The honeybee is an invertebrate model organism that exemplifies the vertebrate molecular mechanisms detailed here. As noted by the authors, these molecular mechanisms are common to microbial species, which indicates the requirement for their ubiquitous and consistent use across life’s evolutionary continuum.

In the honeybee, what the queen eats determines her pheromone production and everything else about the colony, including the neuroanatomy of the worker bee’s brains. From this perspective, the honeybee model tells us that nutrient chemicals calibrate receptor-mediated intracellular signaling and stochastic gene expression associated with the metabolism of nutrients to pheromones in all species from microbes to man.

The pheromones standardize regulatory control of receptor-mediated intracellular signaling and stochastic gene expression required for speciation. Reciprocal bottom-up / top-down relationships among chemicals associated with the “odors” of food are directly responsible for the formation of an ecological niche, which is maintained by the epigenetic effects of pheromones in the social niche.

Changes in nutrient chemicals result in changes in the ecological niche that change the social niche by partial suppression of reproduction in individuals that don’t “smell” right because they are malnourished (or in bacterial colonies where reproduction is suppressed by pheromones and quorum sensing). The ability to acquire sufficient nutrient chemicals is genetically predisposed but also depends on conspecifics and stressors in the social niche (e.g., dominance in mammals) that might prevent access to changing supplies of existing nutrients.

Individuals with genetic predispositions that allow them to adapt to changes associated with available nutrients will reproduce in microbial species like bacteria, or pheromonally signal their reproductive fitness in yeasts or in the multicellular organisms of all other species. These nutritional and social stressors are associated with immune system dysfunction in primates as they are with nutritional deficits or excess in other species.

In species from yeasts to primates, this model allows incorporation of social science theories of individual selection, kin selection, and group selection where nutrition and food odors are as essential to individual survival as they are to the production of pheromones and species survival. In this context, olfaction and odor receptors provide a clear evolutionary trail that can be followed from unicellular organisms to insects to humans. Clearly, however, nothing about this evolutionary trail requires explanations via random mutation, since all that’s required is pre-existing genetic variation.