Human Impact: Stoneflies Evolve New Colors

Recent research from the University of Otago reveals that New Zealand's native stoneflies have altered their coloration due to environmental changes caused by humans. This study, published in the journal Science, presents a clear example of animal evolution influenced by human activity.

Co-author Professor Jon Waters, from the Department of Zoology, explains that these stoneflies have developed different colors following deforestation. In natural forest environments, this native species evolved "warning" colors that mimicked those of a poisonous species to deceive predators into believing they too were toxic. However, the destruction of forests has eliminated these poisonous counterparts. Consequently, in areas where forests have been removed, the stoneflies have shifted away from this mimicry and evolved new colors instead.

Scientists have long questioned whether human actions lead to evolutionary changes in natural populations. The most notable historical example is the peppered moth in the UK, which changed its color in response to industrial pollution in the 1800s, although that case has faced some controversy.

Professor Waters asserts that this new study demonstrates how human activities have modified the interactions among native species. Co-author Dr. Graham McCulloch highlights that humans have disrupted ecological relationships that have developed over millions of years, yet some native species have shown resilience and the ability to adapt.

"This study is significant because it indicates that certain native species can adjust to the environmental changes driven by humans, even when those changes occur rapidly," says Dr. McCulloch. Furthermore, the findings suggest that separate populations of the same species have experienced similar color changes in response to deforestation across different regions, indicating that evolution can be a predictable process.