CANNIBALISM AND THE STAGE-DEPENDENT TRANSMISSION OF A VIRAL PATHOGEN OF THE INDIAN MEAL MOTH, PLODIA-INTERPUNCTELLA

1. The transmission of an insect pathogen by cannibalism was studied b y a series of choice and no-choice experiments. 2. Infection of Plodia interpunctella larvae with a granulosis virus occurred through cannib alism of infected larvae. 3. Depending on the larval instars of the ca nnibal and the victim relative to each other, preferential cannibalism of both infected and healthy larvae was observed. 4. Larvae cannibali se healthy, less vulnerable larvae preferentially, but it is argued th at there is no evidence that they are avoiding infection. 5. The victi m cannibalised can be explained as a balance between the reduced risk of injury and the ease of cannibalism of moribund infected individuals on the one hand and the greater food resource value of healthy indivi duals on the other. 6. The implications for the insect population dyna mics of the transmission of the pathogen via cannibalism and the effec tive removal of infective particles through cannibalism by immune stag es are discussed.