Renyard, A., Hoven, K., Gooding, C., Petrov, J., Chalissery, J.M. & Gries, G.

Contrasting effects of amino acid types on foraging behaviour, colony growth, and worker mortality in red ants and carpenter ants

Foraging ants collect amino acids and proteins for developing larvae in their colony. Both essential amino acids (EAAs; some considered toxic to ants) and non-essential amino acids (non-EAAs) are important building blocks of proteins, but EAAs cannot be synthesized by animals and must be obtained from their diet. Whether ants specifcally forage for EAAs, and how EAAs affect ant colony growth, has rarely been investigated. Using red ants, Myrmica rubra, and western carpenter ants, Camponotus modoc, as model species, we tested the hypotheses that (1) M. rubra and C. modoc colonies with brood preferentially forage for EAAs rather than non-EAAs; (2) M. rubra colonies provisioned with EAAs, instead of non-EAAs, have greater brood production and colony growth; and (3) M. rubra workers feeding on sucrose and EAAs die sooner than workers feeding on sucrose and non-EAAs (which are considered less toxic). In laboratory choice experiments, colonies of M. rubra and C. modoc preferentially foraged for EAAs rather than non-EAAs. Colonies of M. rubra that consumed both EAAs and non-EAAs produced more larvae but not more workers and queens than colonies that consumed only EAAs or non-EAAs. In a mortality experiment, isolated M. rubra workers that consumed sucrose and EAAs died sooner than workers that consumed sucrose and non-EAAs, possibly because they could not feed EAAs to larvae. Our results indicate that EAAs on their own, while critically important, are insufficient for ant colony growth. However, EAAs as key macro-nutrients in combination with sucrose could be offered as a new bait for pest ant control.

Open access, licensed under CC BY 4.0. © 2024 The Author(s).

Hymenoptera, Formicidae, eusociality, brood care, nutrition, macronutrient