| I am currently involved
in a taxonomic treatment and reassessment of species placed in the Oecetis
avara group (Trichoptera: Leptoceridae). There are currently five
described species in the Oecetis avara group, known primarily from
Mexico, the United States and Canada. Oecetis avara itself also
extends into South America. Forms placed in Oecetis avara have proven
to constitute a species complex comprising a number of additional species.
The morphological uniformity of the species from Central and South America,
and the small differences separating them, suggest that they may be species
of recent origin. Morphological evidence from this group, and the fasciatella
group of the genus Smicridea, has led me to speculate on an unsuspected
mechanism for speciation. It would occur when one species or subspecies
acquires a novel method for discriminating among potential mates and introgressively
transfers this selection bias to a related species that has remained plesiomorphic
(nonselective) with respect to the criterion. My speciation hypothesis
involves sexual selection by female choice and the increased variance in
morphological characters resulting from introgressive hybridization as a
triggers for speciation events. New species would emerge from populations
of the originally plesiomorphic (non-discriminating) species. I am interested
in eventually testing this hypothesis with evidence from molecular data,
but my immediate goal is to simply to describe the additional species in
the Oecetis avara complex. |
