Compsilura concinnata (Meigen, 1824), Fig. 40

Laboratory experiment ex. Choristoneura fumiferana: Dowden et al. 1948, ex. Archips fumiferana (lab. experiment in northeastern United States); † Arnaud 1978; † Huber et al. 1996. Host records ex. Choristoneura rosaceana: Wilkinson et al. 2004 (MI); four specimens from QC (examined), from unpublished data of N. Bostanian (Agriculture and Agri­Food Canada, St. Jean­sur­Richelieu).

Host records ex. Choristoneura rosaceana and/or Pandemis limitata: Cossentine et al. 2004 (BC).

Compsilura concinnata is a mostly gray tachinid with four conspicuous, black, longitudinal stripes on the thorax and a black­and­gray banded abdomen. Adults are typically 7– 8mm long but some individuals are as small as 4mm. Compsilura concinnata was introduced repeatedly into North America from Europe throughout the 1900s for control of a number of lepidopterous pests, most notably the gypsy moth ( Lymantria dispar (L.)) and browntail moth ( Euproctis chrysorrhoea (L.)). It became established and is presently recorded from most of southern Canada and the northeastern and western United States (O’Hara & Wood 2004). Because C. concinnata is continuing to expand its range, it may well be more widely distributed than current records suggest.

Compsilura concinnata is an extremely polyphagous parasitoid that has been reared from nearly 200 species of Lepidoptera, Hymenoptera (Symphyta), and Coleoptera in North America (Arnaud 1978; Boettner et al. 2000). Females have a long piercing ovipositor that is used to inject thin­shelled eggs into the body of a host. The eggs hatch immediately and the first instars migrate to the midgut, where they develop within the narrow space between the peritrophic membrane and midgut wall (Ichiki & Shima 2003). The species has two or more generations per year, often alternating hosts throughout the season, and can develop gregariously in larger hosts (Culver 1919; Webber & Schaffner 1926; Schaffner & Griswold 1934). The maggot overwinters within the host prepupa or pupa and emerges in the spring to pupariate nearby (Culver 1919; Webber & Schaffner 1926).

Compsilura concinnata has been recorded only recently from C. rosaceana (see host records above) but readily parasitizes C. fumiferana in the laboratory (Dowden et al. 1948) and hence has the potential to be a significant budworm parasitoid. It is the most polyphagous tachinid known and its parasitism of Choristoneura species will likely occur whenever suitable opportunities arise. Parasitism of Choristoneura larvae can occur only during a summer generation of C. concinnata .