Description and Identification
The Oak Beauty Biston strataria is a medium-sized macro moth of the family Geometridae. It is a large-bodied species which exhibits alternate bands of white and chestnut, interspersed with black, across the forewings, and equipped with attractive feathery antennae. It has a forewing length of 1.7 to 2.7 cm. There is a melanistic, all-black, form however this is rare.
|Oak Beauty, UEA, 28 March 2019 (Max Hellicar)|
It has one generation, with its flight period being from February to April, peaking in March. It occurs in deciduous woodland and suburban environments. Due to its distinctive appearance there are no real confusion species in the UK.
Despite the name, the caterpillars are not restricted to feeding on oak Quercus spp.; they feed on a range of deciduous tree species.
|Oak Beauty head-on, giving it a somewhat ominous appearance! (Max Hellicar)|
Oak Beauty is one of the most stunning of spring Lepidoptera and is a species which I look forward to seeing every year.
Species: B. strataria
Distribution and Status
It is a relatively common species across England and Wales, becoming scarcer in Scotland and Ireland. It is a common species in Norfolk, first recorded in 1873, and it has been recorded in 87% of 10 km squares across the county (Wheeler, 2019).
During its flight period, I have recorded twelve individuals over seven trapping sessions at UEA (using a Robinson moth trap with a mercury vapour bulb), the first of which was a single on the night of 21st-22nd February and peak counts of three individuals on the nights of each 20th-21st, 21st-22nd and 27th-28th March. The final date of which proved to be the best spring night for numbers of moths to date with 135 moths of twelve species, including two Brindled Beauty Lycia hirtaria, a species which is, to some degree, somewhat similar in appearance (disregarding colour) to Oak Beauty.
|Brindled Beauty, UEA, 28 March 2019 (Max Hellicar)|
References and Sources of Information
Kimber, I. (2019). Oak Beauty. Retrieved April 02, 2019, from UK Moths: www.ukmoths.org.uk/species/biston-strataria
Townsend, M., & Waring, P. (2007). Concise Guide to the Moths of Great Brtain and Ireland. London: Bloomsbury Publishing Plc.
Wheeler, J. (2019). Oak Beauty. Retrieved April 02, 2019, from Norfolk Moths: www.norfolkmoths.co.uk/?bf=19300