Cephalotes

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.[2][3]

Not to be confused with Cephalotus.

Cephalotes
Cephalotes atratus, Soberania National Park, Panama
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Cephalotes
Latreille, 1802[1]
Type species
Formica atrata
Diversity
about 130 species
Synonyms
  • Cryptocerus Latreille, 1803
  • Cyathocephalus Emery, 1915
  • Cyathomyrmex Creighton, 1933
  • Eucryptocerus Kempf, 1951
  • Exocryptocerus Vierbergen & Scheven, 1995
  • Harnedia Smith, 1949
  • Hypocryptocerus Wheeler, 1920
  • Paracryptocerus Emery, 1915
  • Zacryptocerus Wheeler, 1911

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.[4] 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.[5]

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.[5]

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.[5] Cephalotes was ideal for the study because it is the only genus to contain extant species displaying four levels of major morphological evolution.[5] 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.[6]

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.[6]

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 [6]

Species
Cephalotes alveolatus
Cephalotes caribicus
Cephalotes coffeae
Cephalotes dieteri
Cephalotes incertus

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

References
  1. Latreille, P.A. (1802). Histoire naturelle, generale et particuliere des crustaces et des insectes (PDF). 3. Paris: F. Dufart.
  2. Yanoviak, S. P.; Munk, Y.; Dudley, R. (2011). "Evolution and Ecology of Directed Aerial Descent in Arboreal Ants" (PDF). Integrative and Comparative Biology. 51 (6): 944–956. doi:10.1093/icb/icr006. PMID 21562023.
  3. Wild, Alex (11 November 2015). "Ants use their flattened heads as doors to lock down their nests". New Scientist. Retrieved 18 November 2015.
  4. Hölldobler, B., Wilson, E. O., & Nelson, M. C. (2009). The superorganism: the beauty, elegance, and strangeness of insect societies. New York: W.W. Norton.
  5. Powell, S. (2008). Ecological specialization and the evolution of a specialized caste in Cephalotes ant. Functional Ecology, 22, 902-911.
  6. Powell, S. (2009). How ecology shapes caste evolution: linking resource use, morphology, performance and fitness in a superorganism. Evolutionary Biology, 22, 1004-1013.
  7. de Andrade, M. L.; Baroni Urbani, C. (1999). "Diversity and adaptation in the ant genus Cephalotes, past and present". Stuttgarter Beiträge zur Naturkunde. Serie B. Geologie und Paläontologie. 271: 537–538.
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