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The Wonderful World
of Insects
Field Natural History
Diagnostic Features, Ecology, and
Economics of Insect Orders
Videos of Interest
• Leaf Cutter Ants • http://www.youtube.com/watch?v=RH3KYBMpxOU
Songs of Insects
Beetle Flight
http://www.youtube.com/watch?v=fC61ZA4uWbs
Class Insecta
• Most abundant animal group—approximately 30% of animal biomass—possible 10 million species
• Ecologically and Evolutionary Diverse – Rapid reproduction (short generation time and great fecundity)
– Rapid adaptation to new environments (overcome chemical warfare)
– Small and agile
• Agricultural and Human Pests – Disease transmission
– Crops destruction
Songs of Insects
Insect Natural Resources
• Pest Management
– Crop protection
• Pollination
– Human nutrition
• Materials
– Silk
– Honey
– Confectioner’s glaze
– Cochineal
Characteristics of Insects
• Insects as Arthropods – Jointed appendages
– Chitinous flexible exoskeleton
– Complex mouth parts
– Three primary body structures
– Segmented body parts
– Generally with six legs, • one pair of antennae, and
• two pairs of wings
– Complete metamorphosis
Insect Orders approximately 1.5 million species named
• Coleoptera (beetles) 370,000
• Lepidoptera (butterflies, moths) 150,000
• Hymenoptera (bees, wasps, ants) 120,000
• Hemiptera (true bugs) 100,000
• Diptera (flies, mosquitoes) 100,000
• Orthoptera (grasshoppers) 20,000
• Odonata (dragonflies) 5,000
• Ephemeroptera (mayflies) 2,000
Diptera—True Flies
• Two-winged insects
• Hind wings modified into halteres which have a role in flight stability
• Large eyes
• Relatively short antennae compared with bees
• Mosquitoes, gnats, and flies
• Diverse ecological roles
– Parasites and disease vectors
– Blood suckers
– Decomposers
– Few pollinators
Diptera—True Flies
Many species of flies mimic
various hymenoptera—note the
short antennae, lack of abdominal
constriction, and one pair of wings
Hymenoptera—
Bees, wasps, and ants • Membrane-winged insects
• Four wings with 2nd pair smaller than 1st pair
• Distinct constriction between thorax and abdomen
• Ecology
– Few parasites on other insects
– Important pollinators of crops
– Some gall forming insects
• Navigational behaviors
– Ants spatial sensitivity
– Bees and sun compass
Ants as farmers, seed dispersers, and protectors
Hymenoptera-Leaf Cutter Ants
An Incredible Example of Coevolution
Social division of labor
Fungus farmers
Sensitivity to needs
of cultivated fungi
http://www.youtube.com/watch?v=RH3KYBMpxOU
Many spring ephemerals
have ant dispersed seeds.
Parasitic Wasps
Hymenoptera—
Important Pollinators
• Crops—almonds, alfalfa, apples, apricots, blackberries, blueberries, cherries, citrus, clover melons, peaches, plums, raspberries, strawberries, squash, tomatoes,
• Hundreds of Millions of dollars in bee services
• Honey and Beeswax production – Orange blossom honey
– Sourwood honey
• European Honey Bee Introduction and Impact on Native Bumble Bee Ecology
Bee Pollination & Human Health
Anti-bacterial Anti-cancer
Minerals
Vitamins
Anti-oxidants
Spices
Anti-aging
Honey is Liquid Gold
To make 1 lbs. of honey
– The colony must visit 2 million flowers
– Travel 45-55,000 miles
– Work 4000 bee hours
• Travel cost-$0.40/mile
– $20,000
• Minimum Wage
– $29,000
• Total = $49,000
Bee Society
Workers
--caretakers, foragers,
honey makers
--female—skilled
communicators,
navigators, and providers
Queen
--one per hive
--egg layer
--phermones regulation
Drones
--fatherless males
--sole purpose—sex
--go out with a bang
Hollywood Violates the Rules of Nature
www.beemovie.com
Language of the Honeybee
Distance from Hive
Waggle Frequency
Language of the Honeybee
NEAR
FAR
Direction from Hive
Relative to Sun
Language of the Honeybee
Hemiptera- True bugs (half wing)
• Half of forewing is thickened and leathery
• Enlarge pronotum extending along dorsal abdomen
• Wings cross over the abdomen forming an “X” pattern
• Piercing, sucking mouth parts—plant pests – Milkweed bugs
– Stink bugs
– Boxelder bugs
• Some species predaceous – Assassin bugs
– Ambush bugs
– Water boatmen
Today’s Natural Moment contributed by Katie W.
What are the red streaks
on this maple (Boxelder)?
Hemiptera
Lepidoptera-Scale-winged Insects • Wings covered in minute,
square-shaped scales
• Large knob-like or feather like antennae
• Division into moths and butterflies is somewhat artificial
• Larvae-caterpillars
• Ecology – Larvae are herbivorous
– Adults short-lived, nectar feeders
– Migratory behavior
• Coevolved with Plant Host – Milkweeds and monarchs
– Fritillaria with violets
• Economics – Silk
– Butterfly gardening
– Pollination--vanilla
Lepidoptera
Silk worm moth feeding
on mulberry leaves Urticating hairs on IO moth caterpillar
Coleoptera—
Sheath-winged Insects • Most abundant insects—
species numbers (1 in 4 animal species)
• 1st Pair of wings (elytra) thickened and protective often colorful and irridescent
• 2nd pair are membranous and used for flight
• Largest insect—Acteon Beetle of South America (9cm x 5 cm)
http://www.youtube.com/watch?v=fC61ZA4uWbs
Beetle Bark Galleries
Elm & Pine
Elm bark beetles also transport the fungus that causes Dutch Elm disease
Weevils are Beetles
Coleoptera—Interesting Beetles
• Lightening Bug
– Enzymatic luminescence for mating
– Coevolved predation
• Blister and Bombardier beetles
– Abdominal chambers mix quinones, hydrogen
peroxide, and oxygen to produce an audible
and caustic explosion for protection
– Cantharidin is a chemical from blister beetles that can be
purchased to help remove warts.
http://www.flickriver.com/places/United+States/Vermont/Shelburne/
Odonata—
Dragonflies and Damselflies • Four long and similar-shaped
wings
• Elongated abdomen
• Large eyes and short bristle-like antennae
• Predaceous
• Dragonflies-wings held flat
• Damselflies-wings held together above abdomen
• Important in stream food chains
• Mating dynamics
• Migratory behavior
Ephemeroptera—
Short-lived Insects
• Freshwater insects whose
adults live only a single day
• Fragile triangular wings held
above fragile body; 2nd pair of
wings much reduced;
• Elongated abdomen with two
or three cerci
• Important member of stream
ecology
Homoptera—Cicadas, Leafhoppers,
Aphids, Scale Insects, Whiteflies
• Wings elevated in roof-like
posture above body at rest
• Plant feeders—often
specialized on small groups
of plants
• Plant pests and disease
vectors
• Confectioner’s Glaze, Resin
Glaze or Lac Resin
http://www.richard-seaman.com/Wallpaper/Nature/TrueBugs/LeafHopper.jpg
Orthoptera—Grasshoppers,
crickets • Enlarged femur-like segment
of 3rd pair of legs
• Well developed tympana on either abdomen or pair of legs
• Shield-like pronotum on thorax
• Long hair-like antennae
• Crickets with courtship and aggressive songs
• Sounds produced either by wings or femora of hind legs
• Mostly herbivorous, some carnivorous
Songs of Insects
Order Mantodea--Mantids
• Generalist predators
• Front pair of legs
modified into vise-like
structures for
grasping prey
• Female cannibalism
of males not
widespread
http://www.birdwatchersdigest.com/bwdsite/learn/hummingbirds/mantis-hummer.php?sc=migrate
Neuroptera-Lacewings, Fishflies,
Dobsonflies
• Four membranous wings
held roof-like over body,
many veined
• Long thread-like
antennae extending
dorsally over thorax and
abdomen
• Predators of other
insects, beneficial aphid
predator
• Aquatic larvae—fish flies
• Attracted to night lights
http://biokeys.berkeley.edu/inverts/images/insecta/drawings/neuroptera.jpg
Order Neuroptera—Fishflies,
Dobsonflies and Lacewings
• Net-like pattern of
wing veins
• Long antennae and
large wings
• Insect predators
• Many important in
stream ecology
Ephmeroptera—
Short-lived Insects
• Freshwater insects
whose adults live only a
single day
• Important member of
stream ecology
• Fragile triangular wings
held above fragile body;
2nd pair of wings much
reduced;
• Elongated abdomen with
two or three cerci
Order Dermaptera--Earwigs
• Nocturnal scavengers
and herbivores
• Hooked cerci
• Never found in ears
http://www.life.illinois.edu/entomology/illustrations/gifs/dermaptera.gif
Order Thyansoptera--Silverfish
• Common in moist, dark,
human dwellings
• Consume and digest both
CELLULOSE and starch
• Flattened bodies, tapered
abdomen, small eyes
• “bookworms”
http://insectphotos.net/orders/thysanura/images/silverfish1.jpg