MARKOVA Т.О., MASLOV М.V.
Amurian zoological journal 2026; 18(1): 180–189
The paper presents data on seasonal colour polyphenism in the bug Urostylis annulicornis Scott, 1874 (Heteroptera, Urostylididae) from the southern part of Primorsky Krai from 2022 to 2024. Eggs were collected in forest biotopes on trunks of Quercus mongolica Fisch. ex Ledeb. attached to sections of rhytidome. Rhytidome sections containing egg masses ofU. annulicornis were maintained until the emergence of second- and third- instar nymphs. Stationary observations were conducted in cages installed on Mongolian oak saplings, where the bugs remained until adult eclosion. The reddish-brown hue of the integument of younger nymphs conceals them against oak bark and the brown scales of emerging buds. Colour variations are most pronounced in older nymphs. By early October, reproductively active adults of U. annulicornis in oak tree canopies exhibit a marked change in the pigmentation of their limbs and the first antennal segment. This brighter colouration conceals pairs that remain in one spot for prolonged periods among the variegated oak foliage.
