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Caiafa MV, Jusino MA, Wilkie AC, Díaz IA, Sieving KE, Smith ME. Discovering the role of Patagonian birds in the dispersal of truffles and other mycorrhizal fungi. Curr Biol 2021; 31:5558-5570.e3. [PMID: 34715015 DOI: 10.1016/j.cub.2021.10.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 09/01/2021] [Accepted: 10/11/2021] [Indexed: 01/16/2023]
Abstract
Dispersal is a key process that impacts population dynamics and structures biotic communities. Dispersal limitation influences the assembly of plant and microbial communities, including mycorrhizal fungi and their plant hosts. Mycorrhizal fungi play key ecological roles in forests by feeding nutrients to plants in exchange for sugars, so the dispersal of mycorrhizal fungi spores actively shapes plant communities. Although many fungi rely on wind for spore dispersal, some fungi have lost the ability to shoot their spores into the air and instead produce enclosed belowground fruiting bodies (truffles) that rely on animals for dispersal. The role of mammals in fungal spore dispersal is well documented, but the relevance of birds as dispersal agents of fungi has been understudied, despite the prominence of birds as seed dispersal vectors. Here, we use metagenomics and epifluorescence microscopy to demonstrate that two common, widespread, and endemic Patagonian birds, chucao tapaculos (Scelorchilus rubecula) and black-throated huet-huets (Pteroptochos tarnii), regularly consume mycorrhizal fungi and disperse viable spores via mycophagy. Our metagenomic analysis indicates that these birds routinely consume diverse mycorrhizal fungi, including many truffles, that are symbiotically associated with Nothofagaceae trees that dominate Patagonian forests. Epifluorescence microscopy of fecal samples confirmed that the birds dispersed copious viable spores from truffles and other mycorrhizal fungi. We show that fungi are a common food for both bird species and that this animal-fungi symbiosis is widespread and ecologically important in Patagonia. Our findings indicate that birds may also act as cryptic but critical fungal dispersal agents in other ecosystems.
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Affiliation(s)
- Marcos V Caiafa
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA; Department of Microbiology and Plant Pathology, University of California Riverside, Riverside, CA 92521, USA.
| | - Michelle A Jusino
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA; Center for Forest Mycology Research, USDA Forest Service, Northern Research Station, Madison, WI 53726, USA
| | - Ann C Wilkie
- Soil and Water Sciences Department, University of Florida, Gainesville, FL 32611, USA
| | - Iván A Díaz
- Instituto de Conservación, Biodiversidad y Territorio, Universidad Austral de Chile, Valdivia, Chile
| | - Kathryn E Sieving
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL 32611, USA
| | - Matthew E Smith
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA
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Amo L, Saavedra I. Attraction to Smelly Food in Birds: Insectivorous Birds Discriminate between the Pheromones of Their Prey and Those of Non-Prey Insects. BIOLOGY 2021; 10:1010. [PMID: 34681109 PMCID: PMC8533543 DOI: 10.3390/biology10101010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 09/28/2021] [Accepted: 10/04/2021] [Indexed: 11/16/2022]
Abstract
Natural selection has favored the evolution of different capabilities that allow animals to obtain food-e.g., the development of senses for improving prey/food detection. Among these senses, chemical sense is possibly the most ancient mechanism used by organisms for environmental assessment. Comparative studies suggest the prime role of foraging ecology in the evolution of the olfactory apparatus of vertebrates, including birds. Here, we review empirical studies that have shown birds' abilities to detect prey/food via olfaction and report the results of a study aiming to analyze the specificity of eavesdropping on prey pheromones in insectivorous birds. In a field study, we placed artificial larvae and a dispenser with one of three treatments-prey (Operopthera brumata) pheromones, non-prey (Rhynchophorus ferrugineus) pheromones, or a control unscented dispenser-on the branches of Pyrenean oak trees (Quercus pyrenaica). We then measured the predation rate of birds on artificial larvae. Our results show that more trees had larvae with signs of avian predation when they contained a prey pheromone dispenser than when they contained a non-prey pheromone dispenser or an unscented dispenser. Our results indicate that insectivorous birds can discriminate between the pheromones emitted by their prey and those emitted by non-prey insects and that they only exhibit attraction to prey pheromones. These results highlight the potential use of insectivorous birds in the biological control of insect pests.
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Affiliation(s)
- Luisa Amo
- Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales (MNCN-CSIC), C/José Gutiérrez Abascal, 2, E-28006 Madrid, Spain;
- Area of Biodiversity and Conservation, Universidad Rey Juan Carlos, c/Tulipán s/n., E-28933 Madrid, Spain
| | - Irene Saavedra
- Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales (MNCN-CSIC), C/José Gutiérrez Abascal, 2, E-28006 Madrid, Spain;
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What is that smell? Hummingbirds avoid foraging on resources with defensive insect compounds. Behav Ecol Sociobiol 2021. [DOI: 10.1007/s00265-021-03067-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Abstract
Hummingbirds utilize visual cues to locate flowers, but little is known about the role olfaction plays in nectar foraging despite observations that hummingbirds avoid resources occupied by certain insects. We investigated the behavioral responses of both wild and captive hummingbirds to olfactory cues of hymenopteran floral visitors, including native wood ants (Formica francoeuri), invasive Argentine ants (Linepithema humile), and European honeybees (Apis mellifera). We demonstrate for the first time that hummingbirds use olfaction to make foraging decisions when presented with insect-derived chemical cues under field and aviary conditions. Both wild and captive hummingbirds avoided foraging on feeders with defensive chemicals of F. francoeuri and aggregation pheromones of L. humile, but showed no response to honeybee cuticular hydrocarbons. Our experiments demonstrate the importance of olfaction in shaping hummingbird foraging decisions.
Significance statement
Recent reviews reveal that avian olfaction is not just limited to vultures and a few taxa. We demonstrate that a very charismatic group, hummingbirds, avoid defensive and aggregatory chemical cues from insects present at nectar resources. Olfactory cues can provide critical information about the presence and potential threat of insect floral visitors. This study raises new questions about the underrated importance of olfaction in avian foraging and specifically, hummingbird foraging.
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Aicardi S, Amaroli A, Gallus L, Di Blasi D, Ghigliotti L, Betti F, Vacchi M, Ferrando S. Quantification of neurons in the olfactory bulb of the catsharks Scyliorhinus canicula (Linnaeus, 1758) and Galeus melastomus (Rafinesque, 1810). ZOOLOGY 2020; 141:125796. [PMID: 32464514 DOI: 10.1016/j.zool.2020.125796] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Revised: 04/01/2020] [Accepted: 04/02/2020] [Indexed: 11/27/2022]
Abstract
In vertebrates, the olfactory bulb (OB) is the zone of the brain devoted to receiving the olfactory stimuli. The size of the OB relative to the size of the brain has been positively correlated to a good olfactory capability but, recently, this correlation was questioned after new investigation techniques were developed. Among them, the isotropic fractionator allows to estimate the number of neurons and non-neurons in a given portion of nervous tissue. To date, this technique has been applied in a number of species; in particular the OB was separately analyzed in numerous mammals and in a single crocodile species. Thus, a quantitative description of the OB's cells is available for a small portion of vertebrates. Main aim of this work was to apply isotropic fractionator to investigate the olfactory capability of elasmobranch fishes, whose traditional concept of outstanding olfaction has recently been scaled down by anatomical and physiological studies. For this purpose, the OB of two elasmobranch species, Galeus melastomus and Scyliorhinus canicula, was studied leading to the determination of the number of neurons vs non-neurons in the OB of the specimens. In addition, the obtained cell quantification was related to the olfactory epithelium surface area to obtain a new parameter that encapsulates both information on the peripheral olfactory organ and the OB. The analyzed species resulted in an overall similar quantitative organization of the peripheral olfactory system; slight differences were detected possibly reflecting different environment preference and feeding strategy. Moreover, the non-neurons/neurons ratio of these species, compared to those available in the literature, seems to place elasmobranch fishes among the vertebrate species in which olfaction plays an important role.
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Affiliation(s)
- Stefano Aicardi
- Department of Earth, Environmental, and Life Sciences (DISTAV), University of Genoa, Corso Europa, 26, 16132, Genoa, Italy
| | - Andrea Amaroli
- Department of Surgical Sciences and Integrated Diagnostics (DISC), University of Genoa, Largo Rosanna Benzi, 8, 16132, Genoa, Italy; Department of Orthopedic Dentistry, Institute of Dentistry, I. M. Sechenov First Moscow State Medical University, Bol'shaya Pirogovskaya Ulitsa, 19с1, Moscow, 119146, Russia
| | - Lorenzo Gallus
- Department of Earth, Environmental, and Life Sciences (DISTAV), University of Genoa, Corso Europa, 26, 16132, Genoa, Italy
| | - Davide Di Blasi
- Institute for the Study of Anthropogenic Impacts and Sustainability in the Marine Environment (IAS), National Research Council (CNR), Via De Marini, 6, 16149, Genoa, Italy
| | - Laura Ghigliotti
- Institute for the Study of Anthropogenic Impacts and Sustainability in the Marine Environment (IAS), National Research Council (CNR), Via De Marini, 6, 16149, Genoa, Italy
| | - Federico Betti
- Department of Earth, Environmental, and Life Sciences (DISTAV), University of Genoa, Corso Europa, 26, 16132, Genoa, Italy
| | - Marino Vacchi
- Institute for the Study of Anthropogenic Impacts and Sustainability in the Marine Environment (IAS), National Research Council (CNR), Via De Marini, 6, 16149, Genoa, Italy
| | - Sara Ferrando
- Department of Earth, Environmental, and Life Sciences (DISTAV), University of Genoa, Corso Europa, 26, 16132, Genoa, Italy.
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Avian and rodent responses to the olfactory landscape in a Mediterranean cavity community. Oecologia 2019; 191:73-81. [DOI: 10.1007/s00442-019-04487-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 08/08/2019] [Indexed: 10/26/2022]
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Doyle JM, Willoughby JR, Bell DA, Bloom PH, Bragin EA, Fernandez NB, Katzner TE, Leonard K, DeWoody JA. Elevated Heterozygosity in Adults Relative to Juveniles Provides Evidence of Viability Selection on Eagles and Falcons. J Hered 2019; 110:696-706. [DOI: 10.1093/jhered/esz048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 08/01/2019] [Indexed: 02/06/2023] Open
Abstract
AbstractViability selection yields adult populations that are more genetically variable than those of juveniles, producing a positive correlation between heterozygosity and survival. Viability selection could be the result of decreased heterozygosity across many loci in inbred individuals and a subsequent decrease in survivorship resulting from the expression of the deleterious alleles. Alternatively, locus-specific differences in genetic variability between adults and juveniles may be driven by forms of balancing selection, including heterozygote advantage, frequency-dependent selection, or selection across temporal and spatial scales. We use a pooled-sequencing approach to compare genome-wide and locus-specific genetic variability between 74 golden eagle (Aquila chrysaetos), 62 imperial eagle (Aquila heliaca), and 69 prairie falcon (Falco mexicanus) juveniles and adults. Although genome-wide genetic variability is comparable between juvenile and adult golden eagles and prairie falcons, imperial eagle adults are significantly more heterozygous than juveniles. This evidence of viability selection may stem from a relatively smaller imperial eagle effective population size and potentially greater genetic load. We additionally identify ~2000 single-nucleotide polymorphisms across the 3 species with extreme differences in heterozygosity between juveniles and adults. Many of these markers are associated with genes implicated in immune function or olfaction. These loci represent potential targets for studies of how heterozygote advantage, frequency-dependent selection, and selection over spatial and temporal scales influence survivorship in avian species. Overall, our genome-wide data extend previous studies that used allozyme or microsatellite markers and indicate that viability selection may be a more common evolutionary phenomenon than often appreciated.
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Affiliation(s)
- Jacqueline M Doyle
- Department of Biological Sciences, Towson University, Baltimore, MD
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN
| | - Janna R Willoughby
- School of Forestry and Wildlife Sciences, Auburn University, Auburn, Alabama
- Department of Biological Sciences, Purdue University, West Lafayette, IN
| | - Douglas A Bell
- Department of Biological Sciences, Towson University, Baltimore, MD
- East Bay Regional Park District, Oakland, CA
- Department of Ornithology and Mammalogy, California Academy of Sciences, San Francisco, CA
| | - Peter H Bloom
- Department of Biological Sciences, Towson University, Baltimore, MD
- Bloom Research Inc., Los Angeles, CA
| | - Evgeny A Bragin
- Department of Biological Sciences, Towson University, Baltimore, MD
- Faculty of Natural Science, Kostanay State Pedagogical University, Kostanay, Kazakhstan
- The Peregrine Fund, Boise, ID
- Science Department, Naurzum National Nature Reserve, Kostanay Oblast, Naurzumski Raijon, Karamendy, Kazakhstan
| | - Nadia B Fernandez
- Department of Biological Sciences, Towson University, Baltimore, MD
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN
- Department of Environmental Conservation, University of Massachusetts Amherst, Amherst, MA
| | - Todd E Katzner
- Department of Biological Sciences, Towson University, Baltimore, MD
- US Geological Survey, Forest and Rangeland Ecosystem Science Center, Boise, ID
| | - Kolbe Leonard
- Department of Biological Sciences, Towson University, Baltimore, MD
- Department of Computer and Information Sciences, Towson University, Baltimore, MD
| | - J Andrew DeWoody
- Department of Biological Sciences, Towson University, Baltimore, MD
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN
- Department of Biological Sciences, Purdue University, West Lafayette, IN
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