We hope you enjoy this artistic representation of a red flour beetle showing changes in the building blocks of its fitness on entering a new corn environment (right).

@deepaagashe.bsky.social

Our work has broad implications for predicting population performance under environmental change using key fitness metrics.

We showed that these phenotypic changes at generation 70 happened over and above those that happen within a single generation in the new environment. Single generation phenotypic changes were also adaptive in most traits, though not enough to reverse population decline.

Average population performance correlated strongly with ancestral development rate (how quickly larvae pupate or eclose as adults). We measured evolved development rate and reproduction at generation 70 in all evolving populations and found striking increases in both, indicating adaptive evolution.

We put these populations in a challenging new environment (corn flour) and tracked their population dynamics for 70 generations. The populations showed the typical U-shaped recovery curve associated with evolutionary rescue, when declining populations recover their growth rates via adaptation.

We used 10 wild-collected populations of the red flour beetle from different locations in India, with different phenotypic trait distributions in key fitness-related traits (like longevity, development rate, starvation resistance, cannibalism and reproduction).

Here is our preprint! www.biorxiv.org/content/10.1...

🌆 Our work has broad implications for predicting evolutionary responses to climate change and human-induced environmental stressors, as well as for managing pest & pathogen populations that develop resistance to pesticides & antibiotics.

🧬 We also saw dramatic trait evolution - after 70 generations, beetles developed much faster in corn and produced more offspring than their ancestors. Evolution finds a way!

🪴 The most interesting finding? Development rate was the single best correlate of population success, female longevity and reproduction were close runners-up. Beetles that could develop faster as juveniles helped their populations thrive both during and after the rescue event.

📈 We collected over 10,000 population census points and found that almost all populations showed remarkably similar "evolutionary rescue" - that classic U-shaped curve where populations first crash, then recover as they adapt to their new conditions.

🫠 We took 10 different populations of flour beetles from across India and moved them to a challenging new environment (corn flour instead of their usual wheat flour). Would they survive or go extinct? And which traits would predict their success?