Length: 7.0 - 9.5 mm
Over much of its range, this species is associated primarily with Ragwort, Senecio anonymus. Males attempt to hold and guard a territory, a cluster of flower heads. Females need access to these flower heads for feeding, mating, and ovipositing.
Females do not select their mates in Neacoryphus bicrucis. Instead, the mating system is one in which "males attempt to subdue resisting females" and in which heavy males have an advantage (McLain, 1992).
Mating typically takes more than ten hours in this species. There is evidence males prolong the copulation as a means of mate guarding, to prevent other males from mating with the female. In this species the last male to mate with a female fertilizes most of the eggs the next time the female oviposits (McLain, 1989).
This is a wide-ranging insect, as the map below shows.
A note about our maps
American Insects site