Biology subjects

Lafond, J.

Publications and source records attributed to Lafond, J..

3 recordsLinked to original sources

bioRxiv2025

Urbanization drives genetic and plastic responses of the spotted jewelweed flower morphology

The spectacular diversity of flowers is largely driven by pollinator-mediated selection that favors attractive flowers and effective pollen transfer. Urbanization has the potential to affect floral trait evolution by altering pollinator communities through environmental changes. Additionally, abiotic changes in urban habitats can induce phenotypic plasticity, further shaping evolutionary trajectories. We investigated how urbanization affects the genetic and plastic components of flower morphology of Impatiens capensis across four Canadian cities. We found that urbanization influenced the pollinator community composition and the body size of bumblebees, the species main pollinator, although the magnitude of the size effect varied among cities. Using a combination of field surveys and a common garden experiment, our results suggest that urbanization affects sepal size - a tubular floral organ in which pollinators enter to access the nectar - through both genetic and plastic responses. While plasticity sometimes masked the genetic determination of sepal size in the field, we observed a positive correlation between the genetic component of the sepal size and bumblebee body size. These results suggest that urban habitats may drive evolutionary changes in floral traits by modifying pollinator communities.

evolutionary biology↗

bioRxiv2023

Latitudinal gradients in predation persist in urban environments

Urbanization can profoundly disrupt local ecology. But while urban areas now stretch across latitudes, little is known about urbanizations effects on macroecological patterns. We used standardized experiments to test whether urbanization disrupts latitudinal gradients in seed predation, a macroecological pattern that shapes community assembly and diversity. Using >56,000 seeds, we compared predation in urbanized and natural areas across 14,000 km of latitude, spanning the Americas. Predation increased 5-fold from high latitudes to the tropics, and latitudinal gradients in predation persisted in urban areas despite significant habitat modification. Urbanization reduced predation by vertebrates, but not invertebrates, and seemed to increase ant predation specifically. Our results show that macroecological patterns in predation intensity can persist in urbanized environments, even as urbanization alters the relative importance of predators. One-Sentence SummaryAcross 56,000 seeds and 112{degrees} of latitude, latitudinal gradients in seed predation are equally strong in natural vs. urban areas

ecology↗

bioRxiv2023

How does fertilization impact the wild blueberry microbiome

Wild blueberries production is regarded as less intensive than other agricultural systems, although several agricultural practices are commonly implemented to increase crop yields and to mitigate pets and pathogen attacks. Fertilization, organic or mineral, is used to increase soil nutrient availability and improve fruit yield. Wild blueberry plants are also known to depend on their microbiome to overcome the lack of nutrient availability in the soil and their symbiosis with ericoid mycorrhizal fungi is thought to be crucial in that regard. As fertilization can alter crop microbial communities, our study aimed to measure the impact of this practice in a wild blueberry setting, focusing on the bacterial and fungal communities found in the roots and rhizosphere of Vaccinium angustifolium Ait., both at the time of application and more than year later during the harvest season. Our study indicates that fertilization, whether mineral or organic, has a minimal effect on microbial communities. One year after application, fertilization does not seem to have a negative repercussion on the ericoid mycorrhizal (ErM) fungal community as no significant differences were observed in terms of relative abundance on known and putative ErM taxa between the control and the two fertilizer treatments. The fact that fertilization is applied at a low rate could explain this absence of effect on the microbial communities. However, longer-term studies are needed to ensure that repeated fertilization does not cause any shifts in microbial communities that could be detrimental to the wild blueberry nutrition. ImportanceThis study examines the impact of fertilization, whether organic or mineral, on microbial communities in the roots and rhizosphere of wild blueberry (Vaccinium angustifolium Ait.). both Fertilization is commonly used to enhance soil nutrient availability and improve fruit yield, but its effects on the plants microbiome, particularly on the ericoid mycorrhizal fungi (ErM), are not well understood. The samples were taken both during the pruning season, 3 months after the treatment, and one year later, during harvest season. The results suggest that fertilization has minimal impact on the microbial communities. One year after application, no significant differences were observed in the relative abundance of known and putative ErM taxa between the control group and the two fertilizer-treated groups. The low amount of fertilization applied could explain these results. However, longer-term research are needed to ensure that repeated fertilization does not lead to detrimental shifts in microbial communities affecting wild blueberry nutrition.

microbiology↗