Blochmannia influences head width and melanization in the Carpenter ant Camponotus floridanus

Many microorganisms have co-evolved with their hosts, creating a mutualistic relationship between the host and symbiont. The carpenter ant Camponotus floridanus has an endosymbiotic relationship with the bacterium Blochmannia floridanus, which provides important nutrients to its host. However, the omnivorous nature of these ants suggests that Blochmannia provides benefits that are more than just alimentary. Here, I test the hypotheses that Blochmannia influences melanization and ant size by treating ants with antibiotics. My results show that Blochmannia increases the melanization process of ant development and increases head width.  These results suggest that Blochmannia provide more than just dietary benefits to their host; the bacteria can influence immune defense and development of Camponotus. These findings further support that this tight-knit relationship is even more evolutionarily adaptive then once thought and also sheds light on how Camponotus lives in such a dangerous and pathogen-filled environment yet continues to be one of the most successful ant species in the world.