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THE STATUS OF S O M E AQUATIC INVERTEBRATES IN SUFFOLK Cladocera — water fieas Ephemeroptera — mayflies Hemiptera Heteroptera — water bugs Hirudinea — leeches A. K. CHALKLEY Since becoming recorder for aquatic invertebrates a little Over a year ago I have been trying to assess past records as well as to make new ones. Having looked through the past issues of the Transactions it was immediately apparent that these groups had not been dealt with in any depth for almost half a Century. As well as redressing the balance a little in their favour I hope that this article, and perhaps others in the future, will serve as a base line from which future survey work in the county may proceed. At this stage I am not trying to be definitive as too many of Suffolk's rivers and ponds remain unsurveyed. although it is to be hoped that one day enough data will be available for a more exact account to be published. Nor, with the limited number of records available for each group, am I yet attempting to publish distribution maps. Instead I will take certain groups where sufficient recording has been done and combine the archive records, from the museum record card system and from the Transactions, with records made mostly in the last five years, but occasionally up to ten years ago. This will serve as a preliminary list for the county which I am sure will be added to in the years to come. Many of the species named in the early editions of the Transactions have gone through revisions and name changes; I have therefore updated the early records to give the correct modern species names and groupings, though for one or two species in the Transactions I can still find no synonyms. These unlisted species are not included. In explanation of the lists I have made notes where applicable as to the proportion of species recorded thus far, added common names to the families where possible and made a few general comments. For the Hirudinea, which are I feel less well known, I have given a brief description of each family's characteristics. Some data has been coded to avoid repetition since many records share the same site and date details. After each species name is a list of numbers referring to Archive records e.g. (A. 23. 35) and another referring to Modern records e.g. (M. 5, 14d). The numbers refer the reader to the lists of sites at the end of this paper whilst letters a, b etc. refer to different dates for the same site.
CLADOCERA The Cladocera or water fleas are well known to many people and popularly are called Daphnia. However the Daphnia are only one family of these fascinating creatures which number approximately 103 species in Britain, including varieties and different forms, and may be found in most permanent water bodies. The term Cladocera is useful in describing crustaceans of similar appearance though in fact they have now been split into four distinct Orders, Trans. Suffolk Nat. Soc. 30 (1994)