Colony size, sex ratio and cohabitation in roosts of Phyllostomus hastatus (Pallas) (Chiroptera: Phyllostomidae)

Abstract

Phyllostomus hastatus bat is species broadly distributed over the Neotropical region, which uses as diurnal roosts caves, hollow trees, palm leaves and human buildings. Thirteen diurnal roosts of P. hastatus were analysed from 1990 to 2009 in several localities of Rio de Janeiro State, regarding environment (rural, urban or protected area), type of roost (hollow tree, basement or roof), sex ratio and cohabitation. A nocturnal roost was also analysed. Sex ratio of P. hastatus varied considerably among roosts what may be explained by the fact this species can roost alone, in couples, in harems or in groups of bachelor males. Phyllostomus hastatus was observed in cohabitation with three other species: Molossus rufus, Molossus molossus and Myotis nigricans. Due to the frequency of cohabitation observed between P. hastatus and species of the genus Molossus, one or more advantages for the members of this association may be expected. The simultaneous usage of a feeding roost by a group of bachelor males is unknown information in the literature, and may suggest that this kind of group may interact with each other even when away from their diurnal roosts.Keywords: diurnal roost, nocturnal roosts, Southeastern Brazil.Tamanho da colônia, proporção sexual e coabitação em refúgios de Phyllostomus hastatus (Pallas) (Chiroptera: Phyllostomidae) ResumoPhyllostomus hastatus é uma espécie de morcego amplamente distribuída na região Neotropical, que utiliza como abrigo diurno cavernas, ocos de árvores, folhas de palmeiras e construções humanas. Treze abrigos diurnos de P. hastatus foram analisados entre 1990 e 2009, em diferentes localidades do Estado do Rio de Janeiro, quanto ao ambiente (rural, urbano ou unidade de conservação), tipo de refúgio (oco de árvore, porão ou telhado), proporção sexual e coabitação. Um abrigo noturno também foi analisado. A proporção sexual de P. hastatus nos agrupamentos estudados variou consideravelmente entre os abrigos, e isto pode ser explicado pelo fato desta espécie refugiar-se isoladamente, em casais, como haréns e em grupos de machos solteiros. Phyllostomus hastatus foi observado em coabitação com Molossus rufus, M. molossus e Myotis nigricans. Dada a frequência de observação da coabitação entre P. hastatus e espécies do gênero Molossus, espera-se uma ou mais vantagens para os integrantes desta associação. O uso de abrigo noturno por um grupo de machos solteiros é fato ainda inédito e pode sugerir que machos solteiros possam estar interagindo mesmo fora de seus abrigos diurnos.Palavras-chave: abrigo diurno, abrigo noturno, Sudeste do Brasil.

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

“…La mayoría de los especímenes presentaban áreas del cuerpo sin pelos, probablemente causadas por alguna enfermedad o parasitismo similar a la sarna de animales domésticos; también llamaba la atención la presencia de manchas de albinismo en la mayoría de los ejemplares. Junto a estos especímenes se colectó un ejemplar de Molossus molossus (Pallas), asociación registrada también en Brasil por Costa et al (2010). Los especímenes de Varillal se refugiaban entre las palmas del techo de paja de una "maloca" (construcción comunitaria con techo de palma).…”

Trichobius longipes (Diptera, Streblidae) as a parasite of Phyllostomus hastatus(Chiroptera, Phyllostomidae)

“…Since roosts may have different sex ratios (MCCRAKEN;BRADBURY, 1981;COSTA et al, 2010), different prevalence and intensity values may be observed, as in the present study. Constant roost changes may also be responsible for re-infestation and dispersal of ectoparasites within the bat population.…”

“…Harems are stable, with females living together for consecutive years, whereas long cohesion has not been observed in bachelor groups. However, even males form clusters (COSTA et al, 2010), and therefore aggregation does not explain the higher infestation observed on females. Long permanence in the same roost may result in higher infestation (LEWIS, 1995;KERTH, 2006KERTH, , 2007PATTERSON et al, 2007).…”

“…This species has wide distribution in South and Central America, and is absent only from Chile, Uruguay, and the islands of Central America (SANTOS et al, 2003). Females of P. hastatus are slightly larger than the males (SANTOS et al, 2003), and this species forms colonies composed of only bachelor males, colonies dominated by females, or harems (COSTA et al, 2010). The most frequently observed ectoparasites on P. hastatus are streblid flies (AUTINO et al, 2011;SANTOS et al, 2009;BERNARD, 2002).…”

Reproductive biology of the bat Sturnira lilium (Chiroptera, Phyllostomidae) in the Atlantic Forest of Rio de Janeiro, southeastern Brazil

“…In harem species a sexual proportion skewed to females can be expected (Mello and Fernandez, 2000), but this data, using long term sampling and a great variety of locals probably inhibit this difference as obtained by Costa et al (2010) in other harem bat species. Subadult bats were more netted from November to February, period that is expect the independence of the youngs borned in each year and less frequent from May to August, when few females showed reproductive activity.…”