Dung beetle resistance to desiccation varies within and among populations

Abstract

The study of desiccation resistance and its underlying traits is key to understanding species responses to changes in water availability, especially in the context of predicted increases in the frequency and severity of droughts due to climate change. We performed laboratory experiments using dung beetles, important ecosystem service providers, to investigate variations in physiological traits within species, both at population and individual levels. Desiccation resistance, water loss tolerance and water content were measured in lowland and mountain populations to investigate whether physiological traits vary (i) according to elevation across four species, and (ii) according to sex or male morphology (minor and major morphs) in two species, and if these responses were consistent across species. Our results showed that desiccation resistance of dung beetles varies both at individual and population levels. We found that desiccation resistance varied between lowland and mountain populations, but no differences were found for other traits such as water loss tolerance. Moreover, differences in individual physiological responses between females, major and minor males suggest that females were more resistant to desiccation than minors and majors, but these responses were species‐dependent. Our analysis at two hierarchical levels, individual and population, emphasizes the importance of considering within‐species variability in predictions of how species may respond to future climatic conditions. Predictions of the responses of species to environmental change may produce different conclusions if they rely on observations from single populations or take into account only a limited range of phenotypes per population.

Intra and interspecific differences in desiccation tolerance in native and alien Antarctic springtails in geothermal grounds

“…Populations from GA had greater desiccation tolerance than populations from NGA (Figure 1). This is in agreement with previous research for different insect taxa showing that populations from drier environments tend to show greater resistance to desiccation (Hoffmann & Harshman, 1999; Nervo et al, 2021; Phillips et al, 1996). Soil moisture is likely associated to temperature variations in GA, with fluctuations of up to 40°C on several consecutive days (see Lezcano et al, 2019).…”

A trait‐based framework for dung beetle functional ecology

“…At longer time‐scales, variation in soil humidity can cause changes in morphological and reproductive traits (Duncan, 2002 ; Hammond, 1976 ; Rougon & Rougon, 1983 ; Verdú & Galante, 2004 ), and even in ontogenetic development (Vessby, 2001 ). In general, larger body sizes allow a higher desiccation resistance (Nervo, Roggero, Chamberlain, Caprio, et al, 2021 ), although physiological responses to desiccation vary at the species and individual levels, with females often being more resistant than males within a species (Nervo, Roggero, Chamberlain, Rolando, et al, 2021 ). Physiological traits also respond to water gradients along with behavioural responses, reducing water loss rate and/or tolerating water loss in dryer conditions (Duncan & Byrne, 2000 ; Nervo, Roggero, Chamberlain, Caprio, et al, 2021 ), or increasing their tolerance to the hypoxic conditions in the wet dung pats of humid environments (Holter, 1991 ; Whipple et al, 2013 ).…”

Comparison of desiccation resistance in the litter-dwelling scorpion Tityus pusillus Pocock, 1893 (Scorpiones: Buthidae) from dry and wet tropical forests

“…https://doi.org/10.1636/JoA-S-22-018 Terrestrial arthropods are particularly vulnerable to water loss because of their relatively small body sizes (e.g., Bujan et al 2016;Nervo et al 2021). Therefore, desiccation resistance is a fundamental trait required for their survival, especially considering the predicted increase in the frequency and severity of droughts (IPCC 2014).…”