Data from: Endogenous colony dormancy shapes seasonal cold tolerance in temperate ants

As eusocial superorganisms, cold-adapted ants must survive multiple
consecutive winters and are shaped by selective pressures acting at both
individual and colony-levels. Following winter reactivation, colonies
enter a fixed developmental phase whose duration is regulated by
“Kipyatkov’s sand-glass device,” an endogenous timer that enforces the
onset of a new dormancy period after a set interval even under permissive
light and temperature conditions. However, how this obligate colony-level
programming interacts with worker physiological responses to produce
cold-tolerant phenotypes capable of withstanding seasonality remains
unknown. Here, we leveraged obligate colony-level seasonal programming in
five temperate ant species to disentangle the relative contributions of
endogenous colony dormancy and exogenous thermal exposure (acclimation) on
worker metabolic rates, metabolomic profiles, and cold tolerance. We show
that across the tested species, the onset of colony dormancy alone is
sufficient to modulate both the critical thermal minimum (CTmin) and the
temperature causing 50% mortality during acute cold exposure (LTe50),and
further interacts with acclimation to shape worker cold tolerance. Cold
acclimation triggered the accumulation of metabolites (e.g. trehalose,
glycerophosphoethanolamine) potentially involved in osmotic balance and
membrane reorganization in individuals. Our results highlight that
programmed, obligate colony dormancy in temperate ants can drive cold
hardening in workers independently of environmental exposure. This
suggests that cold tolerance in temperate social insects can emerge from
the interplay between colonial seasonal programming and individual
responses to environmental cues, reflecting their unique evolutionary
history and social organisation.