Natural History Overview

Male Strauzia flies have greatly inflated frontal bristles compared to the females, and are suspected to play some role in female mate choice during courtship (Stoltzfus, 1988). Courtship before mating is started by the male and female approaching face to face, which means the enlarged frontal bristles are right in view for the female. Mating is varied in terms of time, lasting from a few minutes all the way to several hours (Westdal and Barrett, 1960).

On the topic of the sunflowers, the species of Helianthus or related genera that a Strauzia species uses appears to be very specialized. Any given species of Strauzia fly is only associated with one to three species of sunflowers, which leads it to be another axis of differentiation in the life history of the group (Hippee et al., 2020). Additionally, the adults emerge in the summer and disappear in the fall, but the specific time of these events differ between species along the months of May to August (Stoltzfus, 1988). The times at which the larvae decide to pupate also varies during the Fall for each species, and then they wait in their pupa until the next Summer.

The original description of Strauzia longipennis is a bit confusing, as two different scientists described it in the same year, 1830, in different languages. The first description of this species was by Wiedemann, a German taxonomist, as Trypeta longipennis; he described many fruit flies as being within a single genus Trypeta. The genus Strauzia itself was coined by Robineau-Desvoidy’s French description of Strauzia inermis in 1830, but his was published slightly later, and thus his name is a junior synonym of Wiedemann’s. However, the genus name made by Robineau-Desvoidy was still valid, and Wiedemann’s longipennis was transferred to Strauzia by Coquillett in 1910.

A few decades later, more species of Strauzia were described as varieties of longipennis by Loew, 1873. These include many of the common species, with him describing Strauzia longipennis var. perfecta, typica, longitudinalis, vittigera, intermedia and arculata. All of these are now arguably valid species except for the errantly described confluens, which has apparently had its type material lost and no matching flies have been found, and has now fallen into obscurity (Hippee et al., 2020).

Finally, the most recent taxonomic work was that of Bryan Stoltzfus in 1988. Within it, he effectively combined the work of the two previous authors, accepting the new species of Steyskal while raising all of Loew’s variants of S. longipennis to species level. He also described 3 new species, uvedaliae, rugosum, and noctipennis, differentiated largely from contrasting life cycles of the species. These were relatively controversial moves, and in the work of Foote et al., 1993, these species were not included in the North American handbook of the family Tephritidae because they were “not based strongly enough in morphological differences” to be adequately differentiated from specimens.