|Phyllobius Weevils in Nottinghamshire|
|Conspicuous through their bright
green colouration, Phyllobius Weevils are often
readily obvious to someone with little interest in
Coleoptera. Several species are common and easily found
on low growing plants in a variety of situations, but
identification to species level can often be quite
This page is not designed with accurate identification in mind, but purely to illustrate some of the Phyllobius Weevils found in Nottinghamshire and to make brief comparisons with Polydrusus Weevils, some of which are also green and can create confusion. Any identification points made, will be readily visible under a small hand lens.
Phyllobius and Polydrusus Weevils (Curculionidae) both feed on the foliage of various plants. The commonest species is P. pomaceus, which is sometimes known as the Green Nettle Weevil.
|However, as with many common names, it is slightly misleading from the point that there are other species which are just as frequently found on Nettles. Although usually to be encountered on Nettles, the large (around 10mm) P. pomaceus is just as likely to occur on most other low vegetation types, but in our own experience, it is rarely found on foliage above head height. When beating or sweep netting the lower branches of trees, the commonest of the green weevils at Sherwood Forest are P. pyri and the much smaller P. roboretanus.|
|Separation of Phyllobius from green Polydrusus Weevils|
|Separating green Phyllobius
and Polydrusus Weevils is by the position of the
antennal insertion on the head. This is easily achieved
in the field with a small hand lens. Comparison between
the two is shown in the photographs on the left, with Phyllobius
on the far left.
In all Phyllobius sp, the insertion point is viewable from above, whilst not visible from above in Polydrusus sp.
|Before proceding further,
it is worth pointing out that not all Phyllobius Weevils
are green. Indeed, P. pyri is most easily
recognised by it's lack of green colouration and P.
oblongus (not known from Sherwood) is chestnut
brown. Although extremely variable, P. pyri very
rarely shows any amount of the metallic green scaling of
most other Phyllobius weevils.
As with all Phyllobius weevils, the bright green colouration comes from a covering of dense scales, which are easily rubbed off. Through age, adults can become devoid of virtually all green scaling and generally appear black or very dark brown (especially on the legs) Identification then becomes less straight forward and more reliant on structural differences.
To confuse matters even further, a rare Sherwood Phyllobius (P. viridicollis) loses most of it's scales almost immediately upon hatching, but this species has not been recorded at Sherwood for about a century.
|For those who may wish to
determine a specimen a little further, then a key
identification feature of Phyllobius weevils, is
the presence of a prominent tooth on the underside of the
femora. This is shown in the photograph of P.
pomaceus on the right.
The femoral tooth is often visible (through resting posture) under a hand lens if the beetle is viewed from above. The table on the left shows those Phyllobius Weevils with toothed femora and those without.
Weevils in Nottinghamshire
There are a total of ten species of Phyllobius known from the UK. Nottinghamshire is well represented with nine of these which include P. argentatus, P. glaucus, P. maculicornis, P. oblongus, P. pomaceus, P. pyri, P. roboretanus, P. virideaeris and P. viridicollis. Seven species are currently on the Sherwood Forest species list.
Two species not illustrated are Phyllobius oblongus and Phyllobius glaucus. Historically, Carr in his book The Invertebrte Fauna of Nottinghamshire, lists the following sites for these species.
Phyllobius oblongus - Retford (Pegler) Worksop (Hodding) Barrow Hills near Everton (Thornley) South Leverton, Rampton Marsh 1899, Kingston-on-Soar (Thornley) Nottingham and district (Dodd, Robinson, Ryles etc) Hucknall Torkard 1911, Tollerton (Robinson 1918) and West Leake 1914.
Phyllobius glaucus - Sherwood Forest (Kidson-Taylor) north Notts (Chamberlin) Tresswell Wood 1899, Sutton near Retford, presumably Sutton-cum-Lound? (Thornley) Aspley Woods at Nottingham (Ryles) and Quarry Banks at Linby in 1914.
By the end of 2009, we have been successful in photographing six Phyllobius Weevils. For comparison, we have included photographs of Polydrusus cervinus, the only Polydrusus we have so far found.
|Phyllobius argentatus (Linnaeus, 1758)|
|Phyllobius argentatus is a small species, but equally as bright green coloured and covered with fine white hairs. There are only a few records for Sherwood Forest, despite it being quite common. Size around 6mm. This one was found at Clipstone Old Quarter in May 2009.|
|Pyllobius maculicornis (Germar, 1824)|
|Phyllobius maculicornis is often found on Nettles and a wide range of other plants. Differences between this and P. pomaceus are extremely subtle. This was one of several seen during July 2008 at Sherwood Forest CP, where further searching in 2009 found it to be common.|
|Phyllobius pomaceus (Gyllenhal, 1834)|
|Phyllobius pomaceus is an abundant species throughout Nottinghamshire, appearing in April and remaining common through the Summer. It is found mainly on Nettles and in a wide range of habitats where Nettles occur. This species, shows a certain amount of variation in colouration, with some specimens showing a distinct coppery/purple tinge. Length around 10mm.|
|Phyllobius pyri (Linnaeus, 1758)|
|A common species and one of the first of the Phyllobius to appear, usually in late April or early May. We found Phyllobius pyri to be common on Hawthorn and occasionally on Birch scrub at Sherwood Forest CP, appearing to favour certain bushes. Colouration of the adults we found, ranged from green, through to a rich copper colour. Presumably a common Nottinghamshire weevil. Average length around 8mm.|
|Phyllobius roboretanus (Gredler, 1882)|
|A common weevil which usually appears from late April onwards. This Phyllobius roboretanus was found on low foliage at Sherwood Forest CP in early May and is regularly beaten or swept from foliage above head height. Presumably a common weevil across Nottinghamshire. Length of the one in the photographs was approximately 5mm.|
|Phyllobius virideaeris (Laicharting, 1781)|
|A common weevil which usually appears from late April onwards. Presumably another fairly common weevil across Nottinghamshire, this was one of several found in the flowers and stems of Sorrel at Red Hill, Eakring in early June 2009. Length of the one in the photographs was approximately 4mm.|
other possible confusion species
There are several species of Polydrusus weevils that are green and easily confused with Phyllobius weevils, but we only have photographs of Polydrusus cervinus. In May 2010, we found an additional confusion species, when Pachyrhinus lethierryi was found in a Worksop garden.
|Polydrusus cervinus (Linnaeus, 1758)|
|Probably a fairly common weevil of a variety of foliage around Sherwood Forest NNR. We found this adult P. cervinus on a small Birch in the early part of May 2009 and is our only record to date. Polydrusus weevils are very similar to the Phyllobius group, but the main difference between the two is that the antennal insertions are on the side of the rostrum and not visible from above. Historically, this seems to have been widespread across Nottinghamshire.|
|Pachyrhinus lethierryi (Desbrochers, 1875)|
|A small green weevil, which looks very much like either a Phyllobius or one of the green Poyldrusus weevils. When we first found this species, the colouration immediately made it look something very different from what we had found before, the first specimen being a more vivid green. It's location was also a clue, being found in a small Worksop garden in May 2010, where we also found several adults inside a small conservatory. Pachyrhinus lethierryi was first found in the UK in 2003 and has spread rapidly north since. Beating the commonly planted conifer Thuja occidentalis, or finding a green weevil indoors, may well reveal that this weevil is now found across much of Nottinghamshire, but this is the only Nottinghamshire record we are aware of at the present time. Length around 4.5 - 5mm.|