Echolocaton call characterizaton of insectvorous bats from caves and karst areas in southern Luzon Island, Philippines

Abstract

Bats are excellent bioindicators and are increasingly used to assess ecosystem health and monitor changes in the environment. Due to increased awareness of the potental transmission of pathogens from bats to humans and recognizing the limitatons of traditonal bat sampling methods, the use of of non-invasive sampling techniques such as bat recorders were recommended for feld-based monitoring studies. In the Philippines, however, bat bioacoustcs is stll a growing feld, and the scarcity of acoustc data hinders the use of echolocaton calls to conduct accurate inventories and populaton monitoring of echolocatng bats. Here, we recorded and characterized echolocaton calls of insectvorous bats from caves and karst areas located in southern Luzon Island, Philippines. In additon, we compared our results with other studies performed within and outside the country to identfy possible regional and local variaton in acoustc characters for some species. A total of 441 echolocaton calls were recorded from six bat families: Hipposideridae (fve species), Rhinolophidae (fve species), Vespertlionidae (three species), Miniopteridae (two species), Megadermatdae (one species), and Emballonuridae (one species). Discriminant functon analyses (DFA) with leave-one-out cross validaton correctly classifed bats emitng calls dominated with a constant frequency (CF) component (rhinolophids and hipposiderids) with?>97% success and those producing frequency modulated (FM) calls (Miniopteridae and Vespertlionidae) with 88.9% success. We report echolocaton calls for Philippine populaton of two species (Megaderma spasma and Hipposideros lekaguli) for the frst tme. Moreover, we present geographical variatons in call frequencies for some species by comparing previously reported acoustc data elsewhere across the species’ range. This underscores the importance of establishing a readily accessible and comprehensive local reference library of echolocaton calls which would serve as a valuable resource for examining taxonomic identtes of echolocatng bats, partcularly those whose calls exhibit biogeographic variatons.