Contest dynamics for food and reproductive resources are defined by health condition in a dung beetle

Abstract

Male dung beetles compete to obtain food and females, and early resource recognition and appropriation increase the probability of mating. The outcome of such encounters is expected to be defined by self‐ and the opponent’s health condition. In this study, we analyzed the effect of body condition and immune defense on the contest dynamics between males that rolled a food ball with a partner female (owner males) and intruder males of dung beetle Canthon cyanellus. Body condition was measured as body size, body dry mass, lipid mass, and muscle mass; immune defense was estimated via phenoloxidase activity. Owner males with higher lipid mass contacted the food ball significantly earlier than owner males with lower lipid mass. Individuals with lower phenoloxidase activity started to roll food balls earlier than individuals with higher phenoloxidase activity. Owner males that had higher body dry mass, compared to female partners, began to roll the food ball significantly earlier than male–female pairs with lower differences in dry mass. Heavier males won significantly more contests than lighter males. Our results suggest that the health condition is a key factor related to the dynamics and outcome of male–male contests for resources and females in C. cyanellus. Consequently, differences in individual condition are main determinants of contest outcomes in dung beetles.

Primary forest loss and degradation reduces biodiversity and ecosystem functioning: A global meta‐analysis using dung beetles as an indicator taxon

“…This combination of factors may explain the negative effects of dung beetle assemblages in response to the undisturbed primary forest conversion. Also, it should be noted that, responses could be varied according to the specific micro‐habitat requirements of different beetle species (Davis et al, 2001), given for a physiological restrictions (França et al, 2018; Salomão et al, 2019), associated with elevated soil temperatures and light intensity, lower soil moisture levels and increased soil compaction impacting on feeding, reproduction and establishment (Chown, 2001; Halffter & Edmonds, 1982; Nyamukondiwa et al, 2018; Osberg et al, 1994; Sheldon et al, 2011).…”

“…given for a physiological restrictions (França et al, 2018;Salomão et al, 2019), associated with elevated soil temperatures and light intensity, lower soil moisture levels and increased soil compaction impacting on feeding, reproduction and establishment (Chown, 2001;Halffter & Edmonds, 1982;Nyamukondiwa et al, 2018;Osberg et al, 1994;Sheldon et al, 2011).…”

Dung or carrion? Sex and age determine resource attraction in dung beetles

“…According to the current nutritional condition (Simpson & Raubenheimer, 1993; Chapman & Boer, 1995), individuals in poor condition (e.g. low body mass and starvation, as indicated by low lipid mass) may display alternative competitive strategies in order to successfully obtain a resource (Salomão et al ., 2019). Therefore, evaluating how physiological condition and body size affect resource choice is crucial for a better understanding of nutritional dynamics among animal populations.…”

“…Due to the intense competition for food resources in tropical dung beetles (Hanski & Cambefort, 1991), we could expect that intraspecific segregation could facilitate the establishment of beetle populations in the environments. Furthermore, in the scenario of resource preference, physiological condition is determinant for dung beetles, and larger, heavier dung beetles tend to more successfully obtain food and reproductive resources (Chamorro‐Florescano et al ., 2011, 2017; Salomão et al ., 2019). In this sense, better‐quality individuals (i.e.…”

Taxonomic and Functional Diversity of Aquatic Macroinvertebrate Assemblages and Water Quality in Rivers of the Dry Tropics of Costa Rica

“…The selection of the best model was carried out using the Akaike information criterion (AIC) (Akaike, 1973;Burnham and Anderson, 1998;Arroyo, 2008;Zuur et al, 2009). The use of AIC is little taught in statistics classes and is far less understood in the applied sciences than should be the case (Burnham and Anderson, 1998), although recently its use in ecology and ethology has begun to become more general (Salomão et al, 2019;Souza et al, 2020;Lira et al, 2021). When the model detected significant differences, a DGC (Di Rienzo-González-Casanoves) statistical test was performed to compare means (Di Rienzo et al, 2002).…”