Data from: Sugar-rich resources mediate geographic morphological variation in a dominant, neotropical savanna ant

Aim: Trait variation across geographic gradients can reveal how species
respond to different environmental settings, which is crucial under the
growing threat of climate change. Although on the basis of evolutionary
theory, the patterns and drivers of intraspecific functional variation
remain largely underexplored. In ants, pilosity and body size are
morphological traits associated to thermoregulation and heat tolerance,
which are critical concerns in the context of global warming. Here, we
focused on the dominant ant Camponotus crassus to investigate trait
variation and its potential drivers across a latitudinal gradient in the
Brazilian Cerrado savanna. Location: Brazilian Cerrado savanna Taxon:
Camponotus crassus Mayr, 1862 (Hymenoptera: Formicidae) Methods: We
measured mesosoma pilosity and body size of C. crassus across multiple
sites, and evaluated their relationship with temperature, rainfall, solar
radiation, vegetation, and sugar-rich resource variables. We also assessed
morphological and genetic covariation to search for possible phenotypic
plasticity or adaptation in C. crassus. Results: Only sugar-rich resources
were found to significantly influence C. crassus pilosity. Specifically, a
negative relationship between ant pilosity and sugar-rich resources (i.e.
proportion of plants with extrafloral nectaries and hemipteran
trophobionts) was found. No covariation between pilosity and genetic
dissimilarities was observed, suggesting phenotypic plasticity. None of
the variables were significant to predict body size, while this trait
positively covary with genetics. Main conclusions: Our findings suggest
resource availability as a critical factor for species thermoregulation
under environmental change, a hypothesis previously reported in the
literature. We emphasize the importance of examining intraspecific
variation and phenotypic plasticity across large geographic scales,
particularly under the scenario of rapid global change, and the current
threat to Cerrado savanna. Our work covers a still poorly investigated
aspect of intraspecific variation of tropical eusocial insects, and sheds
new light on trait variation associated with large geographical gradients
and resource availability in a major ecosystem.