Transparency improves concealment in cryptically coloured moths

Mónica Arias (1) , Marianne Elias (2) , Christine Andraud (3) , Serge Berthier (4, 5) , Doris Gomez (1)

1 CEFE - Centre d’Ecologie Fonctionnelle et Evolutive
2 ISYEB - Institut de Systématique, Evolution, Biodiversité
3 MNHN - Muséum national d'Histoire naturelle
4 INSP - Institut des Nanosciences de Paris
5 INSP-E4 - Nanostructures et optique

Predation is a ubiquitous and strong selective pressure on living organisms. Transparency is a predation defence widespread in water but rare on land. Some Lepidoptera display transparent patches combined with already cryptic opaque patches. A recent study showed that transparency reduced detectability of aposematic prey with conspicuous patches. However, whether transparency has any effect at reducing detectability of already cryptic prey is still unknown. We conducted field predation experiments with free avian predators where we monitored and compared survival of a fully opaque grey artificial form (cryptic), a form including transparent windows and a wingless artificial butterfly body. Survival of the transparent forms was similar to that of wingless bodies and higher than that of fully opaque forms, suggesting a reduction of detectability conferred by transparency. This is the first evidence that transparency decreases detectability in cryptic terrestrial prey. Future studies should explore the organization of transparent and opaque patches in animals and their interplay on survival, as well as the costs and other potential benefits associated with transparency on land.

Mots clés: butterfly; camouflage; communication; predation; vision; Insects; Birds

Domaines: Biodiversité et Ecologie

Mónica Arias, Marianne Elias, Christine Andraud, Serge Berthier, Doris Gomez. Transparency improves concealment in cryptically coloured moths. Journal of Evolutionary Biology, 2020, 33 (2), pp.247-252. ⟨10.1111/jeb.13560⟩. ⟨hal-02346924⟩