Insects of Britain and Ireland: the families of Lepidoptera

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L. Watson and M. J. Dallwitz

Character list

#1. <Synonyms:>/

~ (‘alternatively’) is here used to indicate ‘sometimes not unreasonably included in or reduced to’.

Adults

#2. Adults <when active>/

1. diurnal/

2. crepuscular/

3. nocturnal/

#3. Adults <size, in the context of British Lepidoptera (cf. ‘wingspan’)>/

1. tiny <wingspan less than 6 mm>/

2. small <wingspan 6–20 mm>/

3. medium sized <wingspan 20–50 mm>/

4. large <wingspan 5–8 cm>/

5. very large <wingspan over 8 cm>/

#4. The flightless females <approximate length, for keys>/

1. 4–7 mm long/

2. 5–12 mm long/

3. 12–16 mm long/

#5. Adults relatively <body length, relative to hindwings in a ‘set’ position>/

1. short-bodied <the tip of the abdomen clearly exceeded by the hindwings>/

2. medium-bodied <the tip of the abdomen about level with the hindwings>/

3. long-bodied <the tip of the abdomen conspicuously exceeding the hindwings>/

#6. Adults <build - reflecting relative (not absolute) body size>/

1. relatively slender-bodied (wingspan more than 15 times the thoracic width)/

2. medium built (wingspan more than 8 and less than 15 times the thoracic width) /

3. heavily built (wingspan less than 8 times the thoracic width)/

Data calculated from the numeric character relating wingspan to thoracic width (q.v.).

#7. The abdomen <patterned or plain>/

1. conspicuously patterned <with stripes, bands, spots, etc.>/

2. plain <ignoring effect of segmentation on hair distribution, and antero-dorsal crests of darker hairs>/

#8. Adults <whether winged or apterous>/

1. with fully developed wings <operational for flight> /

2. wingless, or with vestigial wings/

Apterous females, or females with greatly reduced wings, occur in several families.

#9. Adults <whether of hymenopterous appearance>/

1. of hymenopterous appearance <with transparent wings>/

2. not of hymenopterous appearance <the wings more or less opaque> /

#10. Adults <carriage of hind-legs in repose>/

1. conspicuously raising the hind-legs above the body in repose/

2. not raising the hind-legs <above the body> in repose/

#11. Adults wings in repose <carriage>/

1. apposed vertically over the back <the forewings often more or less covered by the hindwings>/

2. partially opened/

3. spread flat with their lower surfaces more or less appressed to the substrate <often more or less spread, exposing the abdomen and hindwings>/

4. packed with the forewings directed backwards to <more or less> cover hindwings and abdomen/

5. with the forewings rolled around the hindwings, the pairs borne horizontally at an angle (or at right angles) to the body/

Vertical apposition when at rest is usually associated with camouflage-patterned undersides of the wings, and seems to be almost confined to the families constituting ‘butterflies’.

#12. Head <of adults, whether rough or smooth>/

1. rough <-scaled, or -haired>/

2. smooth <the scales or hairs appressed>/

#13. Antennae <when straightened, in situ length relative to forewing>/

1. very short <extending less than halfway to the wingtip>/

2. of medium length <extending between half and three quarters of the way to the wingtip>/

3. long <extending over three quarters of the way to the wingtip, but not exceeding it>/

4. very long <extending beyond the wingtip>/

In situ length when straightened, relative to the forewing. Approximated from ranges detailed in the next character, mainly from data provided by Meyrick.

#14. Antennae extending to about <length divided by centre-thorax-to-apex length of forewing>/

times the <in situ> length of the forewing/

Data mainly from Meyrick. He seems to have been referring to the centre-thorax-to-forewing-apex measurement (i.e., the one he advocates doubling to obtain ‘wingspan’), although his ‘Method of Description’ details do not specify this.

#15. Antennae <distance apart>/

1. inserted markedly less than one half the width of the head apart/

2. inserted fully one half the width of the head apart/

#16. Antennae <whether clubbed>/

1. clubbed/

2. not clubbed /

‘Clubbed antennae’ could be represented by one state of a multi-state character describing general form, but is offered separately here because it is reliably applicable to lepidopterans of both sexes (i.e., by contrast with the character describing ‘antennae of males’, which is also available).

#17. The <antennal> club <abruptness>/

1. gradual/

2. abruptly terminal/

#18. The <antennal> club <straight or curved>/

1. curved/

2. not curved/

#19. Antennae of males <form; see Notes before applying this character to identifications>/

1. lamellate/

2. bipectinate/

3. <unilaterally> dentate <including ‘serrate’>/

4. simple/

Some caution is required in using this character, because (1), the descriptions refer exclusively to male insects; and (2), the literature consulted is unconvincing regarding details of non-pectinate forms. However, since the occurrence of bipectinated antennae is well documented, and since an insect with bipectinated antennae will presumably be a male, possession by a specimen of state 2 is certainly a useful identificatory state. The other states are best avoided for this purpose. ‘Clubbed antennae’ (q.v.) are dealt with as a separate character which is applicable to lepidopterans of both sexes, and are here arbitrarily classed as ‘simple’ (with reference to the shaft).

#20. Antennae of males <whether ciliate; see Notes before applying this character to identifications>/

1. non-ciliate/

2. simply-ciliate/

3. fasciculate-ciliate/

4. pubescent/

This character is potentially valuable; but the data compiled to date do not inspire confidence, and anyway refer only to males.

#21. The antennal scape <presence of a pecten of hair-scales>/

1. with a pecten <of hair-scales>/

2. without a pecten/

#22. The antennal scape <whether forming an eye cap>/

1. expanded laterally and concave beneath, forming an ‘eye cap’/

2. not forming an ‘eye cap’/

#23. The antennal segments <scales>/

1. each with one or two rings of scales/

2. without rings of scales/

#24. Eyes <of adults, whether notched or emarginate>/

1. notched or emarginate at the bases of the antennae and contiguous with the bases of the antennal sockets/

2. neither notched nor emarginate, and clearly separated from the bases of the antennal sockets /

#25. <Compound, main> eyes <of adults, hairy or glabrous>/

1. hairy/

2. glabrous/

#26. Ocelli <of adults, presence>/

1. present/

2. absent/

‘Ocelli’: tiny paired simple eyes, when present situated above the relatively large compound eyes.

#27. Chaetosemata <in adults, presence>/

1. present/

2. absent/

‘Chaetosemata’: paired secretory or sensory structures of infrequent occurrence and uncertain function. They are situated on either side of the forehead, above and adjoining the compound eyes (intervening between the compound eyes and the ocelli, when the latter are present).

#28. Mandibles <of adults, whether developed>/

1. developed and functional/

2. not developed /

#29. Maxillary palps <presence, development>/

1. well developed <though usually small>/

2. much reduced/

3. absent/

#30. Maxillary palps <number of segments>/

segmented/

#31. Maxillary palps <whether folded>/

1. folded <over the base of the haustellum>/

2. not folded /

#32. Labial palps <size>/

1. well developed /

2. short or rudimentary/

#33. Labial palps <carriage>/

1. drooping/

2. porrect <pointing forward, beak-like>/

3. ascending/

As shown in the illustrations, the popular and euphonious description ‘porrected palps’ refers to labial palps, which lend the delightful, perky appearance to the face presented by several groups of Lepidoptera. These organs generally retain their position in ‘set’ specimens. However, from the standpoint of useful description, there exists in reality an awkward continuum of forms, from ‘porrected’ through ‘ascending’ to ‘erect’.

#34. Labial palps <number of segments>/

segmented/

#35. Proboscis <(tongue, haustellum) of adults, whether fully developed and functional>/

1. fully developed <functional for feeding>/

2. absent <or vestigial, minute>/

#36. Proboscis <(tongue, haustellum) of adults, whether scaly>/

1. scaly towards the base/

2. not scaly/

#37. Wingspan <centre of thorax to tip of forewing, multiplied by 2>/

mm/

#38. Wingspan <relative to maximum thoracic width>/

times the <maximum> thoracic width/

‘Wingspan’: centre of thorax to tip of forewing, multiplied by 2.

#39. Wings <whether deeply divided into plumose segments>/

1. deeply divided into plumose segments/

2. entire <not deeply divided into plumose segments>/

#40. Wings <whether aculeate (strewn with minute spines)>/

1. aculeate (strewn with minute spines)/

2. not aculeate /

#41. Forewings <whether apices strongly up-turned or down-turned>/

1. with their apices conspicuously bent up or down when the insect is at rest/

2. without up- or down-turned apices when the insect is at rest /

#42. Forewings <broad or narrow>/

1. narrow <more than 2.5 times as long as wide>/

2. broad <less than 2.5 times as long as wide>/

The assessments are based on base-to-apex length, divided by the approximate maximum width measured at right angles to a line drawn from base to tornus (i.e., approximately at right angles to the hind or inner margin).

#43. Forewings <proportions, length relative to width>/

times as long as wide <base-to-apex length, divided by maximum width measured at right angles from hind margin to costa>/

The assessments are based on base-to-apex length, divided by the approximate maximum width measured at right angles to a line drawn from base to tornus (i.e., approximately at right angles to the hind or inner margin) from hind margin to costa.

#44. Tornus <of the forewings, presence; refers to wing membrane, ignoring long fringes>/

1. clearly defined <the outer and hind margins readily distinguished>/

2. weakly defined <the outer and hind margins set at a wide angle>/

3. undetectable/

#45. The outer and hind margins <of the forewing membranes> angled at <degrees>/

degrees <at the tornus>/

The angle between the hind/inner margin and the wing apex, measured at the commencement of the tornal curve when the angle is not sharp. Data were obtained by applying a protractor to published photographs. The character is unreliable because of imprecision regarding locations of apex and tornus, and only large differences are meaningful.

#46. The outer margin <(termen) of the forewings, shape>/

1. convexly curved/

2. more or less straight/

3. concavely curved/

4. sigmoid-curved/

5. angulated/

#47. Forewings <whether angulated> /

1. with the outer margin both angulated and markedly scalloped/

2. with outer margin not both angulated and markedly scalloped /

#48. Forewings apically <shape>/

1. blunt/

2. pointed/

3. hooked/

#49. Forewings <whether ‘metallic’ (on the upper surface)>/

1. predominantly shining-metallic <brassy, bronze, coppery, silvery>/

2. exhibiting shining-metallic markings/

3. neither shining-metallic nor with shining metallic markings /

#50. Ground colour <of upper side of forewings> predominantly/

1. white or cream/

2. yellow/

3. green/

4. light brown/

5. dark brown/

6. orange-brown/

7. coppery red/

8. blue/

9. purple/

10. black/

11. grey/

Published descriptions of lepidopteran wing colours are often very inadequate and misleading, with later efforts often comparing very poorly with Newman's. For example, compare the latter's pleasant and genuinely informative word pictures with Meyrick’s inadequate and boring attempts to be scientific.

#51. Forewings <whether eye-spotted above>/

1. eye-spotted above/

2. without eye-spots above /

#52. Forewings <whether eye-spotted near the tip underneath>/

1. eye-spotted underneath near the tip/

2. not eye-spotted underneath near the tip <implicit>/

#53. Forewings <presence of jugum>/

1. with a jugum/

2. without a jugum /

‘Jugum’: a membranous process from the proximal region of the dorsal edge of the forewings, confined to few families, and concerned with locking together of fore- and hindwings.

#54. Forewings <subcostal scale tufts>/

1. with three subcostal tufts of scales <Nolidae>/

2. without subcostal tufts of scales <Arctiidae>/

#55. Hindwings <whether narrow-elongate and long-fringed>/

1. narrow-elongate and very long-fringed <the dorsal (inner) fringes wider than the wing membrane>/

2. neither unusually narrow-elongate nor especially long-fringed /

#56. Hindwings <shape of membrane>/

1. linear/

2. linear-lanceolate/

3. lanceolate/

4. ovate-lanceolate/

5. ovate/

6. broadly rounded/

7. broadly angular/

8. trapezoidal/

#57. Hindwings <breadth relative to forewings, excluding fringes>/

1. very much narrower than the forewings <less than half as broad>/

2. quite markedly narrower than the forewings <from 0.5 to 0.75 times their breadth>/

3. similar in breadth to the forewings <0.75 to 1.25 times their breadth>/

4. markedly broader than the forewings <over 1.25 times as broad>/

#58. Hindwing <maximum> width <relative to that of forewings; excluding fringes> /

times that of the forewings/

#59. Hindwings <shape of apex>/

1. with a pointed apex/

2. with a rounded apex/

#60. The fringe of the hindwings <approximate length relative to width of the membrane>/

times the <maximum> width of the membrane/

#61. Hindwings <whether tailed>/

1. tailed/

2. not tailed /

#62. The upper surfaces <of the hindwings, patterned or plain>/

1. conspicuously patterned above <lined, spotted, banded, streaked, etc.>/

2. plain <concolourous or merely suffused, etc.>/

#63. <The upper surfaces of the hindwings, whether exhibiting a discal spot and/or lines>/

1. with a discal spot/

2. with transverse lines/

3. with neither discal spot nor transverse lines/

#64. Hindwings <whether silver-marked underneath>/

1. silver-marked underneath <with spots and/or streaks>/

2. not silver-marked underneath <implicit>/

#65. Hindwings <with or without frenulum>/

1. with a frenulum/

2. without a frenulum/

‘Frenulum’: comprising a bristle (or bristles) from the base of the costa of the hindwing. In life, the tip of the frenulum passes under a chitinous catch (the ‘retinaculum’) on the underside of the forewing, thus locking fore- and hindwings together.

#66. Neuration of forewings and hindwings <similar or dissimilar>/

1. similar <hindwing with at least 10 veins, exclusive of anals, reaching the margin>/

2. dissimilar <hindwing with no more than 8 veins, exclusive of anals, reaching the margin>/

Basic information on lepidopteran wing neuration and the terminology used here is available via the ‘Lepidopteran morphology’ toolbar button.

#67. Forewings <development of neuration>/

1. with well developed neuration /

2. with greatly reduced neuration/

#68. Forewings <total number of longitudinal tubular veins, counted distally to any bifurcations>/

veined/

#69. Forewings <presence of basally dilated or vesicular veins>/

1. with vein 12 basally dilated or vesicular <Satyridae>/

2. without basally dilated or vesicular veins/

#70. Forewings <number of (at least partially tubular) anal veins>/

1. lacking anal veins/

2. with 1 <at least partly tubular> anal vein/

3. with 2 <at least partly tubular> anal veins/

4. with 3 <at least partly tubular> anal veins/

#71. The <tubular> anal veins of the forewings <identification of those present>/

1. representing 1b only/

2. comprising 1b and 1c <only>/

3. comprising 1a and 1b <only>/

4. comprising 1a, 1b and 1c/

#72. Forewings <whether exhibiting vein 1c>/

1. exhibiting a tubular vein 1c <tubular for at least for at least part of its length>/

2. lacking a tubular vein 1c/

#73. Vein 1b of the forewings <simple or furcate>/

1. furcate proximally/

2. obsoletely furcate <proximally>/

3. simple/

#74. Forewings <neuration: with or without a closed discal cell>/

1. with a <more or less closed> discal cell <and a transverse vein> /

2. without a discal cell <without a transverse vein>/

#75. The transverse vein <of the forewings, complete or incomplete>/

1. complete/

2. incomplete <partially either lacking or vestigial>/

3. vestigial only/

4. lacking/

#76. Forewings <presence of chorda and accessory cell>/

1. with an accessory cell <defined by a tubular chorda>/

2. without an accessory cell <i.e., chorda undeveloped>/

#77. Discal cell of the forewings <whether exhibiting a tubular media (M) vein>/

1. containing a tubular media (M) vein <branched or not>/

2. without a tubular media (M) vein <media vein absent, or vestigial>/

#78. Vein 2 of the forewings <position of departure from the cell>/

1. departing from the hind margin of the cell in its distal quarter/

2. departing from the cell less than three-quarters of the distance from its base/

Meyrick’s vein 2 employed here = the vein CuA2 of modern works.

Basic information on lepidopteran wing neuration and the terminology used here is available via the ‘Lepidopteran morphology’ toolbar button.

#79. <Comments on neuration of forewings:>/

Basic information on lepidopteran wing neuration and the terminology used here is available via the ‘Lepidopteran morphology’ toolbar button.

#80. Hindwings <development of neuration>/

1. with well developed neuration /

2. with greatly reduced neuration/

#81. Hindwings <total number of longitudinal tubular veins, counted distally to any bifurcations>/

veined/

#82. Hindwings <number of at least partially tubular anal veins>/

1. lacking <tubular> anal veins/

2. with 1 anal vein/

3. with 2 anal veins/

4. with 3 anal veins/

#83. The <tubular> anal veins of the hindwings <identification of those present>/

1. representing 1b only/

2. comprising 1b and 1c <only>/

3. comprising 1a and 1b <only>/

4. comprising 1a, 1b and 1c/

#84. Hindwings <whether exhibiting vein 1a>/

1. exhibiting vein 1a/

2. lacking vein 1a/

#85. Hindwings <with well developed neuration, presence of vein 1c (= CuP)>/

1. exhibiting a tubular vein 1c <i.e., tubular for at least part of its length; usually accompanied by three anal veins>/

2. lacking a tubular vein 1c <and with only one or two anal veins>/

#86. Vein 1b of the hindwings <simple or furcate>/

1. furcate proximally/

2. obsoletely furcate <proximally>/

3. simple/

#87. Hindwings <neuration: with or without a closed discal cell>/

1. with a <more or less closed> discal cell <and a transverse vein> /

2. without a discal cell <without a transverse vein>/

#88. The transverse vein <of the hindwings, complete or incomplete>/

1. complete/

2. incomplete <partially either lacking or vestigial>/

3. vestigial only/

4. lacking/

#89. Hindwings <neuration: presence of a praecostal spur (humeral vein)>/

1. with a praecostal spur/

2. without a praecostal spur /

#90. The hindwing cell <whether bearing a cubital pecten of hairs>/

1. bearing a pecten of hairs on its cubital <hind> margin/

2. without a cubital pecten of hairs /

#91. The hindwing cell <with well developed neuration, number of veins emitted from the cell>/

1. emitting more than six veins/

2. emitting no more than six veins /

#92. <Number of tubular veins originating from the hindwing cell>/

<tubular> veins arising from the hindwing cell/

Including vein 8 if this coincides or anastomoses with the cell - see second image.

Basic information on lepidopteran wing neuration and the terminology used here is available via the ‘Lepidopteran morphology’ toolbar button.

#93. The cell-derived hindwing veins <extent of joining>/

1. all arising independently of one another/

2. 2+3 proximally joined <connate or stalked>/

3. 3+4 proximally joined <connate or stalked>/

4. 3+5 proximally joined <connate or stalked>/

5. 4+5 proximally joined <connate or stalked>/

6. 5+6 proximally joined <connate or stalked>/

7. 6+7 proximally joined <connate or stalked>/

8. 7+8 proximally joined <connate or stalked>/

Basic information on lepidopteran wing neuration and the terminology used here is available via the ‘Lepidopteran morphology’ toolbar button.

#94. Veins 6 and 7 of the hindwings <whether parallel>/

1. parallel/

2. not parallel/

#95. Vein 8 of the hindwings <relationship to the cell>/

1. completely independent of the cell/

2. joined to the cell only by a bar/

3. anastomosing with the upper margin of the cell <free from it both basally and distally to the anastomosis>/

4. arising from the upper margin of the cell <coincident with the cell from its base>/

#96. Vein 8 of the hindwings <proximity to vein 7>/

1. approximating to vein 7 beyond the cell <comment if anastomosing with it>/

2. not approximating to vein 7/

#97. <Comments on neuration of hindwings:>/

#98. Adults <number of fully developed legs>/

1. having all 6 legs fully developed and operational for walking /

2. having only 4 fully developed legs <the anterior pair vestigial and useless for walking>/

#99. Fore-legs of female <whether operational for walking>/

1. operational for walking /

2. useless for walking/

#100. Fore-legs <of adults, presence of epiphysis>/

1. with a tibial epiphysis/

2. without a tibial epiphysis/

‘Tibial epiphysis’: a basally articulated, leaf-like or spur-like structure commonly occurring on the tibiae of the front legs, seemingly used by the insect for cleaning its antennae and tongue.

#101. Tibiae of middle legs <of adults, number of tibial spurs>/

1. without spurs/

2. 1-spurred/

3. 2-spurred/

4. 4-spurred/

#102. Posterior tibiae <of adults, number of tibial spurs>/

1. without spurs/

2. 2-spurred/

3. 4-spurred/

#103. Posterior tibiae <of adults, whether hairy>/

1. hairy/

2. not hairy <i.e., smooth or spiny>/

#104. <Paired> tympanal organs <thoracic or abdominal, presence>/

1. present/

2. absent/

#105. <Paired> tympanal organs <location, when present>/

1. metathoracic/

2. abdominal <usually lateral, near the base of the abdomen>/

Eggs, larvae and pupae

#106. Eggs <shape>/

1. markedly flattened/

2. not <markedly> flattened/

#107. Eggs <surface>/

1. smooth or minutely pitted/

2. ribbed and/or reticulate/

3. with projections <papillate or spiny>/

#108. Larval prolegs <number>/

The true legs corresponding with those of the adult (generally 3 pairs) occupy the thoracic segments (segments 2–4) of the larva. The ‘prolegs’ are fleshy, hook-bearing, leg-like organs typically borne on the larval segments 7–10 and 14 (i.e., on the abdominal segments 3–6 and 10). The hindmost pair constitute the ‘anal claspers’.

In some families, the prolegs are reduced in number from the basic 10, and in a few cases they are lacking or vestigial.

#109. Larvae <hairiness>/

1. conspicuously, densely long-hairy/

2. not densely long-hairy /

#110. Larvae <whether with urticating hairs>/

1. with urticating hairs/

2. without urticating hairs /

Hairs of many lepidopteran larvae produce stinging sensations on contact with human skin, or can cause urticaria. Some comprise specialised, brittle setae with basal, eversible poison glands. The causes of irritation are probably diverse, however, with interpretation complicated by human allergies. While species notorious for causing problems are relatively few, all hairy caterpillars should be treated with caution, and children in particular should be dissuaded from handling them.

#111. Larvae <with or without tentacles>/

1. with a pair of tentacles from segment 2 <immediately behind the head>/

2. without tentacles on segment 2 /

#112. Larvae <with or without bristly spines>/

1. with rows of bristly spines/

2. without bristly spines <regardless whether hairy or not> /

#113. Larvae <whether case-bearing>/

1. case-bearing/

2. not case-bearing /

‘Case-bearing’, unusual in Lepidoptera, is the norm in the related Order Trichoptera.

#114. Larvae <whether exposed or concealed feeders>/

1. exposed feeders /

2. concealed feeders <subterranean, mining, etc.>/

#115. Larvae <exposed feeders, whether forming communal tents>/

1. feeding in communal tents/

2. not feeding in communal tents /

#116. Larvae <concealed feeders, whether subterranean>/

1. subterranean <root feeding>/

2. not subterranean /

#117. Larvae <whether leaf-mining>/

1. leaf-mining/

2. not leaf-mining /

#118. Larvae <whether wood-boring>/

1. wood- or stem- boring/

2. not wood- or stem- boring /

#119. <Foodplants:>/

#120. Pupae <ridged/angular or smooth/rounded>/

1. ridged and angular/

2. smooth and rounded <not ridged and angular> /

#121. Pupae <whether conspicuously patterned or coloured>/

1. conspicuously patterned/

2. plain /

#122. Pupae <whether with metallic ornamentation>/

1. with shining-metallic spots/

2. without shining-metallic spots /

#123. Pupae <whether exposed or concealed>/

1. exposed, <above ground, and> with no coccoon/

2. concealed <in various ways, and usually in a cocoon> /

#124. Pupae <exposed, how borne>/

1. suspended <head down> from the tail (cremaster), with no median silk girdle/

2. not suspended, but <upright and> attached at the tail and secured by a median girdle of silk/

#125. Pupae <concealed, location>/

1. subterranean/

2. on the surface of the ground/

3. above the ground/

#126. Pupae <concealed, above ground, detailed location>/

1. under bark/

2. in stems/

3. in wood/

4. in <often dried> leaves/

5. in <often dried> flowers/

6. in fruits/

#127. Empty pupae <whether protruded on emergence of adult>/

1. protruded from place of concealment <after emergence of adult>/

2. not becoming protruded <from place of concealment>/

British representation

#128. Genera <number of genera in Britain>/

#129. <Number of species in Britain, including ‘adventives’>/

species/

Bradley (2000) details in precise terms the national status of species here tagged ‘adventive’. The term as used here denotes ‘not native to this environment’, and includes species usually indicated in check lists as ‘of doubtful British status’. Assignment is inevitably somewhat arbitrary, because situations where specimens have been rarely but genuinely found at large in the British Isles as a result of migrations beyond the normal range of a species, or of accidental transport by human agencies, are hard to disentangle from honest but erroneous records and cases of fraud. Migrant species recorded regularly in Britain as adults but which are unable breed successfully there are treated as ‘native’ in this connection.

#130. <Scientific and common names of British genera and species:>/

Complete lists of species and genera are given here (cf. Bradley et al., 1972, 2000) for British Macrolepidoptera. For Microlepidoptera, only examples illustrated by Curtis are listed, although nearly all the families are represented in the package by at least one illustration.

Bradley (2000) details in precise terms the national status of species here tagged ‘adventive’. The latter term here denotes ‘not native to this environment’, and includes species usually indicated in check lists as ‘of doubtful British status’. Assignment is inevitably somewhat arbitrary, because situations where specimens have been rarely but genuinely found at large in the British Isles as a result of migrations beyond the normal range of a species, or of accidental transport by human agencies, are hard to disentangle from honest but erroneous records and cases of fraud. Migrant species recorded regularly in Britain as adults but which are unable breed successfully there are treated as ‘native’ in this connection.

Classification

#131. <Informal group:>/

1. butterflies/

2. macromoths/

3. microlepidoptera/

#132. Suborder/

1. Zeugloptera/

2. Dachnonypha/

3. Monotrysia/

4. Ditrysia/

Classification after Bradley et al. (1972, 2000).

#133. Superfamily/

1. Micropterigoidea/

2. Eriocranioidea/

3. Hepialoidea/

4. Tischerioidea/

5. Nepticuloidea/

6. Incurvarioidea/

7. Cossidoidea/

8. Zygaenoidea/

9. Tineoidea <including Gracillarioidea>/

10. Sesioidea/

11. Choreutoidea <~ Sesioidea sens. lat.>/

12. Yponomeutoidea/

13. Gelechioidea/

14. Tortricoidea/

15. Epermenioidea/

16. Schreckensteinioidea/

17. Alucitoidea <Copromorphoidea>/

18. Pyraloidea/

19. Pterophoroidea/

20. Hesperoidea/

21. Papilionoidea/

22. Bombycoidea/

23. Geometroidea <including Drepanoidea>/

24. Sphingoidea/

25. Notodontoidea/

26. Noctuoidea/

Comments

#134. <Classificatory comments:>/

#135. <General comments:>/

Miscellaneous

#136. <Incidence of melanism in the family:>/

Melaninism. Melanin is a complex of dark (black, brown, yellowish or dull red) animal pigments, and “melanism” in the present context is the occurrence in a species of some individuals that are darker than the typical form, due to a heritable increase in the proportions of melanins in the epidemis (cf. Kettlewell, 1973). Melanism occurs in numerous moth species. In some it is known only as a rare mutation, but others exhibit populations in which melanic individuals are common or even predominant in certain habitats and/or geographical locations. From an evolutionary standpoint, persistence of melanic populations in relatively natural habitats (“rural” or “non-industrial” melanism”) is sometimes reasonably interpretable with reference to Darwinian natural selection , as in the genus Spilosoma, although few cases have yet been thoroughly investigated (see Majerus, 2002). However, spectacular changes in the proportions of melanic versus “normal” individuals in the populations of some moth species have been observed and quantitatively detailed in Britain for over a hundred years. Being rather obviously correlated with probable habitat pollution consequent on industrialisation, this phenomenon is termed “industrial melanism”, and in the case of the Peppered Moth (Biston betularia) in particular, a causal relationship involving Darwinian selection has been rather convincingly demonstrated via numerous, laborious experiments. Researchers’ disagreements over experimental design and interpretation of results leads to spurious claims by religious extremists, who fail to grasp that the obvious fact of organic evolution is not in the least undermined by arguments over details of the complex mechanisms. For detailed discussion of the Peppered Moth in the context of evolutionary debate in the 21st century, see Majerus (1998, 2002).

Examples of melanism are illustrated under the appropriate family descriptions in the present package (‘The families of Lepidoptera’), or in the generic descriptions in the accompanying ‘Geometridae’ or ‘Noctuidae’ packages, with references to the phylogenetic status of melanism largely following Ford (1955) and Majerus (2002). In the latter connection, “non-industrial to industrial" here implies occurrence of melanics in natural, unpolluted habitats, with observed increased proportions of them in habitats affected by industrialization.

Non-industrial melanism (= “rural melanism”, cf. Ford 1955). The intra-specific variation encompassed by all moth species frequently includes significant levels of heritable melanism (q.v.), which existed prior to the Industrial Revolution and cannot be attributed to selective advantages in the face of environmental pollution. A range of possible, “natural” selective factors that may have been operative in different cases have been postulated (cf. Majerus 2002), mostly assuming either increased crypsis of darker individuals in habitats with low light intensity, or associated with deceiving predators that have learned to associate the “normal” colouring with palatability.

#137. Abbreviated taxon name:/


To view the illustrations with detailed captions, go to the interactive key. This also offers full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2003 onwards. Insects of Britain and Ireland: the families of Lepidoptera. Version: 8th June 2016. delta-intkey.com’.

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