Cephalotes

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Not to be confused with Cephalotus. ‹See Tfd›
Cephalotes
Cephalotes atratus.jpg
Cephalotes atratus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Suborder: Apocrita
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Cephalotini
Genus: Cephalotes
Latreille, 1802[1]
Type species
Formica atrata
Linnaeus, 1758
Species

many

Diversity
134 species
Synonyms

EucryptocerusKempf
ZacryptocerusWheeler
CryptocerusLatreille
CryptocephalusLowne
ParacryptocerusEmery
CyathomyrmexCreighton
CyathocephalusEmery
HarnediaSmith
HypocryptocerusWheeler
ExocryptocerusVierbergen & Scheven

Cephalotes is a Neotropical genus of ant species, all sharing the same odd head style, which tend to be mainly arboreal, and 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]

Species[edit]

Ecological specialization and evolution of a soldier caste[edit]

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 utilize multiple pre-carved nesting cavities found in the trees upon which they live, a cohort of morphologically specialized soldiers have 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 current 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 as follows:

  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 Cephalotes genus 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]

References[edit]

  1. ^ Latreille, P.A. (1802). Histoire naturelle, generale et particuliere des crustaces et des insectes. Vol. 3.. Paris: F. Dufart. 
  2. ^ Yanoviak, S. P.; Munk, Y.; Dudley, R. (2011). "Evolution and Ecology of Directed Aerial Descent in Arboreal Ants". Integrative and Comparative Biology 51 (6): 944–956. doi:10.1093/icb/icr006. PMID 21562023.  edit
  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.