Effects of food deprivation and olfactory and visual cues on movement patterns of two Eleodes species (Coleoptera: Tenebrionidae) in a wind tunnel

Terrestrial arthropods are challenged with locating food in a heterogeneous environment, and this activity may be mediated by the hunger level the animal is experiencing. We performed wind tunnel experiments to determine whether food deprivation in the terrestrial darkling beetles Eleodes extricata Say and Eleodes hispilabris Say affects their movement patterns and whether they orient to food by means of vision, olfaction, or both. Hunger affected foraging behavior with respect to whether beetles actually contacted food. However, the velocity and number of turns of both food-deprived and fed individuals did not significantly differ, indicating that food deprivation affects the ethological consequences but not the velocity and turning mechanics of foraging in these species. Both olfaction and vision were used to find food over short distances (<80 cm). Olfaction elicited a stronger navigational response than did vision, particularly within 25 cm of food.