Research on evolution typically focuses on the importance of social interactions, including parent-offspring bonding, competition for resources, and courtship and mating rituals. But Nathan Bailey at the University of St Andrews in Scotland and his colleague Allen Moore at the University of Georgia realized that isolation must then be an extreme condition worthy of equal attention.
“The environment an animal experiences can influence which genes it expresses, when, and how much, so conditions of social isolation might cause expression of different traits,” says Bailey. “This in turn could affect responses to natural selection in terms of survival and reproduction, which has evolutionary consequences. For some species, it might even mean that temporary social isolation is favorable.”
The invasive cane toad Rhinella marina of Australia, for instance, will venture off on its own to expand into new territory, but the isolation this causes drives an uncharacteristically strong attraction to members of the opposite sex upon the toad’s return to a social environment. This boosts the likelihood of both communication and successful mating, which are necessary for survival as the toads expand into new regions. This means that social isolation itself provides the conditions for natural selection to favor adaptations to cope with it.
“To understand how short-term social isolation experienced by individual animals translates into trans-generational evolutionary impacts for a larger population, we need a number, something measurable that we can compare across different species and contexts,” says Bailey. “After all, isolation that has negative effects for one species could in fact be beneficial for another.” Paper. (open access) – Bailey & Moore. Evolutionary Consequences of Social Isolation. Trends in Ecology and Evolution, 2018 DOI: 10.1016/j.tree.2018.05.008 More.
The key word in this story is “might.” The researchers “might” be onto something and their thesis merits further study – particularly for the purposes of managing the destructive cane toad. But they mention no evidence of significant, long-term evolutionary change in the toad population as a result of the popularity of a “new guy in town.”
See also: Is the recently cited hybrid dolphin-whale a “new species”? No. The concept of speciation in general is a huge mess (see links below), principally because it is taken as confirmation of explicitly Darwinian evolution (you know, On the Origin of Species and all that… ). It’s the same sort of problem as when a religious sect seeks to confirm a miracle. They degrade the definition and damage the concept.
Can sex explain evolution?