L20: Arthropods II

summary:

hexapoda (insecta)

-vast majority of species

-found in all environments (less commonly-marine)

-many forms

-complex body: 3 tagmata - head, thorax, abdomen

how many legs does the thorax have?

3 pair

how many wings does the thorax have?

2 pairs

which type of insect is most abundant?

-beetles

what are the 3 tagmata of insecta?

-head

-thorax

-abdomen

why are insects the champions of terrestrial environment? (8)

-size

-exoskeleton

-excretory system

-advanced resp system

-advanced nervous system

-advanced sensory system

-internal fertilization

-resistant eggs

champion traits:

size

-small

champion traits:

exoskeleton

-provides protection against enviro

-jointed

-hardened locomotory appendages (legs and wings)

champion traits:

excretory system

-composed of tubules that pass through the body

-extract water from waste

-nitrogen water excreted as uric acid

champion traits:

advanced resp system

-spiracles open to outside

-tracheae (tubules) ramify thru body (direct oxygen supply to tissues)

Champion traits:

Advanced sensory system

– Antenna

– Compound eyes

– Cerci in cockroaches

Insect evolution is connected to what?

Plant evolution

subclass:

Apterygota

-invasion of land and appearance of first hexapods

-primatively wingless insects

-mostly simple mouths

modern day apterygotes

-collembola: springtails

-thysanura: silverfish

apterygotes

collembola - springtail

apterygotes

thysanura - silverfish

subclass:

Palaeoptera (3)

-evolution of wings (350 mya)

-simple insects, simple development

-wings did not fold over abdomen

modern day palaeoptera

-odonata: dragonflies

-ephemeroptera: mayflies

modern day Palaeoptera

odonata: dragonflies

modern day Palaeoptera

-ephemeroptera: mayflies

subclass:

Orthopteroida

-development of wings that fold over abdomen

Orthopteroida:

Orthoptera

-grasshoppers

-locusts

Praying mantis

Cockroaches

Orthopteroida
Orthoptera - grasshoppers, locusts

Orthopteroida

Mantodea - praying mantis

Orthopteroida

Blattodea - cockroaches

definition:

ootheca

-cockroach egg case

wings:

cockroaches

-adults have wings

-nymphs (juveniles) do not

Importance of subclasses Hemipterioda, Neuropteroida, Hymenopteroida, Panorpoida

– Enhanced innervation

– Two lineages: simple development, complete metamorphosis

What are the lineages the enhanced innervation subclasses?

– Those that maintain simple development

– Those with complete metamorphosis

Definition:

hemimetabolous

Maintain simple development

Their life cycle consists of egg juvenile and adults

Definition:

holometabolous

Complete metamorphosis

Hemipteroida:

Juvenile form

– Nymph

– Look like adults, but lack wings

– Not sexually mature

– Molt to grow

Hemipteroida:

Adult form

– Wings

– Sexually mature

Hemipteroida

mallophaga, anoplura: lices

Hemipteroida

hemiptera: bugs, aphids

Hemipteroida:

Hemiptera

-bugs, aphids

-plant feeders

– Some parasites

Which Hemipteroida Hemiptera are parasites?

– Bedbugs

– kissing bugs

Chagas disease

– Caused by a trypanosome so from the Americas (Trypanosoma cruzi)

-chronic disease – scarring and swelling of heart, liver, G.I.

– Occurs mostly in South America, but also now US

Transmitted by assessment or Kissing Bugs

What transmits Chaga disease?

– Assassin or kissing bugs

– Triatominae

- Rhodnius species

Trypanosoma cruzi

-causes Chagas Disease

Bed Bugs

which three Insecta subclasses show true metamorphis?

-Neuropteroida

-Hymenopteroida

-Panorpoida

Definition:

Holometabolism

– Involves true metamorphosis

Holometabolism:

Larva

– Specializes in feeding, growth, and development

– Molts to grow into pupates

Holometabolism:

pupa

– A transitional phase

– Internal

-quiescent (period of inactivity)

-larva develops to sexual adult

Holometabolism

Adult

– Specializes in reproduction, dispersion, egg laying

– Can be feeding or non-feeding

What are the advantages of true metamorphosis?

– Allows adults to occupy a completely different habitat from the larva

– Enables larva and adults to exploit different food resources

– Metamorphosis allows insects to escape from temporary habitats

Lepidoptera - moths, butterflies

Coleoptera - beetles, weevils

Siphonaptera - fleas

NO wings

Diptera - flies, mossies