CY501-C08[261-330].qxd 2/15/05 11:10 PM Page 261 quark11 27B:CY501:Chapters:Chapter-08: 8 TheThe Paraneopteran Orders Paraneopteran The evolutionary history of the Paraneoptera – the bark lice, fold their wings rooflike at rest over the abdomen, but thrips true lice, thrips,Orders and hemipterans – is a history beautifully and Heteroptera fold them flat over the abdomen, which reflected in structure and function of their mouthparts. There probably relates to the structure of axillary sclerites and other is a general trend from the most generalized “picking” minute structures at the base of the wing (i.e., Yoshizawa and mouthparts of Psocoptera with standard insect mandibles, Saigusa, 2001). to the probing and puncturing mouthparts of thrips and Relationships among paraneopteran orders have been anopluran lice, and the distinctive piercing-sucking rostrum discussed by Seeger (1975, 1979), Kristensen (1975, 1991), or beak of the Hemiptera. Their mouthparts also reflect Hennig (1981), Wheeler et al. (2001), and most recently by diverse feeding habits (Figures 8.1, 8.2, Table 8.1). Basal Yoshizawa and Saigusa (2001). These studies generally agree paraneopterans – psocopterans and some basal thrips – are on the monophyly of the order Hemiptera and most of its microbial surface feeders. Thysanoptera and Hemiptera suborders and a close relationship of the true lice (order independently evolved a diet of plant fluids, but ancestral Phthiraptera) with the most basal group, the “bark lice” (Pso- heteropterans were, like basal living families, predatory coptera), which comprise the Psocodea. One major issue is insects that suction hemolymph and liquified tissues out of the position of thrips (order Thysanoptera), which either their prey. Diets then reverted to the ancestral habit of comprise the sister group to Psocodea or to Hemiptera. We phytophagy among “higher” heteropterans. Blood feeding prefer the latter of these, in which case the thrips plus arose independently between the ectoparasitic lice and Hemiptera comprise a group called the Condylognatha. The disparate, small groups of Heteroptera. Thus, there are other major issue is the monophyly and relationships of the multiple origins of sucking mouthparts and a liquid diet in leaf hoppers, plant hopper, and tree hoppers (the Auchenor- the Paraneoptera (Figure 8.1). rhyncha). There is little question about the monophyly of the Para- neoptera, based on morphological and molecular evidence. PSOCOPTERA: THE BARK LICE Some features, like reduction in the number of tarsomeres (to three or fewer) and loss of cerci, occur throughout insects. Small and inconspicuous, the approximately 4,400 described Other features, though, are not so homoplasious and reliably species of psocopteran “book lice” and bark lice probably are reflect monophyly, such as abdominal trichobothria, loss or a fraction of the actual diversity. Many live in concealed great reduction of the labial palps, structure of the laciniae in spaces, microscopic structures are required for their identifi- the more basal taxa, and the large postclypeus and cibarial cation, and there is virtually no medical or agricultural signif- muscles, among others. Paraneopterans also have a structure icance of the group. Thus, they are poorly studied. Relation- for coupling the fore- and hind wings in flight that is rather ships are also poorly explored, even though the order may be conservative in design. In Psocopterans, many Sternorrhyn- paraphyletic with respect to the true lice, much the way cer- cha, and even basal Heteroptera, a small clasp formed from tain scorpionflies (Mecoptera) appear closely related to the clumps of stout microtrichia on the hind edge of the forewing fleas. There is little doubt about a monophyletic Psocodea attaches to a clasp on the fore edge of the hind wing. Another (psocopterans ϩ lice), and an intriguing hypothesis even interesting feature defining the Paraneoptera, but one hardly links the true lice with a particular family of Psocoptera – mentioned, is that the antennal flagellomeres have fine possibly a rare example of transitional forms between free- annuli. This is consistently seen throughout the group but living insects and highly specialized parasites. Moreover, the lost in Heteroptera and obscured in many Auchenorrhyncha Psocodea are the living sister group to the rest of the Parane- because of their reduced antenna. Also, many paraneopterans optera, and a very basal, extinct group of psocopterans has 261 CY501-C08[261-330].qxd 2/15/05 11:10 PM Page 262 quark11 27B:CY501:Chapters:Chapter-08: TABLE 8.1. Characters Defining Paraneopteran Relationshipsa Paraneoptera: Ischnoceran Lice: 1. Legs with three or fewer tarsomeres 45. Number of sensilla coelonica and basiconica on antennae 2. Cerci lost are reduced (to two) 3. Ganglia in abdomen fused into one large mass 46. Small rhombic sclerite separated from pronotum 4. Winged forms usually with abdominal trichobothria Rhyncophthirina ϩ Anopluran Lice: 5. Labial palps reduced or lost 47. Pretarsus with only one claw 6. Asymmetrical mandibles 48. Pronotum and forecoxae fused, do not articulate 7. Maxillary laciniae slender, long, detached from stipes; 49. Loss of cervical sclerites independently movable 50. Virtual fusion of head and thorax 8. Postclypeus large, with large cibarial dilator muscles 51. Extreme prognathy Psocodea: 52. Antennal muscles attach to dorsum of head, not to tentorium 9. Simplified ovipositor 53. Loss of anterior tentorial pits 10. Rupturing mechanism at the base of antennnal flagellum 54. Posterior tentorial pits are reduced 11. Postclypeus bulbous, protruding 55. Loss of lacinia 12. Cibarium and hypopharynx specialized for water vapor Rhyncophthirina: absorption 56. Elongate rostrum, at apex of which are the mandibles 13. Cardo lost 57. Mandibles rotated 180Њ Psocoptera: Anopluran Lice: 14. Wings held rooflike over abdomen 58. All thoracic segments fused 15. Forewings with “areola postica” cell 59. Meso- and metathoracic terga reduced 16. Pearman’s organ on hind coxa 60. Complete loss of tentorium 17. Egg with thin, unsculptured chorion; aeropyles and 61. Hypopharynx and labium developed into piercing stylets micropyles lost Condylognatha: ϩ Liposcelidae Phthiraptera: 62. Opisthognathous head 18. Reduction in wings: brachypterous or apterous 63. Expanded hypopharyngeal apodemes 19. Body flattened, including dorsoventral flattening of head 64. Unicondylar mandibular and lacinial stylets 20. Hind femora enlarged 65. Narrowed labrum 21. Fusion of meso- and metanotum 66. Dorsal shift of anterior tentorial pits 22. Loss of abdominal spiracles one and two 23. Reduction or loss of labial palpi Thysanoptera: 24. Prognathous head 67. Wings narrow, with fringe of long setae, venation reduced 25. Eyes reduced or lost 68. Claws reduced in adult 69. Pretarsus with eversible vesicle Phthiraptera: 70. Piercing lacinial stylets 26. Ectoparasitic on warm-blooded vertebrates 71. Left mandibular stylet piercing, right one lost; mouthcone 27. Apterous asymmetrical 28. Eyes highly reduced (only several facets), usually completely lost Hemiptera: 29. Head with very limited movement 72. Maxillary and labial palps lost 30. Dorsal tentorial arms lost 73. Mouthparts developed into suctorial beak, with two pairs 31. Reduction or loss of lacinial stylets of mandibular and maxillary stylets lying in a long, grooved 32. Reduction or loss of maxillae labium 33. Antennae reduced to three flagellomeres Sternorrhyncha: 34. Ocelli lost 74. Absence of vannus, vannal fold in hind wing 35. Egg with hydropile and operculum, cemented 75. Labium originates from prosternum to host hair or feather Auchenorrhyncha: 36. Fusion of third thoracic ganglion with abdominal ganglion 76. Complex tymbal acoustic system 37. Three (versus four) nymphal instars 77. Aristate antennal flagellum 38. Loss of metathoracic spiracle ϩ Amblyceran lice: Coleorrhyncha Heteroptera: 39. First flagellomere pedunculate 78. Wing coupling mechanism 40. Antennae concealed in fossae 79. Thoracic scent glands 80. Gula developed between occipital foramen and mouthparts All Other Lice: 41. Connective tissue occluding occipital foramen Coleorrhyncha: (“obturaculum”) 81. Body highly flattened, with areolate wings 42. Spiracular glands Heteroptera: 43. Occipital apodeme extending into thorax 82. Reduced tentorium 44. Saucer-shaped antennal sensilla (“pore organs”) 83. Nymphal dorsal scent gland on tergites three through seven a Numbers correspond to numbers on phylogeny, Figure 8.1. CY501-C08[261-330].qxd 2/15/05 11:10 PM Page 263 quark11 27B:CY501:Chapters:Chapter-08: THE PARANEOPTERAN ORDERS 263 8.1. Relationships among Recent orders and suborders of the Paraneoptera, with their diets. Significant characters indicated in Table 8.1. Based on Lyal (1985) for Psocodea, Kris- tensen (1975, 1991) and others for orders, and Wheeler et al. (1993b) for Hemiptera. even been proposed as a sister group to the thrips. General The Sternorrhyncha and Auchenorrhyncha also hold the accounts on the biology, morphology, and taxonomy of the wings rooflike over the abdomen, with some Psyllidae and group are by Badonnel (1951), Smithers (1967, 1972, 1991), Aleyrodidae also having the areola postica. Some Sternor- Weidner (1972), Günther (1974, the taxonomy of central rhyncha and even basal Heteroptera have similar wing cou- European species), New (1974, 1987), and Mockford (1987, pling structures (Figure 8.3). 1993, North American species). There is a recent world cata- Morphology of the psocodean head and mouthparts is logue of the species (Lienhard