My Research

Male Reproductive System
Hymenoptera. Vespina. Vespida. Bees, ants, sawflies, horntails and other wasps. Male reproductive system. Male genitalia of Hymenoptera. Symphyta. Phylogenetic systematics of Hymenoptera. Phylogenetic systematics of Symphyta. Xyeloidea, Tenthredinoidea, Pamphilioidea, Cephoidea, Siricoidea, Xiphydrioidea, Orussoidea. Xyelidae, Blasticotomidae, Tenthredinidae, Diprionidae, Cimbicidae, Argidae, Pergidae, Pamphiliidae, Megalodontesidae, Megalodontidae, Cephidae, Siricidae, Anaxyelidae, Xiphydriidae, Orussidae.


I was intrigued by the discovery that plantulae – attachment structures on the ventral side of the tarsi – come in two distinct types and that I could not find any mention of this in the recent (phylogenetic) literature, even though this fact had been mentioned in the old literature and seemed to be well-known. Beutel and Gorb (2001), in a study of the evolution of the attachment structures of insects, concluded that the tarsal plantulae of Hymenoptera are probably uniquely derived, which made the subject even more interesting.

When I needed a topic for a course on scanning electron microscopy that I was about to teach, I realized that the tarsal plantulae were ideal for this purpose. I gave the students hindtarsi from several sawfly species from a number of families, and during the course we discovered in the scanning electron microscope that the plantulae showed fascinating intricate details. This course was the starting point of my study of the tarsal plantulae (Schulmeister 2003a). Unfortunately, I had to learn that the evolution of the plantulae was quite homoplastic; at least one type of plantulae, if not both, must have evolved several times.

Below are micrographs showing the two types of plantuae, which I termed integrated plantulae and distal plantulae. Both types come in two forms, simple and bilobed/double. The left micrograph shows integrated simple plantulae of Macroxyela ferruginea, the right shows double distal plantulae of Xiphydria camelus.

References on this page

Beutel, R. G., and Gorb, S. N., 2001: Ultrastructure of attachment specializations of hexapods (Arthropoda): evolutionary patterns inferred from a revised ordinal phylogeny. Journal of Zoological Systematics and Evolutionary Research 39: 177-207.

Schulmeister, S., 2003a: Morphology and evolution of the tarsal plantulae in Hymenoptera (Insecta), focusing on the basal lineages. Zoologica Scripta 32: 153-172.

Webdesign, Macroxyela photo and HymAToL logo by Susanne Schulmeister