Plebeius agestis is a fairly scarce resident. The species suffered a decline in the mid-20th century; since the early 1960s, its area of distribution has halved. The Dutch Monitoring Scheme shows a moderate decline in numbers since 1990. The species is classified as 'susceptible' on the 2006 Red List. It occurs on nutrient-poor grasslands on dry, sandy soils in an open landscape, as in the dunes and along dykes, roads and railway tracks. Temporary populations sometimes occur on waste ground, such as construction sites, and may persist for a few years. Several species of Geraniaceae are used as larval foodplant; Helianthemum is not known as foodplant, being extremely rare here. The species flies in two generations from early May until early September, and hibernates as a half-grown caterpillar. In dry dunes, extensive grazing can be applied to prevent scrub encroachment and the grassing over of the dune vegetation. Along the large rivers where the species has disappeared from many sites, dykes should be mown less often, and the cut material removed in order to bring about the return of a flower-rich vegetation.
Wynhoff, I., Swaay, C. van, Groenendijk, D., Bos, F., Bosveld, M.
- Bos, F., M. Bosveld, D. Groenendijk, C. van Swaay & I. Wynhoff 2006. De dagvlinders van Nederland, verspreiding en bescherming. Nederlandse Fauna 7. De Vlinderstichting, Wageningen en Nationaal Natuurhistorisch Museum Naturalis, European Invertebrate Survey, Nederland.