Behavior and life history of Leucotrichia pictipes (Banks) (Trichoptera:Hydroptilidae) with special emphasis on case reoccupancy
Leucotrichia pictipes (Banks) has a univoltine life cycle in Owl Creek, a western Montana stream. Early instar (I–IV) larvae appear in mid-July and case acquisition by instar V larvae occurs during July and August. Larvae overwinter in cases and adults emerge the following June and July. Emerging pupae cut round emergence holes at one end of their cases. These old cases remain unoccupied for several weeks but then are reinhabited by the next generation of larvae. Over 75% of cases are reoccupied in this manner. A small proportion of old cases is also occupied by other invertebrates such as early instar hydropsychids. If old cases are not available, newly molted instar V larvae construct new cases. The numerical dominance of Leucotrichia in Owl Creek may be due to its ability to reoccupy old cases as well as to occupy new space by constructing new cases.