Foraging Behavior of Latheticus oryzae (Coleoptera: Tenebrionidae) Is Affected by the Type of Food Source

Latheticus oryzae has emerged as a notorious invasive insect species affecting stored products globally. In the present study, the effect of different types of flour (i.e., whole barley, chickpea, date, potato, white rice, and white soft wheat) on the time L. oryzae required to reach the food source, the time it spent at the food source, the time it spent away from the food source, and the number of visits to the food source were evaluated. The Preference Index (PI, %) was calculated as the percentage of the total observation time (900 s) spent by each insect at the food source. The type of flour had a decisive effect on L. oryzae response. Specifically, potato flour exhibited the highest approach success rate (27 out of 30 insects) and the shortest estimated mean approach time (258.7 s) for L. oryzae. However, the mean PI (%) for potato flour was 10.9%, ranking it third after white soft wheat flour (33.9%) and white rice flour (23.4%). In contrast, significant approach delays, fewer visits, and longer times away from the food source were recorded for whole barley flour and white rice flour. The findings indicate that L. oryzae exhibited differential behavioral responses to the six tested types of flour, with differences in approach success, approach time, time spent at the flour source, and visitation frequency. These results provide evidence of substrate-specific differences in foraging behavior.