Reassessing the Larval Consumption Hypothesis in Neanderthal Diet: A Quantitative and Multi-Proxy Evaluation

Area of Science:

• Paleoecology
• Paleoanthropology
• Isotope Geochemistry

Background:

• Neanderthal trophic ecology is debated due to elevated collagen nitrogen isotope ratios (δ¹⁵N) compared to local herbivores.
• A recent hypothesis proposed fly larvae consumption as a contributor to this nitrogen isotope enrichment.

Purpose of the Study:

• To quantitatively evaluate the hypothesis that fly larvae consumption explains Neanderthal nitrogen isotope enrichment.
• To assess the dietary contribution of fly larvae required to match observed Neanderthal δ¹⁵N values.

Main Methods:

• Utilized a quantitative isotopic mixing model.
• Integrated Middle Paleolithic herbivore baseline δ¹⁵N data and published larval δ¹⁵N values.
• Incorporated multiple trophic enrichment factors.

Main Results:

• Modeled scenarios indicate that larvae would need to supply substantial protein fractions (>40%, often >100%) to account for Neanderthal δ¹⁵N.
• Sensitivity analyses confirmed that variations in baselines or enrichment factors do not alter this outcome.
• Larval intake alone cannot explain the observed nitrogen isotope enrichment.

Conclusions:

• Fly larvae consumption is an isotopically negligible component of Neanderthal diet and cannot independently explain nitrogen isotope enrichment.
• High-trophic-level terrestrial carnivory remains the most parsimonious explanation for Neanderthal nitrogen isotope enrichment.
• Environmental and ecological baseline variations may further amplify observed trophic enrichment.