Asphondylia atriplicis

The midge A. atriplicis oviposits on four-winged saltbush and induces a fleshy, rounded stem-gall near the apical meristems of the plant. Each A. atriplicis larva is contained within its own chamber within the gall. From 1 to 70 larvae per gall have been reported in southern California (Hawkins et al. 1986). Gall shape varies considerably, ranging from small spherical galls to large, slightly irregular, ellipsoid galls. The inner surface of the larval chamber is lined with an obligate fungus upon which A. atriplicis larvae feed (Highland 1964, Shorthouse and Rohfritsch 1992) ... To emerge from the gall, the prepupa bores a channel from its chamber and breaks through to the gall surface. With the pupa extruding from the gall, ecdysis occurs and the adult fly emerges from the pupal case. The populations we sampled [A. atriplicis on four-winged saltbush at three sites in Maricopa County, Arizona] were bivoltine with generations coinciding with the two rainy seasons in the Sonoran desert (R.J.M. and T.P.C., unpublished data). They diapause in the egg stage after oviposition until rains stimulate plant growth, which apparently causes them to break diapause.

Gall Size-Dependent Survival for Asphondylia atriplicis (Diptera: Cecidomyiidae) on Atriplex canescens