We all know hidebound individuals as inflexible as steel. Come what may, they're going to continue in their set pathways. We've found out that behavioral plasticity depends in part on genetics, and inflexibility may be deadly. Studies of a European bird now demonstrate the importance of flexibility. Back in the 1970s, eggs were laid so as to hatch out when numbers of caterpillars, the mainstay of the diet, were at their peak. Warming temperatures since then have resulted in earlier caterpillar hatching, until today, they appear some two weeks earlier.
Most of the birds stuck to the old schedule, with the result that fewer
offspring are surviving. Some females, though, early-on adapted their reproductive
timing to the climate, laying earlier in warm years and later in cool years. The
result? Twice as many surviving young as the "things have always been done this
way" group. As Emerson said, "A foolish consistency is the hobgoblin of
little minds, adored by little statesmen and philosophers and divines"—and maybe
of those Chihuahuan Desert creatures incapable of changing with the evolving
climate.
Listen to the Audio (mp3 format) as recorded by KTEP, Public Radio for the Southwest.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.