The heat of flowers: thermogenic plants and their pollinators

La termogénesis es la capacidad de algunos organismos de generar calor por procesos metabólicos. Un escaso número de familias de angiospermas y gimnospermas presentan flores o estróbilos termogénicos, caracterizados por elevar sus temperaturas por encima a la del ambiente. Aunque existen distintas interpretaciones adaptativas sobre el origen y la evolución de la termogénesis, una de las más aceptadas es que ésta evolucionó como una estrategia de las plantas para asegurar la polinización mediada por insectos polinizadores que, atraídos por los aromas (los cuales son potenciados por el calor emitido), visitan las flores o los estróbilos, y en algunos casos reciben recompensas en forma de calor. A pesar de la importancia ecológica de las especies termogénicas, diversas actividades humanas amenazan las poblaciones de varias especies, comprometiendo el mantenimiento de esta especializada interacción planta-polinizador.Thermogenesis is the ability of some organisms to generate heat through metabolic processes. A small number of angiosperms and gymnosperms families have thermogenic flowers or strobili, which are characterized by raising their temperature above that of the environment. Although there are different adaptive interpretations about the origin and evolution of thermogenesis, one of the most accepted is that it evolved as a plant strategy to ensure pollination mediated by pollinating insects that, attracted by scents (which are promoted by the heat emitted), visit flowers or strobili, and in some cases receive rewards in form of heat. Different human activities threaten the populations of some thermogenic species, compromising the maintenance of this specialized plant-pollinator interaction

The Role of Alien Species on Plant-Floral Visitor Network Structure in Invaded Communities

This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The interactions between pairs of native and alien plants via shared use of pollinators have been widely studied. Community level studies however, are necessary in order to fully understand the factors and mechanisms that facilitate successful plant invasion, but these are still scarce. Specifically, few community level studies have considered how differences in invasion level (alien flower abundance), and degree of floral trait similarity between native and invasive species, mediate effects on native plant-pollinator communities. Here, we evaluated the role of alien species on overall plant-floral visitor network structure, and on species-level network parameters, across nine invaded coastal communities distributed along 205 km in Yucatán, México that vary in alien species richness and flower abundance. We further assessed the potential the role of alien plant species on plant-floral visitor network structure and robustness via computational simulation of native and invasive plant extinction scenarios. We did not find significant differences between native and alien species in their functional floral phenotypes or in their visitation rate and pollinator community composition in these invaded sites. Variation in the proportion of alien plant species and flower abundance across sites did not influence plant-pollinator network structure. Species-level network parameters (i.e., normalized degree and nestedness contribution) did not differ between native and alien species. Furthermore, our simulation analyses revealed that alien species are functionally equivalent to native species and contribute equally to network structure and robustness. Overall, our results suggest that high levels of floral trait similarity and pollinator use overlap may help facilitate the integration of alien species into native plant-pollinator networks. As a result, alien species may also play a similar role than that of natives in the structure and stability of native plant and pollinator communities in the studied coastal sand dune ecosystem

Evolución de la morfología floral en la especie tristílica oxalis alpina en la región de las Sky Islands del noroeste de México y Suroeste de E.U.A. /

 tesis que para obtener el grado de Doctor en Ciencias Biomédicas, presenta Paula Sosenski Correa ; asesor César A. Domínguez Pérez-Tejada. 97, [11] páginas : diagramas. Doctorado en Ciencias Biomédicas UNAM, Instituto de Ecología, 201

Phenotypic plasticity of floral volatiles in response to increasing drought stress

Background and aimsFlowers emit a wide range of volatile compounds which can be critically important to interactions with pollinators or herbivores. Yet most studies of how the environment influences plant volatiles focus on leaf emissions, with little known about abiotic sources of variation in floral volatiles. Understanding phenotypic plasticity in floral volatile emissions has become increasingly important with globally increasing temperatures and changes in drought frequency and severity. Here quantitative relationships of floral volatile emissions to soil water content were analysed.MethodsPlants of the sub-alpine herb Ipomopsis aggregata and hybrids with its closest congener were subjected to a progressive dry down, mimicking the range of soil moistures experienced in the field. Floral volatiles and leaf gas exchange were measured at four time points during the drought.Key resultsAs the soil dried, floral volatile emissions increased overall and changed in composition, from more 1,3-octadiene and benzyl alcohol to higher representation of some terpenes. Emissions of individual compounds were not linearly related to volumetric water content in the soil. The dominant compound, the monoterpene α-pinene, made up the highest percentage of the scent mixture when soil moisture was intermediate. In contrast, emission of the sesquiterpene (E,E)-α-farnesene accelerated as the drought became more intense. Changes in floral volatiles did not track the time course of changes in photosynthetic rate or stomatal conductance.ConclusionsThis study shows responses of specific floral volatile organic compounds to soil moisture. The non-linear responses furthermore suggest that extreme droughts may have impacts that are not predictable from milder droughts. Floral volatiles are likely to change seasonally with early summer droughts in the Rocky Mountains, as well as over years as snowmelt becomes progressively earlier. Changes in water availability may have impacts on plant-animal interactions that are mediated through non-linear changes in floral volatiles

Patterns and Effects of Heterospecific Pollen Transfer Between an Invasive and Two Native Plant Species: The Importance of Pollen Arrival Time to the Stigma

Premise: Invasive plant species can integrate into native plant–pollinator communities, but the underlying mechanisms are poorly understood. Competitive interactions between invasive and native plants via heterospecific pollen (HP) and differential invasive HP effects depending on HP arrival time to the stigma may mediate invasion success, but these have been little studied. Methods: We evaluated patterns and effects of HP receipt on pollen tube growth in two native and one invasive species in the field. We also used hand-pollination experiments to evaluate the effect of invasive HP pollen and its arrival time on native reproductive success. Results: Native species receive smaller and less-diverse HP loads (5–7 species) compared to invasive species (10 species). The load size of HP had a negative effect on the proportion of pollen tubes in both native species but not in the invasive, suggesting higher HP tolerance in the latter. Invasive HP arrival time differentially affected pollen tube success in native species. Conclusions: Our results highlight the need to study reciprocal HP effects between invasive and native species and the factors that determine differential responses to HP receipt to fully understand the mechanisms facilitating invasive species integration into native plant–pollinator communities

Selection of Floral Traits by Pollinators and Seed Predators during Sequential Life History Stages.

AbstractOrganismal traits often influence fitness via interactions with multiple species. That selection is not necessarily predictable from pairwise interactions, such as when interactions occur during different life cycle stages. Theoretically, directional selection during two sequential episodes (e.g., pollination and seed survival) can generate quadratic or correlational selection for a set of traits that passes both selective filters. We compared strength of selection during pollination versus seed predation in the field and tested whether interactions with multiple species give rise to nonlinear selection on floral traits. We planted common gardens with seeds of two species of Ipomopsis and hybrids at sites where pollination was primarily by hummingbirds or also included hawk moths. We examined selection on six floral traits, including corolla width, sepal width, color, nectar, and two scent compounds. Female fitness (seeds) was broken down into fitness during (1) pollination (seeds initiated) and (2) seed predation (proportion of seeds escaping fly predation). All traits showed evidence of selection. Directional and quadratic selection were stronger during seed initiation than during seed predation. Correlational selection occurred mostly during seed initiation rather than arising from combining species interactions at two points in the life cycle. These results underscore how multispecies interactions can combine to exert selection on trait combinations

The role of alien species on plant-floral visitor network structure in invaded communities

The interactions between pairs of native and alien plants via shared use of pollinators have been widely studied. Community level studies however, are necessary in order to fully understand the factors and mechanisms that facilitate successful plant invasion, but these are still scarce. Specifically, few community level studies have considered how differences in invasion level (alien flower abundance), and degree of floral trait similarity between native and invasive species, mediate effects on native plant-pollinator communities. Here, we evaluated the role of alien species on overall plant-floral visitor network structure, and on species- level network parameters, across nine invaded coastal communities distributed along 205 km in Yucata´n, Me´xico that vary in alien species richness and flower abundance. We further assessed the potential the role of alien plant species on plant-floral visitor network structure and robustness via computational simulation of native and invasive plant extinction scenarios. We did not find significant differences between native and alien species in their functional floral phenotypes or in their visitation rate and pollinator community composition in these invaded sites. Variation in the proportion of alien plant species and flower abundance across sites did not influence plant-pollinator network structure. Species-level network parameters (i.e., normalized degree and nestedness contribution) did not differ between native and alien species. Furthermore, our simulation analyses revealed that alien species are functionally equivalent to native species and contribute equally to network structure and robustness. Overall, our results suggest that high levels of floral trait similarity and pollinator use overlap may help facilitate the integration of alien species into native plant-pollinator networks. As a result, alien species may also play a similar role than that of natives in the structure and stability of native plant and pollinator communities in the studied coastal sand dune ecosystemPeer reviewe