Sex sells, but does it also select?

7 June 2011

Sexual attraction is the first step in determining who mates with whom. The evolution of sexual communication thus plays a pivotal role in the process of speciation. It also forms the core of the research of Dr. Astrid Groot who joined the UvA in 2011 as MacGillavry fellow.

Sexual attraction is the first step in determining who mates with whom. The evolution of sexual communication thus plays a pivotal role in the process of speciation. It also forms the core of the research of Dr. Astrid Groot who joined the UvA in 2011 as MacGillavry fellow.

In particular, very little is known on the causes of initial divergence between populations in finding mating partners. It is also still unclear whether variation in sexual attraction can drive divergence between populations or whether such variation follows after populations have diverged due to ecological factors. In her research, Dr. Astrid Groot strives to find answers to these and related questions.

The sex life of nocturnal moths

Groot's research revolves around two major questions: I) what is the genetic basis of intraspecific variation in sexual communication, and II) what environmental factors may (have) cause(d) variation in sexual communication. In her research, Groot uses nocturnal moths as her prime study objects. 'Nocturnal moths are ideal animals to address this research question, because their sexual communication goes almost exclusively via pheromones and the pheromone components are very well defined', says Groot.

Groot’s research can be divided into the following three areas:

  1. Signal and response coevolution.
    By identifying the genes and environmental factors that may influence sexual signals and/or response, she aims to get insight in how such coevolution may arise.
  2. Sex and immunity.
    Possibly, stress factors early in life (i.e. in the larval stage) affect adult (sexual) behavior. Groot is exploring differential immune defense responses in a specialist and a generalist moth species. The latter being exposed to more stress in early life than the former.
  3. Influence of host plants.
    Generalist insects have been hypothesized to exist as populations of 'specialists', which may be due to a combination of host plant adaptation and pheromone differentiation. Groot is assessing posssible interactions between host plant specialization/adaptation and sexual communication in moths that consist of two host strains.

MacGillavry fellowship and international collaboration

MacGillavry fellowships comprise tenure tracks aimed at excellent female researchers in all disciplines of the natural sciences. The fellowships are named after Carolina MacGillavry. The fellow starts as assistant (UD) or associate (UHD) professor in a temporary position, with the prospect of a permanent appointment as associate professor as well as a subsequent career path leading to a full professorship. During this track MacGillavry fellows are stimulated to set up or expand their own independent research programme hosted by one of the Faculty's research institutes. The MacGillavry Fellows are expected to publish in high-profile journals, attract their own external funding and contribute to the teaching programmes within the faculty. Astrid Groot started as associate professor.

Astrid Groot already built up a very impressive track record in the world of evolutionary biology. In 2001 as a postdoc at North Carolina State University (NSCU) in Raleigh, USA, she started her research to find the genetic basis of the sex pheromone differences between the two closely related moth species Heliothis virescens (Hv) and H. subflexa (Hs). During this period she received a W.M. Keck Center for Behavioral Biology Postdoctoral Fellowship. This work is still ongoing in collaboration with Prof. Fred Gould and Prof. Coby Schal at NCSU.

Subsequently, in 2005 she received a New Investigators grant of USDA (USDA-CSREES, and was promoted to Research assistant professor at NCSU and to study the geographic variation in the sexual communication of Hv and Hs. The grant allowed her to start her own laboratory.

In 2007 Groot was recruited as group leader of Population Genetics in the Dept. of Entomology at MPICE, Jena, Germany. At the same time, the NCSU offered her a position as Adjunct Research Assistant Professor. Groot remains affiliated with both universities during her MacGillavry Fellowship, thus bringing with her excellent opportunities of intense collaboration with these two top institutes. What’s more, in 2008 Groot was one of the initiators to form the "European corn borer consortium" between researchers in two Departments at MPICE (Evolutionary Neuroethology and Entomology) and two universities in Sweden (Prof. Christer Löfstedt's group and Dr. Teun Dekker's group), to identify the actual gene that differentiates the two sex pheromone races of Ostrinia nubilalis; A question that had remained unresolved in the past decade. With this joined effort they were able to identify the first gene that is responsible for intraspecific sex pheromone differences in a moth (Lassance et al. Nature 466).

Future outlook

Groot is planning to continue her research in how sexual attraction may evolve to understand how these signals are involved in speciation. Groot’s research already has some great connections with IBED, specifically with research conducted by Prof. Steph Menken and Dr. Peter Roessingh, who have been working on host plant specialization in the small ermine moths (Yponomeuta) for the past few decades, which is thus very much in line with Groot’s research. 'With Peter Roessingh’s expertise on insect sensory physiology we are now setting up a so-called "biological smell detector" where insect antenna (the nose of insects) are used to assess what insects can smell. And we are buying a wind tunnel in which attraction of moths and other insects to odors or plants can be closely observed and measured', says Groot. Since the smell detector and the wind tunnel form the basis of Chemical Ecology research, which is a growing field, the UvA will be able to attract more students in this direction as well.

For the genetic part of her research, Groot will closely collaborate with Dr. Hans Breeuwer. As Breeuwer’s research focuses on insect symbionts, he will also be involved in Groot’s research on how insect immunity may affect sexual attraction, which is the subject of Groot’s first PhD student at the UvA, Heike Staudacher.

Published by  IBED