Double-countershading as a means of camouflage in larvae of Orange-tip Anthocharis cardamines (Linnaeus, 1758) (Lepidoptera: Pieridae)

In Shaw & Otto (2020), Shaw described larvae of the butterfly, Orange-tip Anthocharis cardamines (Linnaeus, 1758), that were visually obvious yet apparently immune to bird predation. He speculated that mustard oils in the foodplants may render them distasteful to birds so that being conspicuous is of little consequence, allowing them to bask in sunshine possibly to aid digestion. In contrast, I argue that in certain lighting conditions larger larvae of Orange-tip can be very well camouflaged. These two different defence mechanisms are not mutually exclusive and each may come into play under different conditions of lighting, larval age and/or food-plant availability. For disguise the larvae make use of double-countershading in what Süffert (1932) called the 'two-surface effect'. Here I briefly describe its mechanism along with that of the better-known ordinary (single) countershading. Photographs are shown of both.

Observations on co-existing late-instar caterpillars of the Orange-tip butterfly, Anthocharis cardamines (Linnaeus) (Lepidoptera: Pieridae)

Co-existence between late instar larvae of Anthocharis cardamines on multiple occupied Lunaria annua plants was monitored in a suburban Edinburgh garden and a stand-off between final instar larvae on Sisymbrium officinale in countryside near Leipzig was recorded photographically. Occupation of mauve-flowered Lunaria plants was significantly higher than white-flowered ones. The notion that the resting behaviour of final instar larva along the top of seed pods camouflages them is challenged. Although not part of that argument, a major predation event by Vespula vulgaris was seen on Lunaria.

I Ropaloceri del litorale a duna della ZSC IT5160004 Padule di Bolgheri (Livorno, Toscana) (Lepidoptera)

Nel 2015 è stata studiata la fauna a Ropaloceri del litorale a duna della ZSC IT5160004 Padule di Bolgheri (provincia di Livorno). I campionamenti sono stati effettuati due volte al mese, da aprile a ottobre, in un transetto di 1 km utilizzando il metodo di Pollard and Yates (1993). Complessivamente sono stati campionati 422 esemplari attribuibili a 30 specie. Le specie dominanti sono 7 (Lasiommata megera, Leptotes pirithous, Colias crocea, Gonepteryx rhamni, Pieris brassicae, Gonepteryx cleopatra, Hipparchia statilinus, Coenonympha elbana, Anthocharis cardamines, Pieris rapae e Limenitis reducta), abbondanti 4, 7 comuni, 7 occasionali e 5 rare. Rilevante è la presenza di Gegenes nostrodamus, in diminuzione in Italia e di Coenonympha elbana, endemica della Toscana. Si tratta di una fauna povera in specie, costituita da entità euriece e che non sono esclusive dell’ambiente di duna. Nel sistema a duna indagato i Ropaloceri sono, quindi, rappresentati in modo limitato e non annoverano entità utili a caratterizzarle in maniera univoca.