Singing strategies are linked to perch use on foraging territories in
heart-nosed bats
Abstract
Acoustic communication allows animals to coordinate and optimize
resource utilization in space. Cardioderma cor, the heart-nosed
bat, is one of the few species of bats known to sing during nighttime
foraging. Previous research found that heart-nosed bats react
aggressively to song playback, supporting the territorial defense
hypothesis of singing in this species. By tracking 14 individuals
nightly during the dry seasons in Tanzania we further investigated the
territorial defense hypothesis from an ecological standpoint, which
predicts singing should be associated with exclusive areas containing a
resource. We quantified the singing behavior of individuals at all
perches used throughout the night. Using home range analysis tools, we
quantified overall use night ranges and singing ranges, as well as areas
used in early and later time periods at night. Males engaged in
antiphonal singing from small (x̄ = 3.48 ± 2.71 ha), largely exclusive
areas that overlapped with overall night ranges used for gleaning prey.
Individuals varied in singing effort; however, all sang significantly
more as night progressed. Subsequently, areas used earlier at night and
overall use areas were both larger than singing areas. Individuals
varied in singing strategies. Some males sang for long periods in
particular trees and had smaller core areas, while others moved
frequently among singing trees. The most prolific singers used more
perches overall. The results support the hypothesis that acoustic
communication repertoires evolved in support of stable foraging
territory advertisement and defense in some bats.