Research of Boris Baer
I use Australian honeybees, Panamanian leaf cutting ants and European bumblebees to study aspects of social insect reproduction and immunity. To do this I decided to pursue an integrative approach, which combines biochemical technology and evolutionary biology. An important part of my work is to conduct biochemical analyses and to use their outcomes to formulate hypotheses that can be experimentally tested in the field. My idea is to help building a new field of research, which I refer to as evolutionary proteomics. Evolutionary proteomics will not only aim to understand evolutionary processes at the protein level, but will also attempt to quantify variations in proteomic profiles and investigate their consequences for natural and sexual selection. The species I use for my work, honeybees, leaf cutting ants and bumblebees are ideal model species for such work as they can be kept in the lab and the availability of techniques such as artificial insemination allow sophisticated experimental manipulations.
I use Proteomics and Metabolomics to analyse sperm and gland secretions, both within the sperm storage organ (spermatheca) and in the male accessory glands (the glands that produce mating plugs in various species). A first analysis showed that the size of the honeybee sperm proteome is relatively small. We detected several proteins within the seminal fluid that are normally produced in response to viral and bacterial infections as well as several chemosensory proteins, that function as pheromone carriers and are known to elicit behavioral responses in honeybees. Experimental studies currently test the biological relevance of these proteins in vivo. I hope that proteomics will also allow me to identify proteins that are instrumental for prolonged sperm storage.
I try to unravel the sophisticated interactions between the ejaculate(s) and the receiving female, to provide a mechanistic explanation for our recent quantification of the cost of sperm storage in ant and bumblebee queens. I am investigating interactions between stored ejaculate(s) and the female immune system. I am quantifying the capacity of sperm and spermathecal fluid to defend microbial infections, and investigate the potential consequences of ejaculate driven immunity for female physiology.
Is there sexual selection via sperm competition and/or cryptic female choice in social insects? Sperm competition, which is the competition between ejaculates from two or more different males over a set of eggs, is widespread in insects and vertebrates. Cryptic female choice is a female mediated process affecting male reproductive success after successful copulation and insemination. Female discrimination between ejaculates is cryptic in the sense that it is a hidden process, taking place inside her body after her more obvious decision to copulate. In social insects, we currently do not know whether sperm competition or cryptic female choice really occurs. Part of my work is therefore testing for the possible presence of sperm competition or cryptic female choice in honeybees and leaf cutting ants.
- ARC Centre of Excellence in Plant Energy Biology
- Centre for Evolutionary Biology
- Centre of Excellence for Social Evolution
- Smithsonian Tropical Research Institute (STRI)
Koos Boomsma, Copenhagen University, Denmark
Paul Schmid-Hempel, ETH Zurich, Switzerland
Bill Hughes, University of Leeds, United Kingdom