Adaptive change in protective coloration in adultstriated shieldbugs Graphosoma lineatum (Heteroptera:Pentatomidae): test of detectability of two colour formsby avian predators
2010 (English)In: Ecological Entomology, ISSN 0307-6946, E-ISSN 1365-2311, Vol. 35, no 5, 602-610 p.Article in journal (Refereed) Published
1. Protective coloration in insects may be aposematic or cryptic, and some species change defensive strategy between instars. In Sweden, the adult striated shieldbugs Graphosoma lineatum (Heteroptera: Pentatomidae) undergo a seasonal colour change from pale brown and black striation in the pre-hibernating adults, to red and black striation in the same post-hibernating individuals. To the human eye the pre-hibernating adults appear cryptic against the withered late summer vegetation, whereas the red and black post-hibernating adults appear aposematic. This suggests a possibility of a functional colour change. However, what is cryptic to the human eye is not necessarily cryptic to a potential predator.
2. Therefore we tested the effect of coloration in adult G. lineatum on their detectability for avian predators. Great tits (Parus major) were trained to eat sunflower seeds hidden inside the emptied exoskeletons of pale or red G. lineatum. Then the detection time for both colour forms was measured in a dry vegetation environment.
3. The birds required a longer time to find the pale form of G. lineatum than the red one. The pale form appears more cryptic on withered late summer vegetation than the red form, not only to the human eye but also to avian predators. The result supports the idea that the adult individuals of G. lineatum undergo a functional change from a cryptic protective coloration to an aposematic one.
Place, publisher, year, edition, pages
2010. Vol. 35, no 5, 602-610 p.
Antipredatory defence, aposematism, background matching, crypsis, great tit, ontogenetic colour change, Parus major, warning coloration
Behavioral Sciences Biology
Research subject Ethology
IdentifiersURN: urn:nbn:se:su:diva-47155DOI: 10.1111/j.1365-2311.2010.01219.xOAI: oai:DiVA.org:su-47155DiVA: diva2:373421