Habitat and estimated density of Magicicada septendecula (Hemiptera: Cicadidae), a 17-year periodical cicada newly discovered in Connecticut, United States of America

Abstract

AbstractPeriodical cicadas in the genus Magicicada Davis (Hemiptera: Cicadidae) of brood II emerged in the eastern United States of America in 2013. In Connecticut, only Magicicada septendecim (Linnaeus) had been recorded until this emergence when Magicicada septendecula Alexander and Moore was found on Totoket Mountain in North Branford, Connecticut, United States of America. This discovery represented the northeastern-most record of this species. In two 0.25-ha plots where M. septendecula and M. septendecim emerged and chorused, species of Carya Nuttall (Juglandaceae) comprised 59.9–63.7% of the total basal area, with Carya glabra (Miller) Sweet, accounting for 43.9–60.0%. In one plot, 31.6% of the total basal area was Fraxinus americana Linnaeus (Oleaceae). By using the proportion of exuviae of M. septendecula (hind tibial length<6.3 mm) and M. septendecim (length ⩾ 6.3 mm) near trees and the mean number of emergence holes per 0.25-m2 quadrat (1.88), it was estimated that 1487 M. septendecula and 17 313 M. septendecim emerged in one 0.25-ha plot. Mean tibial length of M. septendecula was significantly smaller in males (5.53 mm) than females (5.99 mm), and the sex ratio did not depart significantly from 1:1. Magicicada septendecula may be threatened by the decline of F. americana and Juglans cinerea Linnaeus (Juglandaceae), the first a known host and the second a suspected host.