Transcript Insects - East Troy Middle School

Insects
Learning Target Objectives:
•Differentiate between Batesian and Mullerian mimicry
•Compare/contrast arthropods to other invertebrate animals.
•Compare and contrast incomplete with complete metamorphosis
•Evaluate the role/impact of insect vectors, and the diseases they carry,
on human life.
•Evaluate various types of insect defense and survival
strategies/adaptations, including anatomical and physiological
components
Vocabulary:
Entomology * thorax * labrum * labium * mandibles * maxilla *
compound eye * ocelli * tympanum * femur * tibia * fibula * tarsus
* forewings * hindwings * esophagus * crop * gizzard * anus *
malpighian tubules * spiracles * tracheae * ovipositors * incomplete
& complete metamorphosis * nymph * larva * pupa * instar *
cocoon * chrysalis * probosis * mullerian & batesian mimicry
Insects
Phylum: Arthropoda
Subphylum: Uniramia
Class: Insecta
- have survived for over 300 million years (since BEFORE dinosaurs!)
- open circulatory system
- exoskeleton
- jointed appendages
- segmented body, 3 parts: head, thorax (chest region) , and abdomen
- 1 pair of antennae on head
- 3 pair of jointed legs attached to the thorax and POSSIBLY 1 or 2 pair of
wings
- abdomen has 11 segments
Entomology – study of insects
There are more than 900,000 species of insects.
Success of Insects
- flight (in some): flee enemies, find food further away, inhabit new
environments
- reproduce quickly/short life cycle: adaptations can occur each
generation so can adapt rapidly to changing environment (Natural
Selection), large numbers of oofspring are produced also increasing
genetic variability in populations
- variety of adaptations for feeding, etc. and a variety of nutritional
requirements eliminate most competition
- small size means less area needed to survive
Insects as Disease Vectors
Mosquitoes – carry:
malaria (“Anopheles” carries malaria. We have mostly “Aedes” &
“Culex”) Malaria kills huge numbers of people in tropical areas.
Yellow Fever (a viral infection) Many building Panama canal died.
West Nile (even people and animals in Wisconsin have died)
Rat Flea – Bubonic or Black Plague killed 1/4th of Europe’s population
in 14th century (25 million people). Of 992 cases in US between
1900 & 1972, 720 were fatal. (“BaaBaa Black Sheep” came from
this disaster)
Lice – carry typhus (not typhoid fever which is spread by water & flies)
Typhus causes high fever, delirium, blotchy rash, & death. (It’s
related to Rocky Mountain Spotted Fever) – fall of Napolean’s army
Houseflies – carry dysentery & typhoid fever
Tsetse fly - carries African Sleeping Sickness
The Grasshopper
Mouthparts:
1) Labrum – upper “lip”
2) Labium – lower “lip”
3) Mandibles – chewing jaws, move side-to-side
4) Maxilla – help hold food
Grasshopper Anatomy
- 2 compound eyes (multiple lenses – see in several directions at one
time)
- 3 simple eyes (ocelli) – sense light
- 2 antennae
- tympanum – used for hearing, located on abdomen just above
jumping legs
The legs:
- 4 front = walking legs
- 2 back = jumping legs
Femur = upper leg, Tibia = lower leg, tarsus = foot
Wings:
Forewings – leathery, used for gliding & for protecting hind wings
Hindwings – used for flight
Digestive System:
Mouth (with salivary glands)  esophagus (elastic tube)  crop (stores
food)  gizzard (grinds food with chitinous plates)  midgut
(stomach)  hindgut (colon/intestine) & rectum  anus
Excretory System:
Malpighian Tubules – filter blood of liquid wastes  rectum  out anus
Respiratory System:
No lungs or gills !!!
Spiracles – openings on abdomen & thorax where air enters as muscles
expand body
Tracheae – carry oxygen from spiracles directly to tissues & also
collects carbon dioxide from tissues to exhale them
Reproductive System:
Male deposits sperm in female’s seminal receptacle where it is
stored until egg release (internal fertilization). The female
deposits the eggs in the soil using ovipositors.
Anatomy of a
Grasshopper
Section 28-1
Compound eye
Brain
Antennae
Digestive
tract
Malpighian tubules
Heart
Reproductive
organs
Ventral View
Legs
Mouth
Salivary
glands
Anus
Ganglia
Tracheal tubes
Spiracles
Nerve
cord
Tracheal
tubes
Spiracles
Development/metamorphosis:
Incomplete metamorphosis – developmental changes where the egg
hatches into a miniature, immature adult look-alike with NO wings.
This is a nymph.
The nymph molts several times until sexual
maturity (adulthood). Typical of grasshoppers and termites.
Complete metamorphosis – major changes occur as an egg hatches
into a larva which grows and molts several times before becoming a
pupa (“resting” stage) where larval tissue breaks down and a mature
adult develops. Ex: moths, butterflies, flies, etc. (over 80% of
insects)
egg
adult
larva
pupa
Butterflies and Moths
Larva is a caterpillar – eat leafy foods (usually), molt about 4 times,
each stage is called an instar.
Pupa is a cocoon spun of silk for a moth but a chrysalis, made from the
hardening of “skin” after the last molt, for butterflies.
Differences in adults usually include:
Moths
Feathered antennae (esp. males)
Night flights
Somewhat wooly bodies
Butterflies
Club antennae
Day Flights
Non-wooly bodies
Both adult types suck food using a probosis (like a straw or an
elephant’s trunk). Adults feed on nectar, rotting fruit, or dung. They
taste things with their hind feet!
Larva require lots of food for growth, adults need lots of energy for flight
& reproduction. Metamorphosis allows the different forms to meet
their needs without competing.
Insect defense:
- stingers (bees, wasps)
- noxious chemicals (beetles, some caterpillars)
- camouflage (walking sticks, etc.)
- mimicry
Mimicry:
Mullerian mimicry – many “poisonous” insects take on the same
warning coloration to keep away predators (Ex: bees, hornets, etc.
are usually all yellow and black)
Batesian mimicry – nonpoisonous insects imitate poisonous insects in
coloration (Ex: Viceroy (non-toxic mimics Monarch which is toxic)
Monarch:
Viceroy:
Comparison of Arthropods
1) Trilobita
-extinct (lived in warm,
tropical water – oldest known
animal fossils
3) Arachnida
a) 8 legs
b) 2 body regions usually
c) breathe with simple lungs
d) simple eyes
e) no antennae
Ex: spiders, mites, ticks,
horseshoe crabs
2) Crustacea
a) 10 legs (8 walking legs, 2
chelipeds for crayfish)
b) 2 body regions
c) breathe with gills (attached
to legs)
d) compound eyes
Exs: crayfish, crabs, lobster
4) Insecta
a) 6 legs
b) 3 body regions
c) breathe with tracheae
d) mostly compound eyes
Ex: grasshoppers, lice, moths