Host plants:
The caterpillars feed oligophagously on a variety of plants (e.g. Onagraceae, Rubiaceae, Vitaceae). Most of them are Onagraceae like Epilobium species, Circaea or even Fuchsia in gardens. In forests they live very often on the native Impatiens noli-tangere or the neophytic Impatiens glandulifera. Not so rare are also observations on Galium. According to literature the larvae sometimes occur on Menyanthes trifoliatum (bogbean) in peatlands.
Habitat:
The habitat of this species is diverse: from clearcuts and forests over wetlands, ditches, gardens to cemeteries the most mesophilic to hygrophilous habitats are used for reproduction. Deilephila elpenor avoids in contrast dry and warm habitats such as xerothermic grasslands where it is replaced by Deilephila porcellus. Overall, a clear trend towards at least slightly damp biotopes is obvious.
Life cycle:
The development is similar to Deilephila porcellus. But Deilephila elpenor has only a very scarce partial second generation (in most regions/years only one generation). The adults appear between late May and August with peak in June/July. The caterpillars can be observed between late June and October and are sometimes quite common especially in August. In the last instar they are at least partly nocturnal, especially at more open sites.
Endangerment factors:
Deilephila elpenor is still not endangered.
Remarks:
The distribution ranges from Southern Spain across Europe and parts of Asia to China.