Marcus Byrne is an entomologist from South Africa who has been studying the movement and behaviors of dung beetles over the past few years. Dung Beetles feed on the feces of other animals. Some species of Dung Beetle roll their food into balls for easier transport. One behavior that has been observed is how the beetles transport this food by pushing the spheres across the soil by keeping their front two feet on the ground, and their rear feet on the balls.
Researchers observed that beetles would stop pushing, and climb on top of the balls sporadically throughout the transportation of the balls. Marcus Byrne and his team believe that this behavior is a temperature regulatory device used by the beetles to combat the intense heat found in their natural habitat.
In order to test this, the research team created two ‘arenas’ for the beetles to transport the balls across. Each arena was a 10m-diameter circle of the same African soil, which has been kept to different temperatures. One arena was the typical temperature of the natural substrate, while the second arena was kept at a cooler temperature. Researchers then observed how often the beetles would climb onto the top of the dung balls while pushing them through each arena. Data for various trials is shown below.
|Trial||Dung Ball Starting Temperature||Arena Temperature||Number of times beetle climbed atop ball||Duration of trip across arena|
Which data sets were a part of the control group in the experiment?