The potential of entomopathogenic fungi for control of the leaf-cutting ant
The potential of entomopathogenic fungi for control of the leaf-cutting ant
The entomopathogenic Hyphomycete fungi Metarhizium anisopliae and Beauveria bassiana both proved pathogenic to each of three leaf-cutting ant species, Atta sexdens, Atta laevigata, and Acromyrmex octospinosus (Hymenoptera: Formicidae), with some variation apparent between fungal isolates. The detection of these entomopathogens by A.sexdens, and Ac. octospinosus in the laboratory, was characterised by the identification of five specific ant behaviours, namely antennation, tasting, biting, dumping and grooming. The same entomopathogens elicited a distinct recognition and rejection by A.laevigata ants in the field. Presentation of two saprophytic fungi (Aspergillus, and Penicillium) in the field elicited a lower level of response than that towards the pathogenic fungi. Samples of the leaf-cutting ant symbiotic fungus Attamyces were not accepted in laboratory tests with A.sexdens and Ac.octospinosus, and elicited behaviours similar to those towards M.anisopliae and B.bassiana.
Attempts to isolate and identify the component(s) within fungi that elicit the observed responses revealed that aqueous extracts of M.anisopliae, B.bassiana, Attamyces, and the saprophyte P.expansum all contain a component able to elicit a response from laboratory A.laevigata ants. The nature of this component is unclear from this study although biochemical analysis has revealed it to be non-proteinaceous, and feasibly of carbohydrate origin. Fractionation of the extract revealed the strongest ant response to a component with a molecular weight of less than 10,000 Da.
The potential of entomopathogenic fungi for the microbial control of the leaf-cutting ant was explored using a novel bait developed from an alginate-based formulation. Bait granules with a dried orange component of over 50% were readily foraged by A.leavigata and A.sexdens ants in both laboratory and field tests. Granules containing entomopathogenic fungal spores to a concentration of 106 spores/ml were effectively foraged in the laboratory tests, indicating the clear potential of such granules in the introduction of pathogens to the nest itself.
University of Southampton
1994
Blowers, Matthew
(1994)
The potential of entomopathogenic fungi for control of the leaf-cutting ant.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
The entomopathogenic Hyphomycete fungi Metarhizium anisopliae and Beauveria bassiana both proved pathogenic to each of three leaf-cutting ant species, Atta sexdens, Atta laevigata, and Acromyrmex octospinosus (Hymenoptera: Formicidae), with some variation apparent between fungal isolates. The detection of these entomopathogens by A.sexdens, and Ac. octospinosus in the laboratory, was characterised by the identification of five specific ant behaviours, namely antennation, tasting, biting, dumping and grooming. The same entomopathogens elicited a distinct recognition and rejection by A.laevigata ants in the field. Presentation of two saprophytic fungi (Aspergillus, and Penicillium) in the field elicited a lower level of response than that towards the pathogenic fungi. Samples of the leaf-cutting ant symbiotic fungus Attamyces were not accepted in laboratory tests with A.sexdens and Ac.octospinosus, and elicited behaviours similar to those towards M.anisopliae and B.bassiana.
Attempts to isolate and identify the component(s) within fungi that elicit the observed responses revealed that aqueous extracts of M.anisopliae, B.bassiana, Attamyces, and the saprophyte P.expansum all contain a component able to elicit a response from laboratory A.laevigata ants. The nature of this component is unclear from this study although biochemical analysis has revealed it to be non-proteinaceous, and feasibly of carbohydrate origin. Fractionation of the extract revealed the strongest ant response to a component with a molecular weight of less than 10,000 Da.
The potential of entomopathogenic fungi for the microbial control of the leaf-cutting ant was explored using a novel bait developed from an alginate-based formulation. Bait granules with a dried orange component of over 50% were readily foraged by A.leavigata and A.sexdens ants in both laboratory and field tests. Granules containing entomopathogenic fungal spores to a concentration of 106 spores/ml were effectively foraged in the laboratory tests, indicating the clear potential of such granules in the introduction of pathogens to the nest itself.
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Published date: 1994
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Local EPrints ID: 458467
URI: http://eprints.soton.ac.uk/id/eprint/458467
PURE UUID: 91e5f158-e8b3-4202-a000-d4371e6c21f4
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Date deposited: 04 Jul 2022 16:49
Last modified: 04 Jul 2022 16:49
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Author:
Matthew Blowers
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