How a heterostylous plant species responds to life on remote islands: a comparative study of the morphology and reproductive biology of Waltheria ovata on the coasts of Ecuador and the Galápagos Islands

Bramow, Christina; Hartvig, Ida; Larsen, Signe Brandt; Philipp, Marianne

doi:10.1007/s10682-012-9588-9

Cited by 27 publications

(20 citation statements)

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“…Tobago and Trinidad, Spears 1987; Izu Islands and Japan, Inoue, Maki & Masuda 1996). Additionally, some studies have shown the breakdown of outcrossing systems such as the evolution of self-pollination in insular plant populations (Barrett 1985;Inoue, Maki & Masuda 1996;Bramow et al 2013). For example, in a comparison of Brazilian and Jamaican populations of tristylous Eichhornia paniculata, Barrett (1985) determined that individuals of mainland origin presented the expected three floral morphs, whereas individuals of insular origin had exclusively mid-styled, self-pollinating flowers.…”

Section: Introductionmentioning

confidence: 99%

A comparison of reproductive strategies between island and mainland Caribbean Gesneriaceae

et al. 2015

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Summary The evolution of self‐pollination has long been considered an adaptive strategy to cope with low or variable pollinator service; however, alternative reproductive strategies, such as generalized pollination (>1 pollinator functional group), may also ensure plant reproductive success in environments with inadequate pollinator visitation. Island–mainland systems provide ideal settings to assess the interaction between pollination and breeding systems in response to pollinator visitation because islands are often pollinator‐depauperate. This study compared 28 insular and 26 mainland species of Caribbean Gesneriaceae to test the hypothesis that low diversity and possibly low pollinator service on islands would lead to a greater frequency of generalized plant–pollinator interactions and/or a higher potential for autonomous self‐pollination in insular than in mainland species. We also assessed the hypothesis that epiphytic species should have greater autofertility than species occurring in other habitats. Pollinator observations conducted in the field from 2004 to 2014 revealed bat, bee, butterfly, hummingbird, moth, and generalized pollination systems. Functional specialization in pollination systems was high in insular (71% of the species) and mainland sites (all species), but generalized and bat‐pollinated species were more common on islands. Overall, pollinator visitation rates did not differ between island and mainland; however, for hummingbird‐pollinated species, visitation rate was on average three times higher in mainland than island species. Autofertility indices (fruit set of bagged/outcross flowers) ranged from 0 to 1 and did not differ between island and mainland species. Species growing on rocks (rupiculous) and trees (epiphytic) had on average higher autofertility than terrestrial species. Synthesis. This study revealed that alternative reproductive strategies are used in pollinator‐depauperate environments. Pollinator visitation is lower in insular hummingbird‐pollinated species (the ancestral pollination system of insular Gesneriaceae); therefore, generalized pollination may be considered a reproductive assurance mechanism evolved primarily on island environments. Contrary to the long‐standing tenet, however, autonomous self‐pollination was similar in island and mainland Gesneriaceae suggesting that: (i) generalized pollination provides a viable alternative to selfing in pollinator‐depauperate environments, (ii) autofertility as a reproductive assurance mechanism may be frequent in plant species from mainland regions in environments with unpredictable pollinator visitation and resource availability.

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Section: Introductionmentioning

confidence: 99%

A comparison of reproductive strategies between island and mainland Caribbean Gesneriaceae

et al. 2015

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“…Baker proposed that species that are self‐compatible (or capable of asexual reproduction) are more likely to be successful colonizers than those that are obligate outcrossers and rely on pollen transfer between plants (i.e., self‐incompatible species). In support of Baker's contention, a higher frequency of self‐compatibility, as opposed to self‐incompatibility, has been documented on island floras (McMullen, , ; Webb and Kelly, ; Anderson et al., ; Chamorro et al., ; reviewed recently by Grossenbacher et al., ), and empirical work has continued to emphasize the importance of Baker's rule in both plants and animals (Schueller, ; Busch, ; Trouve et al., ; Bramow et al., ). However, the generality of Baker's ideas has also been questioned, especially given observations that complicate his assertion.…”

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confidence: 96%

Colonization, Baker's law, and the evolution of gynodioecy in Hawaii: implications from a study of Lycium carolinianum

Miller

Blank

Levin

2019

American J of Botany

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Premise As Baker’s law suggests, the successful colonization of oceanic islands is often associated with uniparental reproduction (self‐fertility), but the high incidence of dimorphism (dioecy, gynodioecy) on islands complicates this idea. Lycium carolinianum is widespread, occurring on the North American mainland and the Hawaiian Islands. We examined Baker's ideas for mainland and island populations of L. carolinianum and examined inbreeding depression as a possible contributor to the evolution of gynodioecy on Maui. Methods Controlled crosses were conducted in two mainland populations and two populations in Hawaii. Treatments included self and cross pollination, unmanipulated controls, and autogamy/agamospermy. Alleles from the self‐incompatibility S‐RNase gene were isolated and compared between mainland and island populations. Given self‐compatibility in Hawaii, we germinated seeds from self‐ and cross‐ treatments and estimated inbreeding depression using seven traits and a measure of cumulative fitness. Results Mainland populations of Lycium carolinianum are predominately self‐incompatible with some polymorphism for self‐fertility, whereas Hawaiian populations are self‐compatible. Concordantly, S‐RNase allelic diversity is reduced in Hawaii compared to the mainland. Hawaiian populations also exhibit significant inbreeding depression. Conclusions Self‐compatibility in Hawaii and individual variation in self‐fertility in mainland populations suggests that a colonization filter promoting uniparental reproduction may be acting in this system. Comparison of S‐RNase variation suggests a collapse of allelic diversity and heterozygosity at the S‐RNase locus in Hawaii, which likely contributed to mate limitation upon arrival to the Pacific. Inbreeding depression coupled with autonomous self‐fertilization may have led to the evolution of gynodioecy on Maui.

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“…Many reproductive systems studied at oceanic islands have turned out to be "mixed mating systems" able to produce seeds after selfing as well as out-crossing (Barrett, 1989;Bramow et al, 2013;Philipp et al, 2006). Such a system implies reproductive assurance and maintains the potential for generating individuals with different adaptive properties.…”

Section: Introductionmentioning

confidence: 99%

Colonization of an empty island: how does a plant with a plastic gender system respond?

Philipp

Adsersen

2014

Biogeosciences

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Abstract. Honckenya peploides is the most common plant species on the island of Surtsey. It arrived in 1967 and after a juvenile period of 4 years it produced seeds and had increased its number from below 100 to several millions. Most populations had the individuals distributed in a regular or random pattern, suggesting that intraspecific competition is important. H. peploides has a subdioecious reproductive system consisting of pistillate plants producing capsules, and staminate plants delivering pollen. Some of the latter are in addition producing capsules and are denoted hermaphrodites. Populations at the south coast of Iceland had around equal numbers of pistillate and staminate plants. At Surtsey we found more pistillate plants, probably due to their higher water stress tolerance. We also found a tendency to a higher frequency of hermaphrodite plants with a higher number of seeds per capsule compared to populations at the south coast of Iceland and the nearby island of Heimaey. We suggest that this arises from the time right after the colonization of Surtsey where population size was small and the small generalist pollinators were not able to deposit sufficient pollen on pistillate plants, causing the hermaphrodites to have an advantage by being able to set seed after selfing. The result of this initial advantage of the hermaphrodites in combination with the inheritance of the sexes can still be seen due to the longevity of individuals. A generalized account of the colonization history of H. peploides is given.

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How a heterostylous plant species responds to life on remote islands: a comparative study of the morphology and reproductive biology of Waltheria ovata on the coasts of Ecuador and the Galápagos Islands

Cited by 27 publications

References 50 publications

A comparison of reproductive strategies between island and mainland Caribbean Gesneriaceae

A comparison of reproductive strategies between island and mainland Caribbean Gesneriaceae

Colonization, Baker's law, and the evolution of gynodioecy in Hawaii: implications from a study of Lycium carolinianum

Colonization of an empty island: how does a plant with a plastic gender system respond?

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