Assessment of the life history characteristics of Rhinolophus blasii (Mammalia, Chiroptera) in South Africa

Abstract

This study investigated variation in activity, relative abundance, and body condition of Blasius’s horseshoe bat (Rhinolophus blasii) in relation to temperature, season, rainfall, and wind speed across seven years at the Meletse area, Limpopo, South Africa. The study was divided into two chapters: passive (Chapter 2) and active monitor (Chapter 3). An SM2+ bat detector recorded echolocation calls emitted by individual bats, which were used as a measure of the species activity and relative abundance. I also included active monitoring data, which involved the capture of bats (mist-nets and harp traps), where captured individuals were measured to obtain body condition information. Rainfall and season were the main factors that best explained the variation in the response variables relative abundance and activity for R. blasii. Relative activity peaked during winter to spring and reduced from summer to autumn. The largest proportion of R. blasii calls were recorded in the 2016 and 2017 sample periods, lowest in 2019. Rhinolophus blasii shows female-biased sexual dimorphism in body mass. Female body mass increased in winter and spring decreased in summer and autumn and had the lowest body mass in spring. This is the first known study on a southern African population of R. blasii, where southern African populations have different life-history characteristics compared to the European populations. This study would suggest that for southern African populations of R. blasii, monitoring can focus on females and males during spring to predict population trends. Further work is required for both females and males on how the two sexes increase body weight under the lowest food abundance during winter months. This focused monitoring can provide quantitative data that may be used for reporting; on the conservation risk (IUCN Red List) that southern African populations of R. blasii may be experiencing.