Assessment during aggressive contests between male jumping spiders

Abstract

Assessment strategies are an important component in game theoretical models of contests. Strategies can be either based on one’s own abilities (self assessment) or on the relative abilities of two opponents (mutual assessment). Using statistical methodology that allows discrimination between assessment types, we examined contests in the jumping spider Phiddipus clarus. In this species, aggressive interactions can be divided into ‘pre-contact’ and ‘contact’ phases. Pre-contact phases consist of bouts of visual and vibratory signaling. Contact phases follow where males physically contact each other (leg fencing). Both weight and vibratory signaling differences predicted winners with heavier and more actively signaling males winning more contests. Vibratory behaviour predicted pre-contact phase duration, with higher signaling rates and larger differences between contestants leading to longer pre-contact interaction times. Contact phase duration was predicted most strongly by the weight of losing males relative to that of winning males, suggesting that P. clarus males use self-assessment in determining contest duration. While a self-assessment strategy was supported, our data suggest a secondary role for mutual assessment (“partial mutual assessment”). After initial contest bouts, male competitors changed their behaviour. Pre-contact and contact phase durations were reduced while vibratory signaling behaviour in winners was unchanged. In addition, only vibratory signaling differences predicted winners in subsequent bouts suggesting a role of experience in determining contest outcomes. We suggest that the rules and assessment strategies males use can change depending on experience and that assessment strategies are likely a continuum between self- and mutual assessment.

Weaponry, color, and contest success in the jumping spider Lyssomanes viridis

“…Whether conspecific observers actually use the information embedded in coloration, however, remains unknown. In several salticid species, including Phidippus johnsoni, Euophrys parvula, Zygoballus rufipes, Trite planiceps, Plexippus paykulli, Evarcha culicivora, and Phidippus clarus, larger-bodied males have been found to be more likely to win male-male competitive interactions and to gain access to females (Jackson, 1980;Wells, 1988;Faber and Bayliss, 1993;Taylor and Jackson, 1999;Taylor et al, 2001;Cross and Jackson, 2007;Elias et al, 2008), but the relationship between weapon size and contest success remains unexplored.…”

The mechanosensory lateral line is used to assess opponents and mediate aggressive behaviors during territorial interactions in an African cichlid fish

“…This decreased fight motivation was likely due to an impaired ability to adequately assess the opponent. Models of animal assessment range from pure self-assessment to pure mutual assessment but it is likely that animals use a combination of self and mutual assessment throughout an agonistic interaction (Arnott and Elwood, 2009;Enquist et al, 1990;Elias et al, 2008;Hofmann and Schildberger, 2001;Hsu et al, 2008;Neat et al, 1998). For instance, Hsu et al (2008) suggested that animals rely on mutual assessment to determine when to escalate a fight, but then switch to selfassessment to determine how long to sustain the fight.…”

The active metabolic rate predicts a male spider's proximity to females and expected fitness

“…There are numerous examples where contests between similar-sized rivals lead to escalated contests in which morphological traits fail to predict contest outcomes (e.g. spiders [15] and fish [16]). We suggest that greater active metabolic rates may contribute to determining outcomes in these situations.…”