Whether it is flowers blooming in spring, cicadas emerging in the sweltering summer heat, or caterpillars hatching to feast on their preferred host plants, the timing of biological events is so crucial that it has given rise to its own scientific discipline: phenology. This field of study focuses on the seasonal timing of natural phenomena and how these patterns influence ecosystems, species interactions, and environmental balance.
For centuries, plants and animals have evolved in harmony with seasonal cycles, fine-tuning their biological schedules to match the availability of food, climate conditions, and ecological relationships. However, as climate change accelerates, scientists are increasingly documenting disruptions to this delicate balance. Rising global temperatures, shifting precipitation patterns, and, most notably, the increasing frequency of extreme weather events—such as heat waves, cold snaps, droughts, and heavy rainfall—are pushing species out of sync with their traditional phenological patterns.
In a groundbreaking study recently published in Nature Climate Change, a team led by University of Arizona ecologist Daijiang Li investigated the profound impacts of extreme weather on the timing of key biological processes. The researchers examined how butterflies, moths, and flowering plants across the United States respond to these increasingly erratic weather conditions. Their findings provide new insights into how extreme events shape ecological interactions, offering a much-needed expansion of traditional climate change studies that have primarily focused on long-term trends rather than immediate, severe disruptions.
The Role of Extreme Weather in Phenology
Traditionally, phenology research has centered around gradual climate shifts, such as warming trends over decades. However, the reality for organisms is much more dynamic. Individual plants and animals respond not just to long-term climatic trends but also to sudden and extreme environmental stressors. According to Li, an assistant professor in the University of Arizona’s Department of Ecology and Evolutionary Biology, many studies have focused on average temperatures or precipitation patterns. Yet, real-world decisions—such as when to bloom, migrate, or emerge from dormancy—are often dictated by immediate conditions.
“But as individuals, we respond to and make our decisions in response to immediate environmental stress, rather than a 10-year trend, right?” Li pointed out. This underscores the need to factor extreme events into climate models to improve our understanding of biological responses.
The study found that while average temperature remains a dominant factor influencing phenological shifts in plants and insects, extreme weather events play an equally significant role. These findings challenge the notion that gradual climate change alone dictates ecological timing and highlight the urgent need to incorporate extreme weather patterns into climate change models.
How Extreme Weather Disrupts Plants and Insects
To quantify the impact of extreme weather events, Li and his colleagues analyzed extensive datasets collected through iNaturalist, a citizen science platform where users document plant and animal observations. This massive dataset, spanning from 1980 to 2022, was combined with daily weather records to paint a clearer picture of how plants and insects react to sudden temperature fluctuations, droughts, and heavy precipitation events.
The research focused on 581 species of flowering plants and 172 species of butterflies and moths (Lepidoptera) from 2016 to 2022. By examining spatial distribution patterns and how different species responded to extreme weather events, the team identified striking trends in phenological mismatches—situations where plants and pollinators fall out of sync, threatening their survival.
Extreme weather events not only directly impact plants and insects but also interact with broader climatic variables, creating complex and often unpredictable outcomes. For instance, heat waves and droughts can have compounding effects that amplify their individual impacts. A particularly hot and dry season might accelerate plant flowering but also increase water stress, reducing nectar availability for pollinators. Similarly, an extreme cold spell in spring could kill early-emerging insects before their host plants bloom.
The Danger of Phenological Mismatches
One of the most concerning consequences of climate-induced phenological shifts is the decoupling of interdependent species. Many plants rely on specific pollinators, and many insects depend on particular host plants for survival. If these organisms shift their life cycles at different rates due to extreme weather, entire ecological networks can unravel.
A classic example is the relationship between the yucca plant and the yucca moth. The small, white moth spends its adult life around yucca flowers, pollinating them while laying its eggs inside the blooms. In return, the developing larvae feed on yucca seeds. If an early heatwave triggers the moths to emerge before the yucca flowers bloom, or if a late frost delays yucca flowering after the moths have completed their life cycle, both species suffer—the moths lose their breeding ground, and the yucca plants remain unpollinated.
The researchers also found an unexpected response to extreme cold spells in spring. While most would assume cold snaps delay insect activity, butterflies and moths actually emerged earlier than expected—a phenomenon that could increase their vulnerability to further cold shocks or food scarcity. Meanwhile, flowering plants remained relatively unaffected by these cold snaps, further widening the gap between plant-pollinator interactions.
“When insects emerge too early due to sudden temperature spikes, they risk starvation if flowers are not yet blooming,” Li explained. “And when plants flower too early, they may face frost damage before they can set seeds.”
Such mismatches can lead to cascading effects throughout ecosystems. If pollinators disappear due to timing disruptions, plants produce fewer seeds, impacting herbivores that feed on those plants, which in turn affects predators further up the food chain.
The Bigger Picture: Climate Models and Conservation
As climate change continues to fuel more frequent and intense extreme weather events, the risks of phenological mismatches will likely grow. Li and his co-authors stress that climate models must incorporate extreme weather events to improve ecosystem forecasting and conservation planning.
“This work has the potential to be relevant across multiple sectors, from conservation to food security,” said Lindsay Campbell, an assistant professor at the Florida Medical Entomology Laboratory and one of the study’s co-authors.
If flowering cycles become erratic, agricultural pollination could suffer, reducing crop yields and affecting global food supply chains. Similarly, forest ecosystems could face declines in seed dispersal and regeneration, altering biodiversity and ecosystem resilience.
“We are still just beginning to more fully understand how extreme weather impacts insects and plants, which ultimately impacts us and our food security,” said Robert Guralnick, curator of biodiversity informatics at the Florida Museum of Natural History.
As scientists race to refine predictive models and policymakers work to develop adaptive strategies, understanding the role of extreme weather in phenology is an urgent priority. By integrating real-world, high-resolution climate and ecological data, researchers hope to anticipate mismatches before they lead to large-scale disruptions.
Looking Ahead: Mitigation and Adaptation
While the findings highlight alarming trends, they also offer opportunities to develop strategies to protect vulnerable species and ecosystems. Conservationists can prioritize habitats that provide climatic refuges, where temperature fluctuations are less extreme. Farmers can adopt pollinator-friendly agricultural practices, such as planting diverse flowering crops that provide nectar throughout longer growing seasons.
Additionally, citizen science platforms like iNaturalist continue to play a vital role in data collection, empowering nature enthusiasts to contribute to global scientific efforts.
In the end, understanding how extreme weather affects the timing of life itself is not just about plants and insects—it’s about the health and stability of ecosystems that sustain all life on Earth, including humans. By recognizing the importance of phenological harmony, scientists and conservationists can work toward more resilient ecosystems capable of withstanding the unpredictable climate future ahead.
More information: Daijiang Li et al, Extreme weather events have strong but different impacts on plant and insect phenology, Nature Climate Change (2025). DOI: 10.1038/s41558-025-02248-7