Morphological and phenological differences in adult Dolophilodes distinctus (Trichoptera) at urban and rural headwater streams

Urban land use alters the physical and chemical properties of streams draining urban watersheds, which typically decreases the quality of habitat for larval insects living in the stream. Physiochemical properties of the stream can also affect emergence, behavior, dispersal, reproduction and body morphology of the adult stage. We compared peak abundance time, spatial abundance, synchrony of male and females, and body morphology of Dolophilodes distinctus (Trichoptera: Philopotamidae) at urban and rural headwater streams over 32 weeks. We found that peak abundance patterns occurred earlier at urban streams compared to rural streams and that the reproductive asynchrony for rural populations was not observed in populations from urban streams. This suggested that urbanization may impact mating or emergence processes by D. distinctus. Body morphology characteristics for females (i.e., meta-tibia length) differed between individuals caught at urban and rural streams. Differences may have resulted from the proportion of immigrants and residents caught above individual streams. Overall, alterations to streams and the surrounding terrestrial landscapes due to human activities may alter impact life cycle processes important for population persistence.