Background contrast affects detection and recognition of courting wolf spiders by intended and unintended receivers

• Published in: Behavioral ecology and sociobiology 2024-03, Vol.78 (3), p.43, Article 43
• Main Authors: Uetz, George W., Gilbert, Rachel, Wilson, Rebecca, Mann, Jacqueline, Macedonia, Joseph, Clark, David L.
• Format: Article
• Language: English
• Subjects: Animal Ecology; Behavioral Sciences; Biomedical and Life Sciences; Color; Color vision; Coloration; Conspecifics; Courtship; Eavesdropping; Females; Hypotheses; Latency; Leaf litter; Leaves; Life Sciences; Males; Natural selection; Original Article; Playback; Predators; Receivers; Schizocosa ocreata; Scotiotrichia ocreata; Spiders; Stimuli; Toads; Zoology
• ISSN: 0340-5443; 1432-0762
• DOI: 10.1007/s00265-024-03453-8

We used video playback of courting male Schizocosa ocreata wolf spiders to examine responses of intended receivers (conspecific females) and eavesdroppers (competitor males, predatory spiders, toads) to manipulations of spider color (natural color, monochromatic gray, monochromatic RBG average) displayed against complex leaf litter backgrounds (color, grayscale). Models of chromatic and achromatic contrast between spider stimuli and backgrounds were used to predict receiver responses. The results support the hypothesis that interactions between spider and background coloration affect detection and recognition, although responses varied with receiver type. Detection responses of intended receivers (female S. ocreata ) did not fit predictions of the chromatic contrast model in some cases, but showed a fair fit to the achromatic model. Detection responses of social eavesdroppers (male S. ocreata ) fit the chromatic and achromatic contrast models slightly better than did female responses (poor fit and very good fit, respectively). Eavesdropping wolf spider predators ( Rabidosa ) exhibited detection responses that significantly matched predictions of the chromatic (very good fit) and achromatic (excellent fit) models. Whereas jumping spiders ( Phidippus ) showed a good fit to the chromatic and achromatic contrast models, toad predators had a good fit only to the chromatic model. Recognition responses revealed a different pattern of fit to the chromatic and achromatic models across receiver types, although Rabidosa again indicated a significant fit to both models. Taken together, the results of this study identify both chromatic and achromatic features of spider appearance as likely explanations for differences in behavioral responses of intended and unintended receivers. This outcome suggests the possibility that both sexual and natural selection likely target different features of male appearance during courtship. Significance statement Some of the most striking examples of animal displays involve conspicuous male courtship signals, although such signals often can be exploited by eavesdropping competitors and predators. In this study we manipulated the coloration of courting male Schizocosa ocreata wolf spiders and their leaf-litter backgrounds from pre-existing video footage. We then played back the altered video clips to female conspecifics and eavesdroppers (competing conspecific males and potential predators: non-conspecific wolf spiders, jumping spiders,