Fact Check: The food chain. I’m still amazed no one is talking about the fact that insect biomass has declined by ∼47% and abundance declined by ∼61.5% over the last 35  years. In some areas it’s measured 75% decline in a single generation.

The Decline of Insect Populations: An Examination of Claims

Introduction

The claim under scrutiny suggests that insect biomass has declined by approximately 47% and abundance by around 61.5% over the past 35 years, with some regions experiencing declines of up to 75% in a single generation. This assertion raises concerns about the health of ecosystems and the implications for food chains and biodiversity.

What We Know

1. Study Findings: A study published in Ecological Applications reports that insect biomass declined by approximately 47% and abundance by about 61.5% over a 35-year period in a subalpine habitat, correlating these declines with climate changes such as reduced summer precipitation and winter snowfall 67.

2. Additional Research: Another significant study conducted by Hallmann et al. (2017) found a dramatic decline in flying insect biomass of about 76% over 27 years in Germany, indicating a severe reduction in certain insect populations 110.

3. Broader Trends: Møller et al. (2020) also documented a decline of more than 70% in insect abundance in Europe since the mid-1960s, based on paired collections from the same sites 2.

4. Wikipedia Summary: A Wikipedia entry on the decline in insect populations summarizes various studies and highlights that many insect populations are experiencing significant declines, although it does not provide specific percentages for all regions 5.

Analysis

Source Reliability

• Peer-Reviewed Journals: The studies by Hallmann et al. and Møller et al. are published in reputable, peer-reviewed journals, which generally enhances their credibility. Peer review serves as a quality control mechanism, ensuring that the research methodology and findings are scrutinized by experts in the field.

• Wikipedia: While Wikipedia can be a useful starting point for information, it is not a primary source and can be edited by anyone. Therefore, it is essential to verify the information against original research articles or authoritative sources.

• ResearchGate and Other Platforms: Some sources, such as ResearchGate, may contain research papers, but the reliability of these papers can vary depending on the authors and the peer-review status of the work.

Conflicts of Interest

The studies referenced do not appear to have overt conflicts of interest, as they are published in scientific journals and are based on empirical research. However, it is always prudent to consider the funding sources of research, as financial backing from certain industries could potentially influence study outcomes.

Methodological Considerations

The studies mentioned utilize different methodologies, such as long-term monitoring and paired collections, which can yield varying results based on the specific environments and insect groups studied. It would be beneficial to have a meta-analysis that combines findings from multiple studies to provide a more comprehensive overview of insect population trends globally.

Additional Information Needed

To further validate the claim, it would be helpful to have:

• More longitudinal studies from diverse geographic regions to assess global trends.
• Data on specific insect species that are most affected and those that remain stable or are increasing.
• Insights into the ecological impacts of these declines on food webs and ecosystems.

Conclusion

Verdict: True

The evidence supports the claim that insect biomass has declined significantly, with studies indicating a decline of approximately 47% in biomass and 61.5% in abundance over the past 35 years, alongside reports of declines as high as 76% in specific regions. These findings are corroborated by multiple peer-reviewed studies, enhancing their credibility.

However, it is important to note that while the overall trend indicates a decline, the extent and specifics can vary by region and species. The methodologies used in these studies differ, which may affect the comparability of results. Additionally, the available data primarily focuses on certain geographic areas, and more comprehensive global studies are needed to fully understand the scope of the decline.

Readers are encouraged to critically evaluate the information presented and consider the nuances and limitations of the evidence. Ongoing research will be essential to further clarify the trends and implications of declining insect populations.

Sources

1. Hallmann, C. A., et al. (2017). "Decline of the flying insect biomass." PLoS ONE. Retrieved from https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0185809
2. Møller, A. P., et al. (2020). "Quantifying rapidly declining abundance of insects in Europe." Ecology and Evolution. Retrieved from https://pmc.ncbi.nlm.nih.gov/articles/PMC7069279/
3. "Decline in insect populations." Wikipedia. Retrieved from https://en.wikipedia.org/wiki/Decline_in_insect_populations
4. "Long‐term declines in insect abundance and biomass in a subalpine habitat." Ecological Applications. Retrieved from https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecs2.4620