Reproductive ecology of the endemic Lecocarpus pinnatifidus (Asteraceae) in an isolated population in the Galápagos Islands

Abstract

Lecocarpus pinnatifidus is an endemic member of the Asteraceae occurring on only one island in the Galápagos archipelago. The capitula are large with female ray florets and male disc florets. They are self-compatible but this study suggests fruit set is pollen limited. Visits from Xylocopa darwini and other larger insect pollinators are rare, and small insects seem to be the main pollinators. Small insects carry few pollen grains and most likely mediate self-pollinations. Self-compatibility and seed set after selfing are the most common reproductive strategy in the Galápagos Islands and L. pinnatifidus seemingly fits well into this group.

Pollination biology of a night-flowering Galápagos endemic,Ipomoea habeliana(Convolvulaceae)

“…The ability of I. habeliana to produce fruit via autogamous autogamy is a trait shared by many island angiosperms (Rick, 1966; McMullen, 1987, 1990, 2007; Barrett, 1996; Nielsen et al. , 2000; Philipp et al. , 2004).…”

“…The absence of hawk moths early in the history of the archipelago may also explain why I. habeliana is the only extant endemic member of the genus. If other early colonists were strictly xenogamous, they probably would not have been able to establish themselves because of the lack of faithful pollinators (Linsley, 1966; Linsley, Rick & Stephens, 1966; McMullen, 1993; Nielsen, Philipp & Siegismund, 2002; Philipp et al. , 2004).…”

“…In both cases, the difference in fruit set is easily explained by the fact that all stigmas undergoing facilitated autogamy and cross-pollination receive abundant pollen via hand transfer, whereas a portion of the stigmas undergoing autonomous autogamy undoubtedly receive either no pollen or insufficient pollen to stimulate fruit development. The ability of I. habeliana to produce fruit via autogamous autogamy is a trait shared by many island angiosperms (Rick, 1966;McMullen, 1987McMullen, , 1990McMullen, , 2007Barrett, 1996;Nielsen et al, 2000;Philipp et al, 2004). There is also a trend towards more fruit production via facilitated autogamy and cross-pollination than via open pollination.…”

“…The study of breeding systems in island plants has proved to be a productive field of research over the past 25 years, both in the Galápagos archipelago (McMullen, 1987, 1990, 1994, 2007; Elisens, 1989; Nielsen et al. , 2000; Philipp et al. , 2004) and elsewhere (Sakai et al.…”

“…The study of breeding systems in island plants has proved to be a productive field of research over the past 25 years, both in the Galápagos archipelago (McMullen, 1987(McMullen, , 1990(McMullen, , 1994(McMullen, , 2007Elisens, 1989;Nielsen et al, 2000;Philipp et al, 2004) and elsewhere (Sakai et al, 1995;Barrett, 1996;Bernardello et al, 2001;Farwig, Randrianirina & Voigt, 2004;Anderson et al, 2006). Such studies in the Galápagos have been encouraged and facilitated by the accompanying increase in knowledge of the insect fauna (Peck, 1991;Landry & Rindge, 1995;Roque-Albelo & Landry, 2001;Roque-Albelo, 2004;Landry & Roque-Albelo, 2006).…”