Order Neuroptera (Antlions and Lacewings) in the Christopher B. Smith Preserve

Order Neuroptera Characteristics: Worldwide, there are more than 6,000 species of neuropterans. All have complete metamorphosis (egg, larval, pupal, and adult stages). A larva's body form varies among the different families of neuropterans, but usually has three pairs of thoracic legs, each with two claws. It also has large, curved jaws for impaling prey. After impaling its prey, a larva injects toxins and sucks out the juices. Larvae of some species camouflage themselves with debris (bodies of dead insects, lichens, and dead flowers). The pupal stage of a neuropteran is enclosed in a cocoon, made of silk, soil, or other debris.

All adult neuropterans are soft-bodied and have two pairs of large wings of about the same size. The wings are intricately-veined. This characteristic gives neuropterans their nickname, "nerve-winged insects." At rest, the wings are folded flat or held tent-like over the abdomen. They have large compound eyes, long antennae, and chewing mouthparts. Some species are predators, while others eat nectar. They are active at night; most are weak fliers.

Interactions in the Smith Preserve: Most larvae are specialized predators; some eat only aphids, whiteflies, and scale insects; others eat only ants. There are some larvae that eat only freshwater sponges and others parasitize spider eggs. Aquatic larvae are an important part of the food web, being predators of small organisms, and prey for fish and other aquatic animals. Many adults are omnivores, eating both plant and animal tissues. They are prey for moths and beetles.

 
Family
Species Name
Common Name
Chrysopidae
Unknown
Chrysopidae
Unknown
Myrmeleontdae
Unknown

 

 

Family Chrysopidae

Unknown Species ... Green Lacewings

On November 28, 2014, this green lacewing was discovered in an inactive state on the bottom of a leaf of Callicarpa americana (American Beautyberry). A few moments later, after being measured, it flew to the bottom of another leaf.

These photographs were sent to <BugGuide.net> and on February 16, 2015, it was identified as belonging to Tribe Leucochrysini of Subfamily Chrysopinae by "v belov", Contributing Editor of <Bugguide.net>, sponsored by Iowa State University Department of Entomology. The species name is yet to be determined.

Normally, adult green lacewings are active primarily at dawn or dusk, or at night. Depending on the species, they feed on pollen, nectar, honeydew, mites, aphids, and other small arthropods.

As can been seen in the last photograph, this particular individual from its head to the tip of its wings is about 1.5 cm long.

Adults have tympanic organs at the base of the forewings. This allows them to hear a bat's ultrasound calls, and to close their wings, drop to the ground, and avoid being eaten. Green lacewings use body vibrations to communicate among themselves during courtship.

Larvae of this genus are predators of aphids and have been used in biological pest control.

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Family Chrysopidae

Unknown Species ... Green Lacewings

In Florida, there are 22 species in 9 genera in Family Chrysopidae. The photographs shown here may or may not be the sames species as shown above.

A female green lacewing lays her eggs in clusters on a leaf, stem, or piece of bark. To lay an egg, she touches the tip of her abdomen to the surface and draws out a long filament, ending with an egg. The filament hardens instantly. As shown in the first photograph, stalked eggs stand above the vegetation like a series of tiny balloons. The filaments are too slender for predatory insects (ants and beetles) to climb. Photograph two shows a newly hatched lacewing at the base of its egg.

Lacewing larvae are usually found in vegetation, looking for food. As shown in the third photograph, they have specialized mouthparts with large, sickle-shaped mandibles and maxillae that interlock to form pincers. Once impaled on these pincers, a prey's body contents are sucked out through hollow food channels running between the surfaces of the mandibles and maxillae.

As shown in the photograph below, a lacewing larva typically attaches dead carcasses and other objects to its back for camouflage. This behavior gives the lacewing larva its nickname, "trash bug."

Lacewing larvae are considered beneficial because they are predators of agricultural pests (aphids, mites, whiteflies and scale insects).

Adult lacewings are small to medium in size (35 mm or less). Their antennae are long (usually longer than the body) and thread-like. The body is usually greenish and not hairy. Eyes are usually gold or copper-colored. Most lacewings have a tympanum (hearing organ) at the base of the forewing. Adults eat only pollen and nectar from flowers.

 

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Family Myrmeleontidae

Unknown Species ... Antlions

There are 22 species of antlions in Florida, more species than in any other state in the Eastern United States.

As with other neuropterans, larval forms look very different from adults. As shown in photograph one, larval antlions have very spiny bodies and large jaws. Their spines and jaws help them capture prey.

Larval antlion species live in very specific habitats. Some construct pits in the fine-grained sands of the scrub. Each individual constructs its own pit, like the one shown in the second photograph. After pit construction, the antlion waits with open jaws at the bottom of the pit for prey to fall down the slippery funnel of sand grains. Once impaled on its sickle-shaped jaws, the prey's body contents are sucked out through the hollow food channels running between the surfaces of the mandibles and maxillae. The larva (nymph) in photograph one was removed from its pit to photograph.

This photograph shows a "colony" of antlion larvae pits. Antlion larvae are sometimes called "doodlebugs" because they leave curved furrows in the sand when they are looking for the right place to construct pits. Look closely and you can see these "doodles" in the sand.

The photograph at right shows a cockroach has fallen into a pit and an antlion is waiting. Only the antlion larva's jaws are discernible.

Other antlion species do not construct pits, but instead wait just below the surface sediments for prey to wander by. Still others live inside gopher tortoise burrows or in the dry sawdust of decaying trees. These other antlion types have not been photographed in the Smith Preserve.

As an antlion like the one shown in image one ages, it eventually moves deeper into the sand and creates a cocoon. The larva's abdomen extends lengthwise and it extrudes silk threads to form a hollow sphere. The sphere is held in place by the surrounding sand. Inside the sphere, the larva changes into a pupa. Pupation lasts about three weeks. Usually in the evening, the adult emerges from the cocoon. It climbs a plant and waits for its wings to expand and harden.

In early November 2016, Ursula Bartoszek, the 4-year old daughter of Conservancy scientists Melinda and Ian Bartoszek was searching with a strainer in the Preserve for antlions. According to Ian, she found five antlion cocoons just a few inches under the sand and near some antlion pits. After researching on the Internet, she learned they were antlion cocoons. Each cocoon was ~7 mm in diameter. As can be seen in the second photograph below, the exoskeleton of the pupa is left behind as the adult emerges.

Antlion adults are medium to large (40 to 80 mm), and are similar in appearance to damselflies. But, close examination shows they are structurally different. The first image below is an adult antlion. The second image is an adult damselfly. The antennae of the antlion are curved, knobbed, and about the same length as the head and thorax combined. Damselfly antennae are much shorter and unknobbed. The wings of the antlion extend beyond its abdomen. The damselfly's wings do not. Adult antlions and damselflies are behaviorally different too. Damselflies are diurnal while antlions are nocturnal. Although this photograph of an adult antlion was taken during the daytime, the insect was not active; it was resting on the underside of a leaf.

Antlion adults are predators, but will occasionally scavenge insects that recently died. They pick small insects off vegetation at night.

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© Photographs and text by Susan Leach Snyder (Conservancy of Southwest Florida Volunteer), unless otherwise credited above.

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