Research interests

My research synthesizes the fields of cellular aging and sexual selection in order to shed light on the role of sperm age in sperm competition and use. Sperm age, long recognized in the fields of human medicine and animal breeding as an important factor in determining fertilization success and offspring viability, has been largely overlooked by evolutionary biologists. Given that much of the observed across-male variation in fertilization success remains unexplained by commonly-studied sperm and ejaculate traits like sperm number, motility, and morphology, sperm age is a likely candidate for predicting sperm function.

 

Sperm aging and sperm use patterns in Drosophila

Recent work shows that some female insects delay the aging of stored sperm cells by reducing the cells’ metabolic rates, thereby limiting their production of damaging reactive oxygen species. This mechanism may underlie the complex spatial and temporal patterns of sperm storage and use in the model system Drosophila. Drosophila females have two types of sperm storage organs: the seminal receptacle (SR) and the spermathecae (ST). In D. melanogaster, the SR is used for short-term and the ST for long-term storage. In the closely related D. simulans, the two organ types have opposing fertilization biases: the SR favors the first male to mate, while the ST favor the second male. Sister species D. mauritiana, meanwhile, shows no temporal or mating-order biases in sperm use. Our project investigates how differential modulation of sperm metabolism in female storage, across the two organ types and the three species, relates to these different usage patterns. We are also investigating potential mechanisms of delayed sperm aging in storage, including oxygen restriction and high ion concentration.

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Book read aloud

flyer-website22 Sept 2015 Klaus reads from his book at the Berlin Natural History Museum

Topics for Master theses

Arthropods can break down chitin (nobody else can) – do you want to know how? We are looking for somebody who characterises chitinases in insects. More details here (in German).

Bedbug females express a protein in their skin that is self-sealing after wounding. We are interested in how this is anchored in the tissue. If you are interested in addressing this novel topic, please get in touch. More details here (in German).

two new faces, after the summer

Barbara Eckel and Guo Ruijian will join us as PhD students in November and October 2015. Barbara will be working on the Evolution of Sperm Metabolism. Ruijian won a Chinese Government Scholarship. Many congratulations! He will work on the Ecology, Genetics and Molecular Biology of Sperm Storage in Drosophila melanogaster. We are looking forward to meet you, Barbara and Ruijian!

Famous visitor

Becky Rosengaus will give a seminar “Symbiont-mediated social immunity”on 7 May. On her trip to Europe, she visits only Vienna and our lab in Dresden. See her website for her research – come by and meet her on 6 and 7 May.

new faces, transiently

CG_AR_Max2Dr Anne-Cecile Ribou and Prof. Dr Christoph Grunau from the University of Perpignan arrive to spend sabbatical time in our group. Welcome Ance & Christoph! It will be cold, though. Christoph will be giving a seminar Disentangling genetic and epigentic components of heritable phenotypic variation in the coevolution of hosts and parasites on 21 April (Abstract). He will also give a lecture “Epigenetics and Evolution”. Ance’s talk will be Using next-generation fluorescence probes to detect free radicals in living cells: the case of the mitochondria. Come by and meet them.

on tour

Klaus gives a talk at the Max-Planck Inst for Colloids and Interfaces in Potsdam Golm “What does sexual conflict have to do with properties of biological materials?