White Nose Syndrome

In recent years, white-nose syndrome (WNS), a fungal disease caused by Pseudogymnoascus destructans, has devastated bat populations across North America. The fungus thrives in cold, damp environments where many species hibernate, disrupting normal torpor cycles and leading to fatal energy loss during winter. The impact has been particularly severe on the little brown bat (Myotis lucifugus), which was once the most common species in Moorhead but has experienced steep declines throughout Minnesota. The smaller size of these bats make them particularly vulnerable to the disease. 

As little brown bat numbers have dropped, big brown bats (Eptesicus fuscus) now appear to be the dominant species in the region, partly because they are less susceptible to the fungus and more adaptable to urban roosting sites. Understanding how WNS reshapes local bat communities is critical, both for developing conservation strategies and for interpreting future shifts in Moorhead’s species composition.

Recent research demonstrates that the spread of white-nose syndrome (WNS), a deadly fungal disease that has decimated North American bat populations, has significant downstream effects on both agriculture and human health. Using the staggered spread of WNS as a natural experiment, Frank (2024) shows that declines in insect-eating bats reduce natural biological pest control, leading farmers to compensate with increased insecticide use (+31.1% on average). This elevated pesticide exposure is linked to a measurable +7.9% increase in internal infant mortality rates in affected counties. The study provides strong evidence for a causal pathway: WNS-driven bat die-offs → increased insecticide use → negative human health outcomes.

Citation:
Frank, E. G. (2024). The economic impacts of ecosystem disruptions: Costs from substituting biological pest control. Science, 385, eadg0344. https://doi.org/10.1126/science.adg0344