My lab is currently working on the following projects. I am always looking for students either on the undergraduate or graduate level who want to join my lab and work on one of the projects. If you are interested, do not hesitate to contact me. I am also open for developing new projects.

The neurohormonal and neurogenetic mechanisms regulating division on labor in social hymenopterans

Workers of social hymenopterans, such as ants, some bees and wasps, specialize on different tasks, e.g. brood care and foraging. In many species, task selection is  modulated by the responsiveness to task-related cues. Responsiveness in turn, is linked to Juvenile Hormone (JH) titers. For example, treating specialized honeybee brood carers with JH increases their responsiveness towards sugar and triggers a transition towards foraging. Strikingly, this linkage between JH and behavioural specialization has also been found in multiple wasp and ant species in which sociality evolved independently. This strongly suggests that JH is of key importance for the evolution of division of labor. However, how JH regulates responsiveness and how it gained this function is unknown.

By integrating recent work on Drosophila melanogaster with cutting edge technologies such as single cell RNA-sequencing, Drosophila transgenetics, and neurophysiological recordings, I aim at unravelling the mechanisms via which JH modulates repsonsiveness and how it gained this function during the evolution of complex social life.

Project output:

Kohlmeier & Billeter: The genetic mechanisms modulating plastic chemosensory responses and behavior in insects. Molecular Ecology 32: 45-60

The neuronal and epigenetic regulation of adaptive maternal effects.

Collaboration partners: Pinar Kohlmeier, Groningen University, Netherlands / Jennifer Mandel, University of Memphis

Maternal effects enable females to transfer information, e.g. about the temperature to their offspring which can then trigger adaptive phenotypic effects, e.g. advanced cold adaptation. Such information can be transported via several channels, such as maternal mRNAs and transcription factors, and then adjust offspring gene expression. In insects, maternal mRNAs are synthesized in nurse cells attached and then released to the developing oocytes. Maternal effects have been documented in many species, ranging from animals to plants, but the molecular mechanisms that regulate which information the mother transfers are still poorly understood.

We have collected first data suggesting that temperature sensing regulates chromatine remodelling in the ovaries which might result in modifications of the maternal mRNA populations deposited in the egg. Using Drosophila neurogenetics, RNA-sequencing, transgenetics, molecular evolution approaches, and a high throughput assay developed in my lab, we aim at identifying the neurogenetic pathway that connects temperature sensing cells to the ovaries, identify candidate mRNAs involved in eliciting temperature adaptation, at understanding how specific mRNAs impact offspring phenotypes, and at analyzing how these mechanisms evolved.

 

The social and genetic mechanisms regulating foraging preferences

In many social insects such as ants, foraging duties are taken over by a subset of workers, i.e. the foragers. Thus, which nutrients foragers search for is not only influenced by their own physiological demands but also by the demands of their non-foraging nestmates including the larvae. Nutritional demands of larvae change throughout their life cycle and protein consumption typically peaks during a short time window before pupation. As foragers, e.g. for hygienic reasons, avoid direct physical contact with the brood, it raises the question of how they gather information about the food demands of larvae.

We use a combination of field work, behavioral experiments, colony manipulations, RNA-sequencing and chemical techniques to understand how larvae signal their demands, how these signals reach the foragers and how they influence neuronal and genetic networks in the foragers to induce behavioral adaptations.

Project output:

Dunn & Kohlmeier: Larval chemical cues induce rapid adaptations of foraging preferences in ant workers. Submitted.