Asian Lady Beetle

The Asian lady beetle, *Harmonia axyridis*, belongs to the family Coccinellidae, order Coleoptera. Adults measure 5.5–8.5 mm in length and exhibit significant color polymorphism, ranging from pale orange to bright red, with 0 to 22 black spots; a characteristic M- or W-shaped black marking on the white pronotum is diagnostic. Its lifecycle comprises four stages: egg, larva (four instars), pupa, and adult, typically completed in 15–30 days depending on temperature and food availability. Females can lay up to 2,000 eggs over their 1–3 month lifespan, with optimal development occurring between 20–25°C and relative humidity of 60–80%. This high reproductive capacity contributes to its rapid establishment and spread in new environments.

Primarily diurnal hunters, *H. axyridis* are voracious predators of soft-bodied arthropods, particularly aphids, psyllids, and scale insects, consuming hundreds daily as both larvae and adults. During late summer and fall, as aphid populations decline and temperatures drop, they exhibit a strong aggregative instinct, releasing aggregation pheromones (e.g., harmoniaxydin) that draw thousands to overwintering sites. When disturbed or stressed, adults reflexively bleed hemolymph – a yellowish, acrid fluid containing toxic alkaloids (harmoniaxydin, harmonine) – from their leg joints. This 'reflex bleeding' stains surfaces and serves as a defense mechanism against predators, while also posing an ophthalmic contact risk to humans in mass aggregations.