Pictured: mazarine blue, Cyaniris semiargus
Notes from Jenyns: Taken in Gamlingay Wood by J.C. Dale, Esq. ~ Hatley & Madingley Woods. Mr Aikin. Horningsea. ~ E.L.Layard. ~ “One specimen, a female, taken at Stapleford in a chalkpit in June.” ~ Mr Lee.
200-year trend in Cambridgeshire: Decline to extinction.
Modern records
Jenyns lists this species from a few locations by way of a couple of different collectors but the mazarine blue has now been extinct in the UK for over 100 years. It is not certain why this grassland species disappeared, but one theory is that changes in hay cutting practices contributed to its decline. Its foodplant is red clover and a combination of sowing red clover in hay meadows and altering the time of year the hay was cut, may have lured the mazarine blue in to lay eggs, only for the caterpillars to then be killed at harvest time.
National records map
Mazarine blue national records map:https://species.nbnatlas.org/species/NHMSYS0000502047
