Recently I’ve been intrigued by the prospect that, given large data matricies, missing data may not be as big of an issue as one may initially assume. This is exciting when, like aleocharines that live with ants and termites, your focal group shows a combination of being speciose and rare.
Exciting – that’s why lately I’ve been looking for potential morphological character systems that could be evolutionarily informative – especially in reproductive organs. Although the example is limited to the penis (aedeagus), Tishechkin & Caterino (2009) clearly articulate the general reasoning why genitalia might be useful for myrmecophiles:
Those characters [especially of male genitalia] provide one of the best morphological character systems in a taxon in which the external morphology appears to have evolved under strong, host-imposed selection pressure leading to convergent morphologies in distantly related lineages.
Although the phrasing “host-imposed” is rather nebulous and spooky, I generally agree that it seems likely that in many cases (I can see myrmecophilly indirectly interfering with reproductive organ morphology), the reproductive system should be relatively free of direct selective pressures based on a myrmecophilous life style. This, you would think, would also apply to internal reproductive structures.
Yesterday I ripped out some male sexy time organs in Meronera venestula (females to come, if you must know, I messed up my female dissections). A lot larger then I expected, if I may add. Interestingly, the individual testis is composed of four lobes, bifurcated bean-shaped gland and a mysterious gland on the left.
This was the first male internal reproductive system that I’ve observed in a staphylinid and was very fascinating.