The Insecta: Lice, Bugs, and Aphids

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The Insecta: Lice, Bugs, and Aphids
2014-06-11 00:46:08
ENT156 MT3

Six legged frankensteins?
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  1. Phthiraptera: Lice (Classification)
    • chewing lice: mallophaga
    • Sucking lice: anoplura
    • elephant and wart hog live: rhynchophthira
  2. Phthiraptera: Lice (Distribution)
    • World wide on animals and birds
    • a. Inhabit the vestment of the host, including hair,
    • feathers, and clothing

    • b. Highly host specific- parallel evolution with
    • hosts

    c. Not found on reptiles other than birds
  3. Phthiraptera: Lice (Human species)
    • Head lice in body hair
    • Body lice in clothing
    • Crab lice in axial hair
  4. Phthiraptera: Lice (Morphology)
    • Dorso-ventrally flattened
    • claws and appendages with various adaptations for clinging to hair and feathers
    • (not toilet seats)
  5. Phthiraptera: Lice (Biology and life history)
    • complete life history on the host
    • apparently ametaboloys, actually derive from hemimetabolous ancestors
    • -egg attached to hair or feathers-nits
    • -hatches to asexual nymph, resembles adult
    • -several nymphal molts to sexual adult
    • -all stages feed similarly
  6. Phthiraptera: Lice (Feeding specializations)
    • a. Chewing lice, chewing mouth parts
    • 1) Laterally opposed mandibles
    • 2) Feed on surface skin debris, oils etc
    • dont suck on blood, gnaw at skin. just as irritating

    • b. Sucking lice-Anoplura
    • 1) Long thin piercing stylet like mouth parts
    • 2) Feed by sucking blood from capillaries in the
    • epidermis of the skin
    • suck blood from capillaries
    • c. Elephant and Wart hog lice-
    • Rhynchophthira
    • 1) Chewing sucking mouth parts at tip of
    • long rostrum
    • 2) Feed presumably on blood
    • 3) Semi-permanent tick-like attachment
    • to host
    • d. Transmission through direct host contact
  7. Order Hemiptera: True bugs including bed and kissing bugs (Intro/life cycle)
    • 1. Hemimetabolous or incomplete life cycle
    • a. Egg hatches to wingless nymph
    • b. Several nymphal molts to winged adult
    • c. All stages feed on same materials
    • 2. Piercing sucking mouth parts within fascicle
    • 3. Two pair wings, first hemielytra (hard shell like), second membranous
  8. Order Hemiptera: The bed bugs-Cmicidae (Morphology)
    a. Dorso-ventrally compressed (flat)

    b. Wingless, straw colored

    c. 1/4-3/8" long

    d. Walking legs

    • e. Piercing sucking m’parts
    • feed just like kissing bugs, cant dig jump or bore
  9. Order Hemiptera: The bed bugs-Cmicidae (Intro)
    • parasites of colonial or traditionally nesting hosts
    • host specific nest parasites of birds, humans, bats
  10. Order Hemiptera: The bed bugs-Cmicidae (Nest parasites like bed bugs and fleas)
    • usually found only in nest of host
    • do not live on host directly-may ride occasionally
    • complete dependency on host for food.
  11. Order Hemiptera: The bed bugs-Cmicidae (Life history pattern of bed bugs-feed weekly at night)
  12. Order Hemiptera: The bed bugs-Cmicidae (the principle points)
    • a. Found  only  in  “nest”  of  host
    • b. Cannot live freely in the environment
    • c. Do not live on host directly
    • d. Complete dependency on host for food
    • e. Infest locations frequented by the host when quiescent
    • f. No wings although development is incomplete
    • g. No winged dispersal
    • h. All life stages constrained by identical ecology
    • i. All life stages constrained by identical physiology
    • j. All life stages constrained by identical morphology
    • k. All life stages compete for same resources
  13. Order Hemiptera: The bed bugs-Cmicidae (4 human species)
    • a. Cimex lectularius- mostly temperate
    • b. Cimex hemipterus – mostly tropical
    • c. Two other African species – humans share with bats in East African huts
    • d. C. lectularius in the United States (so far)
    • e. Many other species specific for other colonial animals
    • f. Identification very important!
  14. Order Hemiptera: The bed bugs-Cmicidae (blood feeding only)
    • a. The mechanism: the basic mosquito model
    • Fascicle swings forward, splits
    • Stylets saw into tissues
    • Salivation
    • Descend into deep dermis
    • Canulate vein or artery.

    • b. Bite effects
    • Transmit no pathogens
    • Bite effects similar to mosquito
    • Considerable variation with exposure
    • c. Bed bug bite
    • hypersensitivity-
    • Sensitivity to bed bug saliva
    • Anaphylaxis and death!
    • Rare

    • continual biting can lead to no response, not permanent though.
    • d. Feeding frequencies
    • Larval stages feed once between molts (like ticks)
    • Adult stages feed multiple times between egg
    • laying
    • Feeding takes 4-10 minutes, weekly
    • Usually only nocturnal
    • May go 3 months w/o feeding

    • e. Feed only on blood (like ticks) ever!
    • 1. Blood lacks essential nutrients
    • 2. Symbiotic bacteria provide nutrients

    • f. Host location
    • Locate host using host associated cues
    • Use CO2, heat (IR radiation), water vapor
    • CO2 principle bed bug stimulant for feeding, mating
    • Host generally quiescent
  15. Order Hemiptera: The bed bugs-Cmicidae (Repro)
    • a. Traumatic insemination
    • b. Females lay upto ~5 eggs per day; hidden in refugia
    • Up to ~500 eggs in life time
    • Temperature dependent
    • hatching time: 6-30 days
  16. Order Hemiptera: The bed bugs-Cmicidae (Ecology)
    • a. Human nest parasites- found
    • where humans live
    • Increasingly (?)  common  in  “high  end”  hotels
    • In human domiciles- homes to barracks and
    • dormitories
    • Historically in theaters prior and during WWII
    • c. Hide in dark, pre-existing,
    • crevice-like protected refugia
    • Mattress piping (classic location)
    • Under surfaces of bedsteads, bed
    • frames
    • Joints and crevices in bed supports
    • Cracks, crevices in walls, electrical
    • outlets
    • Protected locations in furniture local to bed
  17. Order Hemiptera: The bed bugs-Cmicidae (Dispersal to new sites)
    • a. Phoresis- transmission  to  new  “nests”  by  hitchhiking  on host animals
    • Bat wing membranes (animal example)
    • Human clothing!

    • b. Movement of nest materials- accidental
    • dispersal when relocating furniture, beds
    • and bedding
    • Contaminated moving vans
    • Transportation in luggage

    • c. Recycle of infested materials into new
    • mattresses or bedding

    d. Failure of mattress steam sterilization process

    e. Recycle furniture & dumpster diving
  18. Order Hemiptera: The bed bugs-Cmicidae (symbionts)
    • Feed only on blood
    • blood lacks essential nutrients
    • symbiotic bacteria provide nutrients
  19. Order Hemiptera: The bat bugs- Family Polytinidae
    • Reduced features, no eyes or hind wings, short fore wings
    • Adaptations for clinging to host- ctenidia, flattened spines
    • Entire life history on host all
    • stages blood feed
    • Viviparous, nymphs in advanced state
  20. Relationships with hosts among bug
    • 1. Increasing focus on host
    • 2. Kissing bug free living, loose association with nest
    • 3. Bed bug not free living, close association with nest
    • 4. Bat bug, louse like complete dependency on host