Meeting Abstract
Reproductive success fundamentally shapes an organism’s ecology and evolution. A critical component of individual fertilization success is a sperm’s ability to out-compete the sperm of other males to locate a conspecific egg. Sperm chemotaxis, the ability of sperm to navigate towards eggs using chemical signals, has been studied for over a century, but studies of chemotaxis have long assumed that chemotaxis improves individual male fitness without explicit evidence to support this claim. Here, we use a chemoattractant-digesting peptidase and a microfluidic device coupled with fertilization assays to assess the effect of sperm chemotaxis on individual male fertilization success in the sea urchin Lytechinus pictus. We show that removing chemoattractant from the gametic environment decreases fertilization success. We further find that individual male differences in chemotaxis to a well-defined gradient of species-specific attractant correlate with individual male differences in fertilization success. These results conclusively demonstrate that sperm chemotaxis is an important contributor to individual reproductive success.
