Comparative characteristics of the echolocation signals of three horseshoe bats species (Chiroptera, Rhinolophidae) from the Eastern Caucasus (Dagestan)

Abstract

Background. In the Eastern Caucasus there are three species of horseshoe bats: Rhinolophus hipposideros, R. mehelyi and R. ferrumequinum. Their echolocation characteristics in this part of the range have not been adequately studied. At the same time, the main signal parameters of these species obtained from other parts of the range cannot be used for identification, which is caused by geographical variability. The purpose of the study is to describe the main characteristics of the echolocation signals in three species of horseshoe bats inhabiting the territory of Dagestan and to identify the main features by which they can be identified. Materials and methods. The work was performed during warm periods from 2019 to 2022. Recordings were made with a BATLOGGER M detector and analyzed in the BatSound 3.31 program. In total, about 80 minutes of recordings were collected for three species of horseshoe bats. The total number of echolocation pulses analyzed was 146. Time and hour-ton parameters were measured at the second harmonic: pulse length, initial, final, peak frequencies, and distance between pulses. The peak frequency of the first harmonic was measured. Statistical processing was performed using Statistica®6.0 software. Results and conclusions. In the three species of horseshoe bats inhabiting the territory of Dagestan, the signals possess a complex of specific characters that can be easily used in identification. No special analysis is required to identify R. ferrumequinum does not require special analysis because the main frequency values of the signals are minimal and do not overlap with those of other species. In R. hipposideros and R. mehelyi there are coincidences in frequencies. The values of the peak frequencies of the second harmonic in the species have minimal overlap, so this indicator is convenient for identification. These species are easily recognized by average values of pulse length and interval between them. In addition, a good sign of R. mehelyi can be the presence of sequences of short tandem pulses in the signal.

Keywords

• bats
• horseshoe bats
• rhinolophus ferrumequinum
• r. hipposideros
• r. megelyi
• echolocation signals
• dagestan