A cocoon of Hypera rumicis (L., 1758). The golden net ball
On Sunday 1st July 2012 a group of us visited the Vale Landscape Heritage Trust Reserve on the River Avon flood plain near Lower Moor in the Vale of Evesham. At one point I noticed a tiny golden net ball (c4 mm diameter) attached to a leaf of Gypsywort Lycopus europaeus growing on the edge of a ditch (Fig. 1 & 2.). Nobody present could identify it so I carefully picked the leaf and placed it in a tube for further investigation. Next day a weevil had emerged from the golden ball and was sitting next to it on the leaf (Fig. 3.). I sent pictures to Paul Whitehead who responded as follows:
"Your cocoon is certainly that of a Hypera and from the beetle image you have sent to me I am reasonably confident that the species is Hypera rumicis (L., 1758). The nomenclature of eririnomorph** Hypera is presently somewhat unstable. Some continental workers place Hypera alternans, adspersa, pollux and various other names in synonymy with H. conmaculata (Herbst, 1795) and it remains to be seen whether the forthcoming volume 8 of the Palaearctic Catalogue will follow this. British collections of Hypera may then require reassessment. In my experience Hypera rumicis sensu stricto is locally distributed in the English midlands on floodplains and in wetlands and I have seen it in coastal wetlands in Macedonia."
“** Hypera are subdivided into various subgenera. Most Hypera you will encounter, most of the dry-loving ones, are in the subgenus Hypera. One or two are in the subgenus Dapalinus and Hypera zoilus, a large species that may now be declining, is in Antidonus. Hypera rumicis and Hypera conmaculata are in the subgenus Eririnomorphus hence 'Eririnomorph’.”
I vaguely remembered seeing a similar picture of a golden net ball in the past but could not remember when. Rosemary Winnall reminded me that John Partridge had circulated a picture taken on 14th June 2011 which remained unidentified at the time (Fig. 4.). However, following these clues readers will be able to find similar pictures via an internet search. See for example http://www.flickr.com/photos/23111015@N04/2744112277/
Fig. 1. Hypera rumicis coccoon on Gypsywort.Harry Green
Fig. 2. Hypera rumicis coccoon on Gypsywort with weevil inside.Harry Green
Fig. 3. Hypera rumicis newly hatched from coccoon in Figs. 1 & 2. Harry Green
Fig. 4. Golden ball cocoon 14June 2011.