Effects of nest hoarding on foraging behavior of two species of Apodemus mice, A. speciosus and A. argenteus (Rodentia: Muridae)

Food hoarding is one of the determinant factors of foraging behavior and benefits the hoarder. Two species of Apodemus mice, A. speciosus Temminck and A. argenteus Temminck, hoard acorns for later use. In 1988 and 1989, I conducted laboratory experiments to reveal the effects of food hoarding in the nest on the foraging behavior of these mice. I released a mouse into an indoor arena (2.8 x 2.8 m) and recorded the foraging behavior of four female A. speciosus and four female A. argenteus mice in sessions with and without food hoarding in the nest box. Nest hoarding did not affect the time that a mouse allotted to excursions or the number of peanuts that a mouse ate during the night, but decreased the number of peanuts handled and the intensity of food handling (the number of handled peanuts per visit) at the food stations. The decrease in food handling outside the nest box, which seemed to be beneficial to the survival and reproduction of the hoarder in the field, was more apparent in A. speciosus than in A. argenteus. The different behavioral responses in foraging behavior to nest hoarding between two Apodemus mice may be related to their different microhabitat preferences.