Sexually selected UV signals in the tropical ornate jumping spider, Cosmophasis umbratica may incur costs from predation.
Sexually selected ornaments and signals are costly to maintain if they are maladaptive in nonreproductive contexts. The jumping spider Cosmophasis umbratica exhibits distinct sexual dichromatism with males displaying elaborate UV body markings that signal male quality. Female C. umbratica respond favorably to UV-reflecting males and ignore males that have their UV masked. However, Portia labiata, a UV-sensitive spider-eating specialist and a natural predator of C. umbratica, is known to use UV reflectance as a cue when hunting prey. We investigated the cost of these UV signals in C. umbratica in terms of their predation risk. Under experimental conditions, three choice scenarios were presented to P. labiata individuals. Choices by P. labiata were made between male C. umbratica with and without the UV signal; a UV-reflecting male and non-UV-reflecting female; and a UV-masked male and female. The presence and absence of UV signals was manipulated using an optical filter. Portia labiata exhibited a strong bias toward UV+ individuals. These results suggest the sexually selected trait of UV reflectance increases the visibility of males to UV-sensitive predators. The extent of this male-specific UV signal then is potentially moderated by predation pressure. Interestingly though, P. labiata still preferred males to females irrespective of whether UV reflectance was present or not. This suggests P. labiata can switch cues when conditions to detect UV reflectance are not optimal.
Behavioural Ecology Group, Department of Biological Sciences, Macquarie University North Ryde, New South Wales, Australia ; Behaviour Ecology and Sociobiology Lab, Department of Biological Sciences, National University of Singapore Singapore, Singapore.
Matthew W
MW
Bulbert
Behavioural Ecology Group, Department of Biological Sciences, Macquarie University North Ryde, New South Wales, Australia ; Behaviour Ecology and Sociobiology Lab, Department of Biological Sciences, National University of Singapore Singapore, Singapore.
James C
JC
O'Hanlon
Center for the Integrated Study of Animal Behavior, Program in Cognitive Science, Indiana University Bloomington, Indiana.
Shane
S
Zappettini
Behaviour Ecology and Sociobiology Lab, Department of Biological Sciences, National University of Singapore Singapore, Singapore.
Shichang
S
Zhang
Behaviour Ecology and Sociobiology Lab, Department of Biological Sciences, National University of Singapore Singapore, Singapore ; Centre for Behavioural Ecology and Evolution, College of Life Sciences, Hubei University Wuhan, 430062, Hubei, China.
Daiqin
D
Li
Eavesdropping; Portia; UV; predation; trade-offs