Mating system of a Neotropical roost-making bat: the white-throated, round-eared bat, Lophostoma silvicolum (Chiroptera: Phyllostomidae)

Abstract

The vast majority of bats strongly depend on, but do not make, shelters or roosts. We investigated Lophostoma silvicolum, which roosts in active termite nests excavated by the bats themselves, to study the relationship between roost choice and mating systems. Due to the hardness of the termite nests, roost-making is probably costly in terms of time and energy for these bats. Video-observations and capture data showed that single males excavate nests. Only males in good physical condition attracted females to the resulting roosts. Almost all groups captured from excavated nests were single male-multifemale associations, suggesting a harem structure. Paternity assignments based on ten polymorphic microsatellites, revealed a high reproductive success of 46% by nest-holding males. We suggest that the mating system of L. silvicolum is based on a resource-defense polygyny. The temperatures in the excavated nests are warm and stable, and might provide a suitable shelter for reproductive females. Reproductive success achieved by harem males appears to justify the time and effort required to excavate the nests. Reproductive success may thus have selected on an external male phenotype, the excavated nests, and have contributed to the evolution of an otherwise rare behavior in bats.

A new polytypic species of yellow-shouldered bats, genus Sturnira (Mammalia: Chiroptera: Phyllostomidae), from the Andean and coastal mountain systems of Venezuela and Colombia

“…It has been suggested that males tend to be larger than females in bat species under stronger sexual selection, or in which investing in harem defense is needed to maintain a polygynous mating system (Dechmann et al 2005;Campbell 2008). …”

Refugios naturales y artificiales de Murciélagos (Mammalia:Chiroptera) en la selva baja en el Noroeste de Perú

“…Esta especie típicamente ocupa termiteros, y en Panamá Kalko et al (2006) estudiaron la estructura, modifi cación y disponibilidad de la pecha y determinaron que los machos excavan y mantienen cavidades en el interior de los nidos activos de termitas. El éxito reproductivo de los machos justifi ca el esfuerzo y el microclima en el nido (cálido y estable) provee un refugio adecuado para la reproducción de las hembras (Dechmann et al 2005). Por otro lado, el uso de estos nidos reduce la competencia con otras especies de murciélagos en simpatría, y reduce la carga de parásitos (Kalko et al 2006).…”

All-offspring dispersal in a tropical mammal with resource defense polygyny

“…Such groups are usually called harems, although the female composition is often unstable or only temporarily stable (Storz et al 2000;Dechmann et al 2005). This is also known from other polygynous mammals such as ungulates (e.g., Ruckstuhl and Neuhaus 2000).…”

“…This bat lives year-round in small groups of one adult male with a maximum of 11 females and the most recent cohort of immature offspring. The majority of the males are solitary or live in bachelor groups (Dechmann et al 2005). Solitary males excavate active termite nets and use the resulting cavity as a day roost.…”