The Common Grass Moths of Berkshire (VC22) a Guide to Identification
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Berkshire Moth Group Identification Guide 1 The Common Grass Moths of Berkshire (VC22) A guide to identification Introduction The Crambinae are represented by 39 species in the British Isles. Most are associated with grasses or rushes, and can often be disturbed during the day, sometimes in significant numbers. This guide covers the eleven species most commonly found in Berkshire (VC22). It should be possible to make a positive identification of all these species based on visual characteristics. Where there are similar species which are either uncommon or absent in the region the differences are described. It will not be possible to identify all specimens unequivocally as there will always be oddities and worn individuals where there is room for doubt. The species are grouped according to similar appearance, rather than in taxonomic order. Inset pictures are actual size. Understanding Flight seasonseason (phenology) graphs Key to distribution maps the data J FMAMJJASOND Tetrads (2 kilometre squares) in VC22 where the moth has been recorded. Tetrads where any recording These show the number of records activity has occurred (i.e. at from each month, as a percentage of least one record of any moth). the total (range 0-100%). Total number of records is also shown. Key to text: Data is taken from the VC22 County Moth Records database and includes Status indicates national status. all records up to December 2007. Length is measured from palps to wingtip, with wings closed. Classification numbers used are Bradley & Fletcher. © Berkshire Moth Group 2008 1 Berkshire Moth Group Identification Guide 1 Pyralidae: Crambinae Terminology Side view – typical resting posture Species comparisons Apical Outer Two-thirds Half One-third Inner Flight season Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Body length (mm) 0210 0 Towards or in region of apex. Basal Tornus Palps Crambus lathoniellus Agriphila straminella Dorsum Towards or in region of base. Dorsal edge Base Chrysoteuchia culmella Crambus lathoniellus Costal l streak Termen Longitudina Towards or in region of costa; Costal edge Crambus pascuella Catoptria falsella Fringe costal edge: edge facing costa; Costa costal half: half of wing adjacent Crambus perlella Apex Chrysoteuchia culmella to costa. Subterminal Cross-lines cross-line Dorsal Length measured from tip of wing to palps Agriphila straminella Catoptria pinella Towards or in region of dorsum; dorsal edge: edge facing dorsum; Catoptria pinella Agriphila geniculea dorsal half: half of wing adjacent to dorsum. Top view – wings spread Catoptria falsella Crambus pascuella Fringe Apex Subterminal Long thin scales projecting beyond cross-line Agriphila selasella Crambus perlella Cross-lines termen; also known as cilia. Costa Inner Agriphila inquinatella Agriphila inquinatella Palps Towards head/base of wing. Termen Costal edge Longitudinal streak Agriphila tristella Agriphila selasella Longitudinal Fringe Along length of wing, e.g. Dorsal edge Agriphila geniculea Agriphila tristella longitudinal streak: streak running Base along length of wing Tornus Dorsum Graphs show percentage of records for each Bar indicates range of possible lengths, Oblique month, on a scale of 0 to 100. although this is a guide only. If food At an angle to costa or dorsum, i.e. sources are restricted (e.g. in drought neither parallel nor perpendicular to Hind wing conditions) smaller specimens may well wing edges. be found. One half/one-third/two-thirds etc Approximate position along wing Appearance chart taken from base. To be added. Outer Away from head/base of wing. Subterminal Immediately before termen. Terminal At end of wing; towards termen. Tornal Towards or in region of tornus. 2 3 Berkshire Moth Group Identification Guide 1 Pyralidae: Crambinae Agriphila tristella Common Grass-veneer 1305 Agriphila selasella Pale-streak Grass-veneer 1303 Flight season Flight season J FMAMJJASOND J FMAMJJASOND 3 1 2 1 Length: 12-15mm VC22 distribution VC22 distribution 594 records 71 records 3 2 © Ian Kimber Length: 11-15mm Similar species Variation Status: Common. Status: Local. Ground colour quite variable. Habitat: Tall grasses. Often disturbed Habitat: Grass. Can be disturbed by 1 by day. Comes to light. day. Nocturnal. Comes to light. Distinctive features: Variation Distinctive features: Strong longitudinal streak 1, Pure white longitudinal streak of Generally very variable both in ground often narrowing at one third 2, roughly even width 1 with dark colour and strength of markings. splitting into four ‘fingers’ 3. costal edge 2 dividing into two © Jeff Higgott faint ‘fingers’ 3. Termen rounded, A. tristella ‘Fingers’ more prominent, Similar species perpendicular to costa. Smooth four rather than two 1. Narrowing of appearance. 1 streak at one third. Termen straight, not perpendicular to costa. Rough appearance. © Ian Kimber A. selasella (p5): Fingers less prominent. Streak splits into two fingers 1 rather than four. Termen rounded and roughly perpendicular to costa. Streak pure white, of uniform width. Generally smoother appearance. © Malcolm Storey 4 5 Berkshire Moth Group Identification Guide 1 Pyralidae: Crambinae Crambus perlella Satin Grass-veneer 1302 Chrysoteuchia culmella Garden Grass-veneer 1293 Flight season Flight season J FMAMJJASOND J FMAMJJASOND 2 Length: 10-12mm Length: 11-14mm VC22 distribution VC22 distribution 179 records 962 records 1 © Malcolm Storey Similar species Variation Status: Common/abundant. Status: Very common/abundant Ground colour and strength of markings very variable. ‘C’ shaped Habitat: Tall grass. Very easily Habitat: Tall grasses. Frequently f.warringtonellus cross-line can be rather faint but is disturbed by day. Nocturnal. disturbed by day. Comes to light. always visible. Comes to light. Distinctive features: Distinctive features: ‘C’ shaped outer cross-line Shiny white colour, lack of markings. (C for culmella) 1. Variant f.warringtonellus ( ) has Brassy metallic sheen. A.straminella (p8): Smaller size. No strong white longitudinal streak 1 Fringe uniform colour 2. cross-lines. plus another streak along costa 2. 1 © M.Parsons/Butterfly Conservation 2 © Malcolm Storey Similar species Variation Little variation in typical form. Some © Charly Streets variation in strength of markings in Platytes cerussella (no records): f.warringtonellus. Much smaller (Length 6-8mm). © Richard Eagling © Mathias Biere A.straminella (p8): Smaller size. More tapered overall shape. 6 7 Berkshire Moth Group Identification Guide 1 Pyralidae: Crambinae Agriphila straminella Straw Grass-veneer 1304 Crambus pascuella Inlaid Grass-veneer 1294 Flight season Flight season 1 J FMAMJJASOND 2 J FMAMJJASOND Length: 11-12mm 2 VC22 distribution VC22 distribution 611 records 334 records 4 4 5 1 © Richard Eagling 3 Status: Common/abundant. Status: Common/very common Habitat: Grasses, esp. Sheep’s Habitat: Grasses and bushes. Easily Variation 1 Fescue (Festuca ovina). Often 5 3 disturbed by day. Comes to light disturbed by day. Flies by day and Distinctive features: night. Comes to light, often in Thick, white longitudinal streak 1, numbers. dorsal edge more or less straight 2, Distinctive features: costal edge angled at two-thirds 3, Small size. Lack of cross-lines. broken by thin oblique brown line 4. Fringe metallic, outer half lighter 1. Triangularly shaped and marked apex Ground colour and hence apparent strength of markings fairly variable. Faint longitudinal streak 2. 5. Hind wing pale. Often speckled with brown 3. Strongly tapered overall shape. 2 Similar species Male: Two-tone appearance – dorsal half of 1 wing light, costal half dark 4. Similar species Variation Female: Degree of brown speckling and 1 More uniform in tone. 1 overall colour quite variable . 2 Streak splitting into faint fingers 5 © Jan Haseler © Paul Harris © Jens Christian Schou C.lathoniellus (p10): Narrow, notched Crambus silvella (1 unconfirmed Crambus uliginosellus (5 records in © Malcolm Storey 1 longitudinal streak, costal edge record): Streak more rounded, Baker): Smaller size. Longitudinal fairly straight 2. Less pronounced extending beyond subterminal line 1. streak touches costa to half way 1. C.culmella (p7): Larger size. Angled triangular apex. Hind wing dark. outer cross-line. Metallic sheen. © Richard Eagling © Mathias Biere 1 © Rob Petley-Jones Crambus hamella (4 records): Crambus pratella (no records): Longitudinal streak unbroken. Longitudinal streak with sharply Crambus ericella (no records; northern moorland only): Much © Jeff Higgott angled costal edge 1, notched in C.perlella (p6): Shiny appearance. darker. Longitudinal streak narrower, Larger size. More uniform breadth. a similar way to C.lathoniellus. Hind wing dark. well-separated from costa. 8 9 Berkshire Moth Group Identification Guide 1 Pyralidae: Crambinae Crambus lathoniellus Hook-streak Grass-veneer 1301 Agriphila inquinatella Barred Grass-veneer 1306 Flight season Flight season J FMAMJJASOND J FMAMJJASOND 4 4 6 2 3 Length: 9-11mm 1 Length: 11-14mm VC22 distribution VC22 distribution 189 records 230 records 1 3 5 2 © Jan Haseler Status: Common. Status: Local © Mike Wall Similar species Variation Habitat: Tall grasses. Easily disturbed 7 Habitat: Short grass. Easily disturbed by day. Nocturnal. Comes to light. by day. Active from dusk onwards. Distinctive features: Comes to light. Longitudinal streak 1, notched Distinctive features: halfway along 2, costal edge fairly Strong, dark patch 1 in middle of 1 straight 3. Strong, sharply bent white longitudinal streak 2. subterminal line with dark inner edge