The Social Life of C. elegens

Humans, dogs, lions, fish and birds have a propensity for aggregation., ie. living in tribes, packs, prides, schools and flocks. And C.elegens are no different; they live in colonies like that shown above.

And so it is they we see social behavior even in a worm with exactly 959 somatic cells and another 1000–2000 germ cells (sperm and eggs) but lacking a brain like that of humans.What could possible induce them to form social groups as do humans, dogs, lions, fish and birds?

C. elegens live primarily in decaying in decaying plant matter and sustain themselves primarily with bacteria living it it. But these bacteria are spread through the decaying plant matter and are clumped together. Rather the C. elegens colonies form near the outer boundries of it.

Part of the answer lies in oxygen levels in the environment. C. elegens have a biological preference for certain oxygen levels which are detected by both from both amphid chemosensory neurons and internal gas-sensing neuron. They especially avoid high oxygen levels and clumping enables them lower the oxygen levels in their more closed shared share environment. That is, they are attracted to the lower oxygen levels encounted in colonies.

But C. elegens emit any number of pheromones with which they communicate with each other and regulates their behavior. Hermaphrodites produce at least two distinct chemical classes of sex pheromone that can attract or retain males, and that males produce compounds that have behavioral and physiological effects on hermaphrodites.Others affect aspects of worm physiology, including sex, developmental stage, and nutritional status, as well as the identification of mechanisms underlying this variation. These can have multiple behavioral effects, inducing aggregation, attraction/retention, aversion, and promotion of foraging, depending on their chemical structures, concentrations, and interactions. Moreover, the response of the receiver depends on its sex, stage, previous experience, genetic background, and other factors. Yes, even C. elegens have "Mars and Venus" differences in social behavior . 

And so it is that the social behavior of C. elegens is affected by genetics (male vs, hermaphrodite), the environment,  sensory inputs (touch, chemicals and pheromones), and communication between individuals in the colony.  And, indeed, behavior and socialist interaction of humans, dogs, lions, fish and birds and  is regulated by exactly these same aspect with the difference being in their complexity. In the end, it is all just chemistry following the inviolate laws of nature.