Chinese Dobsonfly
Acanthacorydalis sp.
A nighttime stream-dweller with jaws like dead twigs
The Chinese Dobsonfly is a large insect in the order Megaloptera. Males have dramatically elongated jaws (mandibles) shaped like dead twigs, used for courtship display and combat, with fairly weak bite force; females have shorter, stronger mandibles. Its aquatic larva, the hellgrammite, indicates stream water quality.
Key figures
- Length
- Adult body length about 50–70 mm; a male's jaws can add significantly more length
- Life cycle
- The aquatic larval stage can last 2–3 years; adults typically live only one to two weeks
- Habitat
- Clear mountain streams and their bankside vegetation; larvae live beneath streambed rocks
- Diet
- Larvae are carnivorous, preying on aquatic insects and other small invertebrates; adults feed very little, if at all
- Jaw display
- A male's mandibles are elongated like dead twigs, used mainly for courtship display and combat, with fairly weak actual bite force
- Water-quality indicator
- Larvae are sensitive to water pollution, making them an indicator species for the cleanliness of mountain stream water
Life cycle
Egg → Larva (hellgrammite, 2–3 years) → Pupa (terrestrial) → Adult (one to two weeks)
Ecological role
Chinese Dobsonfly larvae are active aquatic predators in mountain streams, preying on other aquatic insects and serving as an important food source for fish; because they are so sensitive to water quality, they are often used as an indicator species for stream health.
Did you know
Chinese Dobsonfly larvae are often mistakenly called "naiads," a term that actually refers to dragonfly and damselfly nymphs; their correct name is hellgrammite, with dense thread-like gills along their sides.
Range
Clear mountain streams of the Yangtze River basin and areas further south in China
Status
Sensitive to water quality; common in clean mountain streams but rare or absent in polluted waters
Anatomy
- Mandibles — Elongated like dead twigs in males, serving combat and display more than actual feeding
- Wings — Broad-spanned with a dense network of veins, held roof-like over the back at rest
- Compound eyes — Set on either side of the head, aiding orientation during nighttime flight and mate-searching
- Antennae — Thread-like and slender, used to sense the scent and position of others at close range
- Thorax — Bears three pairs of legs and two pairs of wings, its well-developed muscles powering brief but strong bursts of flight
- Abdomen — Slender and soft; in females the tip bears an ovipositor used to lay eggs on rock faces near the water
Open the interactive 3D specimen