Nettle Weevils Phyllobius & Polydrusus

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Phyllobius & Polydrusus

The main Generic differentiator Separating these green weevils is by the position of antennal insertions on the head wheren they emerge from rostrum. In all Phyllobius sp, the insertion point is viewable from above whilst not visible from above in Polydrusus sp.

In progressing the identification further the presence or absence of a tooth on the femora should be noted

TABLE 1

Femora (toothed)	Femora Simple (no tooth)
P. argentatus	P. roboretanus
P. glaucus	P. virideaeris
P. maculicornis	P. viridicollis
P. oblongus .
P. pomaceus .
P. pyri

There is an excellent working Key Here KEY

Species	Toothed front femora	Scales	Femora colour	Tibiae	Elytral slope	Hairy
Phyllobius argentatus	yes	round	pale			fine
Phyllobius maculicornus	yes	elongate	dark			fine
Phyllobius glaucus	yes	pointed	pale			no
Phyllobius pyri	yes	elongate	dark	ridged		no
Phyllobius oblongus	yes	none	pale			yes
Phyllobius pomaceus	yes	oval	dark			no
Phyllobius viridicollis	no	few	dark			no
Phyllobius roboretanus	no	round	dark		steep	no
Phyllobius virideaeris	no	round	dark		shallow	no

Green Nettle Beetle (Weevil) Phyllobius pomaceus

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Identification Phyllobius is a genus of "short-nosed weevils", in which the rostrum is relatively short and extends little beyond the points of attachment of the antennae.

P. pomaceus is a well-known species but requires attention to critical characters for certain identification. It is by no means the only green weevil of metallic appearance

Although described here as "green", it should be noted that the basic colour in this species is black, but with the beetle extensively coated with metallic, typically green to blue-green (sometimes also golden or coppery) scales. With age, more of the black ground colour is revealed as the scales are rubbed off.

There are 10 species of Phyllobius in Britain Morris (2004). A The genus is characterised by a scaly pubescence or by the tiny, metallic scales, which in most species coat the entire dorsal surface of the insect. The colour of these scales varies in many species, including P. pomaceus, from various shades of green to coppery brown. The majority are leaf-eaters, non-specifically on various trees.
The genus Polydrusus is very similar, the distinction being that the "scrobes" (the furrows in the rostrum into which the first joints of the antennae fit) are curved rather than straight – diagram in Joy (1932).

Distribution:

Some sources call this the "Nettle Weevil" or the "Green Nettle Weevil", but see below regarding confusion over these names.

What To look For

i) relatively large size, length 7-9 mm;
ii) the femora each bear a conspicuous, more or less ventral tooth (most easily seen on the front pair of legs); and just visible on the Mid Image below
iii) the legs are black beneath the scales;
iv) the antennae are dark beneath the scales, though tinged rust right at the base and sometimes at the tips;
v) nettles (Urtica) as the host plant.

 

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