Biology Reference
In-Depth Information
1063
1064
1063
Spangle galls of oak leaf spangle-gall cynipid
(
Neuroterus quercusbaccarum
).
1064
Currant galls of oak leaf spangle-gall cynipid
(
Neuroterus quercusbaccarum
).
1065
Neuroterus quercusbaccarum
(Linnaeus)
(
1063-1065
)
syn.
N. lenticularis
(Olivier)
Oak leaf spangle-gall cynipid
A generally abundant gall wasp, associated with oak
(
Quercus
) and often present on young trees. Widely
distributed in Europe.
DESCRIPTION
Adult (asexual) female:
2-3 mm long; black and shiny,
with brownish-yellow legs; wings mainly hyaline;
ovipositor long and curved.
Adult (sexual) female:
1.5-2.0 mm long; black with yellowish legs; wings
hyaline to subhyaline; ovipositor short.
Adult male:
similar to sexual female, but with a long petiolus and no
ovipositor.
1065
Oak leaf spangle-gall cynipid (
Neuroterus
quercusbaccarum
) damage to leaf of
Quercus
.
LIFE HISTORY
In summer, mated female wasps deposit large numbers
of eggs in the tissue on the underside of expanded oak
leaves, inducing the formation of characteristic spangle
galls. The disc-like galls are slightly hairy (the hairs
stellate) and yellowish to yellowish white. Each gall
contains a central chamber within which a single larva
develops. The galls, often 100 or more on a leaf, occur
from July onwards; they mature in October, when about
6 mm in diameter. They then fall to the ground and
swell as they take up moisture. The larvae, which
represent the unisexual generation of the species,
overwinter within the galls and pupate in the spring.
Asexual female wasps then emerge, depositing
unfertilized eggs in male catkins. Characteristic currant-
like galls (currant galls) then develop in strings on the
catkins, each changing from green through pink to red;
they measure about 4 mm in diameter when mature.
Larvae, destined to become either males or females,
occur singly within these galls, completing their
development in June. Adult wasps eventually emerge
and, after mating, the females initiate the familiar
generation of spangle galls.
DAMAGE
Spangle galls often occur in vast numbers, and cause
spotting of the foliage, visible from above. However,
infested trees are seldom if ever harmed. The currant
galls are also unimportant.
Search WWH ::
Custom Search