Observations on the Seventeen-Year Periodical Cicada, Magicicada septendecim (Hemiptera: Homoptera: Cicadidae)

Abstract

Biology of the 17-year periodical cicada, Magicicada septendecim (L.) (Brood II), was investigated in Connecticut during spring and summer 1979. Most nymphs emerged from soil shortly before or after sunset from late May to late June. They emerged slightly earlier in the season in an apple orchard than in a nearby forest. Seasonal emergence of males and females overlapped considerably, although males appeared first. Adult reproductive activity and feeding peaked between 1000 and 1300 h. Calling and initiation of mating reached the highest level at 1000 h and decreased thereafter. Oviposition activity peaked between 1200 and 1300 h, when light intensity and temperature were highest. Females oviposited and both sexes fed on most woody plants, indicating a wide host range. Ages of adults performing each activity were: calling, 5 to 17 days; feeding, 10 to 17 days; mating, 5 to 18 days; and ovipositing, 8 to 16 days. Eggs laid in branches hatched between 30 July and 3 September, ca, 9 to 10 weeks after deposition. Between 5.6 and 55.6% of males or females that were marked dispersed across a 50-m treeless zone separating orchard and forest. Major causes of adult mortality in an apple orchard were predation and fungal infection. Mortality from vertebrate (mostly avian) predation rose from 5.9% for the period from 11 to 20 June to 50.6% for the period from 21 to 30 June whereas death from fungal infection decreased from 27.1 to 15.7% for these respective periods. Only one insectan predator, an unidentified cecidomyiid, attacked cicada eggs.