Susanne Düngelhoefdoctoral student
Tel.: +49 (0)228 9122 421
Fax: +49 (0)228 9122 212
E-Mail: s.duengelhoef.zfmk@uni-bonn.de
Functional morphology of copulation and sperm transfer in leaf and seed beetles (Coleoptera: Chrysomelidae)
Fig. 1: My first alive neotropic hispine:
Sceloenopla sp. (Chrysomelidae: Hispinae), Guayabo, Costa Rica (photo: Lasse Hubweber).
Genitalia of insects have been mainly investigated for taxonomical purpose so far. The function of genital stuctures has been studied much more rarely and remains unclear in several respects, though. This "negligence" of functional morphology may surprise if we consider that most developments in evolution can be explained through an increase of fitness. Structures directly involved in reproduction must play an important role in the effort to increase the own reproductive success.
In my doctoral thesis I compare the functional morphology of copulation in the subfamilies of Chrysomelidae and Bruchidae. This may help to close the gap in functional morphological investigation on genitalia at least for this group.
Fig. 2: Male genital sturctures of
Megalopus armatus (Chrysomelidae: Megalopodinae). E: endophallus (internal sack), F: flagellum (sclerotised part of the ejaculatory duct), M: median lobe (sklerotised tube), P: parameres. The beetle was fixed in copula and therefore shows the state of the gemital structures during copulation.)
My studies focus on the functional role of parameres, endophallus, and flagellum (Fig. 2) and the sperm transfer. I want to compare several species of as many subfamilies of chrysomelids and bruchids as possible to get an idea on the functional importance of different character states of the structures.
Copulating pairs are frozen with Chlorethyl spray, dissected and studied with SEM or histologically.
Fig. 3: Pair of Oulema melanopus fixed in copula, sagittal section. Female: left, male: right. The internal sack (E) fills the whole Bursa copulatrix (B). M: median lobe.
Fig. 4: SEM photos of the surface of the endophallus of Lilioceris lilii (Chrysomelidae: Criocerinae). Left: Sensillum campaniforme. Right: Comb like microstructures.
