Brood semiochemicals across reproductive phases of Liometopum apiculatum: chemical variation linked to worker foraging

Abstract

This study explores the seasonal variation of volatile organic compounds (VOCs) emitted from the brood chambers of the escamolera ant, Liometopum apiculatum, and examines their potential association with worker foraging behavior. Brood chamber samples were collected during pre-season, in-season, and post-season phases and analyzed using gas chromatography–mass spectrometry to identify and quantify VOCs. A total of 44 compounds were detected, revealing distinct seasonal differences in composition and abundance. Multivariate analyses, including principal component analysis and partial least squares discriminant analysis, revealed consistent chemical profiles linked to each reproductive phase. In parallel, VOC patterns from live ants were evaluated using an electronic nose, which showed consistent seasonal clustering of odor signatures. Foraging activity on artificial trails was quantified and analyzed with a generalized linear mixed-effects model, revealing significantly higher activity in the post-season when brood VOC richness was highest. Nominal logistic regression identified undecane, tridecane, tetradecane, and phytol as key predictors of foraging patterns. Although these findings are correlational, they suggest a potential ecological role for brood-emitted VOCs in seasonal regulation of foraging. This study highlights the value of integrating chemical and behavioral analyses to better understand the mechanisms of social communication in ants.