Ivermectin (IVM), a commonly used endectocide in livestock, has been shown to produce adverse effects in dung beetle ecology, physiology, reproduction, and even their ecosystem services. However, the ever-growing ecological importance of thermoregulation and its associated metabolic demand in dung beetles has not received as much focus regarding the effects of this drug. Here, we evaluated experimentally the effects caused by IVM in the metabolic rate and thermoregulation of Ateuchetus cicatricosus (Lucas, 1846), using a standardized ecotoxicity test based on thermolimit respirometry combined with infrared thermography (TLR-IR). The total capacity of excess heat regulation (iTR) and the caloric metabolic rate (MR) gave the most sensitive responses to IVM ingestion. The inhibition concentration at 50% (IC