Evolution of sex ratios in Tigriopus

The harpacticoid copepod, Tigriopus californicus, lives in the splash zone above high tide. Field work on Tigriopus has shown that populations fluctuate drastically from summer to winter and that the sex ratio (proportion of males and females) in natural populations often deviates from 50:50.

This variation in offspring sex ratio is larger than the binomial expectation and females produce male-biased clutches at higher temperatures. The trait is heritable and is transmitted primarily through the paternal line. We are currently trying to establish the mechanism by which this occurs.

Tigriopus californicus
Photo by Arianne Albert

Last modified 5.July.2005.