British Plant Gall Society

The Rose Bedeguar Project

REARING & RECOGNISING INHABITANTS.
by Robin Williams & Simon Randolph

REARING

Fortunately this has proved to be a reasonably simple process, as these galls are of the hard variety, used to spending their life in the very variable conditions of heat, cold and damp exposed to the weather, remaining on the bush, sometimes for years. The first problem is to know when to gather them. If soft and still red, they are very vulnerable to rotting and attack by moulds, which successfully finish off any inhabitants. If you do want to pick at an early stage, in late summer, then they must be kept over damp sand, with a crystal of the chemicals used to keep pot plants moist. They should also have a crystal of thymol added to reduce the tendency for mould. Even so, success is problematical.

Better by far to wait and collect in mid-winter when they have hardened off and reached the final stage of maturity. January is a good time, or later. Then the galls may be stored in a simple closed pot, without sand, but including the thymol crystal as a precaution against mould. The perfect container is the size of a film container, transparent, with a push-on lid. Some bigger bedeguars will not fit in these and something larger is required. Transparency is important, so the pots may be inspected to see when the insects have emerged. Keeping them on the tree well into winter allows all parasites access to the galls and produces the sort of mix natural in the wild.

The pots should labelled: time of collection, location and map-reference, your name and the name of the host-plant. Where importance is attached to dates of emergence, and this is important in understanding the biology of the system, then the pots should be kept in natural temperatures, outside, in a garden shed or open garage. Frost and heat both have a part to play in ensuring the emergence of the insects. Since the galls have many chambers, a variety of insects may emerge and it is important to keep them for several years until they have all emerged.

The pots should be inspected for emergences at least every few days. The insects often die on emergence but otherwise may be killed by a few drops of ethyl acetate in a twist of kitchen roll paper in a small jar and then stored dry in tubes (I use 12 X 50mm, with plastic stoppers), + crystal of thymol . Cynipids and chalcids do not store well in alcohol, as they swell and often disintegrate, as well as changing colour. The tubes should be labelled immediately with as much information as is available and, eventually with: gall type, location/map reference; collection & emergence; collector & determiner; insect name, authority, sex.

The whole process is then traceable in future years. I generally keep the insects and determine them eventually in the quieter winter months. Many people mount cynipids and chalcids on card points on a pin. I prefer to leave them in a tube and examine them under the microscope using glass beads to hold them in any required position. If the keys prove difficult for individuals, or help is needed in getting the process underway, contact Simon Randolph or myself. We will be delighted to determine the insects and will ensure they are entered into MapMate as a permanent record.