Chemical Communication

Dr. Astrid T. Groot and her Research Group

Heliothis matings in field, © MPI CE / S. Hänniger

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. However, very little is known about the causes of initial divergence between populations in finding mating partners, and whether variation in sexual attraction can drive divergence between populations or whether such variation follows after populations have diverged due to ecological factors. Nocturnal moths are ideal animals with which to address this research question, because their communication channel is virtually all pheromonal, and the pheromone components are very well defined.

Our research revolves around the following 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.

Our research can be divided into three main areas:

Heliothis virescens female pheromone gland, © MPI CE / C. Borgwardt

In our efforts to find the genetic basis of female sex pheromone signals and male response, so far we have found that the signal and response traits map to different and non-overlapping genomic regions (QTL). This begs the question of how both traits can coevolve. By identifying the genes and environmental factors that may influence sexual signals and/or response, we aim to get insight into how such coevolution may arise. more >>>

Heliothis virescens larva on garbanzo, © MPI CE / M. Marr

Most likely generalists are exposed and/or affected differently to stress factors in their larval life than specialists, as generalists may encounter a number of different environments. Possibly, stress factors early in life (i.e. in the larval stage) affect adult (sexual) behavior. We are exploring differential immune defense responses in the generalist Heliothis virescens and the specialist H. subflexa and possible effects on their sexual communication. more >>>

Spodoptera frugiperda in corn plant, © MPI CE / S. Hänniger

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. In noctuid moths host plants have been shown to be involved in sexual communication mostly indirectly: females may start producing and/or releasing sex pheromone only when near or on their host plants, while males may be attracted to females in combination with host plant volatiles. We are assessing posssible interactions between host plant specialization/adaptation and sexual communication in moths that consist of two host strains. more >>>