HETEROSEXUALSIGNALLING BY THE LIZARD ANOLIS CAROLINENSIS,WITH INTERSEXUAL COMPARISONSACROSS CONTEXTS

We quanti ed the structure and use of signals exchanged by males and females within the female-defencepolygyny of the lizard,Anolis carolinensis. During heterosexual interactions, both sexes performed three kinds of stereotypic headbob displays (A, B, and C) with equal precision. These three display types were essentially identical to A, B, and C display types previously documented for both sexes during consexual contests, and for males when dis-playing alone (non-directed context). Therefore, there is no courtship-specic headbob dis-play in A. carolinensis. Although interacting males and females displayed at a similar mean frequency (»20 displays/h), signalling was sexually dimorphic in that: (1) males used pre-dominately C displays (89%), whereas females used predominantly A and B displays (48% and 50%, respectively); (2) males extended their dewlaps with almost every display (98%), whereas females extended their dewlaps with few displays (<2%); (3) males sequenced 80% of displays in volleys of two or more displays, whereas females performed only 12 % of dis-plays in volleys; and (4) males concluded 22 % of displays with shudderbobs (i.e. display modi er composed of shallow, quick, double bobs), whereas females never appended dis-plays with shudderbobs. From eld and laboratory data on A. carolinensis signal behaviour during other social contexts and the species ’ female-defencemating system, we interpret het-erosexual signalling from a perspective of intrasexual selection to discuss the: (1) absenc