Plant–pollinator interactions: comparison between an invasive and a native congeneric species

Comparing the reproductive success and pollination biology of an invasive plant to its rare and common native congeners: a case study in the genus Cirsium (Asteraceae)

“…contrasting a single rare and single common species; e.g. Banks 1980;Mehrhoff 1983;Fritz-Sheridan 1988;Purdy et al 1994;Baskin et al 1997;Young and Brown 1998;Lavergne et al 2004;Young et al 2007;Vanparys et al 2008; but see Karron 1987Karron , 1989, and the results of these studies have been mixed (Gaston and Kunin 1997;Bevill and Louda 1999). For example, when contrasting a widespread or invasive species to its native, rare congener, some studies have found that the rare species rely more on autogamous or asexual reproduction than common congeners (Karron 1989;Mehrhoff 1983;Purdy et al 1994; Gaston and Kunin 1997;Burne et al 2003;Lavergne et al 2004).…”

“…Congeneric studies have examined differences in the pollination biology of invasive versus native species (Brown et al 2002;Vanparys et al 2008;Harmon-Threatt et al 2009) or rare versus common species (e.g. Banks 1980;Fritz-Sheridan 1988;Karron 1989;Mehrhoff 1983;Purdy et al 1994;Young and Brown 1998).…”

Generalist <i>versus</i> Specialist Herbivores on the Invasive <i>Senecio inaequidens</i> and a Native Related Species: What Makes the Difference?

“…Germination rates are 67% for S. inaequidens and 57% for J. vulgaris [36]. Adult plants of the invasive S. inaequidens typically have several ramified flowering shoots and produce on average 122 flower heads per plant, even in the first year following germination and each flowering head bears on average 59 seeds [29,43]. The survival of J. vulgaris rosettes to the adult stage was estimated as ca.…”

“…76% [44]. There are on average 6 flowering heads per plant and 32 seeds per flowering head for J. vulgaris [29,45]. Even if the native J. vulgaris suffers from lower damage at the seedling stage and the survival rate remains high during the first year, lower flowering head production, high damage due to the specialist caterpillar and lower seed set per flowering head explain the mean seed production that only reaches 3650 seeds after two years.…”

“…It is a biennial to shortlived perennial monocarpic species which forms a rosette during the first year and a flowering shoot in the second year [27]. It is usually found in later successional stages (closed grasslands on humus-rich soil) compared to S. inaequidens, but both species can occasionally co-exist in open grasslands on dry soils [27][28][29].…”