Sunday, May 16, 2021


 The little fifty gallon pond is now in its third season.  This is the earliest in the year that I've spotted an amphibian.

Tuesday, May 04, 2021

Ant transmutations

 Ever since I read about Indian jumping ants in the Atlantic, I've been wondering how this works (epic-)genetically speaking.

When the queen of an Indian jumping ant colony dies:

Within hours of their queen’s death, female workers will begin to joust, fencing with their antennae, and nipping at each other’s heads. These dominance tournaments can last for more than a month, until, at long last, a dozen or so champions triumph. While the losers slink away to resume their workerly duties, the victors cast aside their former peasant status and become a new class of pseudo-royals called gamergates (no, not that kind). The queen phase of the colony ends, and the gamergate phase begins: Monarchy transforms into oligarchy, and new gamergates step up as each generation dies. The consequences of these tiny tussles range from the sociopolitical to the molecular. In earning the title of gamergate (pronounced gamm-ər-gayt), a female ant gains nearly exclusive rights to her colony’s reproductive responsibilities; she is among the very few of her sisters that can fertilize their eggs with the sperm of their brothers, the only available males. The transition rewires worker ants, altering their behavior and physiology until they become docile, nursery-bound “egg-laying machines,” Penick said. Gamergates stop leaving the nest. They lose their food-foraging chops and the will to hunt, relegating themselves instead to the darkness of their underground chambers, where they churn out eggs. They feast exclusively on the paralyzed prey served to them by workers. Normally these ants leap at assailants when disturbed—the classic “jumping” behavior that earned the species its name—but when confronted by intruders, gamergates cower and hide. Even their bodies reprioritize. The ants’ life span extends from six or seven months to three years or more. Their venom glands recede, and their ovaries swell to about five times their original size; the ants become, in a sense, perpetually pregnant. In perhaps the most astounding change of all, the ants’ brain shrinks by about 20 to 25 percent in volume when they become gamergates. (For humans, that’d be the rough equivalent of losing a hunk of brain the size of two tennis balls.) The downsizing isn’t uniform: The insects appear to selectively jettison bits of their brain devoted to hunting, foraging, spatial mapping, and the anty equivalent of critical thinking—a move that likely reroutes precious bodily resources to the ovaries. Jumping-ant brains are already quite small, about a tenth of a cubic millimeter in volume. But brain tissue is “very energetically costly,” Floria Mora-Kepfer Uy, an entomologist at the University of Rochester, told me. And when the future of the colony is at stake, every calorie counts. “There’s a trade-off between reproduction and cognition,” Uy said. It is a heavy crown to wear atop a newly lightened head.
But what is even stranger is that the changes are reversible:
In a new paper published today in Proceedings of the Royal Society B, Penick, Liebig, and their colleagues report that the gamergate transformation is entirely reversible, down to the mind-boggling changes the ants’ brain tissue undergoes. When the researchers isolated gamergates from their colonies, depriving them of the social signals needed to maintain their über-fertile status, then reintroduced them to their peers, the ants rapidly regressed into workers. Their ovaries shriveled, leaving room for their venom glands to grow; their brains ballooned out. They reacquired their aggressive fighting acumen, and would once again jump when provoked. Functionally sterilized and juiced back up with intellect, they became once again indistinguishable from their commoner kin.
It must be that various genes are turned off and on. How much (or little) of this epigenetic flexibility is retained in homo sapiens?