Biology Reference
In-Depth Information
Figure 13.1.
Percentage of female Edith's checkerspot butterflies selecting the alien
plant
Plantago lanceolata
( )and the native host plant
Collinsia parviflora
()at
Schneider's Meadow, Esmeralda County, Nevada, from 1982 through 1990.
(Reprinted with permission from M. C. Singer, C. D. Thomas, and C. Parmesan.
1993. Rapid human-induced evolution of insect-host associations.
Nature
366:681-683. © 1993 Nature Publishing Group.)
in 1990 (fig. 13.1). Greenhouse-reared checkerspots showed this same
preference trend, strongly indicating that the preference shift was genetic.
In addition, by 1990, individual checkerspots were found that completely
rejected their ancestral
Collinsia
host, refusing to oviposit on
Collinsia
even
when confined with the plant for several days. In California, populations
of Edith's checkerspot in many coastal grassland areas have apparently
made a switch to ribwort plantain, as well (Thomas and Singer 1998).
Preferences of female checkerspots for ribwort plantain are also corre-
lated with success of their larvae on this plant.The stronger the preference
of the female for ribwort plantain, the faster was the growth of offspring
on plantain (Singer et al. 1988). Ribwort plantain, a perennial, remains
green throughout the summer, whereas
Collinsia
, an annual, dies by mid-
summer. Therefore, larval survival is much higher on ribwort plantain
(Singer et al. 1994).Thus, preference for an alien plant was coupled with
