Thanks!

To read the full paper, consult academic.oup.com/evlett/advan...

Overall, we found that urbanization influenced flower morphology through both plastic and genetic changes!

Our study highlights the importance of characterizing the pollinator community and integrating field and common garden data to assess floral evolution in urban habitats.

Sepal shape was affected by urbanization in the field, with longer and more curved nectar spurs, but not in the common garden experiment, indicating a plastic response to urbanization.

Corolla shape was not affected by urbanization.

Bumblebee size was also positively correlated with the genetic component of sepal size.

This suggests that bumblebee size is a key selective agent acting on Impatiens capensis sepal size.

The genetic component of sepal size paralleled this result, the variation in sepal size following the one in bumblebee size.

But in the field, this genetic differentiation was masked by phenotypic plasticity, revealing a case of counter-gradient variation and making evolution harder to detect!

We found that bumblebees were the main pollinator of I. capensis. However, the species pollinating was different in urban and natural habitats. Because of interspecific and intraspecific differences, bumblebees were larger in urban habitats of the Quebec and Montreal regions.

We combined field and common garden experiments to study flower evolution in natural and urban habitats, disentangling plastic from genetic responses. We surveyed pollinators and flower morphology of Impatiens capensis in 16 populations across the Quebec, Montreal, Ottawa, and Toronto regions.

We used I. capensis as a study system because it's an annual plant and a pollination generalist: different functional groups of pollinators visit the flowers, and urbanization may change the partner involved in the interaction, potentially exerting different selective pressures.

📸 J.Burkiewicz

Urbanization alters species richness, abundance, and even evolution—especially of pollinators.

Since pollinators form mutualistic interactions with plants, shifts in their diversity, abundance, or traits can drive selection on flower morphology.

🚨 My first first-authored paper is out in @evolletters.bsky.social

🌆🏵️ Urbanization changed the pollinator community and flower morphology of Impatiens capensis.

🐝 The size of bumblebees—the main pollinators—correlated with sepal size, driving selection for larger sepals in urban populations.

🧵⬇️

1 billion percent endorse this. My colleague @mfrederickson.bsky.social and I share this paper when teaching field courses....

The problem with Canada’s plan to buy scientific prestige The government’s plans to poach 100 US researchers might make good economic sense. But what about the existing community?

Absolutely essential reading for anyone considering those "unicorn" hiring positions in Canada. Observations from researchers who are already there: www.nature.com/articles/d41... 🧪

Folks, the use of AI to write reviews is a clear violation of peer review ethics + it endangers the authors' intellectual property rights. Don't do it.

McGill Biology is hosting a panel to showcase non-academic careers in Biology. Come listen to former PhDs and MScs now working in non-profits, industry, and government. biologygraduatestudent.association.mcgill.ca/events/career-panel

Come out on Tues, March 24 from 2-4:30pm
@biomcgill.bsky.social

Special Issue: Paradigm Shifts in Flower Color: American Journal of Botany: Vol 113, No 1 Click on the title to browse this issue

Check out AJB's special issue "Paradigm shifts in flower color" a bunch of cool papers on flower coloration with a focus on non-pollinator drivers of color variation 🌸🌼🌺bsapubs.onlinelibrary.wiley.com/toc/15372197/2026/113/1

A student wrote to me after the midterm, and they said they should have gotten a lower grade. I think this is important, because I fundamentally disagree with this student, and it took me a while to articulate why. This is my rough draft. 🧵

Picture of MEME students on the beach

Do you want to do a Masters in Evolutionary Biology? The call for applying to the MEME program is now open! MEME is a fantastic 2-year MSc between four European Universities on all areas of Evolutionary Biology. Apply and study in Sweden/France/the Netherlands/Germany/USA/Switzerland! www.evobio.eu

📢 Prochain séminaire // Next conference

AI tools in scientific writing: Should you? And how?

👨‍🔬 Stephen B. Heard, U New Brunswick
📅 Mercredi, 10 septembre 2025, 13:30
📍 Centre sur la biodiversité, B-104

Si vous êtes à Montréal mercredi, vous devriez venir écouter le séminaire de @stephenbheard.bsky.social sur l'utilisation de l'IA en rédaction scientifique! 🧪

If you are in Montreal on Wednesday, you should definitely come to @stephenbheard.bsky.social's talk on AI in scientific writing! 🧪

📢 Prochain séminaire

👩‍🔬 Silvana Martén Rodriguez, UNAM

🧪 Changing tracks towards the summit: pollination and breeding system shifts along tropical mountain gradients

📅 Mercredi 27 août 2025 à 11h30 à l’IRBV (B-354).

Beyond the Grant–Stebbins model: floral adaptive landscapes and plant speciation AbstractBackground. Floral diversity, a striking feature of angiosperm evolution, provides the impetus and rationale for linking pollinator-driven selectio

Is the Most Effective Pollinator Principle a zombie idea? How do plants adapted to one pollinator shift to another without traversing an adaptive valley? How should we measure fitness in pollinator selection studies? We explore these questions and more in a new review doi.org/10.1093/aob/...

Interested in sex chromosomes evolution and want to wrap up today’s talks on a colorful note? Come see my presentation on guppy sex chromosomes today, July 8th! 🐠

#CSEE2025
⌚16h15, 📍 Lac Memphrémagog

Hey #CSEE2025 interested in flowers, natural selection, urbanization or any combination of the three?
I’m presenting results of my thesis at 11am today in the urban ecology session (Rivière Coaticook)

In the field, phenotypic plasticity masked the genetic differences observed in the common garden.

Urbanization influenced flower morphology through both plastic and genetic changes!

This counter-gradient variation means the environment dampens genetic adaptation—making evolution harder to detect!

Bumblebee size was also positively correlated with the genetic component of sepal size.

This suggests that bumblebee size is a key selective agent acting on Impatiens capensis sepal size

But wait—there’s more!

The difference in bumblebee size between urban and natural sites wasn’t the same in every city.

Interestingly, the genetic component of sepal size paralleled this result, the variation in sepal size following the one in bumblebee size.

We combined field and common garden experiments to study flower evolution in natural and urban habitats, disentangling plastic from genetic responses.

We surveyed pollinators and flower morphology of Impatiens capensis in 16 populations across the Quebec, Montreal, Ottawa, and Toronto regions.

Urbanization alters species richness, abundance, and even evolution—especially of pollinators.

Since pollinators form mutualistic interactions with plants, shifts in their diversity, abundance, or traits can drive selection on flower morphology.

🚨 My first first-authored paper is out on bioRxiv!

🌆🏵️ Urbanization changed the pollinator community and flower morphology of Impatiens capensis.

🐝 The size of bumblebees—the main pollinators—correlated with sepal size, driving selection for larger sepals in urban populations.

🧵 More below ⬇️