Determination of the life cycle of Scyphophorus acupunctatus (Coleoptera: Curculionidae) under laboratory conditions

In this study of the development cycle of Scyphophorus acupunctatus Gyllenhal, during the month of Feb the incubation period of eggs averaged of 5.9 d. There were 6 instars, and larval development was completed in an average of 34.9 d. Adults lived an average of 413.8 d. During Sep, eggs hatched in 5.5 d, and there were 8 instars, lasting 54.2 d; adult longevity averaged of 433.7 d. There were 7 instars. The size of the head capsule was 0.7 mm for L1 and up to 2.8 mm for L7. Measurements of head capsule width used to determine instar in the field fell into 9 numerical groups, indicating there are 9 well-defined larval stages for S. acupunctatus. There is high mortality in the egg stage and of larvae in the first stages; while in the final larval stages and in the emergence of the adults there is a long period of stability in which the mortality is reduced to the minimum, and increases noticeably at the end of the adult stage.