Monarch butterflies in Northern California are starting to breed in winter to adapt to climate change. This new strategy could be crucial for their survival, a recent study suggests.

Monarch butterflies winter breeding success is showing a new way forward for these insects in Northern California.

They are now breeding during the winter months. A recent study suggests this shift could be key to their survival. Scientists discovered that Monarchs are adjusting to warmer winters by remaining active and reproducing during colder periods. 

Typically, these butterflies did not breed in winter, but this adaptation appears to be successful. The research, published in the Journal of the Lepidopterists’ Society, highlights how this change could be crucial for their survival as climate conditions continue to evolve.

New Insights On Monarch Butterflies In Northern California

David James, an associate professor of entomology at Washington State University, led the research on winter breeding.

He discovered that monarch pupae developed in an urban site in the San Francisco Bay Area during the winter of 2021/2022 had a survival rate of about 50%.

This builds on earlier findings from the winter of 2020/2021 that first noted winter breeding in the area, likely due to climate warming.

“We are witnessing monarchs evolving and adapting to new environmental circumstances,” James stated. He believes these findings are crucial for understanding how to support the monarchs as their environment changes.

In the past five years, the number of monarchs overwintering on the California coast has varied greatly. From 192,624 in 2017, the number dropped to just 1,899 in 2020, then rebounded to 247,246 in 2021 and 335,479 in 2022. 

Moreover, there has also been a significant increase in monarchs breeding over the winter in urban areas like the Bay Area, where they feed on non-native milkweeds.

This study by James and his team is the first to estimate how viable monarch pupae are during the winter months.

Maria Schaefer, a citizen scientist working with James since 2020, monitored over 100 wild monarch pupae at the Googleplex campus near Palo Alto during the winter of 2021/2022.

Despite some losses due to landscaping activities, the study found a 49.4% success rate in pupal eclosion, which is the process of emerging as an adult butterfly.

Furthermore, the researchers found that pupae can survive and produce adults for up to seven weeks in the winter, compared to just 10 days during the summer.

“Given that winter is a sub-optimal environment for breeding, these results are promising,” James commented. The study also used exuviae, the shed skin of the pupae, to detect the presence of the parasite Ophryocystis elektroscirrha. 

The analysis suggested that about 70% of the winter breeding population was likely infected with the parasite, underscoring the need for further research into its impact and that of other stressors on western monarch populations under natural conditions.

Monarchs’ Winter Breeding Spurs Crucial Ongoing Research

As winter breeding becomes more prevalent among monarch butterflies in Northern California, researchers like James and Schaefer are determined to continue their observations and studies.

Their ongoing work will provide vital data to adjust conservation strategies effectively, ensuring that these iconic insects can thrive in a changing climate. 

Therefore, the findings suggest a promising future where adaptive behaviors may help sustain the monarch population, crucial for both biodiversity and the health of ecosystems.

The efforts to understand and support these adaptations are more critical than ever as environmental conditions continue to evolve.

Source: https://www.sciencedaily.com/releases/2024/07/240729173441.htm