Barklice and booklice, parasitic lice, and thrips

1. Barklice and booklice, parasitic lice, and thrips • (EE, pp. 141-149;169-172)

2. Phylogeny of Hexapoda from p. 52 Hemipteroid Orders 1: Psocoptera Phthiraptera Thysanoptera

3. Thysanoptera • Common name:Thrips (4500 known species (0.45%)) • Derivation: Gk. thysanos - fring, tassle; pteron - a wing • Size: Body length 0.5-12 mm; mostly under 3 mm • Metamorphosis: Incomplete, but with resting pupa-like stages • Distribution: Worldwide • Number of families: 8

4. Thysanoptera(generally small or very small, slender-bodied)

5. damage on a plum How do thrips feed?(piercing and sucking mouthparts are asymmetrical) • Common features: • one mandible is very small, and nonfunctional; the other mandible is sharp and stylet-like • the other mouthparts are like a straw, and are used to suck up liquid foodstuffs

6. Thrips lifecycle(very unusual for a hemimetabolous insect) • one or more pupa-like stages between the nymphal stages and the adult • “pupal” stages have a degree of tissue reorganization

7. Reproduction in thrips • Thrips are haplodiploid • female thrips result from fertilized eggs and are diploid (two sets of chromosomes) • male thrips are haploid and are produced via parthenogenesis

8. Effects on crops(loss can be estimated at billions of dollars) • herbivorous and pollen feeding species are very destructive • they also are responsible for the transmission of many plant diseases • some are beneficial though... • predaceous ones eat other thrips • some control the spread of weeds western flower thrips

9. Thysanoptera • Thrips are very serious ecomonic pests of many crops (horticultural and field crops) • Also vector plant viruses (e.g., tomato spotted wilt virus

10. Psocoptera • Common name:Barklice and booklice (3,000 known world species (0.3%)) • Derivation: Gk. psokos - gnawed; pteron - a wing • Size: Body length 1-10 mm; mostly under 6 mm • Metamorphosis: Incomplete (egg, nymph, adult) • Distribution: worldwide • Number of families: 35

11. Key Features • small and generally cryptic • very common on trees, vegetation, and in litter • microflora feeders • some species are pests of stored products

13. Psocoptera(barklice and booklice are very common) • small, squat and soft-bodied insects, often overlooked because of their small size, cryptic coloration and habits • found in a wide array of habitats, including caves and the nests of birds, bees and wasps, but most abundant in leaf litter, soil, and on bark and foliage

14. Psocoptera(prominent compound eyes and long thread-like antennae) • simple chewing mouthparts, but mandibles are asymmetrical • most are characterized as epiphytic grazers • scrape away at microflora, including algae, lichens, moulds and fungal spores • some species eat pollen

15. Psocoptera • can be wingless as adults • when wings are present, they are held “roof-like” over the body when at rest and arise from thorax that appears slightly humped in side view

16. Psocoptera(many solitary species, but some are gregarious)

17. Psocoptera • They have labial silk glands (labrum)

18. Psocoptera(their association with humans) • these are often very widespread, associated with houses and stored products, including dried fruits and grains, flour and some museum collections (and old books, of course!) • outbreaks often due to poor house-keeping, and a combination of warm and damp conditions

19. Phthiraptera • Common name: Parasitic lice (5000 known world species (0.5%)) • Derivation: Gk. phtheiros - louse; a+pteron - wingless • Size: Body length 1-10 mm; mostly under 6 mm • Metamorphosis: Incomplete (egg, nymph, adult) • Distribution: Worldwide • Number of families: 17

20. Key Features • small, wingless, flattened ectoparasites living permanently on vertebrate hosts • feed on skin debris, secretions, feathers or blood • legs modified for clinging to fur or feathers • several species are significant vectors of human and animal diseases

22. Phthiraptera(ectoparasitic wingless insects found on mammals and birds) • spend entire lives in the microhabitat provided by the skin, fur, hair or feathers • no lice on bats - likely because bats took to the air well before lice became widespread

23. Phthiraptera Suborders Chewing lice (Mallophaga) Sucking lice * some species have mandibles modified to pierce the skin of their hosts

24. Phthiraptera(ectoparasitic wingless insects found on mammals and birds) • Common features: • wingless • tough, flexible, dorso-ventrally flattened bodies • eyes small or absent • antennae are short and stout (may help hold onto host) • legs short and robust • highly modified tarsi and claws for grasping

25. Phthiraptera eggs(usually stuck to hair or feather with a waterproof, fast-acting glue)

26. Phthiraptera lifecycle(three nymphal stages before reaching the adult stage) • it takes about 2 weeks (from hatching) to become an adult • many lice have a symbiotic relationship with bacteria, which allow the lice to digest feather proteins (keratin) and blood • lice die if separated from hosts for too long

27. Sucking, body & head lice(all are found on humans and belong to the Suborder Anoplura) • Head Lice rarely vector pathogens • Body Lice attach eggs to clothing • Body Lice transmitted via clothing, bedding, etc. • Important vectors of pathogens (rickettsiae - epidemic typhus, relapsing fever, etc.) • Historically linked to war

28. Sucking, body & head lice(all are found on humans and belong to the Suborder Anoplura) • Pubic lice are sexually transmitted

29. Journal reference: BMC Biology (DOI: 10.1186/1741-7007-5-7) Lice, humans & evolution(the degree of host specificity in lice is high) • genetic analysis of pubic lice suggests the parasites were transferred between early humans and gorillas about 3.3 million years ago • likely acquired from humans sleeping in abandoned gorilla nests http://www.youtube.com/watch?v=Uvff0-9wXIk