The order Neuroptera includes an interesting cast of six-legged characters: alderflies, dobsonflies, fishflies, snakeflies, lacewings, antlions, and owlflies. The order name derives from the Greek neuron, meaning sinew or cord, and ptera, meaning wings. Though we refer to this group as the nerve-winged insects, their wings aren't laced with sinews or nerves at all, but instead with branching veins and crossveins.
The nerve-winged insects vary enough that some entomologists divide them into three distinct orders (Neuroptera, Megaloptera, and Raphidioptera). I've elected to use the classification system outlined in Borror and DeLong's Introduction to the Study of Insects, and consider them as a single order with three suborders:
- Suborder Megaloptera - alderflies, dobsonflies, and fishflies
- Suborder Raphidioptera - snakeflies
- Suborder Planipennia - dusty-wings, lacewings, mantidflies, spongillaflies, antlions, and owlflies
Adult nerve-winged insects typically have two pairs of membranous wings, all nearly equal in size, and with many veins. Specifically, most Neuropteran wings have abundant crossveins near the leading edge of the wings, between the costa and subcosta, and parallel branches off the radial sector (see this diagram of wing venation if you're unfamiliar with these terms). Insects in this order have chewing mouthparts and filiform antennae with many segments. In general, nerve-winged insects are weak fliers.
The larvae are elongate, with squared heads and long thoracic legs. Most larvae of nerve-winged insects are predaceous, with chewing mouthparts to consume their prey.
Nerve-winged insects undergo complete metamorphosis, with four life stages: egg, larva, pupa, and adult. In the Planipennia, they produce silk from their Malpighian tubules. The silk is extruded from the anus and used to spin a cocoon. All other nerve-winged insects have naked pupae.
Habitat and Distribution:
Nerve-winged insects live worldwide, with roughly 5,500 species known from 21 families. Most insects in this order are terrestrial. The larvae of alderflies, dobsonflies, fishflies, and spongillaflies are aquatic, and inhabit rivers and streams. Adults in these families tend to reside near water.
Major Families in the Order:
- Sialidae - alderflies
- Corydalidae – dobsonflies and fishflies
- Mantispidae - mantidflies
- Hemerobiidae – brown lacewings
- Chrysopidae – common lacewings
- Myrmeleontidae - antlions
- Ascalaphidae – owlflies
Families and Genera of Interest:
- Antlion larvae often go by the nickname doodlebugs. They build pitfall traps in the soil to ensnare ants and other prey.
- Spongillafly larvae prey on freshwater sponges.
- Larvae of mantidflies are parasites of spider egg sacs.
- Some lacewings camouflage themselves by attaching woolly aphid carcasses to their backs. This enables them to live among the aphids without being detected.
- Green lacewing females place each of their eggs on a long, think stalk which is itself attached to a leaf. This is thought to help keep the eggs out of reach of predators.
- Insects - Their Natural History and Diversity, by Stephen A. Marshall
- Borror and DeLong's Introduction to the Study of Insects, 7th edition, by Charles A. Triplehorn and Norman F. Johnson
- Neuroptera, by Dr. Jon Meyer, North Carolina State University, accessed December 6, 2012
- Order Neuroptera - Antlions, Lacewings and Allies, BugGuide.Net , accessed December 6, 2012