G. it. Ent., 4 (22): 217-222
August 31, 1989
Length of last antennal segment as a criterion
to identify collected nymphal instars of aphids
by
RAJENDRA SINGH & MAMTA SRIVASTAVA
Abstract - The length of last antennal segment of 3 aphid species, viz., Aphis craccivora Koch., A. gossypii Glover, Lipaphis erysimi (Kalt.), nymphs and adults reared in the laboratory, were instar- as well as species-specific. The multimodal analysis of this criterion of field collected aphid populations detected five distribution peaks (4 nymphal instars and 1 adult). There was no countable overlap between successive instar distributions in all the species studied. Therefore, the length of last antennal segment proved to be a useful criterion for instar identification of the field populations of A. craccivora, A. gossypii and L. erysimi apterous virginoparae.
