Abstract
Due to their prowess in interspecific competition and ability to catch a wide range of arthropod prey (mostly termites with which they are engaged in an evolutionary arms race), ants are recognized as a good model for studying the chemicals involved in defensive and predatory behaviors. Ants' wide diversity of nesting habits and relationships with plants and prey types implies that these chemicals are also very diverse. Using the African myrmicine ant Crematogaster striatula as our focal species, we adopted a three-pronged research approach. We studied the aggressive and predatory behaviors of the ant workers, conducted bioassays on the effect of their Dufour gland contents on termites, and analyzed these contents. (1) The workers defend themselves or eliminate termites by orienting their abdominal tip toward the opponent, stinger protruded. The chemicals emitted, apparently volatile, trigger the recruitment of nestmates situated in the vicinity and act without the stinger having to come into direct contact with the opponent. Whereas alien ants competing with C. striatula for sugary food sources are repelled by this behavior and retreat further and further away, termites defend their nest whatever the danger. They face down C. striatula workers and end up by rolling onto their backs, their legs batting the air. (2) The bioassays showed that the toxicity of the Dufour gland contents acts in a time-dependent manner, leading to the irreversible paralysis, and, ultimately, death of the termites. (3) Gas chromatography-mass spectrometry analyses showed that the Dufour gland contains a mixture of mono- or polyunsaturated long-chain derivatives, bearing functional groups like oxo-alcohols or oxo-acetates. Electrospray ionization-mass spectrometry showed the presence of a molecule of 1584 Da that might be a large, acetylated alkaloid capable of splitting into smaller molecules that could be responsible for the final degree of venom toxicity.
Highlights
Ants dominate the invertebrate communities in tropical rainforest canopies, often representing ca. 50% of the animal biomass and 90% of the individuals
(1) We studied the termite capture behavior of C. striatula workers as well as their reactions when confronted with workers of another ant species, (2) we conducted bioassays to evaluate the toxicity of the Dufour gland contents, and (3) we analyzed these contents
The predatory behavior of C. striatula workers was stereotypical as we did not note any fundamental differences in their reactions based on the different prey tested
Summary
Ants dominate the invertebrate communities in tropical rainforest canopies, often representing ca. 50% of the animal biomass and 90% of the individuals. In a non-dominant arboreal species, the workers, which hunt solitarily, capture a wide range of prey using their venom; when confronted with termites or competing arboreal ants defending a sugary food source, they use volatile secretions produced by their mandibular gland.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
