O. Orkin Insect Zoo: Thriving Through Change

Thriving through Change

Why have insects been so successful? A talent for adaptation, primarily. Key to insects' evolutionary success are high reproductive rates, short generation times, and specialized ways of eating, hunting, flying, and becoming mature adults.

What a Mouth!

Over the millennia insects have adopted many ingenious eating mechanisms--including tubes, needles, chewers, scrapers, and sponges--which have enabled them to flourish on the food available in their particular environments.

Tubes: Butterflies and moths (Order Lepidoptera) uncurl long tubes to sip the sweet nectar deep inside flowers sponges.

Mosquito Using
Needle-Tipped Tube to Pierce a Person's Skin

Needles: Using needle-tipped tubes, mosquitoes (Order Diptera) can pierce the skin of plants and animals to suck out juices and blood. True bugs (Order Hemiptera) use needle-tipped tubes to suck juices from both animals and plants

Chewers: Most insects, such as this grasshopper (Order Orthoptera) eating lettuce use five different mouthparts to grind their food and move it toward the back of the mouth.

Scrapers/sponges: House flies (Order Diptera) and some other insects have scrapers to dislodge the surface of their food and sponges to collect the draining liquid.

Hunting for Supper

Insects have acute senses that humans do not share. Some can smell odors over great distances; some have sharp vision; others can detect vibrations and hear sounds that people cannot. These diverse strategies help insects find different foods.

Smell: Plant-eaters that have small eyes, such as this katydid (Order Orthoptera), use long antennae to pick up the scent of food.

Vision: Dragonflies (Order Odonata) and other airborne hunters use large eyes to spot a likely lunch of fly or mosquito.

Hearing: Ears on legs. . . Both male and female katydids (Order Orthoptera, Family Tettigoniidae) have slits on their front legs that are sensitive to vibrations--especially from their own kind.

Flexible Flyers

The ability to fly is one of the greatest keys to insects' success! Long before birds or bats, insects were the first creatures to fly. Flight gave them new territories to explore, a way to escape danger, and more places to search for food and mates.

Territories: On the go . . . Cruising at 11 km (7 mi.) per hour, this bluebottle fly (family Calliphoridae) can cover a distance of 300 times its body length per second.

Search: Love on the wing . . . mating pairs of dragonflies and damselflies (order Odonata) stay clasped for several hours and will even fly while joined together.

Mouths on wings: Male katydids (Family Tettigoniidae) make music by rubbing together special structures on their front wings. Each species has its own repertoire of calls for courtship and territorial aggression.

Why Don't They Just Grow Up?
. . .Becoming Mature Adults

Insects' relatively speedy passage from birth to adulthood enables them to breed quickly and increase rapidly in number, adapt swiftly to new opportunities, and meet new challenges. Most insects grow up by either incomplete or complete metamorphosis.

Incomplete metamorphosis: In incomplete metamorphosis, an egg becomes a nymph, which evolves gradually into an adult. Nymphs and adults eat the same food and live in the same surroundings.

Pictures of Stages in Gradual
Metamorphosis

Complete metamorphosis: In complete metamorphosis, an insect progresses through several distinct stages: egg to larva to pupa to adult. Larvae and adults may eat different foods, thus avoiding competition for a single resource.

Pictures of Stages of Complete Metamorphosis