We investigated change of the mortality rates and factors of larvae after hibernation and pupae of the Nymphalid butterfly, Sasakia charonda, in relation to the forest size and community structure surrounding the host plants at Tochigi Prefecture, Japan. Survival rates of the larvae experimentally released on the foodplant, Celtis sinensis, at the center of a grassland (Plot A), the edge of a large broadleaf forest (Plot C) and Japanese cedar forest (Plot D) were significantly different between the control and the test trees covered with a net excluding birds. However, the rates were not different at the edge of a small broadleaf forest (Plot B). At Plots A and B, the survival rates of larvae on the control trees were reduced rapidly soon after our observation of predation by crows. Such rapid reduction was observed at all experimental plots. However, at Plot B, the rapid reduction was delayed than at other plots. The density of larvae per a tree at Plot B was significantly lower than other plots, when the rapid reductions occurred. It was supposed that this low survival rate at Plot B was caused by significantly high number of predacious ants found in this plot. However, total mortality rates of larvae and pupae were not significantly different among four plots. In conclusion, mortality factors of larvae after hibernation and pupae of S. charonda may be changed with size and community structure of the forest surrounding the host plants. However, it is supposed that some mechanisms resulting in high mortality rate remain in each plot.

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In this study, 463 colonies of termites, which were collected from Ryukyu Islands and North and South Daito Islands, southwestern Japan, were classified, and their pattern of distribution was studied. Termites in this area were classified into 20 species in 10 genera belonging to 3 families, based on the morphological characteristics by comparison of the soldier termites. Incisitermes immigrans, Glyptotermes nakajimai and Reticulitermes miyatakei are newly recorded in this area. Incisitermes immigrans is found to occur only in Minami-Daito Island, and Neotermes spp. and Glyptotermes spp. are to occur in separate geographical areas on mainland Okinawa. The species of Coptotermes and Reticulitermes are widely distributed in this area.

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Number of individuals and matings of a Japanese stag beetle, Prosopocoilus dissimilis okinawanus, whose males show three mandible forms, large (L), small (S2) and very small (S1), was examined every hour at a citrus orchard on Okinawa Island in July, 1997. The L males started to mate at 21 : 00-22 : 00 hours. The number of matings of the L males was maximal at 22 : 00-23 : 00 hrs., when the number of females was maximal. The S males started to mate at 19 : 00-20 : 00 hrs., and the maximal number of matings was recorded at 20 : 00-21 : 00 hrs. It was remarkable that the number of matings of the S1 males increased again after 02 : 00-03 : 00 hrs., and reached a second peak at 05 : 00-06 : 00 hrs., when most of the L males had disappeared. Thus, the total number of matings recorded for the S1 males (N=70) was the same as that of the L males (N=70). However, the rate of mated S1 males (total number of mated males observed/total number of males observed) was 18.6%, which was less than one half of the L males (46.1%). The S2 males showed an intermediate rate of matings (25.0%). In spite of the largest number of S1 males among the three forms, their mating success in the single evening of observation was very low, indicating that additional surveys throughout a season are needed.

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Parapodisma tanbaensis (Tominaga et Kano) (Orthoptera, Acrididae) is reported as a host of Blaesoxipha japonensis (Hori) (Diptera, Sarcophagidae), on the basis of a male fly reared from a female adult of the grasshopper collected at Kibune, Kyoto Pref., Japan. This is the first host record for the fly species.

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