Nutrition of Borneo's ‘exploding’ ants (Hymenoptera: Formicidae: Colobopsis): a preliminary assessment |
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| Authors: | Diane W Davidson Alexey Kopchinskiy Kamariah Abu Salim Marica Grujic Linda Lim Chan Chin Mei Tappey H Jones Dale Casamatta Lea Atanasova Irina S Druzhinina |
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| Affiliation: | 1. Department of Biology, University of Utah, Salt Lake City, UT, U.S.A;2. , Portal, AZ, U.S.A;3. Research Area Biotechnology and Microbiology, Institute of Chemical Engineering, Technische Universit?t Wien, Vienna, Austria;4. Environmental and Life Sciences, Universiti Brunei Darussalam, Bandar Seri Begawan, Brunei Darussalam;5. Chemistry Programme, Universiti Brunei Darussalam, Jalan Tungku Link, Bandar Seri Begawan, Brunei Darussalam;6. Department of Chemistry, Virginia Military Institute, Lexington, VA, U.S.A;7. Department of Biology, University of North Florida, Jacksonville, FL, U.S.A |
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| Abstract: | Functional effects of ants in rainforest canopies depend on difficult to characterize ant diets. In Bornean dipterocarp forests, certain diurnal, arboreal, territorial, and ecologically dominant ‘COCY’ ant species (Colobopsis cylindrica clade) grazed epiphytic biofilms on adaxial leaf surfaces, as well as on tree trunks and branches. Microscopic examination of worker buccal pellets revealed numerous (mainly ascomycete) fungal spores, together with insect appendages and cuticle. Direct observations, video‐imaging, and δ15N isotope data rule out feeding by predation, but isotopes cannot separate fungi from plant and insect exudates as principal nitrogen sources. Lipid‐rich products, extracted from pellets in situ, are hypothesized sources of essential sterols. Also present in pellets were colorful mandibular gland (MG) compounds unique to this ant clade and deployed, as a derived character state, in suicidal defense of foraging territories. Mildly antimicrobial and highly adhesive MG products also occur basally in the clade and may have first evolved for roles in microbial sterilization and food‐gathering and processing. Proteomic studies of YG COCY ants detected 2% proteins in hypertrophied, product‐filled MG reservoirs, but SDS‐PAGE qualitative analysis revealed mostly low‐molecular mass proteins and peptides (8–15 kDa), too small for enzymes but consistent with membrane‐binding proteins and/or antimicrobial peptides. Breakdown of chitin and chitosan in pellets may occur with enzymes derived from molting fluids in insect cuticle (proteases and chitinases) and/or fungi and bacteria. To the extent that COCY workers collect and consume pathogenic and/or beneficial phyllosphere microbes, ant effects on plants may be mediated by these activities. |
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| Keywords: | Brunei canopy ants infrabuccal cavity nitrogen isotope analysis phylloplane microbes sterilization chamber territorial ants |
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