Dr. Joris M. Koene, Associate Professor


The main interest of my research group revolves around reproduction in simultaneous hermaphrodites. Many of the questions we address focus on issues of sperm competition and sexual conflict and attempt to integrate different biological levels (e.g., behaviour, evolution, ecology, physiology, neuro-endocrinology). We make use of a range of different techniques, among which quantification of behaviour and resource investment, molecular phylogeny reconstruction, paternity analysis, biochemical and genetic identification and analysis of pheromones and allohormones, immunohistochemistry, micro-surgery, neuroanatomy and physiological experiments. For many of our experiments we use the model species (great pond snail Lymnaea stagnalis), but we also use these findings in comparative approaches within freshwater snails. We also explore sexual conflicts caused by some of the more bizarre reproductive behaviours found in hermaphrodites, such as love darts and other strange sexual attributes. The latter includes the use of the model species Cornu aspersum and other land snails. Our aim is to integrate our findings into a complete and general picture of why and how sexual selection – in this case including sperm competition and sexual conflict – affects simultaneous hermaphrodites. Such a broad synthesis is expected to significantly contribute to a full understanding of hermaphroditism as a reproductive strategy.

Selected Publications

Hoffer JNA, Mariën J, Ellers J, Koene JM (2017) Sexual selection gradients change over time in a simultaneous hermaphrodite. eLife 6:e25139.

Adema, C., …., Koene, J.M., …et al. (2017) Whole genome analysis of a schistosomiasis-transmitting freshwater snail. Nature Communications 8:15451.

Nakadera Y, Swart EM, Hoffer JNA, Den Boon O, Ellers J, Koene JM (2014) Receipt of seminal fluid proteins causes reduction of male investment in a simultaneous hermaphrodite. Current Biology 24:1-4.

Stewart MJ, Wang T, Koene JM, Storey KB, Cummins SF (2016) A love dart allohormone identified in the mucous glands of hermaphroditic land snails. Journal of Biological Chemistry 291:7938-7950.

Koene JM, Sloot W, Montagne-Wajer K, Cummins SF, Degnan BM, Smith JS, Nagle GT, Ter Maat A (2010) Male accessory gland protein reduces egg laying in a simultaneous hermaphrodite. PLoS ONE 5:e10117.

Link to full publication list in PURE