Regurgitated food sharing in vampire bats is a cooperative behavior that has garnered scientific interest as an example of reciprocal helping among kin and non-kin. The amount of food given is estimated via the duration of mouth-licking. However, a growing body of evidence across other animal taxa, especially social insects, shows that mouth-to-mouth material transfer can serve many functions besides food sharing. In this review, we asked whether and to what extent mouth-licking in the common vampire bat (Desmodus rotundus) could be explained by functions other than regurgitated food sharing. We first review the evidence, including new analyses of published data, that food sharing occurs during mouth-licking bouts in vampire bats. We then review interpretations of mouth-licking in other mammal species and assess the likelihood that various hypothetical functions suggested in other species could occur in vampire bats. We conclude that the primary function of prolonged bouts of mouth-licking in vampire bats is sharing of ingested blood, but that microbial sharing is another likely benefit, and that short bouts of mouth-licking also function as social signals of begging or offering of food. Future work on this behavior should keep alternative explanations in mind when interpreting observations.
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The evolution of sanguivory in vampire bats: origins and convergences
Blood-feeding (sanguivory) has evolved more than two dozen times among birds, fishes, insects, arachnids, molluscs, crustaceans, and annelids; however, among mammals, it is restricted to the vampire bats. Here, the authors revisit the question of how it evolved in that group. Evidence to date suggests that the ancestors of phyllostomids were insectivorous, and that carnivory, omnivory, and nectarivory evolved among phyllostomids after vampire bats diverged. Frugivory likely also evolved after vampire bats diverged, but the phylogeny is ambiguous on that point. However, vampire bats lack any genetic evidence of a frugivorous past, and the behavioural progression from frugivory to sanguivory is difficult to envision. Thus, the most parsimonious scenario is that sanguivory evolved in an insectivorous ancestor to vampire bats via ectoparasite-eating, wound-feeding, or some combination of the two—all feeding habits found among blood-feeding birds today. Comparing vampire bats with other sanguivores, the authors find several remarkable examples of convergence. Further, it was found that blood-feeding has been ca. 50 times more likely to evolve in a vertebrate lineage than in an invertebrate one. The authors hypothesize that this difference exists because vertebrates are more likely than invertebrates to have the biochemical necessities required to assimilate the components of vertebrate blood.
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- Award ID(s):
- 2015928
- PAR ID:
- 10482120
- Publisher / Repository:
- Canadian Science Publishing
- Date Published:
- Journal Name:
- Canadian Journal of Zoology
- Volume:
- 101
- Issue:
- 4
- ISSN:
- 0008-4301
- Page Range / eLocation ID:
- 207 to 221
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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