Tents and harems: apparent defence of foliage roosts by tent-making bats

Abstract

Palmate umbrella tents used by tent-making bats in Trinidad, West Indies, were observed in three species of Neotropical palms, Sabal mauritiiformis, Coccothrinax barbadensis and Mauritia flexuosa. Tents were most common in palm leaves that have supporting petioles angled at 50–70° above the horizontal. The shape and volume of tents is influenced mostly by leaf morphology (leaf width and leaflet length) and age of the tent. Tent-crowns varied from being heart-shaped in S. mauritiiformis, oval or round in C. barbadensis and spade-shaped in M. flexuosa. Leaves in which tents were constructed were most often beneath overhanging vegetation, and were generally free of vegetation below, allowing bats to enter and depart from tents without being impeded by the clutter of adjacent vegetation.Singles and small apparent harem groups of two bat species, Artibeus jamaicensis and Uroderma bilobatum, were captured and observed in tents made from the leaves of S. mauritiiformis and C. barbadensis. No bats were observed in tents constructed in leaves of M. flexuosa. The apparent harem social organization in these and other tent-making bat species suggests that leaves modified into tents may provide critical and defendable resources that promote the evolution of polygyny. This hypothesis is based on the observed patchy distribution of suitable palm trees, the inappropriateness of many palm leaves as potential tents and the resultant architecture provided by palmate umbrella tents. We suggest that tent-making is an adult male behaviour.

Roosting Ecology of Amazonian Bats: Evidence for Guild Structure in Hyperdiverse Mammalian Communities

“…The autecological importance of bat roosts is suggested by numerous morphological and behavioral adaptations associated with roost occupancy in a wide range of species (Kunz, 1982;Thewissen and Etnier, 1995;Kunz and Lumsden, 2003;Dechmann et al, 2009;Santana et al, 2011), by the substantial energetic investment made by species that construct their own shelters (Dechmann et al, 2005;Rodríguez-Herrera et al, 2011), and by male defense of roosts in harem-forming species (Bradbury and Emmons, 1974;Morrison, 1979;Morrison and Morrison, 1981;Kunz and McCracken, 1996). Although some structures used as diurnal refugia-such as tree cavities and foliage-are seemingly abundant in many habitats, careful study of roost characteristics suggest that bats are highly selective about where they roost (Kunz and Lumsden, 2003), so ideal refugia may often be in short supply.…”

Bats of Vieques National Wildlife Refuge, Puerto Rico, Greater Antilles

“…For the four species known from Vieques, roost sites commonly used by each species are available. Although N. leporinus and A. jamaicensis roost in caves, both species also commonly roost in trees (Hood and Jones 1984; Kunz and McCracken 1996). We captured 51 of 59 N. leporinus near a suspected tree roost at Playuela in an area consisting mainly of red mangroves (R. mangle).…”

Social structure of a polygynous tent‐making bat,Cynopterus sphinx(Megachiroptera)

“…Tents attract groups of reproductive females that a single male then defends as a harem. Similarly, among several members of the family Phyllostomidae (Artibeus and Uroderma), polygynous mating systems appear to be linked to male defense of reproductive access to tent-roosting females (Kunz & McCracken, 1996). In this paper we report results of one of the first in-depth studies of social structure in a megachiropteran fruit bat.…”

“…Porter, 1979;Williams, 1986;Fleming, 1988) and Artibeus jamaicensis (cf. Morrison, 1979;Kunz, August et al, 1983;Morrison & Handley, 1991;Kunz & McCracken, 1996). Causal factors in this apparent convergence likely include similarities in reproduction (seasonal polyestry), social behavior (female clustering in confined roosting spaces), and various aspects of their foraging ecology that obviate seasonal migration.…”

“…Female gregariousness at diurnal roosting sites has apparently facilitated polygynous mating systems in an ecologically diverse array of species. In each case, the apparent skew in male reproductive access results from the direct and/or indirect defense of female groups in roosts such as the buttress cavities of large trees (Bradbury & Emmons, 1974;Bradbury & Vehrencamp, 1976), tree cavities (Morrison, 1979;Wilkinson, 1985), foliage roosts (Kunz & McCracken, 1996;Storz et al, 2000), and cavities or indentations in cave ceilings (McCracken & Bradbury, 1981;Kunz, August & Burnett, 1983;Williams, 1986). However, superficial similarities in the social mating systems of these species often belie differences in the size and compositional stability of social groups (e.g, Bradbury & Emmons, 1974;Bradbury & Vehrencamp, 1976).…”