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Lopes LE, Frank ET, Kárpáti Z, Schmitt T, Kronauer DJC. The Alarm Pheromone and Alarm Response of the Clonal Raider Ant. J Chem Ecol 2023; 49:1-10. [PMID: 36759430 PMCID: PMC9941220 DOI: 10.1007/s10886-023-01407-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 12/02/2022] [Accepted: 12/08/2022] [Indexed: 02/11/2023]
Abstract
Ants communicate via an arsenal of different pheromones produced in a variety of exocrine glands. For example, ants release alarm pheromones in response to danger to alert their nestmates and to trigger behavioral alarm responses. Here we characterize the alarm pheromone and the alarm response of the clonal raider ant Ooceraea biroi, a species that is amenable to laboratory studies but for which no pheromones have been identified. During an alarm response, ants quickly become unsettled, leave their nest pile, and are sometimes initially attracted to the source of alarm, but ultimately move away from it. We find that the alarm pheromone is released from the head of the ant and identify the putative alarm pheromone as a blend of two compounds found in the head, 4-methyl-3-heptanone and 4-methyl-3-heptanol. These compounds are sufficient to induce alarm behavior alone and in combination. They elicit similar, though slightly different behavioral features of the alarm response, with 4-methyl-3-heptanone being immediately repulsive and 4-methyl-3-heptanol being initially attractive before causing ants to move away. The behavioral response to these compounds in combination is dose-dependent, with ants becoming unsettled and attracted to the source of alarm pheromone at low concentrations and repulsed at high concentrations. While 4-methyl-3-heptanone and 4-methyl-3-heptanol are known alarm pheromones in other more distantly related ant species, this is the first report of the chemical identity of a pheromone in O. biroi, and the first alarm pheromone identified in the genus Ooceraea. Identification of a pheromone that triggers a robust, consistent, and conserved behavior, like the alarm pheromone, provides an avenue to dissect the behavioral and neuronal mechanisms underpinning chemical communication.
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Affiliation(s)
- Lindsey E Lopes
- Laboratory of Social Evolution and Behavior, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA.
| | - Erik T Frank
- Biocentre, Department of Animal Ecology and Tropical Biology, University of Würzburg, D-97074, Würzburg, Germany
- Department of Ecology and Evolution, Biophore, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Zsolt Kárpáti
- Biocentre, Department of Animal Ecology and Tropical Biology, University of Würzburg, D-97074, Würzburg, Germany
- Department of Chemical Ecology, Plant Protection Institute, Centre of Agricultural Research, ELKH, Budapest, Hungary
| | - Thomas Schmitt
- Biocentre, Department of Animal Ecology and Tropical Biology, University of Würzburg, D-97074, Würzburg, Germany
| | - Daniel J C Kronauer
- Laboratory of Social Evolution and Behavior, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA.
- Howard Hughes Medical Institute, New York, NY, 10065, USA.
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Using weapons instead of perfume: chemical association strategies of the myrmecophilous bug Scolopostethus pacificus (Rhyparochromidae). CHEMOECOLOGY 2022. [DOI: 10.1007/s00049-022-00374-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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3
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Richter A, Schoeters E, Billen J. Morphology and closing mechanism of the mandibular gland orifice in ants (Hymenoptera: Formicidae). J Morphol 2021; 282:1127-1140. [PMID: 33835596 DOI: 10.1002/jmor.21358] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/06/2021] [Accepted: 04/07/2021] [Indexed: 11/09/2022]
Abstract
The mandibular gland of ants releases chemical compounds with functions ranging from nestmate alarm and recognition to antimicrobial defense. While the morphology of this ethologically important gland is well investigated in several species, the mechanism of secretion release in ants was not explicitly addressed so far. To clarify this question, we examined the anatomy of the gland orifice in ant species from 14 different subfamilies employing different techniques. The orifice close to the mandibular base is located on an area called mandalus. Our investigations revealed variation in mandalar shape, with clear trends in different subfamilies. By contrast, the internal organization is remarkably congruent across all investigated species. The thin external mandalar cuticle is always connected to the mandibular gland duct by a cuticular lamella, visible as a characteristic anchor-shaped structure in cross section. The slit-like gland orifice at the distal end of the mandalus is usually crescent-shaped. In some ant species with specialized mandibles such as trap-jaws, the organization of the orifice area is adapted to the mandibular shape, but always retains the general internal organization. No muscles were found in association with the orifice, nor with any other part of the mandibular gland. However, the base of the mandalus is connected to the prepharyngeal sucking pump by a cuticular ligament. Additionally, it is continuous with the conjunctiva connecting the mandible to the head capsule. We propose that retraction of the sucking pump by the muscle M. tentoriobuccalis, potentially in concert with opening of the mandible, stretches out the ligament and thus pulls on the mandalus and mandalar lamella to open the gland orifice and allow for secretion release. This hypothesis is congruent with findings on other aculeate Hymenoptera and expands our knowledge on the function of an important gland of ants.
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Affiliation(s)
- Adrian Richter
- Institute for Zoology und Evolutionary Research, University of Jena, Jena, Germany
| | - Eric Schoeters
- Zoological Institute, University of Leuven, Leuven, Belgium
| | - Johan Billen
- Zoological Institute, University of Leuven, Leuven, Belgium
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Basu S, Clark RE, Fu Z, Lee BW, Crowder DW. Insect alarm pheromones in response to predators: Ecological trade-offs and molecular mechanisms. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2021; 128:103514. [PMID: 33359575 DOI: 10.1016/j.ibmb.2020.103514] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 12/11/2020] [Accepted: 12/17/2020] [Indexed: 06/12/2023]
Abstract
Insect alarm pheromones are chemical substances that are synthesized and released in response to predators to reduce predation risk. Alarm pheromones can also be perceived by predators, who take advantage of alarm cues to locate prey. While selection favors evolution of alarm pheromone signals that are not easily detectable by predators, predator evolution selects for better prey detection ability. Here, we review the diversity of alarm signals, and consider the behavioral and ecological conditions under which they have evolved. We show that components of alarm pheromones are similar across many insects, although aphids exhibit different behavioral responses to alarm cues compared to social insects. The effects of alarm pheromones on prey behavior depend on factors such as the concentration of pheromones and the density of conspecifics. We also discuss the molecular mechanisms of alarm pheromone perception underlying the evolutionary arms race between predators and prey, and the function of olfactory proteins and receptors in particular. Our review provides a novel synthesis of the diversity and function of insect alarm pheromones, while suggesting avenues that might better allow researchers to exploit population-level responses to alarm signaling for the sustainable management of pests and vector-borne pathogens.
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Affiliation(s)
- Saumik Basu
- Department of Entomology, Washington State University, Pullman, WA, USA.
| | - Robert E Clark
- Department of Entomology, Washington State University, Pullman, WA, USA
| | - Zhen Fu
- Department of Entomology, Washington State University, Pullman, WA, USA; Department of Entomology, Texas A&M University, College Station, TX, USA
| | - Benjamin W Lee
- Department of Entomology, Washington State University, Pullman, WA, USA
| | - David W Crowder
- Department of Entomology, Washington State University, Pullman, WA, USA
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Yusuf AA, Frank ET, Fombong AT, Pirk CWW, Crewe RM, Schmitt T, Strube-Bloss M, Gordon I, Torto B. Odor-Mediated Group Organization and Coordination in the Termite-Raiding Ant Megaponera analis (Mayr). Chem Senses 2020; 45:635-644. [PMID: 32866968 DOI: 10.1093/chemse/bjaa058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Visual and olfactory communications are vital for coordinated group hunting in most animals. To hunt for prey, the group-raiding termite specialist ant Megaponera analis, which lacks good vision, must first confirm the presence or absence of conspecific raiders. Here, we show that M. analis uses olfactory cues for intraspecific communication and showed greater preference for conspecific odors over clean air (blank) or odors from its termite prey. Chemical analysis of ant volatiles identified predominantly short-chained hydrocarbons. Electrophysiological analysis revealed differential sensory detection of the odor compounds, which were confirmed in behavioral olfactometric choice assays with odor bouquets collected from major and minor castes and the 2 most dominant volatiles and n-undecane n-tridecane. A comparative analysis of the cuticular hydrocarbon profile with those of the short-chained odor bouquet of different populations shows a high divergence in the long-chained profile and a much-conserved short-chained odor bouquet. This suggests that there is less selection pressure for divergence and individual recognition in the short- than the long-chained odor profiles. We conclude that olfactory communication serves as an alternative to visual or sound communication, especially during group raids in M. analis when ants are not in direct contact with one another.
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Affiliation(s)
- Abdullahi A Yusuf
- Social Insects Research Group, Department of Zoology and Entomology, University of Pretoria, Hatfield, Pretoria, South Africa
| | - Erik T Frank
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Ayuka T Fombong
- International Centre of Insect Physiology and Ecology, GPO, Nairobi, Kenya
| | - Christian W W Pirk
- Social Insects Research Group, Department of Zoology and Entomology, University of Pretoria, Hatfield, Pretoria, South Africa
| | - Robin M Crewe
- Social Insects Research Group, Department of Zoology and Entomology, University of Pretoria, Hatfield, Pretoria, South Africa
| | - Thomas Schmitt
- Department of Animal Ecology and Tropical Biology, University of Würzburg, Würzburg, Germany
| | - Martin Strube-Bloss
- Department of Biological Cybernetics, University of Bielefeld, Bielefeld, Germany
| | - Ian Gordon
- BirdLife International Kigali Office, Kigali Post Office, Nyarugenge, Kigali, Rwanda
| | - Baldwyn Torto
- Social Insects Research Group, Department of Zoology and Entomology, University of Pretoria, Hatfield, Pretoria, South Africa.,International Centre of Insect Physiology and Ecology, GPO, Nairobi, Kenya
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Adams RMM, Wells RL, Yanoviak SP, Frost CJ, Fox EGP. Interspecific Eavesdropping on Ant Chemical Communication. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.00024] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Hoenle PO, Blüthgen N, Brückner A, Kronauer DJC, Fiala B, Donoso DA, Smith MA, Ospina Jara B, von Beeren C. Species-level predation network uncovers high prey specificity in a Neotropical army ant community. Mol Ecol 2019; 28:2423-2440. [PMID: 31050080 DOI: 10.1111/mec.15078] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 03/14/2019] [Accepted: 03/15/2019] [Indexed: 12/16/2022]
Abstract
Army ants are among the top arthropod predators and considered keystone species in tropical ecosystems. During daily mass raids with many thousand workers, army ants hunt live prey, likely exerting strong top-down control on prey species. Many tropical sites exhibit a high army ant species diversity (>20 species), suggesting that sympatric species partition the available prey niches. However, whether and to what extent this is achieved has not been intensively studied yet. We therefore conducted a large-scale diet survey of a community of surface-raiding army ants at La Selva Biological Station in Costa Rica. We systematically collected 3,262 prey items from eleven army ant species (genera Eciton, Nomamyrmex and Neivamyrmex). Prey items were classified as ant prey or non-ant prey. The prey nearly exclusively consisted of other ants (98%), and most booty was ant brood (87%). Using morphological characters and DNA barcoding, we identified a total of 1,103 ant prey specimens to the species level. One hundred twenty-nine ant species were detected among the army ant prey, representing about 30% of the known local ant diversity. Using weighted bipartite network analyses, we show that prey specialization in army ants is unexpectedly high and prey niche overlap very small. Besides food niche differentiation, we uncovered a spatiotemporal niche differentiation in army ant raid activity. We discuss competition-driven multidimensional niche differentiation and predator-prey arms races as possible mechanisms underlying prey specialization in army ants. By combining systematic prey sampling with species-level prey identification and network analyses, our integrative approach can guide future research by portraying how predator-prey interactions in complex communities can be reliably studied, even in cases where morphological prey identification is infeasible.
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Affiliation(s)
- Philipp O Hoenle
- Ecological Networks, Department of Biology, Technische Universität Darmstadt, Darmstadt, Germany.,Animal Ecology and Tropical Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Nico Blüthgen
- Ecological Networks, Department of Biology, Technische Universität Darmstadt, Darmstadt, Germany
| | - Adrian Brückner
- Ecological Networks, Department of Biology, Technische Universität Darmstadt, Darmstadt, Germany.,Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California
| | - Daniel J C Kronauer
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York City, New York
| | - Brigitte Fiala
- Animal Ecology and Tropical Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - David A Donoso
- Departamento de Biología, Escuela Politécnica Nacional, Quito, Ecuador
| | - M Alex Smith
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | | | - Christoph von Beeren
- Ecological Networks, Department of Biology, Technische Universität Darmstadt, Darmstadt, Germany
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D’Eustacchio D, Centorame M, Fanfani A, Senczuk G, Jiménez-Alemán GH, Vasco-Vidal A, Méndez Y, Ehrlich A, Wessjohann L, Francioso A. Iridoids and volatile pheromones of Tapinoma darioi ants: chemical differences to the closely related species Tapinoma magnum. CHEMOECOLOGY 2019. [DOI: 10.1007/s00049-018-00275-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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