsal regions of male individuals representing the full geographic and color phenotypic breadth of the genus. Although significant color differences are recovered between the currently recognized species, given their lack of monophyly, our results suggest an ecological role may be maintaining these distinct morphs.