"Cynipid wasps are responsible for the most extreme galls in color and shape. Galls that look like miniature stars, sea urchins, golf balls, cups, saucers, clubs, teardrops, goblets, and bow ties are among the fascinating shapes that stir the imagination....
"Cynipids typically exhibit an ALTERNATION OF GENERATIONS, called HETEROGONY, with a spring sexual generation emerging from a different gall (often from a different plant organ) than the summer-fall generation of unisexual females (agamic generation). The latter females overwinter in diapause as prepupae (usually in the galls) and then pupate and emerge in spring, timed in harmony with the development of the preferred plant organs. Eggs produced and deposited by these females result in larvae and galls of the spring sexual generation. This alternation of generations is rather rare in the animal kingdom but also known in aphids and rotifers. This interesting alternation of reproductive modes confused early entomologists, as the alternating generations of the same species induced galls with different morphologies. This led researchers to believe the different galls belonged to separate species or even other genera."
Ronald A. Russo, Plant Galls of the Western United States, p. 48
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