Biology subjects

Castellanos, M. C.

Publications and source records attributed to Castellanos, M. C..

4 recordsLinked to original sources

bioRxiv2026

Effects of Heat Shock and Smoke on the Germination of Woody Species from Tropical Dry Forests

Fire-dependent or fire-influenced ecosystems harbor species with diverse response strategies, such as smoke-stimulated germination and dormancy release through heat shocks. Although these cues influence germination in many fire-prone ecosystems, their effects on seeds of woody species from tropical dry forests (TDFs) remain poorly understood. We evaluated the germination response of twelve TDF woody species to three heat-shock temperatures (80, 120, and 160C), two exposure times (3 and 5 min), and two smoke conditions (with and without smoke water), plus dry and wet controls. We also assessed the relationship between germination and functional seed traits, including permeability, seed-coat thickness, mass, and shape index. Of the eleven species that germinated, four showed broad tolerance, with no significant reduction in germination even at 160C for 5 min, which was associated with lower permeability, thicker seed coats, and greater mass. Four other species showed restricted tolerance to heat, with significant declines in germination at higher temperatures or longer exposure times, and were associated with higher permeability, thinner seed coats, and lower seed mass. The remaining three species showed heat-stimulated germination between 80 and 120C and tended to have lower shape-index values. Smoke treatments significantly increased germination in three species, Ceiba pentandra, Guazuma ulmifolia, and Samanea saman. In the remaining species, significant differences were either absent or attributable to moisture or imbibition effects rather than to smoke itself. Overall, germination responses to heat were associated with variation in functional seed traits, whereas responses to smoke were less widespread and showed a less consistent functional pattern.

ecology↗

bioRxiv2024

Understanding pollination in urban food production: the importance of data validation and participant feedback for citizen science project design

O_LIThere is a significant knowledge gap regarding the pollination needs of urban farming, partly due to barriers for researchers in accessing these growing spaces. Involving growers in data collection offers a potential solution but presents other challenges in terms of data accuracy and participant retention. C_LIO_LIWe developed a citizen science methodology for monitoring plant-pollinator interactions in urban food systems and evaluated the accuracy of data collected by growers by comparison to data collected by a professionally trained researcher. We also collected feedback from participants at the mid- and endpoints of the project regarding their experiences of taking part. C_LIO_LIWhile there was some agreement between the datasets in terms of the crops most (raspberries and squash) and least attractive (tomatoes) to insects, relying only on the dataset collected by growers themselves (citizen scientists) would lead to an overestimation of the generality of relationships between crops and pollinating insects in urban food production. Possible reasons for discrepancies between the datasets include species misidentification and non-reporting of surveys where no insects were observed by citizen scientists. C_LIO_LICitizen scientists reported lack of time, concerns about data accuracy and too complex methods as barriers to participation. Implementation of their suggestions for improvements led to a 66% increase in participation in the following year, demonstrating the importance of maintaining a two-way dialogue between participants and project organisers. Citizen scientists also reported an increased appreciation and understanding of insect pollinations following participation, highlighting an additional benefit of involving urban growers in data collection. C_LI Social Impact StatementGrowing food in urban areas can contribute towards sustainable food production. We know little about urban crop pollination, and data collection can be challenging due to restricted access to growing spaces. We developed and tested the effectiveness of a method for urban growers themselves to collect data on insects visiting their crops. Comparing data to that collected by a professional researcher, we found similarities in terms of the most and least attractive crops to pollinators, but there were also large discrepancies in the datasets that mean there are limitations to relying on grower-collected data alone to understand urban plant-pollinator interactions.

ecology↗

bioRxiv2022

Wildfires change plant scents but not pollinator attraction in a Mediterranean palm

Natural fire regimes are currently changing worldwide. These alterations may affect not only plant and animal species but also their interactions. Recently, a few studies have shown the effects of different disturbances on pollination through changes on plant fragrances mediating this interaction, yet no studies have focused on the effects of fires. Here, we assessed whether wildfires can modify plant scents and, in turn, pollinator attraction in a widespread palm in the western Mediterranean Basin. We studied the fireadapted palm Chamaerops humilis and its nursery (dominant in unburnt sites) and nonnursery (dominant in recently burnt sites) beetle pollinators. In nursery pollination systems, where pollinators develop inside their host plant, volatile organic compounds (VOCs) emitted by plants to attract pollinators can be crucial because of the tight interdependence among the interacting species. However, these systems can also involve non-nursery copollinators whose importance is context dependent, and potentially relevant for plant success after disturbance. We first compare scent composition between plants growing in burned and unburned sites after recent wildfires; then we conducted olfactory bioassays with the two beetle pollinators. Fires changed the palms scent composition; however, the two pollinators responded similarly to scent from burnt and unburnt areas which may ensure plant reproduction even after recent fire events. We show, for the first time, that wildfires can alter plant fragrances mediating mutualistic interactions, and that flexible pollinator responses to variable odourscapes can enhance resilience in plant performance.

ecology↗

bioRxiv2019

A stable pollination environment limits current but not potential evolution of floral traits

The vast variation in floral traits at a macroevolutionary level is often interpreted as the result of adaptation to pollinators. However, studies in wild populations often find no evidence of pollinator-mediated selection on flowers. Evolutionary theory predicts this could be the outcome of long periods of stasis under stable conditions, followed by shorter periods of pollinator change that provide selection for innovative phenotypes. We asked if periods of stasis are caused by stabilizing selection, absence of other forms of selection on floral traits, or by low trait ability to respond even if selection is present. We studied Ulex parviflorus, a plant predominantly pollinated by one bee species across its range. We measured heritability and evolvability of floral traits, using genome-wide molecular relatedness in a large wild population, and combined this with estimates of selection on the same individuals. We found evidence for both stabilizing selection and low trait heritability as explanations for stasis in flowers. The area of the standard petal is under stabilizing selection, but the variability observed in the wild is not heritable. A separate trait, floral weight, in turn presents high heritability, but is not currently under selection. We show how a stable environment can lead to a lack of evolutionary change, yet maintain heritable variation to respond to future selection pressures.

evolutionary biology↗