Limits
There are physical limits on the practical size of organisms employing pheromones, because at small sizes pheromone diffuses away from the source organism faster than it can be produced, and a sensible concentration accumulates too slowly to be useful. So bacteria are too small to use pheromones as sex attractants on an individual basis but do use them to determine the local population density of similar organisms and control behaviors that take more time to execute (quorum sensing or to promote Natural competence for Transformation (genetics), i.e. sexual gene transfer). In similar manner, the simple animals rotifers are, it appears, also too small for females to lay down a useful trail, but in the slightly-larger copepods the female leaves a trail that the male can follow.
Read more about this topic: Pheromone
Famous quotes containing the word limits:
“An art whose limits depend on a moving image, mass audience, and industrial production is bound to differ from an art whose limits depend on language, a limited audience, and individual creation. In short, the filmed novel, in spite of certain resemblances, will inevitably become a different artistic entity from the novel on which it is based.”
—George Bluestone, U.S. educator, critic. “The Limits of the Novel and the Limits of the Film,” Novels Into Film, Johns Hopkins Press (1957)
“The limits of my language mean the limits of my world.”
—Ludwig Wittgenstein (1889–1951)
“The great ship, Balayne, lay frozen in the sea.
The one-foot stars were couriers of its death
To the wild limits of its habitation.
These were not tepid stars of torpid places
But bravest at midnight and in lonely spaces,
They looked back at Hans’ look with savage faces.”
—Wallace Stevens (1879–1955)