How blood-derived odor influences mate-choice decisions by a mosquito-eating predator.
Evarcha culicivora (Araneae, Salticidae) feeds indirectly on vertebrate blood by choosing, as preferred prey, bloodcarrying female mosquitoes. Mutual mate-choice behavior is also pronounced in this species. Here we show that, when E. culicivora feeds indirectly on blood, it acquires a diet-related odor that makes it more attractive to the opposite sex. The mate-choice decisions of the adults of both sexes were investigated in a series of experiments based on comparing how long the test spider remained close to the odor of one source spider on one day and to the odor of a different source spider on the following day. Four different maintenance diets for source spiders were used in these experiments: bloodfed female mosquitoes (Culicidae, Anopheles gambiae ss), sugar-fed female mosquitoes, male mosquitoes, and lake flies (Chironomidae, Nilodorum brevibucca). Both sexes of E. culicivora spent more time close to the odor of opposite-sex conspecifics that had been on a diet of bloodfed mosquitoes (blood diet) instead of any of the three nonblood diets. Opposite-sex conspecifics that had been on a nonblood diet became more attractive once they were switched to a blood diet. That the attractive odor from blood dissipates was shown when spiders became less attractive once they were switched to a nonblood diet or subjected to a fast. However, there was no evident preference for the odor of a same-sex conspecific on a blood diet instead of a lake fly diet. These findings are discussed in the context of sexual selection and sensory exploitation.
Cross
Fiona R
FR
School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand.
Jackson
Robert R
RR
Pollard
Simon D
SD
D000818:Animals; D000852:Anopheles / Q000502:physiology*; D001769:Blood; D004175:Diptera / Q000502:physiology; D005247:Feeding Behavior; D005260:Female; D008297:Male; D009812:Odorants; D046109:Passeriformes / Q000502:physiology*; D012737:Sex Factors; D013112:Spiders / Q000502:physiology