Disentangle circadian niche effects from lineage identity

Disentangle the effects of circadian activity regime and lineage identity on ant senescence trajectories and thermal vulnerability by conducting cross-phylogenetic sampling that includes multiple matinal lineages from different subfamilies.

Background

Circadian niche and subfamily identity are strongly collinear in the 18-species assemblage: all Rhytidoponera species are matinal, while both Myrmecia species are crepuscular. Consequently, the study cannot determine whether the observed senescence pattern is caused by circadian activity regime, lineage identity, or both.

The authors explicitly identify separation of these explanations as the key empirical question for future cross-phylogenetic work. Resolving it requires sampling multiple matinal lineages across different subfamilies and biogeographic contexts so that activity regime and ancestry are no longer confounded.

References

Claims 2 and 3 cannot be fully separated with $N = 18$ species, so the attribution to \emph{circadian niche} (Claim~2) versus subfamily identity (Claim~3) is operationally indistinguishable at this scale. Two of our conclusions are nonetheless robust to this collinearity: the body-size HR (an interspecific effect, independent of niche classification) and the null size$\times$temperature interaction. Two are tentative: the specific attribution of trajectory structuring to circadian niche rather than lineage identity, and the attribution of thermal vulnerability to Ectatomminae as a subfamily rather than to matinal Rhytidoponera specifically. Disentangling these will require cross-phylogenetic sampling --- multiple matinal lineages drawn from different subfamilies. Reviewers may ask: \emph{``How can you separate circadian niche from lineage identity?''} The honest answer is: we cannot, with $N = 18$ from a single assemblage. We present the attribution to circadian niche (Claim~2) and to lineage identity (Claim~3) as two complementary framings of the same collinear signal, and propose the separation as the key empirical question for future cross-phylogenetic work.

— Body size predicts how long ant workers live - but not how they age or how they die from heat  (2608.14245 - Moscardi et al., 14 Aug 2026) in Limitations, item 5, “Collinearity (circadian niche and subfamily)”