Information transfer at evening bat colonies

Abstract

Abstract. Four lines of evidence indicate that evening bats, Nycticeius humeralis, at nursery colonies in northern Missouri transfer information by following each other to feeding and roosting sites . (1) Daily estimates of insect density from five automated suction traps showed that common prey in evening bat faecal samples, small beetles and flies, occur in rich patches that persist for several days . Bats apparently respond to prey density and variability because these variables independently predict the number of trips and capture success of foraging bats . (2) Videotape records of the time and weight of bats arriving and departing from a colony indicated that adult females leave within 10 s of each other on second and subsequent foraging trips more often than expected within a night . These records also revealed that bats alternate between apparent following and leading over a summer, that unsuccessful foragers follow previously successful foragers within a night, and that the foraging success of putative followers is greater than that of unsuccessful bats which depart solitarily. (3) Radio-tagged bats often returned to foraging sites both within a night and on successive nights . Furthermore, three of 12 radio-tagged bats flew closer to another radio-tagged bat throughout a night than expected if bats foraged independently . (4) Two field experiments in which bats were excluded from their roosts for one night demonstrated that newly volant bats follow adult females to alternate roosts . The possibility that evening bats acquire information passively by monitoring echolocation signals or actively by vocal advertisement is discussed .

Foraging Behaviour and Habitat use by the European Free-Tailed BatTadarida teniotis

“…Prey swarms may be located either during the broad search flights that we observed and/or, as suggested by Wilkinson (1995), by information transfer. This could take place near the roosts, as mentioned above, or by eavesdropping on other foraging individuals.…”

Intra- and Interspecific Responses to Rafinesque's Big-Eared Bat (Corynorhinus rafinesquii) Social Calls

“…Social calls are usually longer in duration and lower in frequency than echolocation calls and thus, are more effective at longer distances (Pfalzer and Kusch, 2003). Social calls include mating calls, alarm calls, territorial calls, and food calls (Wilkinson, 1995) and can aid in finding patchily distributed food resources (Wilkinson, 1992;Safi and Kerth, 2007) and roosts (Ruczyński et al, 2007(Ruczyński et al, , 2009). In contrast, echolocation calls are used to gain information about the environment (Fenton, 2003).…”

Spatio-temporal vigilance architecture of an Australian flying-fox colony

“…Sensu Nelson, the idea behind the "guard hypothesis" (Nelson 1965) is that peripheral individuals have an important role in maintaining the safety of the colony since they are presumably the first to spot predators. Pteropus poliocephalus, the grey-headed flying-fox, has been described to use true acoustic "alarm calls", specific high-pitched calls that may alert others when a potential threat is detected (Wilkinson 1995). Foraging-related causes of vigilance, usually important confounding variables (Hirsch 2007), do not apply to flying-foxes since food resources are absent in forest patches occupied by flyingfox colonies.…”