Recent research from Brazilian universities has unveiled a strikingly specific relationship between certain caterpillars and ant species. Published on January 27, 2025, in the journal Insect Science, the study conducted by scientists from the University of São Paulo (USP), Federal University of Rio Grande do Sul (UFRGS), and Federal University of Alagoas (Ufal) demonstrates that some caterpillars engage exclusively with specific ant species.
In the experiment, researchers observed that when caterpillars from the species Juditha molpe and Nymphidium chione were paired with non-native ant species, the ants attacked and killed them. This aggression occurred despite the caterpillars' attempts to communicate through specialized organs and the secretion of sugary liquids, which typically signals to the ants that they are allies.
“The hydrocarbons, which form the outer layer of both ants and caterpillars, differ significantly. The caterpillars’ hydrocarbons serve as a food signal for the ants,” explains Luan Dias Lima, the study's lead author. This chemical distinction is crucial for survival, as the caterpillars rely on the ants for protection against predators.
The researchers collected caterpillars from the Serra das Araras Ecological Station in Mato Grosso, focusing on the interactions between caterpillars and their respective ant partners. The study highlights how essential the correct ant partner is for the caterpillars' survival, as they only lay eggs on plants inhabited by specific ant species. Without these ants, caterpillars face a high risk of predation.
Future research aims to investigate whether small amounts of hydrocarbons can also deter other natural enemies, such as predators and parasitoids, that utilize chemical cues for locating their targets. This work not only contributes to the understanding of mutualistic relationships in nature but also opens avenues for exploring chemical ecology and potential applications in pest management.