Feron crystallinum
(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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Location: upper leaf, lower leaf, between leaf veins
Form:
Cells: monothalamous
Possible Range:
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.
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Common Name(s):
Crystalline Gall Wasp (bisexual generation)
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
Re-establishment of the Nearctic oak cynipid gall wasp genus Feron Kinsey, 1937 (Hymenoptera: Cynipidae: Cynipini), including the description of six new species
Victor Cuesta-Porta, George Melika, James, A. Nicholls, Graham N. Stone, Juli Pujade-Villar
(2023)
Feron crystallinum (Bassett, 1900) comb. nov.
Gall. Sexual galls (Fig. 148–149) monolocular, they are mostly on the upper surface of leaves, singly or in small groups, green with straw coloured apex, conical, slightly curved. The gall has numerous long cottony, white hairs projecting laterally, which are longer than the greatest width of the gall. The gall is 2.5 mm in length, with the base 1.0 mm tapering to the tip. The position of the gall is indicated on the opposite (usually lower) side of leaf by a pale coloured elliptical swelling (Doutt 1960). The gall is difficult to distinguish from other similar sexual galls such as F. comatum, F. dumosae and F. kingi.
Biology. Alternate asexual and sexual generations were matched by Doutt (1960). Alternate sexual and asexual generations are also confirmed herein using DNA data, with four individuals (three asexual females, one sexual female) sequenced for cytb and three individuals (two asexual females, one sexual female) sequenced for cytb. Cytb sequences grouped into two haplotypes that were 0.23% divergent (GenBank accessions KX683596, MZ030743, OQ446195–OQ446196) and ITS2 sequences were identical among the three individuals (GenBank accessions OQ448237–OQ448239). Asexual galls in autumn on leaves, adults emerge in January–February; sexual galls in spring, adults emerge in March. Both generations develop on oaks from section Quercus, subsection Dumosae: Q. douglasii, Q. dumosa and Q. garryana.
