Cephalotes

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] Because ants within Cephalotes use nesting cavities found in the trees upon which they live, most species have evolved a cohort of morphologically specialized soldiers, which defend these nesting cavities^[5]. They use their distinctive plate-like heads to block the entrances to the nests, essentially creating a living door to the nest cavities.^[5]

The relationship between soldier head morphology and nest defense has been investigated^[5]. Whereas species with less-specialized soldiers engage in both active and passive (blocking) behaviors to defend nests, species with more-specialized soldiers engage in only passive, blocking defense behavior^[5].

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]

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