Dobsonflies
Corydalinae
Classification
- Phylum: Arthropoda
- Subphylum: Hexapoda
- Class: Insecta
- Order: Megaloptera
- Family: Corydalidae
- Subfamily: Corydalinae
Pronunciation
How to pronounce Corydalinae: /ˌkɔːrɪˈdælɪniː/
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Images
Summary
Corydalinae, also known as dobsonflies, is a subfamily of Megalopteran insects characterized by large size, aquatic larvae called hellgrammites, and complex mating behaviors. They play a vital role in their ecosystems and are of interest for both ecological monitoring and as angling bait.
Physical Characteristics
Adult dobsonflies are among the largest non-Lepidopteran insects, with a wingspan up to 18 cm (7.1 in) in some species; the largest, Acanthacorydalis fruhstorferi, can reach up to 21.6 cm (8.5 in). Coloration varies from yellow to dark brown, and males often have elongated, curving mandibles. Larvae, known as hellgrammites, are dark and bear characteristic claw-like structures at the end of the abdomen.
Identification Tips
Males can be recognized by their long, curving mandibles, while females possess shorter, heavily sclerotized mandibles that can deliver bites. The body length typically does not exceed 7.5 cm (3.0 in) for most species, and coloration ranges from yellow to dark brown.
Habitat
Larvae live in aquatic environments, particularly rocky bottoms of streams; adults are found along the same habitats and hide under leaves in the canopy during the day.
Distribution
Found in the Americas, Asia, and South Africa. Predominantly diverse in the Oriental Region, with most species occurring in South America in the New World.
Diet
Larvae are generalist predators, primarily feeding on aquatic immatures of mayflies, caddisflies, stoneflies, and chironomid midges. Adults are not known to feed but have been reported to drink sweet solutions in captivity.
Life Cycle
The life cycle involves a period of larval growth lasting up to five years, followed by pupation and emergence as adults. Males engage in courtship displays, and females lay egg masses along rocky walls of streams.
Reproduction
Mating involves males presenting a nuptial gift (spermatophore) after courtship, which females consume post-mating. Egg masses contain approximately one thousand eggs covered in a protective layer.
Ecosystem Role
Larvae are important predators in aquatic ecosystems, potentially serving as indicators of water quality due to their intolerance of pollution.
Economic Impact
Hellgrammites are used as bait by anglers and may bring high prices. Over-exploitation has occurred in some areas, leading to regulation of their sale.
Collecting Methods
- Using black light traps
- Using mercury-vapor light traps
- Disturbing rocky areas in streams to capture larvae
Evolution
Corydalinae may not be monophyletic, as some lineages appear more closely related to Chauliodinae. They comprise around 60 species distributed among 9 genera.
Similar Taxa
Tags
- insects
- dobsonflies
- Corydalinae
- hellgrammites
- aquatic insects