INVESTIGATIONS OF THE OOGENESIS-FLIGHT SYNDROME IN ANTHONOMUS-GRANDIS(COLEOPTERA, CURCULIONIDAE) USING TETHERED FLIGHT TESTS

This paper investigates the relationship between oogenesis and flight duration and the use of tethered flight as an indicator of tendency to migrate in Anthonomus grandis grandis Boheman (Coleoptera: Curculioni dae), the boll weevil. When boll weevils were flown to exhaustion in t ethered flight tests many flew between 2 and 3 h, with several flying more than 4 h. To test the validity of the tethered flight test as an indicator of tendency to migrate, comparisons of mean flight duration were made between boll weevils trapped in pheromone traps far from any cultivated cotton and those trapped at the edge of heavily infested, flowering cotton fields. There was a significant difference in mean fl ight time between the two groups, supporting the assumption that long- duration tethered flight in the laboratory reflects the tendency to ma ke long-distance flights in the field. Groups of weevils of different ages were killed after flight testing, and the degree of ovarian devel opment and fat body status were determined and related to duration of tethered flight. Insects with undeveloped or partially developed ovari es were the most likely to make long flights. Weevils with ovaries bea ring chorionated eggs made very few long flights. Flight duration was positively correlated with degree of fat body development. In contrast , there were no significant differences in the degree of ovarian devel opment with fat body status. We conclude from these experiments that A . grandis grandis is capable of long-distance flight, that this specie s displays some behavioral and physiological characteristics typical o f many insect migrants including an oogenesis-flight syndrome, and tha t a tethered flight test is an appropriate means of measuring migrator y tendency in this species.