Unusual echolocation behaviour of the common sword-nosed batLonchorhina aurita: an adaptation to aerial insectivory in a phyllostomid bat?

Abstract

Most insectivorous bat species in the Neotropical family Phyllostomidae glean insects from ground, water or vegetation surfaces. They use similar and stereotypical echolocation calls that are generally very short (less than 1–3 ms), multi-harmonic and frequency-modulated (FM). By contrast, the common sword-nosed bat, Lonchorhina aurita , which has the longest noseleaf in the entire phyllostomid family, produces distinctly different echolocation calls. They are composed of a constant frequency (CF) component with a peak frequency of 45 kHz, followed by a short FM down-sweep at the end. With a mean call duration of 6.6 ms (max. 8.7 ms) when flying in the open they have the longest echolocation calls reported from phyllostomid bats. In cluttered environments, the CF-component is very short. In open habitats, however, L. aurita can emit pure CF-calls without the terminal FM-component. We also recorded in the field a distinct terminal group that closely resembles the feeding buzzes of aerial hawking bat species from other bat families. This is the first time the echolocation call design of L. aurita is presented. In addition, we contrast the echolocation behaviour of individuals flying in open and confined situations. Our results suggest that the unique echolocation system of L. aurita represents an adaptation to aerial hawking, a very unusual hunting mode within the phyllostomid family.

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

“…Due to the unique nature of this species' echolocation, records of occurrence may emerge through future canopy surveys utilizing bioacoustics, subsequently improving our understanding of its ecological requirements. Although not present in our study area, Lonchorhina aurita represents another species from the subfamily Phyllostominae whose call Gessinger et al (2019) recently demonstrated to differ fundamentally from the stereotypical echolocation call design of the family, likely reflecting an adaptation to aerial hawking.…”

The Sonozotz project: Assembling an echolocation call library for bats in a megadiverse country

“…Most of the members of Phyllostomidae family emits echolocation calls (usually of low intensity) composed of multiharmonic components and constant modulated frequencies (Gessinger et al, 2019). The adaptability to understory orientation and the similarity among echolocation calls within this diverse group of bats makes almost impossible to detect particular signatures to identify species acoustically.…”

“…The adaptability to understory orientation and the similarity among echolocation calls within this diverse group of bats makes almost impossible to detect particular signatures to identify species acoustically. Nevertheless, we recorded species of the Glyphonycterinae, Macrotinae, Micronycterinae, and Phyllostominae subfamilies because recent descriptions of some species show that they emit intense and distinct calls that could be included in monitoring programs (Brinkløv, Kalko, & Surlykke, 2010; Geipel, Jung, & Kalko, 2013; Gessinger et al, 2019; Weinbeer et al, 2013). This is particularly important as several members of these subfamilies are known to be sensitive to habitat disruption (Clarke, Rostant, & Racey, 2005; Fenton et al, 1992).…”

“…Scientific names were standardized according to Ramírez‐Pulido, González‐Ruiz, Gardner, and Arroyo‐Cabrales (2014), but we considered that Natalidae contains only one species, Natalus mexicanus (López‐Wilchis et al, 2012), and that Molossus sinaloae and M. alvarezi are different species (González‐Ruiz, Ramírez‐Pulido, & Arroyo‐Cabrales, 2011). For this study, we also include the echolocation calls of species from the Glyphonycterinae, Macrotinae, Micronycterinae, and Phyllostominae subfamilies (Phyllostomidae), as most of these species base their diet in insects and also because some species have proven to emit intense and distinct vocalizations that resemble those of aerial insectivorous and trawling bats of other families (Gessinger, Gonzalez‐Terrazas, Page, Jung, & Tschapka, 2019; Weinbeer, Kalko, & Jung, 2013).…”

The sonar beam of Macrophyllum macrophyllum implies ecological adaptation under phylogenetic constraint

“…Macrophyllum macrophyllum emits calls with a timefrequency structure like other phyllostomids, but of higher intensities (Brinkløv et al, 2010). It is one of few phyllostomid bats known to use a distinct search, approach and buzz pattern in its echolocation emission during prey capture, as otherwise observed in the majority of aerial hawking and trawling bats (Brinkløv et al, 2009;Gessinger et al, 2019;Weinbeer and Kalko, 2007). These specific adaptations show that M. macrophyllum has adapted its echolocation to the hunting niche, but it is still a nose-emitting bat originating from a family dominated by gleaners.…”