Abstract
The oviposition behavior of the gregarious tachinid fly, Bessa parallela (Meigen), on Pryeria sinica Moore larvae was studied in a wooded area in Fukuoka, Japan, to increase our knowledge of tachinid behavior in the field. Most B. parallela females were observed to approach or oviposit on P. sinica larvae on the ground, while in contrast only one female was found on a tree and did not oviposit. When hosts on the ground and trees were collected and examined, the number of hosts bearing tachinid eggs was significantly larger for hosts collected on the ground than on trees. When the parasitized hosts collected in the field were reared in the laboratory, the survival rates of B. parallela were not significantly different between hosts collected on the ground and those on trees. In the field, B. parallela females deposited more eggs on the head and thorax of P. sinica larvae than on other body parts.
