Disholcaspis quercusmamma
(sexgen)sexgen:The sexual generation (AKA bisexual generation or sexgen) of an oak gall wasp (cynipini) species consists of both male and female wasps, which mate before the females lay eggs which will mature to form the all-female agamic generation.
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The gall's range is computed from the range of all hosts that the gall occurs on. In some cases we have evidence that the gall does not occur across the full range of the hosts and we will remove these places from the range. For undescribed species we will show the expected range based on hosts plus where the galls have been observed.
Our ID Notes may contain important tips necessary for distinguishing this gall
from similar galls and/or important information about the taxonomic status of
this gall inducer.
Created Feb 4, 2026 1:47 PM UTC
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Last updated Feb 4, 2026 1:47 PM UTC
Description and Biology of the Sexual Generation of Disholcaspis quercusmamma (Walsh and Riley) (Hymenoptera: Cynipidae), with Notes on Associated Parasitoids
Crystal McEwen, Scott Digweed, James A. Nicholls, Whitney Cranshaw
(2014)
Disholcaspis quercusmamma (Walsh and Riley), 1869.
Galls are formed in buds of Q. macrocarpa, Q. bicolor, and Q. lyrata. Galls become conspicuous during leaf flush in early spring, with one or more galls forming in the center among flushing leaves, or outside the bud around the base of new leaves. Galls are 2.7–3.2 mm long, smooth-surfaced, and ovoid with a thin, fragile wall. When developing, they are pale, sometimes creamy with green or pink coloration near the tip. Galls usually fade to light brown or buff when mature, and either fall off or become obscured as the surrounding leaves and twigs develop. Emergence holes from galls are rough-edged and are produced at or just below the gall apex. Blackened galls have been observed with the cause for the color unknown.
Range: throughout eastern and central North America, from southern Manitoba, east through New Brunswick, throughout the eastern USA, and as far south as northern Florida and eastern Texas. However, the range of D. quercusmamma potentially extends anywhere that potential host trees have been transplanted outside their native ranges, if the insects were also translocated (e.g., Edmonton and Fort Collins).
