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widespread species. The queens are generally considerably smaller than those of lapidarius, and
they are 'sooty' rather than 'velvet' black in colour. The red is more 'ginger' than in lapidarius,
but this is not a reliable feature. More distinctive is the red colouration of the corbicular hairs
(black in lapidarius). Though this seems a rather recondite character, it is surprisingly obvious
in the field. The workers arc similar to the queens in colouration, but often have partially black
corbicular hairs (which are in any case often obscured or discoloured by their pollen loads!).
They usually have less brightly red-coloured 'tails', and are less 'velvet' black than lapidarius
but these features arc no more than an aid for selecting individuals for closer identification. The
males usually have two grey-yellow bands on the thorax, but these may be quite obscure. There
is also sometimes a yellow ish band on the thorax. The 'tail' is red. as in the females. Distinction
from male lapidarius can sometimes be difficult without microscopic examination.
Currently available records suggest that this species remains well established in remaining
habitat along the Thames estuary, like so many other Aculeate Hymenoptera. It also seems to be
fairly common in parts of north-east Essex, and there are scattered records across central and
North Essex.
Bombus sylvarum (Linnaeus) cover photograph
This species is the topic of intense concern at both national and local levels. The national
Bumblebee Working Group initiated research on sylvarum in 1997, following the drawing up of
a Biodiversity Action Plan for it. Since then, national surveys have revealed the presence of
populations of this species in less than ten locations. Most of these remaining sites are along the
Thames estuary, in Kent and Essex. One Essex locality has already been designated for
'development' (P. Harvey 1997. p.42), and there may be only two sites where it can be said to
be secure. Given its precarious national status, conservation of this species in Essex must clearly
be of the highest priority. So far surprisingly little is known of its life-history and habitat
requirements. My own seaches for it proved fruitless until it was re-discovered in Essex by Peter
Harvey in 1993.
The 'common' name for sylvarum is the 'Shrill Carder Bee', and, indeed, its presence can often
be detected by its distinctive, high-pitched 'hum'. Its appearance is not very striking. The
abdomen is reddish in colour, and it has a yellow 'collar' and scutellum. The queens are small,
and the workers often tiny. It appears that each nest produces a comparatively small number of
workers, and these are most often seen in August, much later than the 'peak' populations of
oilier species. Work is currently continuing to discover more about the conservation
requirements of this species, and more detail will be provided in the forthcoming Bumblebees of
Essex.
In addition to the true Bumblebees (Bombus), five out of the six British Cuckoo Bumblebees
(Psithyrus) have been recently recorded in Essex. These are:
Psithyrus vestalis (Geoffroy in Fourcroy)
This is currently by far the commonest of the cuckoo Bumblebees in Essex. It parasitises
Bombus terrestris. Both males and females are black, with a yellow 'collar' and white 'tail'.
They are readily distinguished from the other Essex Psithyrus species (P.bohemicus appears to
be absent from the county) by the lemon yellow 'flashes' at the sides of the abdomen, at the
boundary between the black and white areas. Unfortunately this tends to fade in the older
specimens so is not always reliable.
Essex Naturalist (New Series) 16 (1999)