|Anacaena limbata (Fabricius, 1792)|
|Occurs throughout England and Wales including Scilly, Anglesea and Man (NBN).
Th vast majority of records are from England south of Durham, farther north there are a few scattered records
from Scotland north to Inverness but none from the Western Isles, Orkney or Shetland. Balfour-Browne reports a
similar sporadic occurence from Scotland although at the time of publication the closely similar A.lutescens
Stephens was not recognised as a British species. Friday
includes Scotland and the north as areas where the species may be found. Berge Henegouwen (1986) includes a Scottish
record as part of the European distribution and states that it is far less common in acid water than other Anacaena spp.,
an observation also made by Balfour-Browne. They occasionally occur in brackish water
Typically insects of weed choked still or slow moving stagnant water and marginal vegetation, they are common and
usually abundant throughout the Watford area and further south along the Colne valley to Cowley, the extent of our recording.
They occur throughout the year and seem to be as common during the winter as at any other time; winter samples of
decaying pondside vegetation often contains dozens of specimens. Retrieving debris from stagnant water will produce them
throughout the year and a good method of recording the species is to place logs or small branches into marginal water
and examine them after a week or so. From March or April they may be swept from marginal vegetation, adults remain active
through the year until the first cold weather; during 2007 they were swept in numbers from sedges bordering drainage ditches
below Cassiobury park. Reed litter samples fro Radlett road almost always contain them and they are occasionally
recorded from MV locally, they are always much more abundant thenA.globulus.
Less convex and generally lighter in colour than A.globulus; although these become familiar in the field they will need to
be examined under the microscope as A.lutescens can only be separated on the metafemoral pubescence.
2.2-2.8mm. Upper surface shining, sometimes with obscure and weak microsculpture (X40). Head finely and densely punctate, black, generally with reddish lateral margin before eyes, this may be dark and narrow so must be looked for carefully under strong light. We have some specimens in which the head is entirely black when viewed from above or laterally, however viewedfrom below the reddish margins are obvious. Eyes large and weakly convex, continuous with outline of head, with emarginate front and hind margins. Papli testaceous, last segment darkened or entirely black, larger than penultimate. Antennae 9 segmented with pubescent three segmented club, testaceous with black club. Pronotum transverse(53:23), widest near base and very finely bordered. Front angles rounded and weakly protruding. Testaceous with various dark markings, generally centrally and either side of middle, these may be continuous and extend to base. Puncturation a little finer and sparser than on head. Scutellum equilateral, finely punctured. Elytra testaceous with darker markings, often extensively darkened but lighter at least laterally and apically, usually with rows of darker spots. Sometimes with large, dark mark on disc. Puncturation as on pronotum. Sutural stria well impressed apically, absent from basal third. Legs brown. Tibiae with spines on outer side and strong terminal spurs. Tarsi 5-5-5. Basal segment of meso and meta tarsi less then half the length of the second segment so they may appear four segmented.
Description from 10 Watford specimens at X40