Experimental increases in temperature mean and variance alter reproductive behaviors in the dung beetle Phanaeus vindex

Abstract

Temperature profoundly impacts insect development, but plasticity of reproductive behaviors may mediate the impacts of temperature change on earlier life stages. Few studies have examined the potential for behavioral plasticity of adults to buffer developing offspring from warmer, more variable temperatures associated with climate change. We used a field manipulation to examine whether the dung beetle Phanaeus vindex alters breeding behaviors in response to climate change and whether adult behavioral shifts protect offspring from temperature increases. Dung beetles lay eggs inside brood balls made of dung that are buried underground for the entirety of offspring development. Depth of the brood ball impacts the temperatures offspring experience with consequences for beetle development. We placed females in either control or greenhouse treatments that simultaneously increased temperature mean and variance. We found that females produced smaller brood balls but buried them deeper in the greenhouse treatment, suggesting burial depth may come at a cost to brood ball size, which can impact offspring nutrition. Despite being buried deeper, brood balls from the greenhouse treatment experienced warmer mean temperatures but similar amplitudes of temperature fluctuation relative to the controls. Our findings suggest adult behaviors may buffer offspring from increased temperature variation due to climate change.