Cephalotes

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Cephalotes is a genus of tree-dwelling ant species from the Americas, commonly known as turtle ants. All appear to be gliding ants, with the ability to "parachute" and steer their fall so as to land back on the tree trunk rather than fall to the ground, which is often flooded.[1][2]

Ecological specialization and evolution of a soldier caste

One of the most important aspects of the genus' social evolution and adaptation is the manner in which their social organization has been shaped by environmental pressures.[3] This is particularly true of the species Cephalotes rohweri, in which an entire soldier class has evolved as a result of highly specialized nest cavity availability.[4]

Because ants within Cephalotes use multiple carved nesting cavities found in the trees upon which they live, a cohort of morphologically specialized soldiers has evolved to defend these nesting cavities. They use their unique plate-like heads to block the entrances to the nests, essentially creating a living door to the nest cavities.[4]

In one particular study, Scott Powell tested the hypothesis that "specialized use of cavities with entrances close to the area of one ant head has selected for a morphologically and behaviorally specialized soldier in Cephalotes." This was accomplished by performing comparative studies between four Cephalotes species, each representing one of the four character states of soldier evolution.[4] Cephalotes was ideal for the study because it is the only genus to contain extant species displaying four levels of major morphological evolution.[4] These character states are:

  1. No soldier present (ancestral)
  2. Soldiers present with simple domed head
  3. Soldiers present with incomplete head-disk
  4. Soldiers present with complete head disk (most advanced)

Another study by Powell examined the process by which environmental factors shape colonial castes within the worker class. However, this study focused more on how colonies adapt their caste systems to ecological factors in their environment.[5]

For the experiment, a species of the genus Cephalotes was used that displayed the highest level of soldier specialization. Three key findings regarding adaptive caste specialization were supported:

  1. Soldiers were best at defending the specific nesting resource found in nature.
  2. Colonies used only certain nests (out of all the available nests), and selected only the nesting sites that would maximize soldier performance.
  3. Soldier performance and limitations had both direct and indirect effects on colony reproduction.[5]

The results of this experiment support the concept that the most specialized soldier phenotype in Cephalotes is a result of adaptation to ecological specialization within a narrow subset of available nests.[5]

Species

File:Cephalotes coffeae CASENT0919595 dorsal.jpg
Cephalotes coffeae
File:Cephalotes incertus casent0173681 dorsal 1.jpg
Cephalotes incertus

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File:Cephalotes alveolatus SMNSDO5691 profile.jpg
Cephalotes alveolatus
File:Cephalotes caribicus SMNSDO5383 dorsal view.jpg
Cephalotes caribicus
File:Cephalotes dieteri SMNSDO4162 profile.jpg
Cephalotes dieteri

Fossil species

The fossil record is restricted to the Miocene with species recovered from both Dominican and Mexican ambers. Species were initially described by Gijsbertus Vierbergen and Joachim Scheven (1995) whole placed the species into the genera Cephalotes, Eucryptocerus, Exocryptocerus and Zacryptocerus. All four genera were revised four years later by Maria De Andrade and Cesare Baroni Urbani (1999, who synonymized them under Cephalotes.[7] The Dominican amber species: Template:Div col

  • †Cephalotes alveolatus (Vierbergen & Scheven, 1995)Script error: No such module "Check for unknown parameters".
  • †Cephalotes bloosi Baroni Urbani, 1999Script error: No such module "Check for unknown parameters".
  • †Cephalotes brevispineus De Andrade & Baroni Urbani, 1999Script error: No such module "Check for unknown parameters".
  • †Cephalotes caribicus De Andrade & Baroni Urbani, 1999Script error: No such module "Check for unknown parameters".[7]
  • †Cephalotes dieteri De Andrade & Baroni Urbani, 1999Script error: No such module "Check for unknown parameters".[7]
  • †Cephalotes hispaniolicus De Andrade & Baroni Urbani, 1999Script error: No such module "Check for unknown parameters".[7]
  • †Cephalotes integerrimus (Vierbergen & Scheven, 1995)Script error: No such module "Check for unknown parameters".
  • †Cephalotes jansei (Vierbergen & Scheven, 1995)Script error: No such module "Check for unknown parameters".
  • †Cephalotes obscurus (Vierbergen & Scheven, 1995)Script error: No such module "Check for unknown parameters".
  • †Cephalotes resinae De Andrade, 1999Script error: No such module "Check for unknown parameters".
  • †Cephalotes serratus (Vierbergen & Scheven, 1995)Script error: No such module "Check for unknown parameters".
  • †Cephalotes squamosus (Vierbergen & Scheven, 1995)Script error: No such module "Check for unknown parameters".
  • †Cephalotes sucinus De Andrade, 1999Script error: No such module "Check for unknown parameters".
  • †Cephalotes taino De Andrade, 1999Script error: No such module "Check for unknown parameters".

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The Mexican amber species:

  • †Cephalotes maya De Andrade, 1999Script error: No such module "Check for unknown parameters".
  • †Cephalotes olmecus De Andrade, 1999Script error: No such module "Check for unknown parameters".
  • †Cephalotes poinari Baroni Urbani, 1999Script error: No such module "Check for unknown parameters".
  • †Cephalotes ventriosus De Andrade, 1999Script error: No such module "Check for unknown parameters".

See also

  • Aphantochilus, a genus of crab spiders known to mimic Cephalotes species

References

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External links

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  1. ↑ Script error: No such module "Citation/CS1".
  2. ↑ a b Script error: No such module "citation/CS1".
  3. ↑ Hölldobler, B., Wilson, E. O., & Nelson, M. C. (2009). The superorganism: the beauty, elegance, and strangeness of insect societies. New York: W.W. Norton.
  4. ↑ a b c d Powell, S. (2008). Ecological specialization and the evolution of a specialized caste in Cephalotes ant. Functional Ecology, 22, 902-911.
  5. ↑ a b c Powell, S. (2009). How ecology shapes caste evolution: linking resource use, morphology, performance and fitness in a superorganism. Evolutionary Biology, 22, 1004-1013.
  6. ↑ a b c d e Script error: No such module "Citation/CS1".
  7. ↑ a b c d Script error: No such module "Citation/CS1".
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