BIOMI 3310 Lecture 20: Lecture 20
28 Apr 2018
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Lecture 20 – Phthiraptera (Lice) and Hemiptera (Bugs)
Infect: from Latin infectus (to work in, to dye, to taint)
• Used for internal infections (ex. worms)
Infest: from Latin infestare (to attack/molest)
• Used for external infestations (ex. lice, fleas, ticks, etc.)
Speciate: occurs via evolution (i.e. Fly A can evolve/speciate into Fly B)
• You CAN'T evolve/speciate things. You can only identify them.
Insects
• Bodies are divided into three sections:
o Head
• 1 pair of compound eyes
• 1 pair of antennae
• A mouth with 3 pairs of feeding appendages
o Thorax
• 3 segments, each with a pair of legs
• Wings may/may not be present on the 2nd and 3rd segments
o Abdomen
• Contains the genital appendages and most of the other organs
• Gut is divided into several sections
• Open circulatory system with a heart
o Blood is usually clear, but may be green, blue, red, or yellow
• Respiratory system = tracheae
o External openings are covered with spiracles, which are fancy vent covers
• Most are oviparous (lay eggs)
• Newly hatched insects can develop via one of three general patterns:
o Ametabolous: no metamorphosis
• Immature stages appear very similar to the adults, except they lack genitalia
• Ex.) silverfish
o Hemimetabolous: simple metamorphosis
• One Development Pattern:
▪ Wingless nymph hatches. It is a replica of the adult.
▪ The instars grow via molts, but there are no discernable changes in body structure
▪ Stages: egg, nymph(s), adult
• Second Development Pattern - undergoes simple metamorphosis
▪ Wingless nymph that hatches resembles the adult, but lacks wings and mature
reproductive organs.
▪ Instars grow via molts.
▪ Stages: egg, nymph(s), adult
o Holometabolous: complex/complete metamorphosis
• Upon hatching, the wingless, legless larva is vermiform (looks like a worm).
• Instars grow via molts and pupation.
• Stages: egg, larvae, pupa, adult
• Few are parasitic:
o Phthiraptera: lice
• Live on the external surface of vertebrates (birds and mammals)
▪ No lice/lice relatives are found on fish, amphibians, or reptiles.
▪ All major groups of mammals have lice except:
• Chiroptera (bats)
• Cetacea (whales and dolphins)
• Microbiotheria
• Monotremata (echidna and platypus)
• Notoryctemorphia (marsupial moles)
• Pholidota (pangolins)
• Sirenia (dugongs and manatees)
• Use claws at the end of their legs to grasp hairs or feathers
• Have 3 pairs of legs (because they're insects)
• Glue their eggs to hairs or feather shafts.
▪ One exception: human body louse
• Hemimetabolous (simple/incomplete metamorphosis)
▪ Nymph undergoes 3 molts to adult
• Female lays a few hundred eggs (nits, as in nit-picking) in her life.
• Two Major Groups:
▪ Mallophaga: found on birds and mammals (including marsupials) - only on
terrestrial hosts; most species are found on a single host
• Heads are as wide as the thorax
• Feed via mouthparts on the ventral surface - used for chewing
• Feed on skin detritus, hair, and feathers
• Some are vectors of filariid parasites, which requires them to feed
relatively deep into the dermis to get blood/tissue fluids.
• The female glues eggs to hairs.
• Females lay ~1 egg per day.
• Damalinia equi: in horses
• Felicola subrostratus: in cats
▪ Anoplura: found only on placental mammals (not on bats, whales, anteaters, or
armadillos)
• Head is much narrower than the thorax
• Mouthparts are adapted for feeding from blood vessels (like a mosquito)
• Mouthparts are inserted through the skin, reach down into the vessel,
inject saliva, and suck blood
• Haematopinus asini: on horses
• The eggs have an operculum (cap).
• The louse hatches by sucking air in through its mouth and
explosively expelling it from its anus to blow off the operculum.
• Echidnopthirus horridus: on seals
• Breathes air - just before the seal submerges, the lice catch an air
bubble and hold onto it, using it to breathe underwater for extended
periods.
• Feed by sucking blood from the infested seal
• Phthirus pubis: the crab/pubic louse
• Transmitted between people during sex or who are sleeping next to
each other
• Found only on people
• Moves very slowly (sloth-like)
• Claws are large and designed for clinging to pubic hairs
• Pediculus humanus capitus: head louse
• Very common in schools - spread between students by close contact
• Prefer finer hairs, which are blonde/dark brown
• Black hair tends to be thicker and less preferable
Document Summary
Lecture 20 phthiraptera (lice) and hemiptera (bugs) Infect: from latin infectus (to work in, to dye, to taint: used for internal infections (ex. worms) Infest: from latin infestare (to attack/molest: used for external infestations (ex. lice, fleas, ticks, etc. ) Speciate: occurs via evolution (i. e. fly a can evolve/speciate into fly b: you can"t evolve/speciate things. Immature stages appear very similar to the adults, except they lack genitalia: ex. ) silverfish, hemimetabolous: simple metamorphosis, one development pattern, wingless nymph hatches. Instars grow via molts: stages: egg, nymph(s), adult, holometabolous: complex/complete metamorphosis, upon hatching, the wingless, legless larva is vermiform (looks like a worm), stages: egg, larvae, pupa, adult. Louse-borne typhus: a rickettsial infection that is often fatal. Infects people when louse feces are rubbed into the bite would or by biting the lice to kill it: killed anne frank. How many wings do bugs typically have: 2 pairs of wings, bed bugs and bat bugs are wingless and highly adapted to parasitism.
