Emergence patterns and an assessment of collecting methods for adult stoneflies (Plecoptera) in an Ozark foothills stream

Abstract

Emergence periods and patterns for adult stoneflies were assessed using five collecting methods on a second-order stream in northeastern Oklahoma. Twenty-two species, representing six families, displayed successional emergence periods with at least one species being present every month of the year. Searching emergent leaf packs, logs, and rocks with an aspirator and forceps resulted in the collection of 21 of 23 species (91%) and was particularly suited to cryptic species such as Amphinemura delosa, Allocapnia rickeri, Prostoia completa, and Isoperla namata. Sweeping resulted in the collection of fewer species (13 species, 57%), and was most applicable to actively flying, late spring emerging Haploperla brevis and Alloperla caudata. Light-trapping (12 species, 52%) was successful only during late spring and summer for crepuscular Perlids such as Neoperla spp., Acroneuria evoluta, and Perlesta placida. Significantly greater numbers of females were found in light trap collections. Sticky traps (8 species, 35%) and pit traps (6 species, 26%) collected relatively few species. Significant correlations existed between benthic density and numbers of adults collected by searching and all methods combined. Collections of Paracapnia angulata, Leuctra tenuis, Isoperla signata, Perlinella ephyre, Neoperla stewarti, and Neoperla catharae represent extensions of the reported ranges of these species.