Pictures of our experimental system, the common earwig, Forficula auricularia (Forficulidae: Dermaptera). From left to right: female tending clutch in defensive posture, male displaying the typical, curved and horn-like forceps (note the much straighter shape of female forceps), female cleaning an egg, male in front view. Pictures by Joel Meunier.
In our research, we are specifically interested in how cooperation evolves and conflicts are resolved in social communities. A particularly interesting community is the family. Family members are closely related, parents often invest substantially into their offspring, yet siblings often vigorously compete for parental attention and resources. Such conflicts may be resolved by aggression (going sometimes as far as siblicide) or by communication. We focus on the evolution and heritable basis of behaviours and signals that parents, offspring and siblings use to interact with each other. Our experimental systen is an insect group that shows extensive and a great diversity of forms in maternal care and social behaviour - the earwigs (dermapterans). We study how chemical communication and behavioural interactions are used among earwig siblings and between earwig offspring and their caring mothers to settle conflicts by using behavioural experiments and chemical analysis (Gas-Chromatography Mass-Spectrometry).
Behaviors expressed inside families are fascinating from an evolutionary perspective. Conflicts of interests are an inherent part of family life. An individual offspring would usually gain a fitness advantage by taking more than its fair share from the parent, while parents would do better by sticking to the mathematical definition of fairness to maximize their reproductive success. This parent-offspring conflict is thought to underlie the widespread evolution of conspicuous begging by offspring. Prominent examples for such behaviour are the begging calls of nestling birds and the tantrums of primate and human infants, but - as our own research showed - insect babies can use chemical signals (pheromones) to influence the care behaviour of their parents. A family can also be viewed as a social environment consisting of genetically related, behaviorally interacting and evolutionarily inter-dependent individuals. Caring parents provide critical resources for offspring development and juvenile survival. And offspring affect their parents' behaviors by scrambling for their attention and/or signalling their needs of quality. Thus, offspring and their parents are social environmental components potentially affecting each other's behavioral decisions and reproductive life. Interestingly, families often differ considerably in the duration or quantity of care and/or the level of demand by offspring providing the raw-material for ongoing adaptation of the family interactions to to the ecological environment. Recent evidence supports the hypothesis that this diversity is partly genetic in nature and maintained by co-adaptation. Coadaptation is evolution's answer to the questions: As a caring (or non-caring) parent, should I produce demanding or undemanding offspring? Or: Having a caring (or non-caring) parent, should I (as an offspring) demand more care still, or be happy with what I get? Finally, it is widely accepted that families are at the origin of so-called "higher" forms of sociality including cooperative breeding systems and eusocial systems, and that traits that evolved to mediate family interactions anticipated more specialized forms of social behaviour. Thus, in order to understand the evolutionary origin of sociality, it is critical to understand the evolutionary causes and consequences of family life.
We use the common earwig, Forficula auricularia for our experimental research. Earwigs are easily recognized by their conspicuous cerci ("forceps"). Females of this species guard their clutch of eggs and hatched nymphs, provide food to them and protect them against natural ennemies.
Our research is funded by the Swiss National Science Foundation and the Fonds zur Förderung von Lehre und Forschung.
Several Master-projects are available in our group to work experimentally on cooperation, conflict and chemical signalling in earwig Forficula auricularia families. Interested students should contact Mathias Kölliker by e-mail (mathias.koelliker@unibas.ch). More info can be downloaded here