Title

Display behavior and territoriality in the lizard Anolis sagrei

Date of Award

1998

Availability

Article

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Biology

First Committee Member

Richard R. Tokarz, Committee Chair

Abstract

Many territorial animals have repertoires of signals. However, it is generally not known what is indicated by specific variants of these signals, particularly when the interactants are relatively far apart. I studied how changes in several social/spatial factors affected the relative proportions of different display variants of territorial male lizards (Anolis sagrei).I experimentally studied the effects of differences of residence time that affected competitiveness in males that were establishing territories. I studied these effects in a long-distance context when males were on separate patches of high-quality habitat about 5 m. apart. I also studied these effects in a short-distance context when both opponents were on a single high-quality habitat patch. In both long- and short-distance contexts, I created encounters in which 1-day residents met new arrivals and encounters in which both individuals were new arrivals.I additionally examined whether the relative proportions of different display variants varied with differences in social contexts among free-living males. These contexts included the distance of the displayer from the center of its home range and whether another male was near the displayer. I also examined whether males moved their home ranges during the breeding season to test whether males frequently established new territories during the months that I conducted my experiments. I also tested whether stress caused by the lizards being handled affected the relative proportions of different display variants.Residence time affected the relative frequencies of display elements called nods and bobs. However, the effects differed, depending on opponent proximity. In long-distance encounters 1-day residents performed more nods relative to bobs than new arrivals; in short-distance encounters 1-day residents performed fewer nods relative to bobs than new arrivals. Possible reasons for this complex pattern are discussed.Free-living males produced more volleys of nods (nodding displays) relative to volleys of bobs (bobbing displays) when they were in the more-frequently occupied central portions of their home ranges than when they were in the less-frequently occupied peripheries of their home ranges. The presence/absence of other males within 2 m. of displaying males did not affect the relative proportions of nodding displays and bobbing displays, but there were very few very close-range encounters. Handling did not affect the relative proportions of nodding displays and bobbing displays. Males shifted their home-range locations during the course of the study. These results, combined with the results of the experimental work, suggest that the familiarity of a lizard with the area from which it is displaying strongly affects the relative proportions of different display variants.

Keywords

Psychology, Behavioral; Biology, Zoology

Link to Full Text

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