Male secondary sexual structures and the systematics of the Thereus oppia species group (Lepidoptera, Lycaenidae, Eumaeini).

Robert Robbins,Robert C Busby,Maria Dolores Heredia

doi:10.3897/zookeys.520.10134

Abstract

The Thereus oppia species group includes species with and without a scent pad, which is a histologically and morphologically characterized male secondary sexual structure on the dorsal surface of the forewing. To assess the hypothesis that these structures are lost evolutionarily, but not regained (Dollo’s Law), the taxonomy of this species group is revised. Thereus lomalarga sp. n., and Thereus brocki sp. n., are described. Diagnostic traits, especially male secondary structures, within the Thereus oppia species group are illustrated. Distributional and biological information is summarized for each species. Three species have been reared, and the caterpillars eat Loranthaceae. An inferred phylogeny is consistent with the hypothesis that scent pads in the Thereus oppia species group have been lost evolutionarily twice (in allopatry), and not re-gained.

Highlights

Evolutionary “losses” and “gains” of male secondary sexual structures are being actively documented in the Eumaeini
Another two Thereus species have been discovered with scent patches similar to those of the T. oppia species group (Figs 10, 12, 13)
The third purpose is to propose a preliminary phylogenetic hypothesis for the T. oppia species group to assess whether male scent pad re-evolution is likely to have occurred in this species group

Summary

Introduction

Evolutionary “losses” and “gains” of male secondary sexual structures are being actively documented in the Eumaeini. Thereus oppia has a “brush” of piliform androconia on the ventral surface of the forewing (Fig. 14), a structure that has not been previously reported in the Eumaeini Another two Thereus species have been discovered with scent patches similar to those of the T. oppia species group (Figs 10, 12, 13). One of these species has a ventral forewing androconial “brush”, and both share virtually indistinguishable male and female genitalic structures with T. orasus and T. oppia (Figs 15–24). One purpose of this paper is to illustrate the proposed traits that characterize Thereus and to provide a brief overview of the biology of the genus Another is to delimit the T. oppia species group and to provide names for the two unnamed species in this group. The third purpose is to propose a preliminary phylogenetic hypothesis for the T. oppia species group to assess whether male scent pad re-evolution is likely to have occurred in this species group

Materials and methods

Discussion