On Wednesday, October 22, 2025, sun‑lit walls across Warsaw swarmed with thousands of Asian ladybirds, the so‑called “clowns”, as temperatures rose.
Mass invasion on Warsaw facades
The afternoon of Wednesday, October 22 2025, the sun‑lit exteriors of many Warsaw buildings were overrun by the so‑called “clown” Asian ladybirds (Harmonia axyridis). Residents sent videos showing thousands on single walls; the surge was driven by rising temperatures and intense sunshine. A repeat may occur if the sun is strong later today.
Asian ladybird introduces itself
Harmonia axyridis originates from eastern Asia and was brought to Europe as a natural aphid enemy. Within a short span it spread across large parts of the continent and is classified as an invasive species. First records in Poland date to the mid‑first decade of the 21st century; the beetle is now common, even in cities.
Autumn wintering strategy
In autumn the “clowns” seek hibernation sites, attracted strongest to warm, bright, well‑sunlit surfaces—mainly south‑ and west‑facing walls. On sunny, warm afternoons they gather on façades, window frames and under sills before slipping into cracks, under coverings and into building interiors where they spend winter in a state of torpor.
Key identifying features
Harmonia axyridis shows very variable coloration, from ochre‑orange with many black spots to dark forms with red patches. A useful diagnostic mark is a bright pattern on the pronotum that resembles the letter “M” or “W”.
Diet and competition with natives
The “clowns” are voracious aphid predators but also consume eggs and larvae of other insects, including native ladybirds. Their broad environmental tolerance and high fecundity allow them to outcompete local species. In cities their numbers can rise rapidly under favorable weather, producing spectacular gatherings on façades.
Human and health concerns
Asian ladybirds can bite humans, especially when irritated or seeking moisture. Most bites end in brief stinging; sensitive people may experience allergic reactions ranging from skin and eye irritation to runny nose and asthma attacks. The yellowish hemolymph that the beetles secrete in stress has a strong smell and can permanently dirty surfaces. The mass clustering on walls is mainly an aesthetic and sanitary nuisance; beetles can enter apartments, accumulate in stairwell galleries and attics, leave stains, and trigger allergic reactions in some residents. The phenomenon intensifies on warm, sunny late‑autumn afternoons when the insects search intensely for hibernation sites. If today’s afternoon brings clear sunshine, expect another surge on sun‑exposed façades.
