Insectes Sociaux

, Volume 57, Issue 4, pp 441–452 | Cite as

Community-level interactions and functional ecology of major workers in the hyperdiverse ground-foraging Pheidole (Hymenoptera, Formicidae) of Amazonian Ecuador

  • A. L. Mertl
  • M. D. Sorenson
  • J. F. A. Traniello
Research Article


Ants of the genus Pheidole are abundant and hyperdiverse, particularly in Neotropical rainforests. Very little is known, however, about the degree of ecological and behavioral differentiation of coexisting species comprising Pheidole communities. Additionally, the ecological role of the major worker subcaste, thought to be significant to the diversification of Pheidole, is poorly understood. We investigated the ecology and behavior of a ground-foraging Pheidole community of at least 56 species in Amazonian Ecuador. Pheidole species differed strongly in tolerance to flooding, nest site usage, foraging range, major worker foraging, and control of baits, but not in daily activity or ability to discover baits. A molecular phylogeny based on mitochondrial DNA was characterized by poorly resolved basal relationships and long terminal branches, suggesting an ancient diversification of many Pheidole lineages. Comparison of well-supported sister species suggests that both phylogenetic history and ecologically induced differentiation contribute to interspecific variation in Amazonian Pheidole. Ground-nesting species had larger major workers than twig-nesting species, whereas dominant species with stronger recruitment had a higher proportional abundance of major workers at baits. Variation among species suggests the presence of behavioral groups within the Amazonian Pheidole community that appear to segregate according to nest site usage and/or tolerance to flooding disturbance. Our results suggest an important role for major worker differentiation in the diversification of Pheidole.


Formicidae Caste evolution Species coexistence Flooding Molecular phylogeny 



We thank the directors and staff of TBS for assistance and support in the field. We thank Clifton Meek, Megan Johnson, Brian Henry, Noah Reid, Scott Appleby, Elise Koncsek, Frank Azorsa Salazar and Wendy Mertl for assistance in the field, and Winston McDonald for laboratory assistance. We thank Dr. Kari Ryder Wilkie for specimen donations. We are very grateful to Stefan Cover for confirming Pheidole identifications and to Dr. Gary Alpert for instruction on digital imaging. We thank Dr. Marcio Pie and Jeff Tetrault for advice and assistance with sequencing methods, and Dr. Corrie Moreau for help with PCR primers. This work was funded by a National Science Foundation Graduate Research Fellowship awarded to ALM, and NSF Grant IOB 0725013 to J.T. Voucher samples were collected and transported under permit 017-IC-FA-PNY-MA issued to A.L.M. by the Ecuadorian Ministry of the Environment and this work complied with all current laws of Ecuador and the United States of America.


  1. Adis J. 1997. Survival strategies of terrestrial invertebrates in central Amazonian inundation forests: A response to long-term flooding. Acta amazon. 27: 43-54Google Scholar
  2. Andersen A.N. 2008. Not enough niches: Non-equilibrial processes promoting species coexistence in diverse ant communities. Austral Ecol. 33: 211-220Google Scholar
  3. Benjamini Y. and Hochberg Y. 1995. Controlling the false discovery rate: A practical and powerful approach to multiple testing. J. R. Stat. Soc. Ser. B. 57: 289-300Google Scholar
  4. Bestelmeyer B.T. 2000. The trade-off between thermal tolerance and behavioural dominance in a subtropical South American ant community. J. Anim. Ecol. 69: 998-1009Google Scholar
  5. Brose U., Martinez N.D. and Williams R.J. 2003. Estimating species richness: Sensitivity to sample coverage and insensitivity to spatial patterns. Ecology 84: 2364-2377Google Scholar
  6. Brown J.J. and Traniello J.F.A. 1998. Regulation of brood-care behavior in the dimorphic castes of the ant Pheidole morrisi (Hymenoptera: Formicidae): Effects of caste ratio, colony size, and colony needs. J. Insect Behav. 11: 209-219Google Scholar
  7. Burnham K.P. and Overton W.S. 1979. Robust estimation of population size when capture probabilities vary among animals. Ecology 60: 927-936Google Scholar
  8. Byrne M.M. 1994. Ecology of twig-dwelling ants in a wet lowland tropical forest. Biotropica 26: 61-72Google Scholar
  9. Chiotis M., Jermiin L.S. and Crozier R.H. 2000. A molecular framework for the phylogeny of the ant subfamily Dolichoderinae. Mol. Phylogenet. Evol. 17: 108-116Google Scholar
  10. Clarke K.R. 1993. Nonparametric multivariate analysis of changes in community structure. Austral Ecol. 18: 117-143Google Scholar
  11. Colwell R.K. 2005. EstimateS: Statistical Estimation of Species Richness and Shared Species from Samples. 7.5 ednGoogle Scholar
  12. Davidson D.W. 1998. Resource discovery versus resource domination in ants: A functional mechanism for breaking the trade-off. Ecol. Entomol. 23: 484-490Google Scholar
  13. Delsinne T. Roisin Y. and Leponce M. 2007. Spatial and temporal foraging overlaps in a Chacoan ground-foraging ant assemblage. J. Arid Environ. 71: 29-44Google Scholar
  14. Detrain C. 1990. Field study on foraging by the polymorphic ant species, Pheidole pallidula. Insect. Soc. 37: 315-332Google Scholar
  15. Droual R. 1983. The organization of nest evacuation in Pheidole desertorum Wheeler and P. hyatti Emery (Hymenoptera: Formicidae). Behav. Ecol. Sociobiol. 12: 203-208Google Scholar
  16. Felsenstein J. 1985. Phylogenies and the comparative method. Am. Nat. 125: 1-15Google Scholar
  17. Fowler H.G. 1984. Recruitment, group retrieval and major worker behavior in Pheidole oxyops. Rev. Bras. Biol. 44: 21-24Google Scholar
  18. Fowler H.G. 1993. Relative representation of Pheidole (Hymenoptera: Formicidae) in local ground ant assemblages of the Americas. Anales Biol. 19: 29-37Google Scholar
  19. Gordon D.M. 1992. How colony growth affects forager intrusion between neighboring harvester ant colonies Behav. Ecol. Sociobiol. 31: 417-427Google Scholar
  20. Gotelli N.J. and Ellison A.M. 2004. A Primer of Ecological Statistics. Sinauer Associates, Inc. Sunderland, MA. 510 ppGoogle Scholar
  21. Hammer Ø., Harper D.A.T. and Ryan P.D. 2001. PAST: Paleological Statistics Software Package for Education and Data Analysis. Palaeontologia Electronica 4: 9 ppGoogle Scholar
  22. Harvey P.H. and Pagel M.D. 1991. The Comparative Method in Evolutionary Biology. Oxford University Press, Oxford, UK. 239 ppGoogle Scholar
  23. Hölldobler B. and Möglich M. 1980. The foraging system of Pheidole militicida (Hymenoptera: Formicidae). Insect. Soc. 27: 237-264Google Scholar
  24. Huelsenbeck J.P. and Ronquist F. 2001. MRBAYES: Bayesian inference of phylogenetic trees. Bioinformatics 17: 754-755Google Scholar
  25. Kaspari M. 1996a. Testing resource-based models of patchiness in four Neotropical litter ant assemblages. Oikos 76: 443Google Scholar
  26. Kaspari M. 1996b. Worker size and seed size selection by harvester ants in a Neotropical forest. Oecologia 105: 397-404Google Scholar
  27. Kaspari M. and Vargo E. 1995. Does colony size buffer environmental variation? Bergmann’s rule and social insects. Am. Nat. 145: 610-632Google Scholar
  28. Kaspari M., Yuan M. and Alonso L. 2003. Spatial grain and the causes of regional diversity gradients in ants. Am. Nat. 161: 459-477Google Scholar
  29. King J.R., Andersen A.N. and Cutter A.D. 1998. Ants as bioindicators of habitat disturbance: Validation of the functional group model for Australia’s humid tropics. Biodivers. Conserv. 7: 1627-1638Google Scholar
  30. Levey D.J. and Byrne M.M. 1993. Complex ant–plant interactions: Rain-forest ants as secondary dispersers and post-dispersal seed predators. Ecology 74: 1802-1812Google Scholar
  31. Levings S.C. and Franks N.R. 1982. Patterns of nested dispersion in a tropical ground ant community. Ecology 63: 338-344Google Scholar
  32. Longino J.T., Coddington J. and Colwell R.K. 2002. The ant fauna of a tropical rain forest: Estimating species richness three different ways. Ecology 83: 689-702Google Scholar
  33. Mertl A.L., Ryder Wilkie K.T. and Traniello J.F.A. 2009. Impact of flooding on the species richness, density and composition of Amazonian litter-nesting ants. Biotropica 41: 633-641Google Scholar
  34. Mertl A.L. and Traniello J.F.A. 2009. Behavioral evolution in the major worker subcaste of twig-nesting Pheidole (Hymenoptera: Formicidae): Does morphological specialization influence task plasticity? Behav. Ecol. Sociobiol. 63: 1411-1426Google Scholar
  35. Moreau C.S. 2008. Unraveling the evolutionary history of the “hyperdiverse” ant genus Pheidole (Hymenoptera: Formicidae). Mol. Phylogenet. Evol. 48: 224-239Google Scholar
  36. Palmer T.M. 2004. Wars of attrition: Colony size determines competitive outcomes in a guild of African acacia ants. Anim. Behav. 68: 993-1004Google Scholar
  37. Patel A.D. 1990. An unusually broad behavioral repertory for a major worker in a dimorphic ant species: Pheidole morrisi (Hymenoptera, Formicidae). Psyche 97: 181-192Google Scholar
  38. Pie M.R. 2007. Morphological Evolution in a Hyperdiverse Clade: The Ant Genus Pheidole. Ph.D. Dissertation. Boston University, Boston, MA. 129 ppGoogle Scholar
  39. Pie M.R. and Traniello J.F.A. 2007. Morphological evolution in a hyperdiverse clade: The ant genus Pheidole. J. Zool. 271: 99-109Google Scholar
  40. Pizo M.A. 2007. The use of seeds by a twig-dwelling ant on the floor of a tropical rain forest. Biotropica 40: 119-121Google Scholar
  41. Rambaut A. 2007. Se-al: Application for creating multiple sequence alignments from nucleotide and amino acid sequences. 2.0 ednGoogle Scholar
  42. Rasband W.S. 2007. ImageJ. U.S. National Institutes of Health, Bethesda, Maryland. 1.38 ednGoogle Scholar
  43. Ryder Wilkie K.T., Mertl A.L. and Traniello J.F.A. 2007. Biodiversity below ground: Probing the subterranean ant fauna of Amazonia. Naturwissenschaften 94: 725-731Google Scholar
  44. Ryder Wilkie K.T., Mertl A.L. and Traniello J.F.A. 2009. Diversity of ground-dwelling ants in primary and secondary forests in Amazonian Ecuador. Myrmecol. News 12: 139-147Google Scholar
  45. Ryti R.T. and Case T.J. 1992. The role of neighborhood competition in the spacing and diversity of ant communities. Am. Nat. 139: 355-374Google Scholar
  46. Sempo G. and Detrain C. 2004. Between-species differences of behavioural repertoire of castes in the ant genus Pheidole: A methodological artefact? Insect. Soc. 51: 48-54Google Scholar
  47. Tobin J.E. 1995. Ecology and Diversity of Neotropical Rainforest Canopy Ants. Ph.D. Dissertation. Harvard University, Cambridge, MA. 149 ppGoogle Scholar
  48. Traniello J.F.A. 1989. Foraging strategies of ants. Annu. Rev. Entomol. 34: 191-210Google Scholar
  49. Wilson E.O. 1984. The relation between caste ratios and division of labor in the ant genus Pheidole (Hymenoptera: Formicidae). Behav. Ecol. Sociobiol. 16: 89-98Google Scholar
  50. Wilson E.O. 1986. The organization of flood evacuation in the ant genus Pheidole (Hymenoptera: Formicidae). Insect. Soc. 33: 458-469Google Scholar
  51. Wilson E.O. 2003. Pheidole in the New World: A Dominant, Hyperdiverse Ant Genus. Harvard University Press, Cambridge, MA. 794 ppGoogle Scholar

Copyright information

© International Union for the Study of Social Insects (IUSSI) 2010

Authors and Affiliations

  • A. L. Mertl
    • 1
  • M. D. Sorenson
    • 1
  • J. F. A. Traniello
    • 1
  1. 1.Biology DepartmentBoston UniversityBostonUSA

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