Echolocation of Central Amazonian ‘whispering’ phyllostomid bats: call design and interspecific variation

Abstract

Phyllostomids (New World leaf-nosed bats) are the ecologically most diverse bat family and have undergone the most extensive adaptive radiation of any mammalian family. However comprehensive, multi-species studies regarding phyllostomid echolocation are scarce in the literature despite abundant ecological research. In this study, we describe the call structure and interspecific variation in call design of 40 sympatric phyllostomid species from the Central Brazilian Amazon, focussing on general patterns within genera, subfamilies and between feeding guilds. All but one species utilized short, broadband FM calls consisting of multiple harmonics. As reported for other bat families, peak frequency was negatively correlated with body mass and forearm length. Twenty-five species alternated the harmonic of maximum energy, principally between the second and third harmonic. Based on PCA, we were unable to detect any significant differences in echolocation call parameters between genera, subfamilies or different feeding guilds, confirming that acoustic surveys cannot be used to reliably monitor these species. We present Ametrida centurio as an exception to this generalized phyllostomid structure, as it is unique in producing a mono-harmonic call. Finally, we discuss several hypotheses regarding the evolutionary pressures influencing phyllostomid call structure.

Olfactory tracking strategies in a neotropical fruit bat

“…Like other neotropical leaf-nosed frugivores, Sturnira produces low-intensity, high-frequency echolocation calls, with peak frequencies ranging from 65 kHz to 92 kHz ( Jennings et al, 2004 ; Yoh et al, 2020 ), emitted via the nose. Fruit- and nectar-feeding bats within the family Phyllostomidae (including Sturnira ) are thought to primarily use echolocation for general orientation, as well as the final approach and selection of food items ( Gonzalez-Terrazas et al, 2016 ; Kalko and Condon, 1998 ; Leiser-Miller et al, 2020 ; Thies et al, 1998 ).…”

Phylogenetic Patterns in Mouth Posture and Echolocation Emission Behavior of Phyllostomid Bats

“…Yet, phyllostomid species show remarkably homogenous echolocation call structure, often assumed to be associated with the presence of a noseleaf, and, by extension, nasal emission of calls. In the context of recent growing interest in phyllostomid echolocation behavior (Gonzalez-Terrazas et al, 2016;Rodríguez-San Pedro and Allendes, 2017;Gessinger et al, 2019;Yoh et al, 2020;Zamora-Gutierrez et al, 2020), we explored mouth and head angle postures during echolocation within this family to make predictions about call emission modes. Following anecdotal and photographic evidence of phyllostomid bats flying with an open mouth, we investigated whether this behavior occurs occasionally or consistently across the family.…”

“…Emission of echolocation calls through nostrils integrated into a noseleaf has the advantage of a reduced vertical and horizontal beam width (Hartley and Suthers, 1987;Vanderelst et al, 2010). Phyllostomid bats usually filter out the fundamental harmonic and use several higher harmonics instead (Yoh et al, 2020). This is probably achieved through a filtering process in the nasal cavities, as demonstrated for Rhinolophus hildebrandti (Rhinolophidae).…”

“…Generally, echolocation is shaped by the respective ecological niche (Schnitzler and Kalko, 2001;Jones and Holderied, 2007), so we expect differences between species with differing foraging behaviors. However, on first glance most phyllostomid bat species use very similar echolocation calls, which are usually short (<2 ms), multiharmonic, frequency-modulated (FM), and cover a broad bandwidth (Kalko, 2004;Korine and Kalko, 2005;Weinbeer and Kalko, 2007;Gessinger, 2016;Yoh et al, 2020). The free-standing noseleaves found in almost all phyllostomid bats are thought to play an essential role in the emission of these echolocation calls (Hartley and Suthers, 1987;Arita, 1990;Vanderelst et al, 2010).…”

Estándares para registrar señales de ecolocalización y construir bibliotecas de referencia de murciélagos en Colombia

“…que emitan a una corta distancia del detector (Fenton et al, 2001). Las principales limitantes para implementar estudios acústicos sobre la familia Phyllostomidae son la baja especificidad de los diseños de señal, la baja amplitud (Anexo 1) y la alta frecuencia de estas señales (Yoh et al, 2020). En esta familia hay pocos casos de especialización en el diseño de las señales acústicas, y puede que esto se deba probablemente a que muchas especies usan el olfato o la visión en combinación con la ecolocalización para ubicar a sus objetivos (Leiser-Miller et al, 2020).…”