TY - JOUR
T1 - Evolution of cheaper workers in ants
T2 - A comparative study of exoskeleton thickness
AU - Peeters, Christian
AU - Molet, Mathieu
AU - Lin, Chung Chi
AU - Billen, Johan
N1 - Funding Information:
We thank G. Buczkowski, D. Fresneau and D. Grasso for providing specimens, Brian Fisher and Decha Wiwatwitaya for making C.P.’s fieldwork possible in Madagascar, Sabah (Ant Course 2010) and Thailand, An Vandoren for histological sections and Claudie Doums for statistical help. We thank four anonymous reviewers for helpful comments. C.P. and M.M. are funded by the French National Research Agency (ANTEVO ANR-12-JSV7-0003-01).
PY - 2017/7
Y1 - 2017/7
N2 - The great evolutionary success of insects is partly linked to the innovation of the cuticle, which underlies a complex exoskeleton with varied functions. Cuticle development is costly because chitin and cuticular proteins require ingested nitrogen. Studying cuticle thickness on a comparative basis allows insight into the trade-off between offspring quality and quantity. This trade-off takes a particular meaning in ant workers because they are wingless, non-dispersers and generally sterile. We selected a comprehensive sample of 42 ant species (40 genera belonging to nine subfamilies) and measured cuticle thickness in workers using labour-intensive histological sectioning of the prothorax. Thickness varied substantially across genera, ranging from 1.3 to 109.8 µm. We correlated thickness with body size, measured as head width. Our results show a strong influence of body size, but also phylogeny, because workers in ‘formicoid’ species tend to have a thinner cuticle (two exceptions). The effect of body size is also obvious in species having size-polymorphic workers. We discuss the idea that a thinner cuticle is associated with miniaturization of workers, and its ecological consequences are buffered in a social environment. We reveal that the bulk of ant species have a very thin cuticle, and this represents cost savings that may partly underlie the massive increase in colony size during adaptive radiation.
AB - The great evolutionary success of insects is partly linked to the innovation of the cuticle, which underlies a complex exoskeleton with varied functions. Cuticle development is costly because chitin and cuticular proteins require ingested nitrogen. Studying cuticle thickness on a comparative basis allows insight into the trade-off between offspring quality and quantity. This trade-off takes a particular meaning in ant workers because they are wingless, non-dispersers and generally sterile. We selected a comprehensive sample of 42 ant species (40 genera belonging to nine subfamilies) and measured cuticle thickness in workers using labour-intensive histological sectioning of the prothorax. Thickness varied substantially across genera, ranging from 1.3 to 109.8 µm. We correlated thickness with body size, measured as head width. Our results show a strong influence of body size, but also phylogeny, because workers in ‘formicoid’ species tend to have a thinner cuticle (two exceptions). The effect of body size is also obvious in species having size-polymorphic workers. We discuss the idea that a thinner cuticle is associated with miniaturization of workers, and its ecological consequences are buffered in a social environment. We reveal that the bulk of ant species have a very thin cuticle, and this represents cost savings that may partly underlie the massive increase in colony size during adaptive radiation.
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U2 - 10.1093/biolinnean/blx011
DO - 10.1093/biolinnean/blx011
M3 - Article
AN - SCOPUS:85028619854
VL - 121
SP - 556
EP - 563
JO - Biological Journal of the Linnean Society
JF - Biological Journal of the Linnean Society
SN - 0024-4066
IS - 3
ER -