Movement patterns of threeAthalia sawflies in relation to the spatio-temporal distributions of their habitats

I compared the differences in the movement intensity of three species of sympatric Athalia sawflies, A. japonica, A. rosae and A. infumata feeding on cruciferous plants. Mark-release-recapture census was conducted to estimate movement distance, sex ratio and age composition of adult sawflies. In addition, the sex ratio of newlyemerged adults was examined by rearing field-collected larvae until adult emergence. Age composition and longevity of adults were estimated experimentally. The movement intensity was evaluated mostly with the indirect information thus obtained. Females moved more actively than males in all three sawflies. A. japonica females of all age classes moved actively in spring and autumn, but in summer they disappeared. Also, A. rosae females of all age classes moved actively in spring and autumn. In summer, in contrast with A. japonica, A. rosae females moved most actively among the three species in all seasons. A. infumata females, in particular the young females, moved most actively among the three species, except A rosae in summer. The movement patterns of the three sawflies were deduced in relation to the spatio-temporal distributions of their habitats. In spring and autumn, when host plants were abundant, A. japonica and A. rosae females were dispersed among the host patches within the census are. In summer, however, when host plants were scarce, A. japonica entered diapause, whereas A. rosae migrated to neighboring areas. On the other hand, A. infumata, in particular young famale, innately dispersed to seek for temporary host plants throughout the census seasons.