scholarly journals Reproductive system of a mixed-mating plant responds to climate perturbation by increased selfing

2013 ◽  
Vol 280 (1766) ◽  
pp. 20131336 ◽  
Author(s):  
N. T. Jones ◽  
B. C. Husband ◽  
A. S. MacDougall
Keyword(s):  
Population Structure ◽  
Environmental Change ◽  
Inbreeding Depression ◽  
Reproductive System ◽  
Fruit Production ◽  
Mixed Mating ◽  
Reproductive Assurance ◽  
Pollinator Visitation ◽  
Chasmogamous Flowers

How plants respond to climatic perturbations, which are forecasted to increase in frequency and intensity, is difficult to predict because of the buffering effects of plasticity. Compensatory adjustments may maintain fecundity and recruitment, or delay negative changes that are inevitable but not immediately evident. We imposed a climate perturbation of warming and drought on a mixed-mating perennial violet, testing for adjustments in growth, reproduction and mortality. We observed several plasticity-based buffering responses, such that the climatic perturbation did not alter population structure. The most substantial reproductive adjustments, however, involved selfing, with a 45% increase in self-pollination by chasmogamous flowers, a 61% increase in the number of cleistogamous flowers that produced at least one fruit and an overall 15% increase in fruit production from selfed cleistogamous flowers. Reproductive assurance thus compensated for environmental change, including low pollinator visitation that occurred independently of our climate treatment. There was also no immediate evidence for inbreeding depression. Our work indicates that plants with vegetative and reproductive flexibility may not be immediately and negatively affected by a climatic perturbation. The stabilizing effects of these reproductive responses in the long term, however, may depend on the implications of significantly elevated levels of selfing.

Costs and benefits of the mixed-mating system of Narcissus serotinus (Amaryllidaceae) in the conservation of small fragmented populations

Botany ◽  
2014 ◽  
Vol 92 (2) ◽  
pp. 113-122 ◽  
Author(s):  
Isabel Marques ◽  
David Draper ◽  
José María Iriondo
Keyword(s):  
Inbreeding Depression ◽  
Floral Biology ◽  
Mixed Mating ◽  
Reproductive Assurance ◽  
Evolutionary Potential ◽  
Mixed Mating System ◽  
Fragmented Populations ◽  
Large Populations ◽  
Fruit And Seed Set ◽  
Plant Pollinator

Small fragmented populations often exhibit reduced plant–pollinator interactions and scarce outcrossing opportunities. In this context, mixed-mating systems can be advantageous since selfing can provide reproductive assurance, but they may also carry relevant costs such as those involved in inbreeding depression. This study examines the advantages and costs of selfing in Narcissus serotinus L., a mixed-mating geophyte that currently occurs in several fragmented populations in Portugal, that resulted from the construction of the largest European dam. Observation of pollinators revealed that cross-pollination is less frequent in small than in large populations. Manual self-pollinations significantly increased fruit and seed set in small-size populations, also suggesting limited insect pollination. The existence of selfing may provide reproductive assurance in small-size populations of N. serotinus where outcrossing pollination is reduced. Although floral biology and experimental pollinations showed that N. serotinus is capable of autonomous selfing, four of the six fitness traits studied showed significant inbreeding depression in all populations. The high levels of inbreeding depression found in N. serotinus suggest that the initial reproductive assurance advantage of selfing may be counterbalanced by lower survival of the resulting individuals and a decrease in the evolutionary potential of the populations.

scholarly journals Geographic variation in reproductive assurance of Clarkia pulchella

2018 ◽  
Author(s):  
Megan Bontrager ◽  
Christopher D. Muir ◽  
Amy L. Angert
Keyword(s):  
Geographic Variation ◽  
Fruit Production ◽  
Mixed Mating ◽  
Reproductive Assurance ◽  
Resource Reallocation ◽  
Temperature And Precipitation ◽  
Pollinator Community ◽  
Climatic Drivers ◽  
Plant Mating Systems ◽  
Clarkia Pulchella

AbstractClimate can affect plant populations through direct effects on physiology and fitness, and through indirect effects on their relationships with pollinating mutualists. We therefore expect that geographic variation in climate might lead to variation in plant mating systems. Biogeographic processes, such as range expansion, can also contribute to geographic patterns in mating system traits. We manipulated pollinator access to plants in eight sites spanning the geographic range of Clarkia pulchella to investigate geographic and climatic drivers of fruit production and seed set in the absence of pollinators (reproductive assurance). We examined how reproductive assurance and fruit production varied with the position of sites within the range of the species and with temperature and precipitation. We found that reproductive assurance in C. pulchella was greatest in populations in the northern part of the species’ range, and was not well-explained by any of the climate variables that we considered. In the absence of pollinators, some populations of C. pulchella have the capacity to increase fruit production, perhaps through resource reallocation, but this response is climate-dependent. Pollinators are important for reproduction in this species, and recruitment is sensitive to seed input. The degree of autonomous self-pollination that is possible in populations of this mixed-mating species may be shaped by historic biogeographic processes or variation in plant and pollinator community composition rather than variation in climate.

scholarly journals A stochastic model of selection on selfing rates in structured populations

1995 ◽  
Vol 65 (3) ◽  
pp. 209-222 ◽  
Author(s):  
J. Ronfort ◽  
D. Couvet
Keyword(s):  
Population Structure ◽  
Stochastic Model ◽  
Mating System ◽  
Inbreeding Depression ◽  
Structured Populations ◽  
Empirical Literature ◽  
Mixed Mating ◽  
Selfing Rate ◽  
Mixed Mating System ◽  
Biparental Inbreeding

SummaryPrevious theoretical studies of the evolution of the selfing rate have shown that mixed mating systems are not evolutionary stable states. Such models have, however, not included the effects of population structure and thus biparental inbreeding together with the evolution of selfing rates and inbreeding depression. In order to examine selection on selfing rates in structured populations, a stochastic model simulating a finite population with partial selfing and restricted pollen and seed dispersal has been developed. Selection on the mating system was followed by introducing modifiers affecting the selfing rate. The major result was that, with density dependent recruitment, a process which maintains the population structure necessary for biparental inbreeding to occur, a mixed mating system could be maintained. This result was associated with an increase of the mutation load with high selfing rates, and the selected selfing rate depended on the degree of population structure rather than on the initial selfing rate. With low dominance of deleterious alleles, complete allogamy can be selected for. Further studies showed that the more general condition of spatial heterogeneity of recruitment can lead to similar results, the most important condition being the maintenance of genetic structure within populations. A brief survey of the empirical literature shows that a positive relationship between the magnitude of inbreeding depression and the inbreeding coefficient within populations has been observed, in support of the present model.

scholarly journals Fitness costs of delayed pollination in a mixed-mating plant

2019 ◽  
Vol 124 (5) ◽  
pp. 869-881 ◽  
Author(s):  
Laura S Hildesheim ◽  
Øystein H Opedal ◽  
W Scott Armbruster ◽  
Christophe Pélabon
Keyword(s):  
Inbreeding Depression ◽  
Population Variation ◽  
Mixed Mating ◽  
Reproductive Assurance ◽  
Fitness Costs ◽  
Cross Pollination ◽  
Floral Longevity ◽  
Self Pollination ◽  
Evolutionary Consequences ◽  
Pollinator Declines

Abstract Background and Aims To predict the evolutionary consequences of pollinator declines, we need to understand the evolution of delayed autonomous self-pollination, which is expected to evolve as a mechanism of reproductive assurance when cross-pollination becomes unreliable. This involves estimating the costs of increased levels of selfing as well as those associated with floral senescence. Methods We studied the mechanisms and costs of delayed self-pollination in the mixed-mating vine Dalechampia scandens (Euphorbiaceae) by first assessing among-population variation in herkogamy and dichogamy, which together determine the rate and timing of autonomous self-pollination. We then tested whether floral longevity responds plastically to delayed pollination. Finally, we assessed the costs of delayed self-pollination in terms of seed number and size, explicitly separating inbreeding depression from effects of floral senescence. Key Results Herkogamy varied extensively, while variation in dichogamy was more limited. Unpollinated blossoms increased their longevity, but seed quantity and quality decreased with increasing delays in pollination, independently of inbreeding depression. Conclusions In D. scandens, earlier autonomous selfing is facilitated by reduced herkogamy rather than reduced protogyny, providing reproductive assurance while maintaining the possibility for outcrossing events. Effective early autonomous self-pollination may evolve under reduced cross-pollination reliability in response to costs associated with floral senescence.

Reproduction of Viola mirabilis in relation to light and nutrient availability

1995 ◽  
Vol 73 (12) ◽  
pp. 1917-1924 ◽  
Author(s):  
Tanja Mattila ◽  
Veikko Salonen
Keyword(s):  
Leaf Area ◽  
Nutrient Availability ◽  
Environmental Conditions ◽  
Plant Size ◽  
Fruit Production ◽  
Mating Strategies ◽  
Forest Understory ◽  
Mixed Mating ◽  
Mode Of Reproduction ◽  
Chasmogamous Flowers

Mixed mating strategies in plants, such as chasmogamy and cleistogamy, may have evolved to optimize reproductive response to local, often variable, environmental conditions. A 2-year field experiment was conducted to examine the effects of light and nutrient availability on growth and chasmogamous and cleistogamous flower and fruit production in Viola mirabilis, a perennial forest understory herb. Using a factorial design, we examined whether the mode of reproduction or reproductive output of V. mirabilis would be influenced by a repeated fertilizer application and (or) gradual shading with artificial plants. In this population of V. mirabilis, the predominant mode of reproduction during both study years was chasmogamy. In the 2nd year of study, the number of both chasmogamous and cleistogamous flowers per plant decreased with decreasing light intensity, while the increased nutrient supply had no effect on flower or fruit production or plant growth. In addition, the proportion of cleistogamous flowers was smaller for shaded plants. However, the change in the proportion of cleistogamous or chasmogamous flowers from 1993 to 1994 was not affected by shading or fertilization. The production of cleistogamous flowers correlated positively with final total leaf area during both study years, while no correlation was found between the number of chasmogamous flowers and leaf area. In most studies, chasmogamy has been found to be dependent on plant size and favourable environmental conditions, whereas cleistogamy is generally considered to be relatively independent of these factors. However, our results suggest that only plants reaching a large size were capable of producing cleistogamous flowers in addition to chasmogamous flowers produced earlier in the season. Also, it seems that the general assumption of cleistogamic reproduction as a more advantageous mode of reproduction in poor light conditions compared with chasmogamy does not apply to V. mirabilis. Key words: chasmogamy, cleistogamy, light, nutrients, reproductive success, Viola mirabilis.

scholarly journals Contributions to Management Strategies in the NE Atlantic Regarding the Life History and Population Structure of a Key Deep-Sea Fish (Mora moro)

Biology ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 522
Author(s):  
Régis Santos ◽  
Wendell Medeiros-Leal ◽  
Osman Crespo ◽  
Ana Novoa-Pabon ◽  
Mário Pinho
Keyword(s):  
Population Structure ◽  
Life History ◽  
Deep Sea ◽  
Management Strategies ◽  
Size Composition ◽  
Large Size ◽  
The Common ◽  
Fishing Impacts ◽  
Sea Fish

With the commercial fishery expansion to deeper waters, some vulnerable deep-sea species have been increasingly captured. To reduce the fishing impacts on these species, exploitation and management must be based on detailed and precise information about their biology. The common mora Mora moro has become the main deep-sea species caught by longliners in the Northeast Atlantic at depths between 600 and 1200 m. In the Azores, landings have more than doubled from the early 2000s to recent years. Despite its growing importance, its life history and population structure are poorly understood, and the current stock status has not been assessed. To better determine its distribution, biology, and long-term changes in abundance and size composition, this study analyzed a fishery-dependent and survey time series from the Azores. M. moro was found on mud and rock bottoms at depths below 300 m. A larger–deeper trend was observed, and females were larger and more abundant than males. The reproductive season took place from August to February. Abundance indices and mean sizes in the catch were marked by changes in fishing fleet operational behavior. M. moro is considered vulnerable to overfishing because it exhibits a long life span, a large size, slow growth, and a low natural mortality.

scholarly journals Selection Response in Finite Populations

Genetics ◽  
1996 ◽  
Vol 144 (4) ◽  
pp. 1961-1974 ◽  
Author(s):  
Ming Wei ◽  
Armando Caballero ◽  
William G Hill
Keyword(s):  
Linkage Disequilibrium ◽  
Inbreeding Depression ◽  
Genetic Variance ◽  
Relative Rate ◽  
Selection Response ◽  
Rate Of Change ◽  
Effective Population ◽  
Short Term ◽  
Model Account

Formulae were derived to predict genetic response under various selection schemes assuming an infinitesimal model. Account was taken of genetic drift, gametic (linkage) disequilibrium (Bulmer effect), inbreeding depression, common environmental variance, and both initial segregating variance within families (σAW02) and mutational (σM2) variance. The cumulative response to selection until generation t(CRt) can be approximated asCRt≈R0[t−β(1−σAW∞2σAW02)t24Ne]−Dt2Ne,where Ne is the effective population size, σAW∞2=NeσM2 is the genetic variance within families at the steady state (or one-half the genic variance, which is unaffected by selection), and D is the inbreeding depression per unit of inbreeding. R  0 is the selection response at generation 0 assuming preselection so that the linkage disequilibrium effect has stabilized. β is the derivative of the logarithm of the asymptotic response with respect to the logarithm of the within-family genetic variance, i.e., their relative rate of change. R  0 is the major determinant of the short term selection response, but σM2, Ne and β are also important for the long term. A selection method of high accuracy using family information gives a small Ne and will lead to a larger response in the short term and a smaller response in the long term, utilizing mutation less efficiently.

The Southern Ocean benthic fauna and climate change: a historical perspective

1992 ◽  
Vol 338 (1285) ◽  
pp. 299-309 ◽  
Keyword(s):  
Global Warming ◽  
Southern Ocean ◽  
Environmental Change ◽  
Benthic Communities ◽  
Benthic Fauna ◽  
Marine Fauna ◽  
Short Term Change ◽  
Term Change ◽  
Continental Ice Sheets

Environmental change is the norm and it is likely that, particularly on the geological timescale, the temperature regime experienced by marine organisms has never been stable. These temperature changes vary in timescale from daily, through seasonal variations, to long-term environmental change over tens of millions of years. Whereas physiological work can give information on how individual organisms may react phenotypically to short-term change, the way benthic communities react to long-term change can only be studied from the fossil record. The present benthic marine fauna of the Southern Ocean is rich and diverse, consisting of a mixture of taxa with differing evolutionary histories and biogeographical affinities, suggesting that at no time in the Cenozoic did continental ice sheets extend sufficiently to eradicate all shallow-water faunas around Antarctica at the same time. Nevertheless, certain features do suggest the operation of vicariant processes, and climatic cycles affecting distributional ranges and ice-sheet extension may both have enhanced speciation processes. The overall cooling of southern high-latitude seas since the mid-Eocene has been neither smooth nor steady. Intermittent periods of global warming and the influence of Milankovitch cyclicity is likely to have led to regular pulses of migration in and out of Antarctica. The resultant diversity pump may explain in part the high species richness of some marine taxa in the Southern Ocean. It is difficult to suggest how the existing fauna will react to present global warming. Although it is certain the fauna will change, as all faunas have done throughout evolutionary time, we cannot predict with confidence how it will do so.

Pleistocene–Holocene environmental change in the Canary Archipelago as inferred from the stable isotope composition of land snail shells

2011 ◽  
Vol 75 (3) ◽  
pp. 658-669 ◽  
Author(s):  
Yurena Yanes ◽  
Crayton J. Yapp ◽  
Miguel Ibáñez ◽  
María R. Alonso ◽  
Julio De-la-Nuez ◽  
...  
Keyword(s):  
Environmental Change ◽  
Canary Islands ◽  
Environmental Changes ◽  
Isotope Composition ◽  
Moving Average ◽  
Land Snail ◽  
Balance Model ◽  
Low Latitude ◽  
The Times

AbstractThe isotopic composition of land snail shells was analyzed to investigate environmental changes in the eastern Canary Islands (28–29°N) over the last ~ 50 ka. Shell δ13C values range from −8.9‰ to 3.8‰. At various times during the glacial interval (~ 15 to ~ 50 ka), moving average shell δ13C values were 3‰ higher than today, suggesting a larger proportion of C4 plants at those periods. Shell δ18O values range from −1.9‰ to 4.5‰, with moving average δ18O values exhibiting a noisy but long-term increase from 0.1‰ at ~ 50 ka to 1.6–1.8‰ during the LGM (~ 15–22 ka). Subsequently, the moving average δ18O values range from 0.0‰ at ~ 12 ka to 0.9‰ at present. Calculations using a published snail flux balance model for δ18O, constrained by regional temperatures and ocean δ18O values, suggest that relative humidity at the times of snail activity fluctuated but exhibited a long-term decline over the last ~ 50 ka, eventually resulting in the current semiarid conditions of the eastern Canary Islands (consistent with the aridification process in the nearby Sahara). Thus, low-latitude oceanic island land snail shells may be isotopic archives of glacial to interglacial and tropical/subtropical environmental change.

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