Anatomy, Life Cycles and More Insects 8.01 Anatomy, Life Cycles and More

Insects are unique, small animals with three body regions and three pairs of legs

Insect Body Head Thorax Abdomen

Mouth Five types of mouth parts Chewing Piercing-sucking Rasping-sucking Siphoning Sponging

Mouth- chewing Tear Chew Grind food

Piercing-sucking Punctures plant Sucks sap

Rasping-sucking Rasps Break surface Sucks Sap

Siphoning Coiled tube Dip into nectar food Proboscis Draw up food

Sponging Two sponge-like structure Collect liquid food Move it into the food canal

Life Cycle- Complete Four Stages Egg Larva (worms and caterpillars) Pupa Adult(flies, beetles, and more)

Life Cycle- Incomplete Three stages Egg Nymph- aquatic Adult Examples Damselfly Mosquito Dragonfly

Egg Most insects lay eggs Some insects have live births Eggs then become larva

Larva Larva is the worm-like baby Larva can be grubs, maggots, caterpillars They do have little legs

Nymph These are immature stages (just smaller versions of adults) Part of an incomplete life cycle

Adult Man…. You know there are all kinds of cool adults To be an adult, it has to have six legs, head, thorax, abdomen, and a mouthpart!

Pupa These are the ugly teenager stage of a complete life cycle They can be in a chrysallis or cacoon at this time

Insect Control Insects must be killed when they are actively feeding or moving on the plant Control depends upon mouth part Chewing= stomach Piercing= systemic Contact poisons can be used on soft body

Insecticides- Stomach A pest will ingest this poison. This poison is often sprayed on the leaf and works well with chewing insects

Insecticides- Contact This is when you spray or fumigate an area Think of Raid or using a flea bomb in your house

Insecticide- Systemic Systemic runs through the system of the plant through the xylem and phloem Applied to the roots and sucked up by the insects (eat sap and die sucker! Get it?)

Damage Damage depends on the type of mouthpart Chewing Sucking Piercing Siphoning Sponging

Beetles Chewing: Eats it ALL Mainly a pest Complete LC Stomach Poison

Cutworms Chewing- Usually attacks stems May eat other plant parts Complete LC Stomach Poison/contact poison

Caterpillars Larva of Moths and Butterflies Chewing- Eats young leaves and stems Can Sting Complete LC Stomach and Contact Poisons

Grasshoppers Chewing- Eat all parts of plants Incomplete LC- hatches and babies just keeping molting skin to become adult! Enstar can prevent it from molting- expensive!

Incomplete Life Cycles Revisited

Aphids AKA Plant Lice Pierces and suck juices Cause stunted growth, yellow spotted leaves Poop called honeydew, attracts ants (symbiotic relationship) Incomplete Life Cycle Asexual reproducers Aphids produce 12 babies/day!

Mealy Bugs Pierce and suck from underside of leaves Suck in leaf axils Causes yellow appearance Sticky secretions Incomplete LC

Scales Piercing Sucking Incomplete LC Pain in the butt! Sticky Secretions Wingless- crawls

Rasping Sucking- Thrips Chews and then sucks Causes plant tissue to become speckled or whitened Leaf tip withers Leaf curls and dies Incomplete LC

Piercing Sucking- Whiteflies Feeds on underside of young leaves Little flying white specks when plants are shaken Vector for disease Incomplete LC

Piercing Sucking- Spider Mites Not a “true” insect Attacks underside of leaf Causes leaves to turn gray to grayish Severe infestations cause webbing Incomplete LC

Nematode A microscopic worm (not a “true” insect) A vector of disease Causes root knot and other sickness Don’t worry about life cycle or mouth

Complete life cycle Chewing mouthpart when they are eating their prey (like aphids) Do not want to control them, want to keep them in your greenhouse or garden.

Hornets and Wasps Some bugs, like this wasp, have two types of mouthparts, both siphoning and chewing Complete LC Pest- stings and causes damage to structures Can use contact or stomach

Praying Mantid (Mantis) Incomplete LC Beneficial Insect- eats bad guys in garden. Chewing mouthpart.

Honey Bee Complete life cycle Chewing and siphoning mouthpart Beneficial because it is a pollinator.

Lady Bug Complete life cycle Chewing mouthpart As an adult, as a larva (pictured here) it is a voracious eater of other insects…mmmmm.

Braconid (Parasitic) Wasp Complete life cycle Chewing and siphoning mouthpart Beneficial because this is an egg layer. The eggs are laid and it will parasitize (eat off of) what it is laid on. Babies are demons!

Leaf Bugs Piercing Sucking Incomplete Life Cycle Causes plants to look unhealthy Lose normal color and wilt

Japanese Beetles Chewing Pest Complete LC Stomach and contact poisons work

White Grub Chewing- roots Larva of beetle Complete LC Contact and stomach

Tomato Hornworm Complete life cycle: this is the larva of a moth. Chewing mouthpart when it is a pest. Can be parasitized by the brachonid wasp.

Tent Worm Larva of moth Complete LC Chewing Frass all over the place! Ugly tent!

Squash Bugs Piercing Sucking Incomplete LC

Piercing Sucking Incomplete LC

Leaf Miner Burrows into the leaf Makes little track marks on the leaf Chewing Mouthparts Systemic works best Complete LC

Fungus Gnats Little flying pests in greenhouse when it is too moist Larvae can damage plants Mainly a pest to people Chewing Complete LC Reduce watering for control