# Thermal patterns in stingless bee colonies

## TL;DR

Stingless bees with specific nest structures maintain stable brood temperatures, which is important for their thermal biology and sustainable farming.

## Contribution

The study identifies the involucrum as a key adaptation for thermal regulation in stingless bees, overriding phylogenetic constraints.

## Key findings

- Species with defined brood combs and cerumen envelopes maintain higher and more stable brood temperatures (~30°C).
- The presence of an involucrum predicts warmer internal colony temperatures (~4.8°C warmer).
- Thermal stability is highest in brood areas (CV = 11.7%) and decreases toward the outer nest (CV = 35.3%).

## Abstract

Understanding the thermal dynamics of stingless bee colonies is essential for developing effective monitoring systems and promoting sustainable meliponiculture. In this study, we compiled and analyzed brood, nest periphery, and ambient temperature data from 36 stingless bee species reported across several published studies. The data were systematized into graphical visualizations, phylogenetic comparative methods, Generalized Least Squares both for heteroscedasticity or autocorrelation in the errors, coefficients of variation (CV), and calculated temperature deltas (ΔT), i.e. the differences between distinct nest zones, to evaluate thermal regulation and summarize temperature patterns across a broad diversity of stingless bees. Our findings show that species with defined brood combs and cerumen envelopes tend to maintain significantly higher and more stable brood temperatures, averaging close to 30 °C, compared to species lacking these structures. Nest temperatures in stingless bees showed a weak but significant phylogenetic signal, indicating partial evolutionary structuring of thermal traits. Yet, the presence of an involucrum was a strong predictor of internal colony temperature, with species constructing this structure maintaining nests approximately 4.8 °C warmer than those lacking it. These results suggest that involucrum construction is a key adaptive trait that largely overrides phylogenetic constraints on thermal regulation. Thermal stability was highest in brood areas (CV = 11.7%) and progressively decreased toward the outer nest and ambient environment (CV = 35.3%), indicating strong internal buffering mechanisms. These findings identify the involucrum as a key adaptation driving elevated and stable brood temperatures in stingless bees, largely independent of phylogenetic constraints, with important implications for thermal biology, monitoring, and sustainable meliponiculture.

The online version contains supplementary material available at 10.1007/s00114-026-02083-6.