Experimental warming disrupts reproduction and dung burial by a ball-rolling dung beetle

Abstract

1. Insects are sensitive to climate change. Consequently, insect-mediated ecosystem functions and services may be altered by changing climates. <br/> 2. Dung beetles provide multiple services by burying manure. Using climate-controlled chambers, the effects of warming on dung burial and reproduction by the dung beetle Sisyphus rubrus Paschalidis, 1974 were investigated. Sisyphus rubrus break up dung by forming and rolling away balls of manure for burial and egg deposition. <br/> 3. To simulate warming in the chambers, 0, 2 or 4°C offsets were added to field-recorded, diurnally fluctuating temperatures. We measured dung ball production and burial, egg laying, survival and residence times of beetles. <br/> 4. Temperature did not affect the size or number of dung balls produced; however warming reduced dung ball burial by S. rubrus. Because buried balls were more likely to contain eggs, warming could reduce egg laying via a reduction in ball burial. Warming reduced the humidity inside the chambers, and a positive relationship was found between the number of dung balls produced and humidity in two temperature treatments. Temperature did not affect survival, or whether or not a beetle left a chamber. Beetles that did leave the chambers took longer to do so in the warmest treatment. <br/> 5. This study demonstrates that climate warming could reduce reproduction and dung burial by S. rubrus, and is an important first step to understanding warming effects on burial services. Future studies should assess warming effects in field situations, both on individual dung beetle species and on aggregate dung burial services