Complex signal usage by advertising male Green Anoles (Anolis Carolinensis): A test of assumptions

摘要

The Green Anole (Anolis carolinensis) has three stereotyped head bob displays (labeled A, B, and C) which it differentially uses during directed hetero- and consexual exchanges. We found free-ranging males advertise (i.e., nondirected signaling) with the same three displays in a complex but consistent manner. From videotapes of 10 adult males recorded across breeding and postbreeding seasons, we analyzed 2308 nondirected displays from two functional subsets of the advertisement context - "monitor" (stationary males signaling from monitoring sites) and "travel" (males signaling while moving between monitoring sites). Using five hypotheses to guide the analysis, we found breeding males (1) used all three display types during both monitor and travel; (2) averaged mostly C displays during monitor (ratio of C:A + B = 4:1); (3) increased A and B displays four-fold during travel (C:A + B = 1:1); (4) averaged a four-fold lower display rate during monitor than during travel (displays/min = 0.8 vs. 3.5, respectively); (5) averaged three-fold more volleys of displays (i.e., a rapid succession of displays) during monitor than during travel (ratio of volleys:singly performed displays = 1.7:1 vs. 0.5:1, respectively); (6) averaged longer volleys during monitor than during travel (displays/volley = 3.3 vs. 2.5, respectively); and (7) appended the "shudderbobbing" modifier (rapid, shallow bobs) to a third of all displays. Males maintained these seven tendencies into the postbreeding, but with much reduced frequencies. The nondirected signaling during monitor and travel are respectively similar to that of long- and short-range aggressive signaling used by contesting males, and bears little similarity to the signaling males use toward females. From our data and those of other studies, we argue that males intend their nondirected signaling for an unidentified male audience (i.e., intrasexually selected), and not for an unidentified female audience (i.e., intersexually selected).