Sexual communication and speciation

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 four main areas:

 

Heliothis virescens,  © IBED, UvA / Jan van Arkel

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. We are also assessing the bacterial midgut community in different moth species and their possible role in host plant preference and performance. more >>>

 

 

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

Many moth species show specific daily rhythms in their sexual activities, some species being sexually active early at night while others are sexually active late at night. However, the genetic differentiation of this allochronic separation has not been examined in any species so far. We are investigating the genetic basis of allochronic differentiation in two strains of the noctuid moth Spodoptera frugiperda. more >>>

Heliothis virescens,  © IBED, UvA / Jan van Arkel

Speciation is caused by the evolution of reproductive isolation barriers that reduce or prevent gene flow between diverging populations. In contrast to premating isolation mechanisms, postmating isolation mechanisms do not act directly on the members of the diverging populations, but on the resulting hybrids and thus come into play when premating isolation is incomplete or absent. We investigate the genetic basis of hybrid incompatibility in two moth species. more >>>