Raphidioptera are an ancient insect order with a distinctive appearance. With adult wings typically ranging from 5 to 20 millimeters in length, while they once had a global presence, modern snakeflies are primarily found in temperate or high-altitude regions of the Northern Hemisphere, with approximately 260 species identified across two extant families: Raphidiidae and Inocelliidae. These insects are recognized for their unique body structure, which gives them their common name.
Distinctive Characteristics
Snakeflies possess a unique physical form. Their most notable feature is an elongated, cylindrical prothorax, which creates a “neck-like” appearance and allows for significant head movement. Their head is prognathous, featuring large compound eyes and strong, biting mouthparts.
They have two pairs of transparent, membranous wings that are held roof-like over their abdomen when at rest. These wings are characterized by a net-like vein pattern and a pigmented pterostigma. Their bodies are generally slender, and females often have a long, needle-like ovipositor used for egg-laying. Most species range in length from 15 to 30 millimeters.
Life Cycle and Behavior
Raphidioptera undergo complete metamorphosis. Females deposit eggs either singly or in small clusters, often in concealed locations like bark crevices, under bark, or within leaf litter.
The larval stage is terrestrial and characterized by an elongate, flattened body with a prognathous head and chewing-biting mouthparts, allowing them to be active predators. These larvae typically inhabit environments such as under tree bark, in dead leaves, or among debris, where they actively hunt small arthropods. The pupal stage is free-living and active, and it does not form a cocoon. Pupation usually occurs in similar habitats to the larvae, such as dead leaves, debris, or crevices.
Adult snakeflies are also predatory, primarily feeding on other small arthropods, particularly soft-bodied insects like aphids, mites, and other Sternorrhyncha. While their diet mainly consists of insects, adults have also been observed consuming pollen or nectar. They possess strong biting mouthparts with mandibles designed for catching and holding prey. Adult snakeflies are known to be active predators, though they typically fly only short distances.
Ecological Significance
Snakeflies serve a beneficial role in their ecosystems as natural predators. Both the adult and larval stages are carnivorous, primarily consuming other arthropods, particularly insects. They are especially recognized for their predation on various common pests, including aphids, mites, and other soft-bodied insects. This predatory activity contributes to the regulation of pest populations, particularly in arboreal environments such as forests and woodlands. Their presence can also serve as an indicator of certain environmental conditions, as they are typically found in temperate or high-altitude regions with pronounced winter periods.