Figure 1. Relationship between normalized metabolic rate and body mass for unitary organisms and whole colonies (from Hou et al 2010)
The notion that insect colonies and their constituent individuals are analogous to multicellular organisms and their constituent cells has been a controversial idea for decades. Is it useful, for example, to think of an ant colony as a single individual? Do superorganisms really exist as coherent entities? Or do insect colonies function more as aggregations of individuals?
Last week, PNAS published the first application of empirical methods to test the superorganism concept. This is a significant paper. The researchers, led by Chen Hou, asked whether the set of relationships between mass, energy, and reproduction that govern multicellular organisms show the same patterns when measured across whole insect colonies.
The answer, in most cases, was a resounding Yes: social insect colonies grow and breathe just like regular organisms.
source: Hou, C., Kaspari, M., Vander Zanden, H. B., Gillooly, J. F. 2010. Energetic basic of colonial living in social insects. PNAS early edition.
One might also wonder, given Hou et al.'s results, why ants and termites are still so dang abundant and (bio)massive? I have an idea .
Yes, it is a shameless plug. No, I'm not ashamed of myself (at least not for this).
Oops, no linking allow. I forgot. Oh well.
Cool- thanks for pointing out Josh. I'd not seen it- looks highly relevant.
I saw that last week...pretty cooooooooool.
"Yes: social insect colonies grow and breathe just like regular organisms.
As opposed to what?
As opposed to a single social insect. A social insect colony in some respects behaves more as a single organism than does a single worker ant.
For example, a worker ant invests almost no energy in reproductive organs. If we were to plot it in a regression of mass versus reproductive investment among solitary organisms, the ant would be an extreme outlier. Same for a queen ant that puts relatively more mass into reproduction than solitary organisms of her same mass.
Only when the workers and queens are considered together as a colony does the scaling relationship resemble that of nonsocial organisms.