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PLOS ONE  2013 

The Morphometry of Solenopsis Fire Ants

DOI: 10.1371/journal.pone.0079559

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Size-related changes of body shape were explored in 15 polymorphic species of Solenopsis fire ants by analyzing body weight along with linear measurements of 24 body parts. Log regression slopes were used to detect changes of shape with increasing size. Within species, the largest workers weighed from about 5 to 30-fold as much as the smallest. The range of within-species body lengths varied from 1.6 mm to 4 mm. As worker size increased, the gaster tended to make up a larger proportion of body length, usually at the cost of the petiole, and rarely at the cost of head length or mesosoma length. In most, the relative volume of the gaster increased and that of the head and mesosoma decreased. Most also showed an increasingly “humped” mesosoma. For all species, head shape changed from barrel-shaped to heart-shaped as worker size increased. Antennae became relatively shorter as the relative size of the club decreased. Shape changes of the legs were more variable. S. geminata was exceptional in the extreme nature of its head shape change, and was the only species in which relative head volume increased and gaster volume decreased with increasing body size. With the exception of S. geminata, the allometric rules governing shape are remarkably similar across species, suggesting a genus-level developmental scheme that is not easily modified by evolution. It also suggests that the evolution of shape is highly constrained by these conserved growth rules, and that it acts primarily (perhaps only) through allometric growth. The results are discussed in light of the growth of imaginal discs in a resource-limited body (the pupa). The substantial variation of allometries within species and across localities is also discussed in relation to using allometric patterns to identify species or to construct phylogenies.


[1]  Huxley J (1932) Problems of relative growth, Dover Publications, Inc. 2nd edition, reprinted 1972.
[2]  Calabi P, Porter SD (1989) Worker longevity in the fire ant Solenopsis invicta: ergonomic considerations of correlations between temperature, size and metabolic rates. J. Insect Physiol. 35: 643–649.
[3]  Vogt JT, Appel AG (1999) Standard metabolic rate of the fire ant, Solenopsis invicta Buren: effects of temperature, mass, and caste. J. Insect Physiol. 45: 655–666.
[4]  Frears SL, Webb PI, Telford SR (1996) The allometry of metabolism in southern African millipedes (Myriapoda: Diplopoda). Physiol. Entomol. 21: 212–216.
[5]  Waters JS, Holbrook CT, Fewell JH, Harrison JF (2010) Allometric scaling of metabolism, growth, and activity in whole colonies of the seed-harvester ant Pogonomyrmex californicus. American Naturalist. 176: 501–510.
[6]  Tschinkel WR, Adams ES, Macon T (1995) Territory area and colony size in the fire ant, Solenopsis invicta, J. Anim. Ecol. 64: 473–480.
[7]  Castillo A, Wcislo WT (2011) The allometry of brain miniaturization in ants. Brain, behavior and evolution 77: 5–13.
[8]  Wehner R, Fukushi T, Isler K (2007) On being small: brain allometry in ants. Brain, Behavior & Evolution. 69 220–228.
[9]  Espadaler X, Gómez C (2001) Formicine ants comply with the size-grain hypothesis. Funct. Ecol. 15: 136–138.
[10]  Smith CR, Tschinkel WR (2006) The sociometry and sociogenesis of reproduction in the Florida harvester ant (Pogonomyrmex badius) J. Insect Sci. 6: 32. Available: Accessed 2013 Oct 21.
[11]  Bruce AI, Burd M (2012) Allometric scaling of foraging rate with trail dimensions in leaf-cutting ants. Proceedings of the Royal Society B. 279: 2442–2447.
[12]  H?lldobler B, Wilson EO (2008) The Superorganism: The Beauty, Elegance, and Strangeness of Insect Societies, Harvard Univ. Press.
[13]  Mosiman J, James F (1979) New statistical methods for allometry with application to Florida red-winged blackbirds. Evolution 33: 444–459.
[14]  Nijhout HF, Wheeler DE (1996) Growth models of complex allometries in holometabolous insects. Am. Nat. 148: 40–56.
[15]  Pie MR, Traniello JFA (2007) Morphological evolution in a hyperdiverse clade: the ant genus Pheidole. J. Zool. 271 99–109.
[16]  Franks NR, Norris PJ (1987) Constraints on the division of labour in ants: D’Arcy Thompson’s Cartesian transformations applied to worker polymorphism. From individual to collective behavior in social insects: les Treilles Workshop. Pasteels JM, Deneubourg JL. Basel, Birkhauser. 54: 253–270.
[17]  Sch?ning C, Kinuthia W, Franks NR (2005) Evolution of allometries in the worker caste of Dorylus army ants. Oikos 110: 231–240.
[18]  Emlen DJ (2010) Diversity in the weapons of sexual selection: Horn evolution in the beetle genus Onthophagus. In: Evolution Emerging: Essays From the Field and Laboratory From Leading Evolutionary Biologists. Ed: Losos J, Roberts & Company Publishers Pp. 149–170.
[19]  Wilson EO (1953) The origin and evolution of polymorphism in ants. Quarterly Review of Biology 28: 136–156.
[20]  Wilson EO (1971) The Insect Societies, Harvard/Belknap Univ. Press.
[21]  Wilson EO (1979) The evolution of caste systems in social insects. Proc. Am. Philos. Soc. 123: 204–210.
[22]  Wilson EO (1985) The principles of caste evolution. Experimental behavioral ecology and sociobiology: in memoriam Karl von Frisch,1886–1982. H?lldobler B, Lindauer M. Sunderland, Mass., Sinauer Associates. 31: 307–324.
[23]  Oster GF, Wilson EO (1978) Caste and Ecology in the Social Insects, Princeton Univ. Press.
[24]  Rissing SW (1984) Replete caste production and allometry of workers in the honey ant, Myrmecocystus mexicanus Wesmael (Hymenoptera: Formicidae). J. Kansas Entomol. Soc. 57: 347–350.
[25]  Busher CE, Calabi P, Traniello JFA (1985) Polymorphism and division of labor in the neotropical ant Camponotus sericeiventris Guerin (Hymenoptera: Formicidae). Ann. Entomol. Soc. Am. 78: 221–228.
[26]  H?lldobler B, Wilson EO (1990) The Ants, Harvard/Belknap Univ. Press.
[27]  Tschinkel WR (2006) The Fire Ants, Harvard/Belknap Univ. Press.
[28]  Powell S, Franks NR (2006) Ecology and the evolution of worker morphological diversity: a comparative analysis with Eciton army ants. Funct. Ecol. 20 1105–1114.
[29]  Huang MH, Wheeler DE (2011) Colony demographics of rare soldier-polymorphic worker caste systems in Pheidole ants (Hymenoptera, Formicidae). Insect. Soc. 58: 539–549.
[30]  Wheeler DE (1991) The developmental basis of worker caste polymorphism in ants. Am. Nat. 138: 1218–1238.
[31]  Tschinkel WR (1988) Colony growth and the ontogeny of worker polymorphism in the fire ant, Solenopsis invicta Buren. Behav. Ecol. Sociobiol. 22: 103–115.
[32]  Tschinkel WR (1993) Sociometry and sociogenesis in colonies of the fire ant, Solenopsis invicta during one annual cycle. Ecol. Monogr. 63: 425–457.
[33]  Feener DH Jr, Lighton JRB, Bartholomew GA (1988) Curvilinear allometry, energetics and foraging ecology: a comparison of leaf-cutting ants and army ants. Funct. Ecol. 2: 509–520.
[34]  Diniz-Filho JAF, Von Zuben CJ, Fowler HG, Schlindwein MN, Bueno OC (1994) Multivariate morphometrics and allometry in a polymorphic ant. Insectes Soc. 41: 153–163.
[35]  Tobler A, Nijhout HF (2010) Developmental constraints on the evolution of wing-body allometry in Manduca sexta. Evol. Devel. 12: 592–600.
[36]  Tschinkel WR, Mikheyev A, Storz S (2003) The allometry of worker polymorphism in the fire ant, Solenopsis invicta. J. Insect Sci. 3: 2. Available: Accessed 2013 Oct 21.
[37]  Wilson EO (1985) The sociogenesis of insect colonies. Science 228: 1489–1495.
[38]  Araujo M, Tschinkel WR (2010). Worker allometry in relation to colony size and social form in the fire ant, Solenopsis invicta. J. Insect Sci. 10: 94. Available: Accessed 2013 Oct 21.
[39]  Porter SD, Tschinkel WR (1985) Fire ant polymorphism: factors affecting worker size. Ann. Entomol. Soc. Amer. 78: 381–386.
[40]  Breed MD (2002) Allometry in the giant tropical ant, Paraponera clavata. Insectes Soc. 49: 125–128.
[41]  Kenne M, Dejean A, Fénéron R, Durand J-L (2000) Changes in worker polymorphism in Myrmicaria opaciventris Emery (Formicidae, Myrmicinae). Insectes Soc. 47: 50–55.
[42]  Carroll CR, Risch SJ (1984) The dynamics of seed harvesting in early successional communities by a tropical ant. Oecologia 61: 388–392.
[43]  Litsinger JA, Barrion AT, Soekarna D (1987) Upland rice insect pests: their ecology, importance and control, International Rice Research Institute, Manila, Philippines, IRRI Research Paper Series No. 123: 41.
[44]  Trabanino CR, Pitre HN, Andrews KL, Meckenstock DH (1989) Effect of seed size, colour, number of seeds per hill and depth of planting on sorghum seed survival and stand establishment: relationship to phytophagous insects. Trop. Agric. 66: 225–229.
[45]  Howard RA, Zanoni TA (1989) Two atypical examples of seed distribution in the Dominican Republic. Moscosoa 5: 216–225.
[46]  Tennant LE, Porter SD (1991) Comparison of diets of two fire ant species (Hymenoptera: Formicidae): solid and liquid components. J. Entomol. Sci. 26: 450–465.
[47]  Wilson EO (1978) Division of labor in fire ants based on physical castes (Hymenoptera: Formicidae: Solenopsis). J. Kansas Entomol. Soc. 51: 615–636.
[48]  Knell (2009) On the analysis of non-linear allometries. Ecol. Entomol. 34: 1–11.
[49]  Pitts JP, McHugh JV, Ross KG (2005) Cladistic analysis of the fire ants of the Solenopsis saevissima species-group (Hymenoptera: Formicidae). Zool. Scripta 34: 493–505.


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