Não aparentados herdam recursos de colônia em um cupim primitivo

Nonrelatives inherit colony resources in a primitive termite

Philip M. Johns a, Kenneth J. Howard a, Nancy L. Breisch b, Anahi River ab and Barbara L. Thorne b,1
+ Author Affiliations

aBiology Program, Bard College, Annandale-on-Hudson, NY 12504; and

bDepartment of Entomology, University of Maryland, College Park, MD 20742

Communicated by Edward O. Wilson, Harvard University, Cambridge, MA, August 18, 2009 (received for review April 2, 2009)

Abstract

The evolution of eusociality, especially how selection would favor sterility or subfertility of most individuals within a highly social colony, is an unresolved paradox. Eusociality evolved independently in diverse taxa, including insects (all ants and termites; some bees, wasps, thrips, and beetles), snapping shrimp, and naked mole rats. Termites have received comparatively less focus than the haplodiploid Hymenoptera (ants, bees, and wasps); however, they are the only diploid group with highly complex colonies and an extraordinary diversity of castes. In this study we staged encounters between unrelated colonies of primitive dampwood termites, Zootermopsis nevadensis, mimicking natural meetings that occur under bark. During encounters, kings and/or queens were killed and surviving members merged into one colony. After encounters, members of both unrelated colonies cooperated as a single social unit. We determined the colony of origin of replacement reproductives that emerged after death of kings and/or queens. Here, we document that replacement reproductives developed from workers in either or both original colonies, inherited the merged resources of the colony, and sometimes interbred. Because this species shares many characteristics with ancestral termites, these findings demonstrate how ecological factors could have promoted the evolution of eusociality by accelerating and enhancing direct fitness opportunities of helper offspring, rendering relatedness favoring kin selection less critical.

ancestral termites evolution of eusociality replacement reproductives selection Zootermopsis

Footnotes

1To whom correspondence should be addressed. E-mail: bthorne@umd.edu

Author contributions: P.M.J., K.J.H., N.L.B., and B.L.T. designed research; P.M.J., K.J.H., N.L.B., A.R., and B.L.T. performed research; P.M.J., K.J.H., N.L.B., A.R., and B.L.T. analyzed data; and P.M.J., K.J.H., N.L.B., and B.L.T. wrote the paper.

The authors declare no conflict of interest.

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