Dr. Joris M. Koene

Curriculum Vitae & Publications

Research interests

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 genetical identification and analysis of pheromones and allohormones, immunohistochemistry, micro-surgery, neuroanatomy and physiologal 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. In a second line of research we explore sexual conflicts caused by some of the most bizarre reproductive behaviours found in hermaphrodites, which often involve love darts and other strange sexual attributes

Selected Publications

Escobar, J.S., Auld, J.R., Correa, A.C., Alonso, J.M., Bony, Y.K., Coutellec, M.-A., Koene, J.M., Pointier, J.-P., Jarne, P. & David, P. (2011) Patterns of mating-system evolution in hermaphroditic animals: Correlations among selfing rate, inbreeding depression and the timing of reproduction. Evolution, 65: 1233-1253.

Hoffer, J.N.A, Ellers, J. & Koene, J.M. (2010) Costs of receipt and donation of ejaculates in a simultaneous hermaphrodite. BMC Evolutionary Biology, 10: 393.

Koene, J.M., Sloot, W., Montagne-Wajer, K., Cummins, S.F., Degnan, B.M., Smith, J.S., Nagle, G.T. & Ter Maat, A. (2010) Male accessory gland protein reduces egg laying in a simultaneous hermaphrodite. PLoS ONE, 5: e10117.

Bedhomme, S., Bernasconi, G., Koene, J.M., Lankinen, A., Arathi, S., Michiels, N.K. & Anthes, N. (2009) How does breeding system variation modulate sexual antagonism? Biology Letters, 5: 717-720.

Koene, J.M.& Chiba S. (2006) The way of the samurai snail. American Naturalist, 168: 553-555.

Research project

Integrative biology of sex and conflict in simultaneous hermaphrodites

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 research lines

Sperm and seminal fluid
We investigate both components of semen, sperm(atozoa) and seminal fluid in hermaphrodites. For sperm, we are especially interested in how they compete for the fertilization of eggs and get stored and digested. For seminal fluid, we focus on those components that influence female physiology to enhance fertilization success of the sperm donor, possibly beyond the recipient's optimum.

Nervous motivation to give and receive sperm
One important stimulus to mate in the male role is prostate gland size, which is detected via a nervous connection to the central nervous system. This has been shown for L. stagnalis, we are now testing the generality of this mechanism in other snail species. Female motivation to lay eggs and/or be inseminated is still under investigation. Understanding these decision mechanisms should ultimately allow for experimental manipulation of sex allocation.

Mate choice and pheromones
Animals are often choosy about whom they mate with. We are investigating the involvement of factors such as shell shape (chirality), mucus trails and pheromones. In addition, we aim to link this to how animals detect cues that are relevant for mate choice.

Love darts, penial glands and more
We investigate and compare love dart shape, function and use both within and between dart-possessing land snail species. Other odd sexual organs, such as elaborate penial glands in land slugs and dart-like stabbing devices in snails, are also addressed.



picture copyrights: C. Levesque


Participants:
Yumi Nakadera, Elferra Swart, Jeroen Hoffer, Valentina Zizzari, Kora Montagne-Wajer, Dick Roelofs, Nico van Straalen, Jacintha Ellers, Andries ter Maat, Menno Schilthuizen.

Additional information:
http://www.joriskoene.com

www.jkoene.dds.nl