Henry Doorly Zoo: Insects

Insects make up more than half of all living things on the planet! They play a significant role in pollinating our crops, controlling pests and are an essential food source for wildlife. Insects and spiders are invertebrates, meaning they do not have an internal skeleton and backbone. Instead, they have a tough chitin outer covering called an exoskeleton.

The loudest insects are male cicadas, which can be heard about a quarter of a mile away.

Insects have compound eyes, which are eyes that are divided into many six-sided compartments.

The insects with the biggest nests are termites. The largest termite mound, found in Australia, was 18 feet across at the base. The tallest termite mound, found in Africa, was 37 feet high, however only 9 feet across.

What insects live the longest?
Queen termites—they have been known to live up to 50 years.

Spiders
All spiders are both carnivorous and venomous, but only a small percentage of them are potentially dangerous to humans. Spiders use their venom to paralyze their prey and bite if cornered or trapped.

Spider web silk is known as the strongest natural fiber. Spiders use webs for many purposes. Cobwebs or tangle-web are disorganized, non-sticky webs that are often found in bushes or buildings. Orb-webs are well organized and made of structural silk plus sticky silk threads used to capture flying prey. Funnel-webs are built down into the entrance of a spider’s burrow, which is lined with silk. Some spiders use their silk-webbing to construct a silken sac for their eggs and young. Spiders use web vibrations to detect prey. Not all spiders use webs to capture prey. Some sit and wait, ready to ambush.

Tarantulas
Tarantulas are the biggest spiders in the world and are found on every continent except Antarctica. Like all spiders, they have 2 body parts and most have powerful jaws with venomous fangs. Their abdomen is covered with tiny hairs that they flick fof using their legs when they are disturbed or threatened. Tarantulas are nocturnal hunters, eating insects, other spiders, small lizards, snakes and frogs.

Beetles
Beetles are the largest group in the Animal Kingdom, representing one fourth of all animals. Currently, more than 350,000 species have been identified, but scientists who study beetles are certain there are thousands more that have not been discovered.

All beetles go through a complete metamorphosis in which there is a change in form from the larva stage to the adult stage.

Beetles create usable soil for vegetation by eating animal waste, rotten wood, and animal carcasses.

How do diving beetles breathe underwater?
They capture surface air and store it under their wing covers. Sunburst diving beetles carry a bubble on their rear end. This bubble pulls oxygen from the water and helps the beetle stay under just a little longer.

Are beetles beneficial?
Even though some beetles are considered pests, many are beneficial. Ground beetles, for example, are very common garden insects that feed on many soil pests such as cutworms and root maggots.

Scorpions
California and Arizona have the greatest diversity of scorpions with about 60 different species.

Scorpions can easily be seen at night with an ultraviolet light due to a florescent material found in their exoskeleton, giving them a “glow in the dark” appearance.

A scorpion’s first sting is made up of different toxins than later stings. The first is usually strong enough to stun a vertebrate prey or predator; later stings are usually milder or used on invertebrates.

Arthropod
What is an arthropod?
Arthropods are invertebrates with segmented bodies and hollow jointed legs.
There are four groups of invertebrates: insects, crustaceans, arachnids, and myriapods. Insects have three body parts and six legs and include flies, bees, butterflies, and beetles. Crustaceans include crabs, shrimp and lobsters. Arachnids have two body parts and eight legs and include spiders, scorpions, ticks and mites. Myriapods have over eight legs and include centipedes and millipedes.

Nebraska
While some insects like locusts and mosquitoes are considered pests, many beneficial insects are becoming endangered due to habitat loss.

Can you name the endangered insects found in Nebraska? The Salt Creek Tiger Beetle and American Burying Beetle are the two insects that are listed on the Nebraska endangered species list.

The Salt Creek Tiger Beetle is confined to eastern Nebraska saline wetlands and associated streams and tributaries of Salt Creek in the northern third of Lancaster County. It is found along mud banks of streams and seeps, and in association with saline wetlands.

The American Burying Beetle was thought to be extinct in the Nebraska Sandhills. Recently, they have been rediscovered in Gothenburg, Brady, North Platte and Valentine.

Mantids
The two front legs of the mantids are highly specialized. When hunting, mantids assume a “praying” position, folding the legs under their head. They use the front legs to strike out and capture their prey.

Camouflage coloration allows mantids to blend in with the background as they sit on twigs, stems, and flowers waiting to ambush prey.

Mantids lay their eggs in a “foam home” called an ootheca. A female will usually deposit her ootheca on a plant stem or branch. The hard ootheca helps to keep the eggs safe from predators and to keep the eggs dry and warm. One ootheca can hold up to 200 eggs.

Crustaceans
Crustaceans are a very diverse group ranging from water fleas to lobsters. Crabs and lobsters are the largest arthropods.