Not all gall wasps (household Cynipidae) have an effect on the leaves of their hosts—some as a substitute have an effect on the twigs. One instance of such is Disholcaspis quercusglobulus (spherical bullet gall wasp), which varieties spherical, removable galls, singly or in small clusters, on the twigs of Quercus alba (white oak).
There are a few dozen different species on this genus, all of which appear to to have succeeded in eliminating the necessity for males (Weld 1959). All galls produce feminine wasps, which emerge from their galls throughout the fall and instantly lay eggs in twigs to start the subsequent yr’s crop of females—no males wanted. Ain’t evolution grand?!
Weld, D. 1959. Cynipid Galls of the Japanese United States. Privately printed in Ann Arbor, Michigan [pdf].
©️ Ted C. MacRae 2021