Controversial chemical bisphenol A can cause sexual barriers to break down between fish species

Fish exposed to the endocrine disruptor bisphenol A (BPA) become much less choosy when courting a mate, says new research published in Evolutionary Applications. Jessica Ward at the University of Minnesota in Saint Paul, US, exposed two species of fish - blacktail shiners and red shiners - to BPA for 14 days and then compared their courtship behaviour to fish that had not been exposed. She found that the BPA exposed fish were much more likely to approach and court other species. As blacktail shiners and red shiners can interbreed BPA pollution could increase hybridisation, reducing the numbers of blacktail shiners in the wild.

BPA is most often in the news due to its suspected effects on humans, although it is also sometimes blamed for ‘feminising’ aquatic species and preventing them from breeding. Earlier this year the US Food and Drug Administration rejected calls to ban BPA from food containers.