Figure 1. Mechanisms of mate choice influencing sexual isolation.

Mate choice is any bias in male reproductive success caused by female responses (active or passive) to phenotypic differences between males (6; Text S1). The labelled female tissues (seminal receptacle not tested for overrepresentation of candidate mate choice genes; green  =  other untested parts of the reproductive tract) are possible locations for mechanisms of mate choice (bullet points). The arrows represent routes by which mate choice may occur. Active female choice is represented by arrows starting or finishing at the female brain; passive female choice by any arrows that do not involve the female brain. Arrows between tissues within the female represent neuronal and/or hormonal responses. The digestive tract, containing the majority of the remainder of the tested tissues, is represented in dark grey. ACPs  =  accessory gland proteins; CHCs  =  cuticular hydrocarbons.