Andricus grossulariae
Encyclopedia
Andricus grossulariae is a gall wasp species inducing agamic
acorn cup or gooseberry galls on oak tree acorn cups and sexual phase galls on catkins. Synonyms include Andricus fructuum (Trotter, 1899), Andricus gemellus (Belizin & Maisuradze, 1961), Andricus intermedius (Tavares, 1922), Andricus mayri (Wachtl, 1879) and Cynips panteli (Kieffer, 1897).
s which lay eggs within the tissues of the acorn cup.
The sexual phase appears on catkins as rounded structures (6 mm × 3–4 mm) possessing a characteristic point, and when young are covered with fine hairs. The galls, shiny and hard, turn red in colour and then black or dark purple.
The asexual or parthenogenetic
phase, about 10 mm across, develops on acorn cups of English oak Q. robur and sessile oak Q. petraea. The galls, formed of flattend projections, often enclose the immature acorn. The galls first appear pink in colour and as they mature they turn red, then green and finally brown during their development. Previously the causer of this stage was known as Andricus mayri (Wachtl).
Although normally distinctive the asexual acorn cup gall can, under some growth conditions, be mistaken for the knopper gall
, caused by the gall wasp Andricus quercuscalicis.
A. grossulariae, although usually found on acorns, is also found on buds.
s from galls of A. grossulariae, such as Torymus auratus, Megastigmus dorsalis, Ormyrus pomaceus, Sycophila variegata, Sycophila biguttata, Mesopolobus xanthocerus, and Aulogymnus trilineatus. Ceroptres cerri is an inquiline of A. grossulariae.
in 2000.
Asexuality
Asexuality , in its broadest sense, is the lack of sexual attraction and, in some cases, the lack of interest in sex. Sometimes, it is considered a lack of a sexual orientation...
acorn cup or gooseberry galls on oak tree acorn cups and sexual phase galls on catkins. Synonyms include Andricus fructuum (Trotter, 1899), Andricus gemellus (Belizin & Maisuradze, 1961), Andricus intermedius (Tavares, 1922), Andricus mayri (Wachtl, 1879) and Cynips panteli (Kieffer, 1897).
Galls
Acorn cup galls develop as a chemically induced distortion of the growing acorn cups on oak trees, caused by gall waspGall wasp
Gall wasps , also called Gallflies, are a family of the order Hymenoptera and are classified with the Apocrita suborder of wasps in the superfamily Cynipoidea...
s which lay eggs within the tissues of the acorn cup.
The sexual phase appears on catkins as rounded structures (6 mm × 3–4 mm) possessing a characteristic point, and when young are covered with fine hairs. The galls, shiny and hard, turn red in colour and then black or dark purple.
The asexual or parthenogenetic
Parthenogenesis
Parthenogenesis is a form of asexual reproduction found in females, where growth and development of embryos occur without fertilization by a male...
phase, about 10 mm across, develops on acorn cups of English oak Q. robur and sessile oak Q. petraea. The galls, formed of flattend projections, often enclose the immature acorn. The galls first appear pink in colour and as they mature they turn red, then green and finally brown during their development. Previously the causer of this stage was known as Andricus mayri (Wachtl).
Although normally distinctive the asexual acorn cup gall can, under some growth conditions, be mistaken for the knopper gall
Knopper gall
Andricus quercuscalicis is a gall wasp species inducing Knopper galls.Knopper galls develop as a chemically induced distortion of growing acorns on Pedunculate Oak trees, caused by gall wasps, which lay eggs in buds with their ovipositor...
, caused by the gall wasp Andricus quercuscalicis.
A. grossulariae, although usually found on acorns, is also found on buds.
Life cycle
As stated, two forms of galls exist for this species, the asexual phase inducing the acorn cup gall on the cups in late summer and the sexual phase inducing gooseberry galls on the oak catkins in spring.Parasitoids and inquilines
One study identified twenty-four parasitoidParasitoid
A parasitoid is an organism that spends a significant portion of its life history attached to or within a single host organism in a relationship that is in essence parasitic; unlike a true parasite, however, it ultimately sterilises or kills, and sometimes consumes, the host...
s from galls of A. grossulariae, such as Torymus auratus, Megastigmus dorsalis, Ormyrus pomaceus, Sycophila variegata, Sycophila biguttata, Mesopolobus xanthocerus, and Aulogymnus trilineatus. Ceroptres cerri is an inquiline of A. grossulariae.
Distribution
A. grossulariae has been recorded from the United Kingdom, Spain, Belgium, and Israel. A. grossulariae was first seen in Britain in BerkshireBerkshire
Berkshire is a historic county in the South of England. It is also often referred to as the Royal County of Berkshire because of the presence of the royal residence of Windsor Castle in the county; this usage, which dates to the 19th century at least, was recognised by the Queen in 1957, and...
in 2000.