Insects of Britain and Ireland: the families of Hemiptera

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L. Watson and M. J. Dallwitz

Character list

#1. <Nomenclature:>/

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

#2. <Colloquial name(s):>/

Salient features of adults.

#3. <Habitat:>/

1. terrestrial/

2. dwelling (skating) on the surface of water/

3. foraging under water <genuinely aquatic>/

#4. <Whether littoral:>/

1. littoral/

2. not littoral <implicit>/

#5. The insects <nymphs and/or adults, whether dwelling under shelters>/

1. dwelling under specially constructed shelters, in the form of scales or lerps/

2. free living <not dwelling under specially constructed shelters — implicit>/

#6. <(Adult) feeding habits:>/

1. phytophagous/

2. mycophagous/

3. predacious <on arthropods>/

4. feeding on dead arthropods/

5. blood-suckers <on birds and mammals>/

#7. <Adult size:>/

1. tiny <less than 5 mm long>/

2. small <5 mm to 1 cm long, with less than 2 cm wingspan>/

3. large <more than 1 cm long or more than 2 cm wingspan>/

#8. <Adult head-to-tail body length:>/

mm long/

Head-to-tail body length of the insect in its natural posture, exclusive of appendages.

Data (British representatives only) from Dolling (1991).

#9. <Whether adults show extreme polymorphism:>/

1. represented exclusively by greatly reduced, sedentary forms/

2. represented by both greatly reduced, sedentary forms and ‘normal’, mobile insects/

3. represented by ‘normal’ insects only <implicit>/

#10. <Sound emission by adults:>/

1. the males very noisy, emitting loud, continuous sounds/

2. not extremely noisy <implicit>/

Detectable sound production (as distinct from the often very loud and continuous creaking of Cicadidae) is common among Hemiptera, although there is a paucity of properly comparative data taxonomic data.

Stridulation is known to be conducted in a variety of ways:

1. By rubbing the tip of the labium against a cross-striated furrow in the prosternum (many Reduviidae).

2. By rubbing wart-like, toothed tubercles in the hind tibia against the femur (Scutelleridae).

3. By rubbing a spinose area inside the front femur against the clypeus (Corixidae).

4. By rubbing dorsal abdominal files against teeth on the under-sides of the hind-wings (some Pentatomoidea, Lygaeoidea).

5. By rubbing tubercles on the hind femura against strigose regions on abdominal sterna (some Pentatomoidea).

Sound is generated by Cicadidae and (less noticeably by many other auchenorrhynchous Homoptera) not by stridulation, but via paired tymbals at the base of the abdomen. This phenomenon seems to be restricted to males (by contrast with sound production by other means, as exemplified in Pentatomoidea).

#11. <Whether adults fliers:>/

1. fliers/

2. non-fliers <‘apterous’, with hind-wings absent or reduced>/

#12. Swimming and moving under water <adult posture>/

1. on their backs/

2. the right way up/

#13. <Whether adults are conspicuous jumpers:>/

1. conspicuous jumpers <often with modified hind-legs>/

2. not jumpers <implicit>/

#14. <Whether adults emit repugnatorial liquid: cf. metathoracic glands:>/

1. emitting repugnatorial liquid as a defence reaction/

2. not emitting repugnatorial liquid <dubiously implicit>/

Many Hemiptera (e.g., in Pentatomoidea)notoriously emit repugnatorial fluid when alarmed, but precise taxonomic data have not been located.

#15. <Adult general form, regardless of absolute size:>/

1. relatively stout bodied/

2. with narrow-elongate bodies/

#16. <Whether adults stilt-legged:>/

1. conspicuously stilt-legged <the legs long and slender>/

2. not stilt-legged <not especially long-legged: implicit>/

#17. <Whether adults exhibit dark-and-pale banding of antennae and legs:>/

1. with conspicuous dark-and-pale banding on the antennae and legs <Stenocephalidae>/

2. without conspicuous dark-and-pale banding of antennae and legs <implicit>/

#18. Head <of adults, length relative to width>/

1. linear <several times longer than wide>/

2. non-linear <no more than twice as long as wide>/

#19. Head <of adults, whether constricted between the eyes>/

1. strongly transversely grooved (constricted) between the eyes <Reduviidae, Berytidae>/

2. not transversely grooved between the eyes <implicit>/

#20. Head plus thorax of apterae <volume relative to that of abdomen>/

1. greater in volume than the abdomen/

2. not exceeding that of the abdomen/

#21. Rostrum <ostensible position of insertion>/

1. clearly arising from the head/

2. ostensibly originating between the front legs <Sternorrhyncha>/

‘Rostrum’: the piercing and sucking mouthparts (beak) characteristic of Hemiptera. This organ comprises two pairs of sclerotized, flexible stylets, the (external) mandibular and the (internal) maxillary stylets, residing in a dorsal groove of the 1–4 segmented labium.

#22. Rostrum <insertion relative to the prosternum>/

1. clearly separated ventrally from the prosternum by a sclerotized gula <the rostrum brought forwards: Heteroptera>/

2. not separated from the prosternum by a gula <inserted further back, under or apparently behind the head: Homoptera>/

‘Rostrum’: the piercing and sucking mouthparts (beak) characteristic of Hemiptera. This organ comprises two pairs of sclerotized, flexible stylets, the (external) mandibular and the (internal) maxillary stylets, residing in a dorsal groove of the 1–4 segmented labium.

#23. Rostrum <number of segments>/

segmented/

‘Rostrum’: the piercing and sucking mouthparts (beak) characteristic of Hemiptera. This organ comprises two pairs of sclerotized, flexible stylets, the (external) mandibular and the (internal) maxillary stylets, residing in a dorsal groove of the 1–4 segmented labium.

#24. Antennae <of adults, position of insertion>/

1. from the upper part of the head/

2. from the lower part of the head/

#25. Antennae <of adults, whether readily visible from above>/

1. longer than the head, readily visible from above <not in grooves>/

2. inserted underneath the head and much shorter than it, generally invisible from above <lying in grooves in the head>/

#26. Antennae <of adults, number of segments>/

segmented/

Note that the data here refer to adults - nymphs may have fewer antennal segments.

#27. Antennae of apterae <number of segments>/

segmented/

#28. Antennae <of adults, form>/

1. consisting of short segments with a terminal, unsegmented <tapered> arista that is much longer than the segments <Homoptera-Auchenorrhyncha>/

2. non-aristate/

#29. Antennae <4-segmented, relative lengths of segments>/

1. with segments 3 + 4 very slender, and twice as long as segments 1 + 2/

2. with segments 3 + 4 less than twice as long as 1 + 2/

#30. Ocelli <presence in adults>/

1. present/

2. absent/

#31. Ocelli <of adults, number>/

#32. Ocelli <of adults, position>/

1. between the eyes <on the crown of the head>/

2. behind the eyes/

#33. Thorax <(pronotum) of adults, whether crested>/

1. conspicuously crested/

2. not crested <implicit>/

‘Pronotum’: the single, dorsal sclerite of the ‘prothorax’, which is large in Heteroptera and variable in expression but often small and collar-like in Homoptera.

‘Prothorax’: the first (anterior) segment of the (three-segmented) thorax, which bears the front pair of legs.

‘Mesothorax’ and ‘Metathorax’: the second and third thoracic segments, which bear the fore- and hind-wings and the mid- and hind-legs.

#34. Scutellum <of adult Heteroptera, size>/

1. very large <at least half as long as the distance from the hind margin of the pronotum to the tip of the abdomen>/

2. relatively small <shorter than half the distance from the hind margin of the pronotum to the tip of the abdomen>/

‘Scutellum’ (= mesoscutellum): the dorsal posterior portion of the ‘mesonotum’ (i.e., of the visible portion of the dorsal sclerite of the mesothorax). The literature available to me is unclear regarding the application and/or morphological applicability of this term to Homoptera.

#35. Metathorax <of adults, presence of (repugnatorial) scent glands>/

1. with a <repugnatorial> scent-gland opening, comprising a funnel surrounded by a dull patch of elaborately sculptured cuticle, visible laterally on either side <near the coxae of the hind-legs>/

2. without laterally visible scent gland openings/

The metathorax of “most adult Heteroptera” is routinely stated to incorporate a large gland, which opens either by a single median aperture on the sternum (e.g., Gerridae), or by paired apertures on the metapleura (i.e., laterally). These gland openings are discussed in all the standard texts, but are used in the keys seen only to help separate Rhopalidae from Coreidae. Comparative data on their presence or absence, location and structure in other families is hard to find, and it is not even clear whether Homoptera exhibit metathoracic glands at all.

#36. Tegulae <presence>/

1. present/

2. absent <implicit>/

‘Tegula’: a scale-like sclerite basally subtending the costa of each fore-wing.

#37. Fore-wings <of adults, degree of development>/

1. well developed <macropterous: more or less equalling or exceeding the abdomen when folded>/

2. conspicuous, but much shorter than the abdomen <brachypterous>/

3. vestigial or absent <apterous>/

Immature bugs (nymphs) are wingless, and might be mistaken for apterous or brachypterous adults. They are recognisable in having an incomplete separation of the scutellum from the wing pads, whereas in adults the scutellum is a separate structure.

#38. Fore-wings in the resting <adult macropterous> insect <orientation>/

1. lying more or less flat over the abdomen <often with their tips overlapping>/

2. sloping roof-like over the abdomen/

#39. Fore-wings <of macropterous adults, when well developed, texture>/

1. differentiated into a basally thickened <or horny> and a distally membranous region/

2. more or less uniform in texture/

Note that some Heteroptera have ‘homopterous’ forewings, in that their fore-wings lack the distal membrane characteristic of that assemblage.

#40. Fore-wings <of adult Homoptera, when well developed and uniform in texture, whether cells transparent or opaque>/

1. with transparent cells/

2. with opaque cells/

#41. Fore-wings <of adults, when well developed, whether with a costal fracture and cuneus>/

1. with a costal fracture and cuneus/

2. without costal fracture and cuneus <dubiously implicit - explicitly recorded negatives encoded as such>/

#42. Fore-wings <presence of claval furrow and clavus>/

1. with a clavus <delimited by a claval furrow>/

2. without a clavus <and no claval furrow>/

‘Clavus’: in (most or all?) alate Hemiptera, a narrow basal-posterior portion of the fore-wing (next to the scutellum) is delimited from the corium (in Heteroptera) or from the rest of the wing (Auchenorrhyncha) by a concave vein (the claval suture). In Sternorrhyncha, however, the claval suture (and hence, the clavus) is lacking in all but the Psylloidea.

#43. Fore-wings <number of oblique veins>/

1. with three oblique veins/

2. with four oblique veins/

#44. Fore-wings <of adults, when well developed, whether with raised, reticulate venation>/

1. with conspicuously raised, reticulate venation/

2. without conspicuously raised, reticulate venation <implicit>/

#45. Fore-wings <whether finely areolate or reticulate>/

1. finely reticulate or areolate throughout/

2. not finely reticulate throughout <implicit>/

#46. Membrane of the hemelytron <venation>/

1. with 4 or 5 veins reaching or almost reaching the margin/

2. with numerous <more than 5> veins reaching or almost reaching the margin/

#47. Clavus <of the fore-wing, venation>/

1. with two veins uniting posteriorly to form a Y/

2. without convergence of veins to form a Y/

#48. Trochanters <apparent segmentation>/

1. apparently two-segmented <Miridae>/

2. not apparently segmented <implicit>/

#49. Fore-legs <of adults, whether raptorial>/

1. modified and raptorial/

2. non-raptorial <implicit>/

#50. Hind coxae <of adults, mobile or immobile>/

1. mobile/

2. immobile/

#51. Hind coxae <of adults, when mobile, whether rotatory or hinged>/

1. rotatory/

2. hinged/

#52. The posterior tibiae <presence of moveable, apical spur>/

1. with a large, moveable apical spur <Delphacidae>/

2. without a large, moveable apical spur <implicit>/

#53. The posterior tibiae <cylindrical or keeled>/

1. cylindrical/

2. longitudinally keeled/

#54. Tarsi <of adults, number of segments>/

segmented/

Note that the data here refer to adults - nymphs may have fewer tarsal segments.

#55. Tarsi <of adults, one or two clawed>/

1. one-clawed/

2. two-clawed/

#56. Claws <whether apical>/

1. all apical/

2. of fore-legs <at least> inserted short of the tip of the terminal segment/

#57. Pulvilli <presence>/

1. present/

2. absent/

#58. The abdominal tergites with <number of visible abdominal connexivia>/

visible connexivia/

#59. The abdomen <of adults, presence of teminal respiratory siphon>/

1. terminating in a long, bristle-like respiratory siphon/

2. without a respiratory siphon <implicit>/

#60. The abdomen <of adults, whether equipped with secretory tubes (siphunculi) towards the rear>/

1. equipped with a pair of secretory ‘cornicles’ (siphunculi) towards the rear/

2. without secretory ‘cornicles’/

#61. The abdomen <of adults, whether silvery-pubescent ventrally>/

1. covered ventrally with dense, silvery pubescence/

2. without ventral silvery pubescence/

#62. The second visible abdominal sternite <(sternite 3) whether with a long, spine-like anterior process>/

1. with a long, spine-like, forwardly directed anterior process <Acanthosomatidae>/

2. without a long, spine-like anterior process <implicit>/

#63. The second dorsal abdominal scent gland aperture <displacement>/

1. displaced forwards into the fifth tergite, thus close to that of the first gland <Rhopalidae>/

2. not displaced into the fifth tergite, and distant from the first gland/

Comments.

#64. <General comments:>/

Classification.

#65. Suborder <see Notes>/

1. Homoptera/

2. Heteroptera/

K. Kinman (Taxacom, 2015) points out that, contrary to currently fashionable cladistic classifications which lump the traditional suborders in an enormous, heterogeneous Hemiptera, there is strong molecular evidence for accepting the Homoptera as a holophyletic sister group to Heteroptera. See Nan Song et al. (2012), http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0048778

#66. <Division of Homoptera:>/

1. Auchenorrhyncha/

2. Sternorrhyncha/

#67. <Superfamily of Homoptera:>/

1. Cercopoidea/

2. Cicadoidea/

3. Cicadelloidea/

4. Fulgoroidea/

5. Membracoidea/

6. Adelgoidea/

7. Aphidoidea/

8. Psylloidea/

9. Coccoidea/

10. Aleyrodoidea/

#68. <Superfamily of Heteroptera:>/

1. Aradoidea/

2. Cimicoidea/

3. Coreoidea/

4. Gerroidea/

5. Lygaeoidea/

6. Notonectoidea/

7. Pentatomoidea/

8. Reduvioidea/

9. Saldoidea/

10. Tingoidea/

11. Corixoidea/

12. Dipsocoroidea/

British representation:

#69. <Number of species in Britain>/

species in Britain/

#70. Genera <in Britain, number>/

#71. <Genera:>/

#72. E.g., <genera and species, with colloquial names>/

Miscellaneous.

#75. <Illustrations>/


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 Hemiptera. Version: 16th May 2016. delta-intkey.com’.

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