Person:
López Teixido, Alberto

First Name

Alberto

Last Name

López Teixido

URI

https://hdl.handle.net/20.500.14352/87101

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Ciencias Biológicas

Department

Biodiversidad, Ecología y Evolución

Area

Botánica

Identifiers

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Search Results

Now showing 1 - 9 of 9

Intraspecific variation in fruit–frugivore interactions: effects of fruiting neighborhood and consequences for seed dispersal
(Oecologia, 2017) Guerra, Tadeu J.; Dayrell, Roberta L. C.; Arruda, André J.; Dáttilo, Wesley; López Teixido, Alberto; Messeder, João V. S.; Silveira, Fernando A. O.
The extent of specialization/generalization continuum in fruit–frugivore interactions at the individual level remains poorly explored. Here, we investigated the interactions between the Neotropical treelet Miconia irwinii (Melastomataceae) and its avian seed dispersers in Brazilian campo rupestre. We built an individual-based network to derive plant degree of interaction specialization regarding disperser species. Then, we explored how intraspecific variation in interaction niche breadth relates to fruit availability on individual plants in varying densities of fruiting conspecific neighbors, and how these factors affect the quantity of viable seeds dispersed. We predicted broader interaction niche breadths for individuals with larger fruit crops in denser fruiting neighborhoods. The downscaled network included nine bird species and 15 plants, which varied nearly five-fold in their degree of interaction specialization. We found positive effects of crop size on visitation and fruit removal rates, but not on degree of interaction specialization. Conversely, we found that an increase in the density of conspecific fruiting neighbors both increased visitation rate and reduced plant degree of interaction specialization. We suggest that tracking fruit-rich patches by avian frugivore species is the main driver of density-dependent intraspecific variation in plants’ interaction niche breadth. Our study shed some light on the overlooked fitness consequences of intraspecific variation in interaction niches by showing that individuals along the specialization/generalization continuum may have their seed dispersed with similar effectiveness. Our study exemplifies how individual-based networks linking plants to frugivore species that differ in their seed dispersal effectiveness can advance our understanding of intraspecific variation in the outcomes of fruit–frugivore interactions.
Large and abundant flowers increase indirect costs of corollas: a study of coflowering sympatric Mediterranean species of contrasting flower size
(Oecologia, 2013) López Teixido, Alberto; Valladares, Fernando
Large floral displays receive more pollinator visits but involve higher production and maintenance costs. This can result in indirect costs which may negatively affect functions like reproductive output. In this study, we explored the relationship between floral display and indirect costs in two pairs of coflowering sympatric Mediterranean Cistus of contrasting flower size. We hypothesized that: (1) corolla production entails direct costs in dry mass, N and P, (2) corollas entail significant indirect costs in terms of fruit set and seed production, (3) indirect costs increase with floral display, (4) indirect costs are greater in larger-flowered sympatric species, and (5) local climatic conditions influence indirect costs. We compared fruit set and seed production of petal-removed flowers and unmanipulated control flowers and evaluated the influence of mean flower number and mean flower size on relative fruit and seed gain of petal-removed and control flowers. Fruit set and seed production were significantly higher in petal-removed flowers in all the studied species. A positive relationship was found between relative fruit gain and mean individual flower size within species. In one pair of species, fruit gain was higher in the large-flowered species, as was the correlation between fruit gain and mean number of open flowers. In the other pair, the correlation between fruit gain and mean flower size was also higher in the large-flowered species. These results reveal that Mediterranean environments impose significant constraints on floral display, counteracting advantages of large flowers from the pollination point of view with increased indirect costs of such flowers.
Sex-dependent selection on flower size in a large-flowered Mediterranean species: an experimental approach with Cistus ladanifer
(Plant Systematics and Evolution, 2014) Barrio, Miguel; López Teixido, Alberto
Larger flowers increase pollinator visit rates and reproductive success, so selection on flower size is usually mediated by pollinators. However, larger flowers involve costs imposed by resource limitation so environmental conditions may also modulate flower size. “Male function” hypothesis entails that the intensity of selection is sex-dependent, being greater through male fitness, whereas female fitness is more limited by resources. In this study we analyse pollinator-mediated phenotypic selection on flower size through both sexes in a large-flowered Mediterranean species, Cistus ladanifer. We experimentally manipulated flower size in two populations, measured its effect on male and female fitness and estimated the strength and direction of phenotypic selection through both sexes and populations. Unmanipulated control flowers received higher pollinator visit rates and dispersed a higher pollen amount than reduced flowers. This translated into selection towards larger flowers through male fitness in both populations. Nevertheless, flower size had little effect on female fitness. Fruit set was high but selection through this component of female function was not significant. Seed number increased in control flowers, especially in one population, where we detected positive selection on flower size. Our results suggest that pollinator-mediated phenotypic selection on flower size in this large-flowered Mediterranean species is especially modulated by male fitness, but flower size adjustment may also be a result of a simultaneous selection through both sexes that, in turn, is dependent of ecological context.
Size Matters: Understanding the Conflict Faced by Large Flowers in Mediterranean Environments
(The Botanical Review, 2016) López Teixido, Alberto; Barrio, Miguel; Valladares, Fernando
Flower size is a key trait in the reproductive ecology of animal-pollinated plants. However, pollinator-mediated selection does not always modulate this trait and environmental conditions and/or antagonist interactions may favor smaller flowers. We evaluate the occurrence of a large-flowered family in a hot and dry Mediterranean environment, mediated by a cost-benefit balance and a male–female conflict. Large flowers have sizeable benefits in terms of pollination and reproductive success and pollinators mediate selection through male function, but female fitness is context-dependent. High floral production and maintenance costs and florivore incidence in large flowers limit female function, which counteracts pollinator-mediated selection. Large flowers are highly costly in the Mediterranean and flower size is mediated by a sexual conflict between the benefits of male function and the costs of the female one. However, a short floral longevity, occasional pollen limitation and selection through maleness keep the existence of large flowers in these environments.
Reproductive assurance weakens pollinator-mediated selection on flower size in an annual mixed-mating species
(Annals of Botany, 2019) López Teixido, Alberto; Aizen, Marcelo A.
Background and Aims In animal-pollinated plants, direct and indirect selection for large and small flowers in predominantly outcrossing and selfing species, respectively, is a common consequence of pollen limitation (PL). However, many hermaphroditic species show a mixed-mating system known as delayed selfing, which provides reproductive assurance (RA) only when outcrossing is not realized. Although RA is expected to reduce pollinator-mediated selection towards larger flowers, the consequences of delayed selfing for selection on flower size in mixed-mating species remain overlooked. We investigated whether RA weakens selection on flower size in Tuberaria guttata, a mixed-mating annual herb. Methods We related pollinator visitation rates to flower size and measured seed production in emasculated, hand cross-pollinated and intact (control) flowers in three natural populations. For each population, we estimated variation in PL and RA across individuals differing in flower size and phenotypic selection on this trait. Key Results Pollinator visitation increased and RA decreased with flower size in all populations. Increasing RA diminished but did not fully alleviate PL, because of early-acting inbreeding depression. In the least-visited and most pollen-limited population, RA increased seed production by >200 %, intensely counteracting the strong pollinator-mediated selection for larger corollas. In the most-visited population, however, RA increased seed production by an average of only 9 %. This population exhibited the largest fraction of individuals that showed a decrease in seed production due to selfing and the weakest pollinator-mediated selection on flower size. Conclusions The results suggest that the balance between the extent of RA and outcrossing contributes to determine flower size in mixed-mating systems. Pollinator-mediated selection favours larger flowers by increasing outcrossed seeds, but the benefits of RA greatly lessen this effect, especially under severe conditions of pollen limitation. Our findings also indicate that a mixed-mating system can represent an ‘evolutionary trap’ under an adequate pollinator supply.
Assessing bias and knowledge gaps on seed ecology research: implications for conservation agenda and policy
(Ecological Applications, 2016) Ribeiro, Guilherme; López Teixido, Alberto; Barbosa, Newton; Silveira, Fernando
Sampling biases permeate ecological research and result in knowledge gaps that have vital consequences for conservation planning. The consequences of knowledge gaps on species identity and distribution (the Wallacean and Linnean shortfalls, respectively) have become apparent recently, but we know little about the extent that research biases and knowledge gaps on traits that influence species’ niches (the Hutchinsonian shortfall) affect conservation policy. To examine whether knowledge of species’ traits based on seed ecology is geographically, phylogenetically, and ecologically biased, we retrieved research data on seed germination, seed dormancy, seed dispersal, seed banks, seed predation, and seed removal from a database of 847 papers, 1648 species, and 5322 cases. Brazil was selected as a model system for megadiverse, undersampled countries. Kernel density maps showed that research was geographically biased towards highly populated sites, with vast areas remaining historically unexplored. We also show that research was clustered into protected areas. We detected a significant positive phylogenetic bias at genus-level, indicating research concentration in few genera and lower relative bias rates for many herbaceous genera. Unexpectedly, information on seed banking was available for only 74 (3.4%) of threatened species, which suggests that information deficits are highest for species with critical needs for ex situ conservation strategies. Tree, fleshy-fruited, and biotic dispersal species were disproportionately overstudied. Our data indicate that information deficits on seed ecology preclude our ability to effectively restore ecosystems and to safeguard endangered species. We call for a systematic improvement of environmental agenda in which policy makers and scientists target sites, clades, and functional groups historically neglected. Lessons from developed countries and collaborative efforts will be important for megadiverse, underdeveloped countries to achieve the targets of international agreements that depend on seed ecology knowledge aiming to secure biological diversity and ecosystem services.
Disproportionate carbon and water maintenance costs of large corollas in hot Mediterranean ecosystems
(Perspectives in Plant Ecology, Evolution and Systematics, 2014) López Teixido, Alberto; Valladares, Fernando
Larger corollas increase the reproductive success of entomophilous plants, but are also associated with increased carbon and water costs, especially under hot and dry conditions. Minimizing floral carbon and water loss by reducing corolla size should be potentially advantageous for plants living in these environments. We quantify maintenance costs of corollas (water and carbon) in large-flowered rockroses (Cistus spp.) in a Mediterranean ecosystem. We performed field studies of two coflowering sympatric Cistus of contrasting corolla size to analyze water costs. Additionally, we used the larger-flowered species (C. ladanifer) to analyze the effects of intraspecific variation in corolla size on floral net carbon exchange and transpiration rates. We also assessed the mean daily percentage of plant water and carbon consumed by corollas by comparing with that of leaves at the time of flowering in C. ladanifer. Temperature and corolla area increased water maintenance costs, following an allometric relationship where transpiration rate per unit of area increased with corolla area. Larger flowers tended to heat less under strong irradiance than smaller ones in both species, especially in C. ladanifer, demonstrating a stronger transpirational cooling effect on larger flowers. In terms of carbon, temperature significantly affected net carbon exchange rates, which were not affected by corolla size. Daily water and carbon expenses of corolla were ca. 50% of those of leaves on an organ surface area basis. Our results suggest that water and carbon maintenance costs of large flowers in the Mediterranean impose significant constraints to corolla size, ecophysiologically favoring smaller-flowered individuals in these ecosystems.
Flower size and longevity influence florivory in the large-flowered shrub Cistus ladanifer
(Acta Oecologica, 2011) López Teixido, Alberto; Méndez, Marcos; Valladares, Fernando
Plants with larger and longer-lived flowers receive more pollinator visits and increase reproductive success, though may also suffer more from antagonistic interactions with animals. Florivores can reduce fruit and seed production, so selection on flower size, floral longevity and/or number of flowers may thus be determined by the relative effects of both pollinators and florivores. In this study flowers of Cistus ladanifer, a large-flowered Mediterranean shrub, were monitored to evaluate the effects of flower size, floral longevity and number of flowers on levels of florivory in four populations. Number of flowers was variable but did not differ among populations. Both flower size and floral longevity of C. ladanifer showed broad variation and significantly differed among populations. Overall, 7% of flowers suffered attack by florivores, which were mainly ants picking the stamens and beetles consuming petals and pollen. Within-populations, larger and longer-lived flowers tended to be affected by florivores more frequently. The low overall incidence of florivores and its lack of between-population variation suggest that florivory may not influence intraspecific variation of these floral traits. However, moderate florivory levels on the largest and longest-lived flowers open the possibility of exerting selection towards smaller and shorter-lived flowers in some of the populations studied.
Temperature-Limited Floral Longevity in the Large-Flowered Mediterranean Shrub Cistus Ladanifer (Cistaceae)
(International Journal of Plant Sciences, 2015) López Teixido, Alberto; Valladares, Fernando
Premise of research. Larger and longer-lived flowers are more frequently pollinated, but they are associated with high maintenance costs due to greater water usage. The Mediterranean climate limits plant reproduction and maximizes resource use efficiency, so smaller and short-lived flowers are potentially advantageous under hot and dry conditions. Methodology. We experimentally evaluated the relationship between the floral longevity of Cistus ladanifer, a large-flowered Mediterranean shrub, and pollination, flower size, and temperature at two different altitudes with contrasting climatic conditions. We hypothesized that flower size and longevity would be reduced in the drier and hotter conditions of the lower-altitude site. In addition, we expected that floral longevity would decrease with experimental pollen deposition, flower size, and temperature. We pollinated and capped flowers to evaluate the variation in floral longevity by comparing actual and potential floral longevity at low and high altitudes. Pivotal results. In agreement with our hypothesis, flower size was observed to increase with altitude, but, contrary to expectations, floral longevity decreased at the high altitude since temperature increased during the flowering time. Floral longevity tended to be short but depended on pollination, such that potential floral longevity was greater than actual floral longevity. Capped flowers lasted longer (1.31 ± 0.65 d) than control (0.95 ± 0.39 d) or hand-pollinated (0.60 ± 0.08 d) flowers. At the high altitude, larger flowers and higher temperatures resulted in a reduction in both the observed and potential floral longevity, but temperature had a differential effect in limiting potential floral longevity. Conclusions. Our experimental survey reported short-lived flowers and limitations in floral longevity when flowers were larger and temperatures were higher. Overall, the results reveal an important effect of temperature on increasing floral maintenance costs, imposing selective pressures on flower size, and longevity in large-flowered Mediterranean plants.