Differential habitat use and reproductive patterns of frugivorous bats in tropical dry forest of northwestern Costa Rica

To determine if frugivorous bats in tropical dry forest differentially use a particular habitat and if this use is related to their reproductive patterns, I monitored populations from one site from January 1994 to January 1997 in Parque Nacional Palo Verde in northwestern Costa Rica. Abundance, reproductive condition, sex ratio, age-classes, and recapture data were compared across seasons and years. During 56 nights of sampling, 13 species of frugivores and 5 nectarivores were captured (N = 998). Carollia perspicillata, Artibeus jamaicensis, and Sturnira lilium were significantly more abundant in 1994 than in 1995 or 1996. Carollia perspicillata and A. jamaicensis were captured year-round, but there were peaks of abundance in the dry season and the middle of the rainy season. Sixteen percent of 244 adult female C. perspicillata and 20% of 87 A. jamaicensis were reproductive, principally in February through June. Forty-three percent of 28 adult female S. lilium were reproductive from February to June and in October and December. Fifty-four percent of 26 adult female Centurio senex were reproductive between December 1995 and February 1996. Few subadults were captured at this site. Sex ratios were significantly different across seasons for C. perspicillata and A. jamaicensis. Seventy-three C. perspicillata were recaptured and 25 (34%) of these were recaptured after more than 4 months. The results of this study indicate that the abundance of some tropical frugivorous bats varies between years and (or) over seasons at a particular site within tropical dry forest.