Chemical convergence between a guild of facultative myrmecophilous caterpillars and host plants

Author(s)

Lima, Luan Dias ^[1] ; Trigo, Jose Roberto ^[2] ; Kaminski, Lucas Augusto ^[1]

Affiliation

^[1] Univ Fed Rio Grande do Sul, Dept Zool, Programa Posgrad Biol Anim, BR-91501970 Porto Alegre, RS - Brazil

^[2] Univ Estadual Campinas, Dept Biol Anim, Inst Biol, Campinas, SP - Brazil

• Document type: Journal article
• Source: ECOLOGICAL ENTOMOLOGY; v. 46, n. 1, p. 66-75, FEB 2021.
• Web of Science Citations: 0

Abstract

1. Ants exert strong selective pressure on herbivorous insects, although some caterpillars can live in symbiosis with them using chemical defensive strategies. 2. We investigated the adaptive resemblance of cuticular hydrocarbons (CHCs) in multitrophic systems involving a guild of facultative myrmecophilous caterpillar species (Lepidoptera: Lycaenidae), tending ants (Hymenoptera: Formicidae), and host plants from three families. We hypothesised that the CHCs of the caterpillars would resemble those of their host plants (chemical camouflage). 3. We analysed CHCs using gas chromatography/mass spectrometry. Morisita's similarity index (SI) was used to compare CHC profiles of caterpillar species with different types of ant associations (commensal or mutualistic), ants, and host plants. 4. We found strong convergence between caterpillars' CHCs and plants, especially for commensal species that do not provide secretion rewards for ants. Moreover, we found unexpected chemical convergence among mutualistic (trophobiotic) caterpillar species that offer caloric reward secretions to ants. 5. These results show that the studied caterpillars acquire CHCs through their diet and that they vary according to host plant species and type of ant association (commensalism or mutualism). This `chemical camouflage' of myrmecophilous caterpillars may have arisen as a defensive strategy allowing coexistence with ants on plants, whereas `chemical conspicuousness' may have evolved in the context of honest signalling between mutualistic partners. 6. We suggest the existence of chemical mimicry among myrmecophilous species, especially between mutualistic caterpillars. Cuticular chemical mixtures can play a key adaptive role in decreasing ant attacks and increasing caterpillar survival in multimodal sensory systems. (AU)

• FAPESP's process: 10/51340-8 - Symbiotic interactions between butterfly larvae and ants: natural history, morphology and patterns in host plants use
• Grantee: Lucas Augusto Kaminski
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 11/17708-0 - Chemical defense in plants and insects in neotropical environments
• Grantee: Jose Roberto Trigo
• Support Opportunities: Regular Research Grants