Deporaus betulae (Linnaeus, 1758)
birch leaf roller
polyphagous on woody plants
Betula pendula © Frits Bink, Saxifraga Foundation: adult beetje with feeding traces
Betula pendula © Pieter van Breugel, Saxifraga Foundation: leaf rolls
The adult beetles cause window feeding in the spring. The female makes about 15 leaf rolls in her lifetime, each one with mostly 2 or 3 eggs. For the construction of the leaf roll she first builds an imago of the shape and size of the leaf by walking around several times. Then she makes two sigmoid cuts from the two leaf margins to the midrib, then rolls the distal part of the leaf into an acute cone. Often after some time the roll drops to the ground. After about four months the larvae are full grown and crawl into the soil for pupation.
Mainly on birch.
Univoltine; hibernation as imago.
distribution within Europe
The trajectory of the cut made by the female in the leaf has attracted the attention of several mathematicians; see for instance Horváth.
Dieckmann (1974a), Horváth (1988a), Reinheimer & Hassler (2010a), Roques, Cleary, Matsiakh & Eschem (2017a), Urban (2012c), Yunakov, Nazarenko, Filimonov & Volovnik (2018a).