Seasonal emergence counts from a multispecies horseshoe bat (Chiroptera: Rhinolophidae) roost in the Philippines

Abstract

The seasonal roost use of Philippine horseshoe bats (Family: Rhinolophidae) is poorly known. Here, we monitored an undisturbed rock crevice roost comprised of four Rhinolophus species on Mount Makiling, Philippines, to document seasonal changes in colony size and species composition. Evening emergences were videotaped using an IR spotlight and an IR-sensitive camera and were acoustically recorded using an ultrasonic detector. Emergence counts ranged from an average of 7,965 bats in the wet season to 177 bats in the dry season. Higher emergence counts in the wet season, and the presence of post-lactating females and juveniles, together indicated that Rhinolophus arcuatus and Rhinolophus inops used the rock crevice as a maternity roost. Rhinolophus macrotis and Rhinolophus virgo were detected during all survey months but comprised a smaller proportion of the wet-season emergence than R. arcuatus and R. inops. These data, while limited in scope, provide the first evidence of seasonal cave use by Philippine horseshoe bats and highlight the potential conservation value of this particular roost as a maternity site for horseshoe bats within the Makiling Forest Reserve.

Echolocation call characterization of insectivorous bats from caves and karst areas in southern Luzon Island, Philippines

“…in Bohol Island which recorded an average FmaxE value of 54 kHz, whileDimaculangan et al (2019) recorded an average FmaxE value of 54.3 kHz for this species in Mt. Makiling in Luzon Island.…”

“…In the Philippines, bat bioacoustics is still in its infancy, and a comprehensive bat call library is still lacking. Relevant studies based on bioacoustics of bats are limited to very few localities and islands such as in Luzon (Sedlock 2001;Sedlock & Weyandt 2009;Esselstyn et al 2012;Dimaculangan et al 2019;Sedlock et al 2019;Amberong et al 2021;Taray et al 2021), Panay Island (Mould 2012), Bohol Island (Phelps et al 2018;Sedlock et al 2014a), and Siquijor Island (Sedlock et al 2014b). Previous works have focused on examining taxonomy (Sedlock & Weyandt 2009;Sedlock et al 2014b) and studying behaviour, cave emergence, and activity (Dimaculangan et al 2019;Sedlock et al 2019) using few available acoustic data.…”

“…Relevant studies based on bioacoustics of bats are limited to very few localities and islands such as in Luzon (Sedlock 2001;Sedlock & Weyandt 2009;Esselstyn et al 2012;Dimaculangan et al 2019;Sedlock et al 2019;Amberong et al 2021;Taray et al 2021), Panay Island (Mould 2012), Bohol Island (Phelps et al 2018;Sedlock et al 2014a), and Siquijor Island (Sedlock et al 2014b). Previous works have focused on examining taxonomy (Sedlock & Weyandt 2009;Sedlock et al 2014b) and studying behaviour, cave emergence, and activity (Dimaculangan et al 2019;Sedlock et al 2019) using few available acoustic data. Meanwhile, the works of Sedlock (2001), Amberong et al (2021), and Taray et al (2021) have delved into the characterization of acoustic calls of echolocating bats, aiming to establish a foundational dataset for creating a local bat call library for the Philippines.…”