Mantidfly
Mantispa sp.
A lacewing relative with a mantis's arms
At first glance the mantidfly looks like a small mantis: its forelegs are spined raptorial forelegs, its thorax stretched like a neck. But its wings are packed with net-like veins, marking it a true lacewing (Neuroptera) — a costume built by convergent evolution, not kinship.
Key figures
- Length
- About 10–20 mm, slender in build like a small wasp
- Life cycle
- Mostly 1–2 generations a year; larval development depends on the host
- Habitat
- Shrubs at forest edges and grassland; often flies to lights at night
- Diet
- Adults prey on small flying insects; larvae mostly feed on spider eggs
- Raptorial foreleg
- The foreleg tibia and femur fold together like a clasp, striking like a mantis's arm
- Hypermetamorphosis
- Larvae start out active and mobile, then turn maggot-like after parasitizing a host, a form of hypermetamorphosis
Life cycle
Egg (short-stalked, laid in clusters) → Larva (hypermetamorphic) → Pupa (inside a cocoon) → Adult
Ecological role
Adults hunt aphids, moths, midges, and other small insects around flowers and lights; larvae bore into spider egg sacs and feed on the eggs, holding some spider populations in check. This 'spider-egg diet' life cycle is quite rare among insects, which also keeps its numbers naturally low.
Did you know
Many first-instar mantidfly larvae hitch a ride on a passing female spider, sneak into her egg sac, and drain the eggs one by one before pupating — the entire life hangs on that one ride.
Range
Throughout China, north and south; widespread across warm regions worldwide
Status
Uncommon, with naturally low population density
Anatomy
- Raptorial Foreleg — A sickle-shaped foreleg strikingly like a mantis's, yet the product of entirely separate evolution
- Wing — Membranous and transparent, densely veined in a net-like pattern that gives away its true identity as a lacewing relative, not a mantis
- Pronotum — The plate behind the head (pronotum) is stretched out like a neck, giving the raptorial foreleg a wider strike range
- Compound Eye — Rounded with a metallic sheen, relying entirely on sharp vision for daytime ambush
- Antenna — Short and beaded, quite unlike the long, thread-like antennae of a true mantis
- Abdomen — Many species carry yellow-and-black markings, mimicking a wasp to scare off predators
Open the interactive 3D specimen