Some plants and grasshoppers in hot environments have reflective body surfaces, which make their radiative heat gain, Hr, less than it would be otherwise. If you were to design a tiger beetle that could best cope with thermal conditions on black beaches (see fig. 5.4), what color would it be? The beetles on the black beaches of New Zealand are black, and the beetles on the white beaches are white. What do the matches between the color of these beetles and their beaches tell us about the relative roles of thermoregulation and predation pressure in determining beetle color? What does this example imply about the ability of natural selection to "optimize" the characteristics of organisms?