Examination of prior contest experience and the retention of winner and loser effects

Abstract

In many animal taxa, prior contest experience affects future performance such that winning increases the chances of winning in the future (winner effect) and losing increases the chances of losing in the future (loser effect). It is, however, not clear whether this pattern typically arises from experience effects on actual or perceived fighting ability (or both). In this study, we looked at winner and loser effects in the jumping spider Phidippus clarus. We assigned winning or losing experience to spiders and tested them against opponents of similar fighting ability in subsequent contests at 1-, 2-, 5-, and 24-h intervals. We examined the strength of winner and loser effects, how long effects persist, as well as how experience affected perceived and actual fighting ability. Our results demonstrate that winner and loser effects are of approximately the same magnitude, although loser effects last longer than winner effects. Our results also demonstrate that previous experience alters actual fighting ability because both the assessment and escalation periods were affected by experience. We suggest that the retention time of experience effects depends on expected encounter rates as well as other behavioral and ecological factors. In systems with short breeding seasons and/or rapidly fluctuating populations, context-dependent retention of experience effects may allow males to track their status relative to the fluctuating fighting ability of local competitors without paying the costs necessary to recall or assess individual competitors.

Figure 1

The proportion of male Phidippus clarus that won a contest with a naive size-matched rival at 4 time intervals after first winning (black) or losing (white) an initial contest. In P. clarus, relative size predicts competitive success, so if there is no experience effect, 50% of previous winners or losers should win subsequent contests (dotted line). Stars indicate proportions significantly different from 50% (see text).

Figure 2

Average duration of the escalation period of prior winners that won (black) and prior losers that lost (white) in their second contests with a naïve male.

Figure 3

Average duration of the escalation period of prior losers that lost (white) and won (black) and prior winners that lost (white) and won (black) in their second contests at the different time frames.