Submitted to: World Cotton Research Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: June 18, 2007
Publication Date: June 18, 2007
Citation: Suh, C.P. 2007. Using wing pad characteristics and head capsule widths to distinguish nymphal instars of the cotton fleahopper (Miridae: Hemiptera). Proceedings of World Cotton Research Conference, September 10-14, 2007, Lubbock, TX. CDROM. Technical Abstract: Studies of the cotton fleahopper, Pseudatomoscelis seriatus (Reuter), often require the ability to distinguish between the five nymphal instars. The only guideline for distinguishing instars, based primarily on wing pad characteristics, was published in an experiment station bulletin in 1929. Although accurate and detailed illustrations were provided, some individuals may have difficulty obtaining this antiquated, but valuable publication. The objectives of the current study were to provide additional guidelines for distinguishing instars based on head capsule widths and to reiterate the differences in wing pad characteristics among instars. Both laboratory-reared and field-collected nymphs were measured to establish robust ranges of head capsule widths. Overall, the mean and range (mm) of head capsule widths observed for first, second, third, fourth, and fifth instars were 0.26 (0.200-0.280), 0.34 (0.313-0.375), 0.42 (0.381-0.463), 0.51 (0.450-0.569), and 0.60 (0.550-0.669), respectively. Although there was a slight overlap of ranges between third and fourth instars and between those of fourth and fifth instars, wing pads on fourth and fifth instars are comparatively distinct. Consequently, these instars can be easily distinguished from each other and from third instars. In contrast, distinctions between wing pad characteristics of first, second, and third instars are rather subtle and wing pads on these earlier instars can be difficult to discern, particularly on nymphs that have recently molted or are about to molt. Given that the ranges of head capsule widths for first, second, and third instars did not overlap, the respective ranges reported herein should be useful for distinguishing these earlier instars.