Actia diffidens Curran, 1933,

O’Hara, James E., 2005, A review of the tachinid parasitoids (Diptera: Tachinidae) of Nearctic Choristoneura species (Lepidoptera: Tortricidae), with keys to adults and puparia, Zootaxa 938, pp. 1-46: 15-17

publication ID 10.5281/zenodo.171153

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Actia diffidens Curran, 1933


Actia diffidens Curran, 1933  , Fig. 37View FIGURES 37 – 42

Host records ex. Choristoneura conflictana:  Prentice 1955 (SK, MB); O’Hara 1991 (†SK, MB); † Arnaud 1978 (SK, MB); † Huber et al. 1996 ( America north of Mexico). Host records ex. Choristoneura rosaceana:  O’Hara 1991 (ON); † Huber et al. 1996 ( America north of Mexico).

This species is an uncommonly recorded parasitoid of Choristoneura  species. It is similar in size and appearance to A. interrupta  except that wing vein CuA 1 is almost always bare dorsally (only rarely with one to several hairs; veins R 1 and R 4 + 5 haired as in A. interrupta  ; cf. Figs. 12 and 13View FIGURES 11 – 13. 11). Actia diffidens  is common and widespread throughout Canada and the northern and eastern United States, with scattered records throughout the rest of the United States and Mexico ( O’Hara 1991). The first instar of A. diffidens  was figured by O’Hara (1988) and the adult was redescribed by O’Hara (1991) in his revision of the Nearctic species of Actia  . The three larval instars, pupa, and puparium were described and illustrated by Prebble (1935).

Prebble (1935) studied parasitism of the tortricid Acleris variana (Fernald)  (as Peronea variana  ) by A. diffidens  in Nova Scotia. He found that adult A. diffidens  appeared in June, parasitism of third to fifth instar A. variana  occurred from late June to mid July, and fully developed maggots emerged from their hosts and formed puparia from mid July to mid August. Known hosts of A. diffidens  are mostly Tortricidae  but include a few species of Geometridae  , Gracillariidae  , Noctuidae  , and Pyralidae  ( Arnaud 1978; O’Hara 1991).