Following on from his plant gall workshop last year, Michael Kirby is calling for records of the Marble Gall from Oak trees. He needs you to fill out a short census questionnaire, which can be copied out onto a separate sheet of paper from the details below. You can also Right Click Here and choose Save As to download a Word file to enter data on. This can be printed out and sent or e-mailed to Michael.
The common galls of Oak trees are illustrated in the photographs below and as can be seen the smooth, round and hard mature Marble Gall is quite distinctive.

A marble gall with the wasp's exit hole

Young green  marble gall opened to obtain the insect in a central chamber.

A group of marble galls on an oak sapling showing marble galls some with exit holes and some broken into to get at the insect.

The marble gall is well protected against predators and inquilines (freeloaders, using the gall as shelter and food, but not harming the gall-making wasp larva). It has a hard outer layer and the larva is in a chamber in the centre of the spherical gall. Other animals also predate the gall. Mature galls are sometimes broken open by vertebrate predators to recover the larva or pupa. Woodpeckers, other birds or squirrels have been suggested as predators, but it is not known how widespread or common this practice is in the wild. To find out more about this, members are asked to help undertake a survey by completing the census below. Look for galls from mid-July onwards, either on the lower shoots of oak trees or sometimes on fallen twigs, especially after strong winds.

The following data are required for the Marble Gall Census.

        I have found marble galls YES / NO

(please submit negative records - the lack of galls is also of interest,
but give site details even where NOT found).

        Did any have several exit holes i.e. made by inquilines,
in addition to the wasp exit hole? YES / NO

        If so, how many? What proportion of the galls had inquilines?

        Have any galls been opened to extract the wasp? YES / NO

        Are there Lesser Spotted Woodpeckers in the area? YES / NO / UNSURE

        I think the gall damage was caused by (please tick one):

        If possible please give a map reference or postcode. If you are uncertain about the damage to a gall please send specimens to:

Michael Kirby,
The Studio, Blythburgh Road, Westleton, Saxmundham, IP17 3AS

An update on the appeal for records of Suffolk Marble Galls

During 2005 I got about 8 responses to the marble gall census (3-4 by word of mouth from Westleton people whom I had also asked via the Common notice board) the remainder from SNS mebers by e-mail.

None reported bird damage or evidence of inquilines, some mentioned that they thought that there were few galls in 2005. However , Westleton was well provided for, including a cluster of 12 galls, the most I have seen, but there was no bird damage. What will happen in 2006?