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Abstract: Despite empirical evidence for a positive relationship between dispersal and self‐fertilization (selfing), theoretical work predicts that these traits should always be negatively correlated, and the Good Coloniser Syndrome of high dispersal and selfing (Cf. Baker's Law) should not evolve. Critically, previous work assumes that adult density is spatiotemporally homogeneous, so selfing results in identical offspring production for all patches, eliminating the benefit of dispersal for escaping from local resource competition. We investigate the joint evolution of dispersal and selfing in a demographically structured metapopulation model where local density is spatiotemporally heterogeneous due to extinction‐recolonization dynamics. Selfing alleviates outcrossing failure due to low local density (an Allee effect) while dispersal alleviates competition through dispersal of propagules from high‐ to low‐density patches. Because local density is spatiotemporally heterogeneous in our model, selfing does not eliminate heterogeneity in competition, so dispersal remains beneficial even under full selfing. Hence the Good Coloniser Syndrome is evolutionarily stable under a broad range of conditions, and both negative and positive relationships between dispersal and selfing are possible, depending on the environment. Our model thus accommodates positive empirical relationships between dispersal and selfing not predicted by previous theoretical work and provides additional explanations for negative relationships. [ABSTRACT FROM AUTHOR]

Ability to self-fertilize is correlated with invasiveness in several introduced floras, and this has been attributed to its mitigating effect on fecundity when pollinator visitation and mate availability are inadequate. Cross-pollination opportunities are expected to be most limited in isolated individuals and small populations, both typical of the leading edge of an invasion. Thus, self-pollination may promote invasion in part by mitigating pollen-limitation Allee effects., We used emasculation and pollen supplementation experiments to test whether the importance of self-pollination for fecundity increased as plant abundance decreased and isolation increased, in the hawkmoth-pollinated and autonomously self-pollinating invasive lily Lilium formosanum, in its introduced range in KwaZulu-Natal, South Africa. As inbreeding depression is negligible in these populations, seed production through selfing is likely to be demographically important., In naturalized populations of L. formosanum, varying in size and degree of isolation, emasculation reduced seed production by two-thirds, indicating strong reliance on self-fertilization for fecundity due to inadequate pollinator visitation. However, this was not related to population size and was only greater for more isolated populations in one of the 3 years in which the experiment was carried out. Pollen supplementation experiments showed that pollen limitation was low - 12% on average - and significant in only one of 3 years, demonstrating that autonomous self-pollination was highly effective., In artificial arrays, consisting of plants placed inside naturalized populations or in pairs isolated (3-702 m) from populations, the effect of emasculation on fecundity was greater in isolated plants than those inside the population in one of two populations. Isolation reduced fecundity when emasculated plants were placed next to a second emasculated plant, but not when emasculated plants were partnered with an intact plant, from which they could receive pollen., We conclude that self-fertilization in L. formosanum compensates for inadequate pollinator visitation across all levels of population size and for a pollen-limitation Allee effect due to decreased mate availability in isolated plants, and may thus play an important role in invasion. [ABSTRACT FROM AUTHOR]

Generalized pollination systems and autonomous self-fertilization are traits that have been linked with plant invasiveness. However, whether specialized pollination requirements pose a significant barrier to plant invasions is not yet clear. Likewise, the contribution of pollinators to the fecundity of facultatively self-pollinating invasive plant species is poorly understood. We addressed these issues using the self-compatible and autonomously self-pollinating Lilium formosanum, which also has large, showy flowers that are adapted for pollination by hawk moths. We investigated the pollination of this lily-which is indigenous to Taiwan-in KwaZulu-Natal, South Africa, where it is invasive. The long-tongued hawk moth Agrius convolvuli was identified as the primary pollinator on the basis of field observations, pollen load analysis, presence of lepidopteran scales on stigmas, and higher seed production in emasculated flowers exposed at night than in those exposed during the day. Remarkably, this moth is native to much of the Old World, including Taiwan and South Africa. Autonomous self-pollination resulted in seed production, but at a reduced level relative to the seed production of open- and hand-pollinated flowers, which was significant in one out of two populations examined. Thus, pollinators potentially contribute to invasion by increasing seed production and genetic variability through cross-pollination, although contributions of pollinators to seed set versus that of autonomous self-pollination may vary between populations. We conclude that specialized pollination requirements do not present a barrier to invasions when plants are specialized to pollinators or pollinator functional groups with very wide distributions. [ABSTRACT FROM AUTHOR]