Behavioral Observations on the Dobsonfly, Corydalus cornutus (Megaloptera: Corydalidae) with Photographic Evidence of the Use of the Elongate Mandibles in the Male.

摘要

Dobsonflies in the genus Corydalus should be well known to insect collectors (amateur or professional) who have collected using lights at night in eastern North America. Both males and females readily come to light. Fishermen, and fisherwomen, easilyrecognize these insects as exceptionally potent bait. The males of the genus Corydalus and of other genera of the family Corydalidae are well known for their enormously elongate, sickle-shaped mandibles (Parfin 1952, Theischinger 1991, Contreras-Ramos 1998, Preston-Mafham and Miller 2002, Grimaldi and Engel 2006, and others; see Fig. 1). Despite this conspicuous morphological modification, little attention has apparently been paid to the functional significance of these structures, and Grimaldi and Engel (2006, p. 340) simply state that "the function of the huge male mandibles remains unknown," whereas Preston-Mafham and Miller (2002, p. 105) state that "they [the mandibles] are unable to inflict a painful bite, however, and are probably used in sexualcompetition with other males."