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.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.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.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.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.

El Niño impacts on human‐modified tropical forests: Consequences for dung beetle diversity and associated ecological processes

“…Droughts and warming can also affect the survival and brood production in adult dung beetles. Previous research has found a large number of beetles reabsorbing their oocytes—suggested as physiological response to heat and water stress (Tyndale‐Biscoe, Wallace, & Walker, ), while artificial warming experiments have shown that hotter and drier conditions affected the relative survival and emigration of two dung beetle species (Holley & Andrew, ), as well as disrupted dung beetle reproduction via a decline in ball burial (Holley & Andrew, ).…”

“…Although spatial patterns of movement can vary among species (Silva & Hernández, 2015), most dung beetles are poor fliers-for example, having an estimated movement of 90 m in 48 hr (Silva & Hernández, 2015) and may not be able to escape understory fires; (Holley & Andrew, 2019b).…”

Experimental warming alters the relative survival and emigration of two dung beetle species from an Australian dung pat community

“…). Our previous study found that a 2–4°C increase in temperature reduced dung ball burial by S. rubrus , which may reduce egg laying in this species (Holley & Andrew ). Consequently, ecosystem service provision and reproduction by S. rubrus may be vulnerable to the effects of climate warming.…”

“…To address the accumulation of unburied cattle manure, exotic species of dung beetles that are adapted to process bovine dung have been released into Australia (Edwards ). We have previously assessed the effect of warming on ecosystem service provision by Sisyphus rubrus (Coleoptera: Scarabaeidae; Holley & Andrew ), a ball‐rolling dung beetle native to southern Africa that was introduced into Australia between 1973 and 1980. Sisyphus rubrus is found throughout much of Queensland and parts of New South Wales (Edwards ; Edwards et al .…”

“…To assess beetle performance under warming, we measured several aspects of beetle reproduction (dung ball production and burial by S. rubrus , brood production by E. fulvus , and egg laying in both species), pat departure behaviour and survival of S. rubrus and E. fulvus (Table ). Similar to our previous study (Holley & Andrew ), we used climate‐controlled chambers to investigate the effect of a 2 and 4°C increase in air temperature on beetle performance. Our measures of dung ball and brood production, and dung ball burial allowed us to examine warming effects on the ecosystem service of dung burial, in addition to quantifying beetle reproduction.…”