Assessing how changes in temporal resource quality influence the reproductive performance of the dung beetle Onthophagus binodis

Abstract

<ol><li> Both larval and adult dung beetles depend on dung resources for nutrition. The quality of the dung resources utilised by beetles can influence adult morphology, adult biomass, and life history parameters of dung beetles. Although several studies have compared dung nutrients of different vertebrate dung types, variation in dung nutrients over time has been less studied.</li> <li> Here, moisture content and chemical parameters of dung were analysed at monthly intervals over 12months. The reproductive output of <i>Onthophagus</i> binodis fed dung collected at four different months of the year is also measured to assess the relationship between dung resources and dung beetle performance. The experiments were carried out under controlled conditions: 25±1 °C: 15±1 °C (L: D) and 60±5% RH, respectively, with a photoperiod of 14L:10D.</li> <li> Over the 12-month sampling period, the maximum number of broods and highest brood weight were observed from beetles utilising dung collected in the Austral summer (February 2018). The analysis of dung over the 12-month period showed that the electrical conductivity and phosphorous, manganese, and magnesium content of dung were highest in February 2018.</li> <li> The results suggest that the variation in dung resources, such as moisture and minerals, across the year affected the reproductive performance of <i>Onthophagus binodis</i>, which was highest when beetles were provisioned with summer dung.</li>