no longer being grazed at least during 1993. The scarp grasslands there
are already mown each year in late summer. Because of the extent of
this virtually all the nectar and pollen sources for the bees are being
removed at one time, inevitably with serious effects on their populations
and ability to survive. Areas of ground bare scraped bare by the
mowing are allowing vigorous invasion of thistles, which although an
important nectar source for many insects, are probably the main cause
for mowing in the first place. Now mowing of the grazing marsh has
also started, destroying many of the old ant hills that form an important
part of the habitat. Both the grazing marsh and scarp grasslands must
have historically been grazed. The continuity of this management is
almost certainly essential in order to maintain the invertebrate
importance of the grasslands. Mowing is a most unsatisfactory
replacement and in my view this should be addressed at the earliest
opportunity.
Acknowledgements
I am extremely grateful to John Felton for identifying a considerable
amount of my hymenoptera material. This has resulted in my collection
containing many reliably determined species which now form a valuable
reference collection. This in turn has lead me to have a much increased
interest in Aculeate hymenoptera in the last two years. I am grateful to
George Else of the Natural History Museum for looking at and
determining several of my specimens and for giving me details of old
records for Andrena hattorfiana and Ceratina cyanea together with
helpful information on the recent spread of Philanthus triangulum. I am
also very grateful to Colin W. Plant and Mark Hanson who made a
number of helpful comments about the draft for this article. Additional
material of relevance to this paper has been published in Field Club
newsletters 11,12 and 13.
References
Falk, S. (1991) A review of the scarce and threatened bees, wasps and
ants of Great Britain. Nature Conservancy Council.
Payne, R. (1992) Social Wasps in Essex. Essex Field Club Newsletter
No. 4 (November 1992).
Shirt, D.B. (1987) British Red Data Books: 2. Insects. Nature
Conservancy Council.
Watson, S. & C. (1993) Botany Group Meeting, August 15th at
Strethall. Essex Field Club Newsletter No.8 (November 1993).
32