1
|
Knutie SA, Webster CN, Vaziri GJ, Albert L, Harvey JA, LaRue M, Verrett TB, Soldo A, Koop JAH, Chaves JA, Wegrzyn JL. Urban living can rescue Darwin's finches from the lethal effects of invasive vampire flies. GLOBAL CHANGE BIOLOGY 2024; 30:e17145. [PMID: 38273516 DOI: 10.1111/gcb.17145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 12/15/2023] [Accepted: 12/21/2023] [Indexed: 01/27/2024]
Abstract
Human activity changes multiple factors in the environment, which can have positive or negative synergistic effects on organisms. However, few studies have explored the causal effects of multiple anthropogenic factors, such as urbanization and invasive species, on animals and the mechanisms that mediate these interactions. This study examines the influence of urbanization on the detrimental effect of invasive avian vampire flies (Philornis downsi) on endemic Darwin's finches in the Galápagos Islands. We experimentally manipulated nest fly abundance in urban and non-urban locations and then characterized nestling health, fledging success, diet, and gene expression patterns related to host defense. Fledging success of non-parasitized nestlings from urban (79%) and non-urban (75%) nests did not differ significantly. However, parasitized, non-urban nestlings lost more blood, and fewer nestlings survived (8%) compared to urban nestlings (50%). Stable isotopic values (δ15 N) from urban nestling feces were higher than those from non-urban nestlings, suggesting that urban nestlings are consuming more protein. δ15 N values correlated negatively with parasite abundance, which suggests that diet might influence host defenses (e.g., tolerance and resistance). Parasitized, urban nestlings differentially expressed genes within pathways associated with red blood cell production (tolerance) and pro-inflammatory response (innate immunological resistance), compared to parasitized, non-urban nestlings. In contrast, parasitized non-urban nestlings differentially expressed genes within pathways associated with immunoglobulin production (adaptive immunological resistance). Our results suggest that urban nestlings are investing more in pro-inflammatory responses to resist parasites but also recovering more blood cells to tolerate blood loss. Although non-urban nestlings are mounting an adaptive immune response, it is likely a last effort by the immune system rather than an effective defense against avian vampire flies since few nestlings survived.
Collapse
Affiliation(s)
- Sarah A Knutie
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut, USA
- Institute for Systems Genomics, University of Connecticut, Storrs, Connecticut, USA
| | - Cynthia N Webster
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut, USA
| | - Grace J Vaziri
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut, USA
| | - Lauren Albert
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut, USA
| | - Johanna A Harvey
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut, USA
- Department of Science and Technology, University of Maryland, College Park, Maryland, USA
| | - Michelle LaRue
- School of Earth and Environment, University of Canterbury, Christchurch, New Zealand
| | - Taylor B Verrett
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut, USA
| | - Alexandria Soldo
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut, USA
| | - Jennifer A H Koop
- Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois, USA
| | - Jaime A Chaves
- Department of Biology, San Francisco State University, San Francisco, California, USA
- Colegio de Ciencias Biológicas y Ambientales, Universidad San Francisco de Quito, Quito, Ecuador
| | - Jill L Wegrzyn
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut, USA
- Institute for Systems Genomics, University of Connecticut, Storrs, Connecticut, USA
| |
Collapse
|
2
|
Solomon G, Love AC, Vaziri GJ, Harvey J, Verrett T, Chernicky K, Simons S, Albert L, Chaves JA, Knutie SA. Effect of urbanization and parasitism on the gut microbiota of Darwin's finch nestlings. Mol Ecol 2023; 32:6059-6069. [PMID: 37837269 DOI: 10.1111/mec.17164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 09/20/2023] [Accepted: 10/02/2023] [Indexed: 10/15/2023]
Abstract
Host-associated microbiota can be affected by factors related to environmental change, such as urbanization and invasive species. For example, urban areas often affect food availability for animals, which can change their gut microbiota. Invasive parasites can also influence microbiota through competition or indirectly through a change in the host immune response. These interacting factors can have complex effects on host fitness, but few studies have disentangled the relationship between urbanization and parasitism on an organism's gut microbiota. To address this gap in knowledge, we investigated the effects of urbanization and parasitism by the invasive avian vampire fly (Philornis downsi) on the gut microbiota of nestling small ground finches (Geospiza fuliginosa) on San Cristóbal Island, Galápagos. We conducted a factorial study in which we experimentally manipulated parasite presence in an urban and nonurban area. Faeces were then collected from nestlings to characterize the gut microbiota (i.e. bacterial diversity and community composition). Although we did not find an interactive effect of urbanization and parasitism on the microbiota, we did find main effects of each variable. We found that urban nestlings had lower bacterial diversity and different relative abundances of taxa compared to nonurban nestlings, which could be mediated by introduction of the microbiota of the food items or changes in host physiology. Additionally, parasitized nestlings had lower bacterial richness than nonparasitized nestlings, which could be mediated by a change in the immune system. Overall, this study advances our understanding of the complex effects of anthropogenic stressors on the gut microbiota of birds.
Collapse
Affiliation(s)
- Gabrielle Solomon
- Department of Ecology and Evolutionary Biology, University of Connecticut, Connecticut, Storrs, USA
| | - Ashley C Love
- Department of Ecology and Evolutionary Biology, University of Connecticut, Connecticut, Storrs, USA
| | - Grace J Vaziri
- Department of Ecology and Evolutionary Biology, University of Connecticut, Connecticut, Storrs, USA
| | - Johanna Harvey
- Department of Ecology and Evolutionary Biology, University of Connecticut, Connecticut, Storrs, USA
| | - Taylor Verrett
- Department of Ecology and Evolutionary Biology, University of Connecticut, Connecticut, Storrs, USA
| | - Kiley Chernicky
- Department of Ecology and Evolutionary Biology, University of Connecticut, Connecticut, Storrs, USA
| | - Shelby Simons
- Department of Ecology and Evolutionary Biology, University of Connecticut, Connecticut, Storrs, USA
| | - Lauren Albert
- Department of Ecology and Evolutionary Biology, University of Connecticut, Connecticut, Storrs, USA
| | - Jaime A Chaves
- Colegio de Ciencias Biológicas y Ambientales, Universidad San Francisco de Quito, Quito, Ecuador
- Galapagos Science Center, Puerto Baquerizo Moreno, Galapagos, Ecuador
- Department of Biology, San Francisco State University, California, San Francisco, USA
| | - Sarah A Knutie
- Department of Ecology and Evolutionary Biology, University of Connecticut, Connecticut, Storrs, USA
- Colegio de Ciencias Biológicas y Ambientales, Universidad San Francisco de Quito, Quito, Ecuador
- Institute for Systems Genomics, University of Connecticut, Connecticut, Storrs, USA
| |
Collapse
|
3
|
Herman JM, Fiorini VD, Crudele I, Reboreda JC, Pladas SA, Watson AP, Bush SE, Clayton DH. Co-parasitism in the face of predation: Effects of natural enemies on a neotropical mockingbird. J Anim Ecol 2023; 92:1992-2004. [PMID: 37583129 DOI: 10.1111/1365-2656.13991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 07/13/2023] [Indexed: 08/17/2023]
Abstract
Co-parasitism is ubiquitous and has important consequences for the ecology and evolution of wild host populations. Studies of parasite co-infections remain limited in scope, with few experimental tests of the fitness consequences of multiple parasites, especially in natural populations. We measured the separate and combined effects of Philornis seguyi nest flies and shiny cowbirds Molothrus bonariensis on the fitness of a shared host, the chalk-browed mockingbird (Mimus saturninus) in Argentina. Using a two-factor experimental approach, we manipulated the presence of nest flies and cowbirds in mockingbird nests and assessed their effects on mockingbird haemoglobin levels, begging and provisioning rates, body size, and fledging success. We also monitored rates of nest predation in relation to parasitism by flies and cowbirds. Nest flies reduced the haemoglobin concentration, body size, and fledging success of mockingbirds, likely because mockingbirds did not compensate for parasitism by begging more or feeding their nestlings more. Cowbirds also reduced the fledging success of mockingbirds, even though they had no detectable effect on haemoglobin or body size. Nests with cowbirds, which beg more than mockingbirds, attracted more nest predators. There was no significant interaction between the effects of flies and cowbirds on any component of mockingbird fitness. The combined effects of nest flies and cowbirds were strictly additive. In summary, we show that nest flies and cowbirds both reduce host fitness, but do not have interactive effects in co-parasitized nests. Our results further suggest that predators exacerbate the effects of nest flies and cowbirds on their hosts. Our study shows that the fitness consequences of co-parasitism are complex, especially in the context of community-level interactions.
Collapse
Affiliation(s)
- Jordan M Herman
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
| | - Vanina D Fiorini
- Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, IEGEBA-UBA-CONICET, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Ignacio Crudele
- Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, IEGEBA-UBA-CONICET, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Juan C Reboreda
- Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, IEGEBA-UBA-CONICET, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Shawn A Pladas
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
- Department of Biological Sciences, Southeastern Louisiana University, Hammond, Louisiana, USA
| | - André P Watson
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
| | - Sarah E Bush
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
| | - Dale H Clayton
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, USA
| |
Collapse
|
4
|
Pike CL, Kofler B, Richner H, Tebbich S. Parental food provisioning and nestling growth under Philornis downsi parasitism in the Galapagos Green Warbler-Finch, classified as 'vulnerable' by the IUCN. JOURNAL OF ORNITHOLOGY 2023; 164:669-676. [PMID: 37205902 PMCID: PMC10188583 DOI: 10.1007/s10336-023-02049-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 01/31/2023] [Accepted: 02/04/2023] [Indexed: 05/21/2023]
Abstract
In the Galapagos Islands, many endemic landbird populations are declining due to habitat degradation, food availability, introduced species and other factors. Given nestlings typically lack efficient defense mechanisms against parasites, hematophagous ectoparasites such as the larvae of the introduced Avian Vampire Fly, Philornis downsi, can impose high brood mortality and cause threatening population declines in Darwin finches and other landbirds. Here, we assess whether the food compensation hypothesis (i.e., the parents' potential to compensate for deleterious parasite effects via increased food provisioning) applies to the Green Warbler-Finch. We differentiated nests with low or high infestation levels by P. downsi and quantified food provisioning rates of male and female parents, time females spent brooding nestlings, and nestling growth. Male provisioning rates, total provisioning rates and female brooding time did not significantly vary in relation to infestation levels, nor by the number of nestlings. Opposed to the predictions of the food compensation hypothesis, females showed significantly reduced provisioning rates at high infestation levels. Nestling body mass was significantly lower and there was a reduction of skeletal growth, although not significantly, in highly infested nests. The females' response to high infestation may be due to parasites directly attacking and weakening brooding females, or else that females actively reduce current reproductive effort in favor of future reproduction. This life-history trade-off may be typical for Darwin finches and many tropical birds with long lifespans and therefore high residual reproductive value. Conservation strategies may not build on the potential for parental food compensation by this species.
Collapse
Affiliation(s)
- Courtney L. Pike
- Department of Behavioral and Cognitive Biology, University of Vienna, Vienna, Vienna Austria
| | - Barbara Kofler
- Department of Behavioral and Cognitive Biology, University of Vienna, Vienna, Vienna Austria
| | - Heinz Richner
- Department of Biology, University of Bern, Bern, Bern Switzerland
| | - Sabine Tebbich
- Department of Behavioral and Cognitive Biology, University of Vienna, Vienna, Vienna Austria
| |
Collapse
|
5
|
Romine MG, Knutie SA, Crow CM, Vaziri GJ, Chaves JA, Koop JAH, Lamichhaney S. The genome sequence of the avian vampire fly ( Philornis downsi), an invasive nest parasite of Darwin’s finches in Galápagos. G3 GENES|GENOMES|GENETICS 2022; 12:6456303. [PMID: 34878103 PMCID: PMC9210292 DOI: 10.1093/g3journal/jkab414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 11/15/2021] [Indexed: 11/14/2022]
Abstract
The invasive avian vampire fly (Philornis downsi, Diptera: Muscidae) is considered one of the greatest threats to the endemic avifauna of the Galápagos Islands. The fly larvae parasitize nearly every passerine species, including Darwin’s finches. Most P. downsi research to date has focused on the effects of the fly on avian host fitness and mitigation methods. A lag in research related to the genetics of this invasion demonstrates, in part, the need to develop full-scale genomic resources with which to address further questions within this system. In this study, an adult female P. downsi was sequenced to generate a high-quality genome assembly. We examined various features of the genome (e.g., coding regions and noncoding transposable elements) and carried out comparative genomics analysis against other dipteran genomes. We identified lists of gene families that are significantly expanding or contracting in P. downsi that are related to insecticide resistance, detoxification, and counter defense against host immune responses. The P. downsi genome assembly provides an important resource for studying the molecular basis of successful invasion in the Galápagos and the dynamics of its population across multiple islands. The findings of significantly changing gene families associated with insecticide resistance and immune responses highlight the need for further investigations into the role of different gene families in aiding the fly’s successful invasion. Furthermore, this genomic resource provides a necessary tool to better inform future research studies and mitigation strategies aimed at minimizing the fly’s impact on Galápagos birds.
Collapse
Affiliation(s)
- Melia G Romine
- School of Biomedical Sciences, Kent State University, Kent, OH 44240, USA
| | - Sarah A Knutie
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA
- Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269, USA
| | - Carly M Crow
- Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115, USA
| | - Grace J Vaziri
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Jaime A Chaves
- Department of Biology, San Francisco State University, San Francisco, CA 94132, USA
- Colegio de Ciencias Biológicas y Ambientales, Universidad San Francisco de Quito, Quito 170901, Ecuador
| | - Jennifer A H Koop
- Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115, USA
| | - Sangeet Lamichhaney
- School of Biomedical Sciences, Kent State University, Kent, OH 44240, USA
- Department of Biological Sciences, Kent State University, Kent, OH 44240, USA
| |
Collapse
|
6
|
Pike CL, Ramirez IE, Anchundia DJ, Fessl B, Heimpel GE, Causton CE. Behavior of the Avian Parasite Philornis downsi (Diptera: Muscidae) in and Near Host Nests in the Galapagos Islands. JOURNAL OF INSECT BEHAVIOR 2021; 34:296-311. [PMID: 35153376 PMCID: PMC8813692 DOI: 10.1007/s10905-021-09789-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 10/22/2021] [Accepted: 10/29/2021] [Indexed: 06/14/2023]
Abstract
UNLABELLED The Avian Vampire Fly, Philornis downsi, has invaded the Galapagos Islands, where it causes high mortality of endemic and native landbird species, including most species of Darwin's finches. Control methods are under development, but key information is missing about the reproductive biology of P. downsi and the behavior of flies in and near nests of their hosts. We used external and internal nest cameras to record the behavior of P. downsi adults within and outside nests of the Galapagos Flycatcher, Myiarchus magnirostris, throughout all stages of the nesting cycle. These recordings showed that P. downsi visited flycatcher nests throughout the day with higher fly activity during the nestling phase during vespertine hours. The observations also revealed that multiple P. downsi individuals can visit nests concurrently, and that there are some interactions among these flies within the nest. Fly visitation to nests occurred significantly more often while parent birds were away from the nest than in the nest, and this timing appears to be a strategy to avoid predation by parent birds. We report fly mating behavior outside the nest but not in the nest cavity. We discuss the relevance of these findings for the adaptive forces shaping P. downsi life history strategies as well as rearing and control measures. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s10905-021-09789-7.
Collapse
Affiliation(s)
- Courtney L. Pike
- Charles Darwin Research Station, Charles Darwin Foundation, Puerto Ayora, Santa Cruz Ecuador
- Department of Behavioral and Cognitive Biology, University of Vienna, Vienna, Vienna Austria
| | | | - David J. Anchundia
- Charles Darwin Research Station, Charles Darwin Foundation, Puerto Ayora, Santa Cruz Ecuador
- Department of Behavioral and Cognitive Biology, University of Vienna, Vienna, Vienna Austria
| | - Birgit Fessl
- Charles Darwin Research Station, Charles Darwin Foundation, Puerto Ayora, Santa Cruz Ecuador
| | | | - Charlotte E. Causton
- Charles Darwin Research Station, Charles Darwin Foundation, Puerto Ayora, Santa Cruz Ecuador
| |
Collapse
|
7
|
Boutry J, Tissot S, Ujvari B, Capp JP, Giraudeau M, Nedelcu AM, Thomas F. The evolution and ecology of benign tumors. Biochim Biophys Acta Rev Cancer 2021; 1877:188643. [PMID: 34715267 DOI: 10.1016/j.bbcan.2021.188643] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 10/22/2021] [Accepted: 10/23/2021] [Indexed: 12/12/2022]
Abstract
Tumors are usually classified into two main categories - benign or malignant, with much more attention being devoted to the second category given that they are usually associated with more severe health issues (i.e., metastatic cancers). Here, we argue that the mechanistic distinction between benign and malignant tumors has narrowed our understanding of neoplastic processes. This review provides the first comprehensive discussion of benign tumors in the context of their evolution and ecology as well as interactions with their hosts. We compare the genetic and epigenetic profiles, cellular activities, and the involvement of viruses in benign and malignant tumors. We also address the impact of intra-tumoral cell composition and its relationship with the tumoral microenvironment. Lastly, we explore the differences in the distribution of benign and malignant neoplasia across the tree of life and provide examples on how benign tumors can also affect individual fitness and consequently the evolutionary trajectories of populations and species. Overall, our goal is to bring attention to the non-cancerous manifestations of tumors, at different scales, and to stimulate research on the evolutionary ecology of host-tumor interactions on a broader scale. Ultimately, we suggest that a better appreciation of the differences and similarities between benign and malignant tumors is fundamental to our understanding of malignancy both at mechanistic and evolutionary levels.
Collapse
Affiliation(s)
- Justine Boutry
- CREEC/CANECEV, MIVEGEC (CREES), University of Montpellier, CNRS, IRD, Montpellier, France
| | - Sophie Tissot
- CREEC/CANECEV, MIVEGEC (CREES), University of Montpellier, CNRS, IRD, Montpellier, France
| | - Beata Ujvari
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin, University, Vic., Australia
| | - Jean-Pascal Capp
- Toulouse Biotechnology Institute, University of Toulouse, INSA, CNRS, INRAE, Toulouse, France
| | - Mathieu Giraudeau
- CREEC/CANECEV, MIVEGEC (CREES), University of Montpellier, CNRS, IRD, Montpellier, France; LIENSs, UMR 7266 CNRS-La Rochelle Université, 2 Rue Olympe de Gouges, 17000 La Rochelle, France
| | - Aurora M Nedelcu
- Department of Biology, University of New Brunswick, Fredericton, New Brunswick, E3B 5A3, Canada
| | - Frédéric Thomas
- CREEC/CANECEV, MIVEGEC (CREES), University of Montpellier, CNRS, IRD, Montpellier, France.
| |
Collapse
|
8
|
Hayes CD, Hayes TI, Quiroga M, Thorstrom RK, Bond L, Anderson DL. Is the grass always greener on the other side? Weak relationships between vegetation cover and parasitic fly infestations. Parasitol Res 2021; 120:3497-3505. [PMID: 34490523 DOI: 10.1007/s00436-021-07287-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 08/10/2021] [Indexed: 10/20/2022]
Abstract
Understanding parasite-host ecology is increasingly important for conservation efforts in a changing world. Parasitic nest flies in the genus Philornis (Diptera: Muscidae) have been implicated in the decline of endemic island species and are also known to negatively impact breeding success of the critically endangered Ridgway's hawk (B. ridgwayi) on the island of Hispaniola. Despite the importance of these effects on hosts, and extensive research of Philornis downsi in the Galápagos, the ecology of most species of philornid nest flies is poorly understood. We examined biotic factors related to Philornis pici infestations of nestling Ridgway's hawks in the Dominican Republic, where both fly and hawk are native. We found grass-cover was negatively associated with P. pici infestations, while coverage and height of other vegetation classes (tree, shrub, herbaceous, and bare ground) had no association, which is interesting considering recent landscape-level changes to Ridgway's hawk habitat. Anthropogenic activities in Los Haitises National Park, the last strong-hold of Ridgway's hawk, have shifted the landscape from primary forest to a fragmented secondary forest with smallholder or subsistence farms and grassy patches. New information on the ecology of nest flies in their native habitat can inform conservation efforts and allow us to make recommendations for future research.
Collapse
Affiliation(s)
- Christine D Hayes
- The Peregrine Fund, Boise, ID, USA. .,Department of Biological Sciences, Boise State University, Boise, ID, USA.
| | | | - Martín Quiroga
- The Peregrine Fund, Boise, ID, USA.,Laboratorio de Ecología de Enfermedades, Instituto de Ciencias Veterinarias del Litoral (ICIVET-Litoral), Universidad Nacional del Litoral - Consejo Nacional de Investigaciones Científicas y Técnicas (UNL-CONICET), Esperanza, Santa Fe, Argentina.,Instituto Tecnológico de Santo Domingo, Santo Domingo, República Dominicana
| | | | - Laura Bond
- Biomolecular Research Center, Boise State University, Boise, ID, USA
| | | |
Collapse
|
9
|
Katsis AC, Colombelli-Négrel D, Common LK, O’connor JA, Dudaniec RY, García-Loor J, Kleindorfer S. Nestling behaviour predicts naris deformation in Darwin’s finches parasitized by the avian vampire fly. Biol J Linn Soc Lond 2021. [DOI: 10.1093/biolinnean/blab092] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Although in-nest parasitism can reduce the fitness of avian hosts, the severity of these effects may vary with host physiology and behaviour. If certain nestling behaviours are beneficial for resisting parasitism, then selection may favour some behavioural phenotypes over others. Here, we tested whether differences in nestling behaviour mediate the negative effects of parasitism, using small ground finches (Geospiza fuliginosa), on Floreana Island, that had been parasitized by the invasive avian vampire fly (Philornis downsi). We first established, using 4 years of breeding data (2005, 2006, 2010 and 2020), that nestlings exposed to more parasites had larger nares and, among older nestlings only, lower body mass. We then examined, using data from the 2020 season, whether each nestling’s behaviour (specifically, its response to human handling) predicted the severity of its naris deformation. When faced with high-intensity parasitism, more responsive nestlings (i.e. those that struggled more during handling) had larger nares compared to more docile nestlings. This suggests that more responsive nestlings suffer greater fitness costs due to parasitism, although we also discuss alternative explanations. Future work should consider the stability and heritability of these nestling behavioural differences and whether parasite-induced selection shapes behavioural variation at the population level.
Collapse
Affiliation(s)
- Andrew C Katsis
- College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia
| | - Diane Colombelli-Négrel
- College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia
| | - Lauren K Common
- College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia
| | - Jody A O’connor
- College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia
- Department for Environment and Water, Government of South Australia, Adelaide, South Australia, Australia
| | - Rachael Y Dudaniec
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
| | | | - Sonia Kleindorfer
- College of Science and Engineering, Flinders University, Adelaide, South Australia, Australia
- Konrad Lorenz Research Centre for Behaviour and Cognition and Department of Behavioural and Cognitive Biology, University of Vienna, Vienna, Austria
| |
Collapse
|
10
|
Timing of infestation influences virulence and parasite success in a dynamic multi-host-parasite interaction between the invasive parasite, Philornis downsi, and Darwin's finches. Oecologia 2020; 195:249-259. [PMID: 33258992 PMCID: PMC7882474 DOI: 10.1007/s00442-020-04807-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Accepted: 11/16/2020] [Indexed: 12/30/2022]
Abstract
Recently commenced host–parasite interactions provide an excellent opportunity to study co-evolutionary processes. Multi-host systems are especially informative because variation in virulence between hosts and temporal changes provides insight into evolutionary dynamics. However, empirical data under natural conditions are scarce. In the present study, we investigated the interaction between Darwin’s finches and the invasive fly Philornis downsi whose larvae feed on the blood of nestlings. Recently, however, the fly has changed its behavior and now also attacks incubating females. Two sympatric hosts are affected differently by the parasite and parasite load has changed over time. Our study observed a reversal of trends described two decades ago: while, currently, small tree finches (Camarhynchus parvulus) experience significantly higher parasite load than warbler finches (Certhidea olivacea), this was the opposite two decades ago. Currently, fledging success is higher in warbler finches compared to small tree finches. Our data indicate that not only intensity but also timing of infestation influences hosts’ reproductive success and parasite fitness. During incubation, prevalence was higher in warbler finches, but once chicks had hatched, prevalence was 100% in both species and parasite load was higher in small tree finches. Furthermore, our results suggest faster development and higher reproductive success of P. downsi in small tree finch nests. A change in host preference driven by larvae competition could have led to the reversal in parasite load.
Collapse
|
11
|
Wappl C, Cimadom A, Filek N, Heyer E, Tebbich S. Under adverse conditions, older small tree finch males ( Camarhynchus parvulus) produce more offspring than younger males. Ethology 2020; 126:966-975. [PMID: 33162627 PMCID: PMC7604768 DOI: 10.1111/eth.13069] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 04/29/2020] [Accepted: 05/04/2020] [Indexed: 11/30/2022]
Abstract
Females of many bird species prefer mating with older males, presumably because they provide superior parental care and possibly superior genes. A previous study found that female small tree finches (Camarhynchus parvulus) preferred pairing with old males and had a higher breeding success when paired with old males because their nests were more concealed, higher up in the canopy and therefore less likely to be depredated. However, causes for brood loss have changed over the last decade: predation of small tree finch nests has decreased, whereas brood losses due to parasitism by the invasive parasitic fly Philornis downsi have increased. In the present study, we investigated (a) how the change in predation and parasitism by P. downsi influenced the breeding success of small tree finches, (b) whether there were still differences in breeding success between young and old males, (c) whether P. downsi infestation had a differential effect on nests of young and old males and (d) whether young and old males differed in foraging success. During 2012-2016, we found an overall low influence of predation and a high influence of P. downsi, but neither differed between nests of young and old males. Nests of old males had more fledglings than those of young males. However, the difference in breeding success disappeared when P. downsi numbers were experimentally reduced by injecting an insecticide into nests. This indicates that older males were able to compensate for the detrimental effects of parasitism.
Collapse
Affiliation(s)
- Christian Wappl
- Department of Behavioural BiologyUniversity of ViennaViennaAustria
| | - Arno Cimadom
- Department of Behavioural BiologyUniversity of ViennaViennaAustria
| | - Nikolaus Filek
- Department of Behavioural BiologyUniversity of ViennaViennaAustria
| | - Eileen Heyer
- Department of Behavioural BiologyUniversity of ViennaViennaAustria
| | - Sabine Tebbich
- Department of Behavioural BiologyUniversity of ViennaViennaAustria
| |
Collapse
|
12
|
Trypanosomatids Detected in the Invasive Avian Parasite Philornis downsi (Diptera: Muscidae) in the Galapagos Islands. INSECTS 2020; 11:insects11070422. [PMID: 32659927 PMCID: PMC7411904 DOI: 10.3390/insects11070422] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 07/06/2020] [Indexed: 11/17/2022]
Abstract
Alien insect species may present a multifaceted threat to ecosystems into which they are introduced. In addition to the direct damage they may cause, they may also bring novel diseases and parasites and/or have the capacity to vector microorganisms that are already established in the ecosystem and are causing harm. Damage caused by ectoparasitic larvae of the invasive fly, Philornisdownsi (Dodge and Aitken) to nestlings of endemic birds in the Galapagos Islands is well documented, but nothing is known about whether this fly is itself associated with parasites or pathogens. In this study, diagnostic molecular methods indicated the presence of insect trypanosomatids in P. downsi; to our knowledge, this is the first record of insect trypanosomatids associated with Philornis species. Phylogenetic estimates and evolutionary distances indicate these species are most closely related to the Crithidia and Blastocrithidia genera, which are not currently reported in the Galapagos Islands. The prevalence of trypanosomatids indicates either P. downsi arrived with its own parasites or that it is a highly suitable host for trypanosomatids already found in the Galapagos Islands, or both. We recommend further studies to determine the origin of the trypanosomatid infections to better evaluate threats to endemic fauna of the Galapagos Islands.
Collapse
|
13
|
Quiroga MA, Hayes TI, Hayes CD, Garrod H, Soares L, Knutie SA, Latta SC, Anderson DL. More than just nestlings: incidence of subcutaneous Philornis (Diptera: Muscidae) nest flies in adult birds. Parasitol Res 2020; 119:2337-2342. [PMID: 32500371 DOI: 10.1007/s00436-020-06696-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 04/21/2020] [Indexed: 11/30/2022]
Abstract
Philornis flies Meinert (Diptera: Muscidae) have been documented parasitizing over 250 bird species, some of which are endemic species threatened with extinction. Philornis parasitism is hypothesized to affect nestlings disproportionately more than adult birds because limited mobility and exposed skin of nestlings increase their vulnerability to parasitism. We used a comprehensive literature review and our recent fieldwork in the Dominican Republic, Puerto Rico, and Grenada to challenge the idea that parasitism by subcutaneous Philornis species is a phenomenon primarily found in nestlings, a fact that has not been quantified to date. Of the 265 reviewed publications, 125 (49%) reported incidences of parasitism by subcutaneous Philornis, but only 12 included the sampling of adult breeding birds. Nine of these publications (75%) reported Philornis parasitism in adults of ten bird species. During fieldwork in the Dominican Republic, Puerto Rico, and Grenada, we documented 14 instances of parasitism of adult birds of seven avian species. From literature review and fieldwork, adults of at least fifteen bird species across 12 families and four orders of birds were parasitized by at least five Philornis species. In both the published literature and fieldwork, incidences of parasitism of adult birds occurred predominantly in females and was frequently associated with incubation. Although our findings indicate that Philornis parasitism of adult birds is more common than widely presumed, parasite prevalence is still greater in nestlings. In the future, we recommend surveys of adult birds to better understand host-Philornis relationships across life stages. This information may be essential for the development of effective control measures of Philornis to ensure the long-term protection of bird species of conservation concern.
Collapse
Affiliation(s)
- Martín A Quiroga
- The Peregrine Fund, 5668 W Flying Hawk Lane, Boise, ID, 83709, USA. .,Laboratorio de Ecología de Enfermedades (ICiVet Litoral - UNL - CONICET), R.P. Kreder 2805, S3080HOF, Santa Fe, Argentina. .,Department of Biology, Universidad Autónoma de Entre Ríos, Ruta Provincial N 11 Km. 10.5, Oro Verde, E3100XAD, Entre Ríos, Argentina. .,Instituto Tecnológico de Santo Domingo, Avenida de Los Próceres #49, Santo Domingo, 10602, República Dominicana.
| | - Thomas I Hayes
- The Peregrine Fund, 5668 W Flying Hawk Lane, Boise, ID, 83709, USA
| | - Christine D Hayes
- The Peregrine Fund, 5668 W Flying Hawk Lane, Boise, ID, 83709, USA.,Department of Biological Sciences, Boise State University, 1910 W University Drive, Boise, ID, 83725, USA
| | - Holly Garrod
- Department of Biology, Villanova University, 800 Lancaster Ave, Villanova, PA, 19085, USA
| | - Leticia Soares
- Department of Biology, University of Western Ontario, 1151 Richmond Street, Ontario, N6A5B7, Canada
| | - Sarah A Knutie
- Department of Ecology and Evolutionary Biology, University of Connecticut, 75 N. Eagleville Rd., Unit 3043, Storrs, CT, 06269-3043, USA
| | - Steven C Latta
- National Aviary, 700 Arch Street, Pittsburgh, PA, 15212, USA
| | - David L Anderson
- The Peregrine Fund, 5668 W Flying Hawk Lane, Boise, ID, 83709, USA
| |
Collapse
|
14
|
McNew SM, Goodman GB, Yépez R J, Clayton DH. Parasitism by an invasive nest fly reduces future reproduction in Galápagos mockingbirds. Oecologia 2020; 192:363-374. [PMID: 31897722 DOI: 10.1007/s00442-019-04582-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Accepted: 12/13/2019] [Indexed: 11/30/2022]
Abstract
Organisms allocate limited resources to competing activities such as reproduction, growth, and defense against parasites and predators. The introduction of a novel parasite may create new life history trade-offs. As hosts increase their investment in self-maintenance or defense, the cost of parasitism may carry over to other aspects of host biology. Here, in an experimental field study, we document delayed effects of an introduced nest parasite, Philornis downsi, on reproduction of Galápagos mockingbirds (Mimus parvulus). Parasitism of first nests reduced both the number and size of chicks that parents hatched when they re-nested several weeks later. The delayed effect of P. downsi on future reproduction may have been mediated by behavioral shifts by the parents to avoid or resist parasitism. Our results demonstrate that effects of parasitism can persist even after immediate exposure ends. We draw attention to the potential implications that introduced parasites have for host reproductive strategies.
Collapse
Affiliation(s)
- Sabrina M McNew
- Department of Biology, University of Utah, Salt Lake City, UT, 84112-0840, USA.
- Fuller Evolutionary Biology Program, Cornell Lab of Ornithology, Ithaca, NY, 14850, USA.
| | - Graham B Goodman
- Department of Biology, University of Utah, Salt Lake City, UT, 84112-0840, USA
- Department of Biology, Hobart and William Smith Colleges, Geneva, NY, 14456, USA
| | - Janai Yépez R
- Charles Darwin Research Station, Santa Cruz Island, Galápagos, Ecuador
| | - Dale H Clayton
- Department of Biology, University of Utah, Salt Lake City, UT, 84112-0840, USA
| |
Collapse
|
15
|
McNew SM, Knutie SA, Goodman GB, Theodosopoulos A, Saulsberry A, Yépez R. J, Bush SE, Clayton DH. Annual environmental variation influences host tolerance to parasites. Proc Biol Sci 2019; 286:20190049. [PMID: 30963843 PMCID: PMC6408884 DOI: 10.1098/rspb.2019.0049] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 02/06/2019] [Indexed: 12/16/2022] Open
Abstract
When confronted with a parasite or pathogen, hosts can defend themselves by resisting or tolerating the attack. While resistance can be diminished when resources are limited, it is unclear how robust tolerance is to changes in environmental conditions. Here, we investigate the sensitivity of tolerance in a single host population living in a highly variable environment. We manipulated the abundance of an invasive parasitic fly, Philornis downsi, in nests of Galápagos mockingbirds ( Mimus parvulus) over four field seasons and measured host fitness in response to parasitism. Mockingbird tolerance to P. downsi varied significantly among years and decreased when rainfall was limited. Video observations indicate that parental provisioning of nestlings appears key to tolerance: in drought years, mockingbirds likely do not have sufficient resources to compensate for the effects of P. downsi. These results indicate that host tolerance is a labile trait and suggest that environmental variation plays a major role in mediating the consequences of host-parasite interactions.
Collapse
Affiliation(s)
- Sabrina M. McNew
- Department of Biology, University of Utah, Salt Lake City, UT 84112-0840, USA
| | - Sarah A. Knutie
- Department of Biology, University of Utah, Salt Lake City, UT 84112-0840, USA
| | - Graham B. Goodman
- Department of Biology, University of Utah, Salt Lake City, UT 84112-0840, USA
| | | | - Ashley Saulsberry
- Department of Biology, University of Utah, Salt Lake City, UT 84112-0840, USA
| | - Janai Yépez R.
- Charles Darwin Research Station, Santa Cruz Island, Galápagos, Ecuador
| | - Sarah E. Bush
- Department of Biology, University of Utah, Salt Lake City, UT 84112-0840, USA
| | - Dale H. Clayton
- Department of Biology, University of Utah, Salt Lake City, UT 84112-0840, USA
| |
Collapse
|
16
|
Hayes CD, Hayes TI, McClure CJW, Quiroga M, Thorstrom RK, Anderson DL. Native parasitic nest fly impacts reproductive success of an island‐endemic host. Anim Conserv 2018. [DOI: 10.1111/acv.12449] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- C. D. Hayes
- Department of Biological Sciences Boise State University Boise ID USA
- The Peregrine Fund Boise ID USA
| | | | | | - M. Quiroga
- The Peregrine Fund Boise ID USA
- Laboratorio de Ecología de Enfermedades Instituto de Ciencias Veterinarias del Litoral (ICIVET‐Litoral) Universidad Nacional del Litoral – Consejo Nacional de Investigaciones Científicas y Técnicas (UNL‐CONICET) R.P. Kreder 2805 Esperanza Santa Fe Argentina
- Facultad de Ciencia y Tecnología Universidad Autónoma de Entre Ríos (UAdER) Oro Verde Argentina
| | | | | |
Collapse
|
17
|
Edworthy AB, Langmore NE, Heinsohn R. Native fly parasites are the principal cause of nestling mortality in endangered Tasmanian pardalotes. Anim Conserv 2018. [DOI: 10.1111/acv.12444] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- A. B. Edworthy
- Research School of Biology Australian National University Canberra ACT Australia
| | - N. E. Langmore
- Research School of Biology Australian National University Canberra ACT Australia
| | - R. Heinsohn
- Fenner School of Environment and Society Australian National University Canberra ACT Australia
| |
Collapse
|
18
|
Knutie SA, Owen JP, McNew SM, Bartlow AW, Arriero E, Herman JM, DiBlasi E, Thompson M, Koop JAH, Clayton DH. Galápagos mockingbirds tolerate introduced parasites that affect Darwin's finches. Ecology 2018; 97:940-950. [PMID: 28792593 DOI: 10.1890/15-0119.1] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 09/28/2015] [Accepted: 11/05/2015] [Indexed: 01/17/2023]
Abstract
Introduced parasites threaten native host species that lack effective defenses. Such parasites increase the risk of extinction, particularly in small host populations like those on islands. If some host species are tolerant to introduced parasites, this could amplify the risk of the parasite to vulnerable host species. Recently, the introduced parasitic nest fly Philornis downsi has been implicated in the decline of Darwin's finch populations in the Galápagos Islands. In some years, 100% of finch nests fail due to P. downsi; however, other common host species nesting near Darwin's finches, such as the endemic Galápagos mockingbird (Mimus parvulus), appear to be less affected by P. downsi. We compared effects of P. downsi on mockingbirds and medium ground finches (Geospiza fortis) on Santa Cruz Island in the Galápagos. We experimentally manipulated the abundance of P. downsi in nests of mockingbirds and finches to measure the direct effect of the parasite on the reproductive success of each species of host. We also compared immunological and behavioral responses by each species of host to the fly. Although nests of the two host species had similar parasite densities, flies decreased the fitness of finches but not mockingbirds. Neither host species had a significant antibody-mediated immune response to P. downsi. Moreover, finches showed no significant increase in begging, parental provisioning, or plasma glucose levels in response to the flies. In contrast, parasitized mockingbird nestlings begged more than nonparasitized mockingbird nestlings. Greater begging was correlated with increased parental provisioning behavior, which appeared to compensate for parasite damage. The results of our study suggest that finches are negatively affected by P. downsi because they do not have such behavioral mechanisms for energy compensation. In contrast, mockingbirds are capable of compensation, making them tolerant hosts, and a possible indirect threat to Darwin's finches.
Collapse
Affiliation(s)
- Sarah A Knutie
- Department of Biology, University of Utah, Salt Lake City, Utah, 84112, USA
| | - Jeb P Owen
- Department of Entomology, Washington State University, Pullman, Washington, 99164, USA
| | - Sabrina M McNew
- Department of Biology, University of Utah, Salt Lake City, Utah, 84112, USA
| | - Andrew W Bartlow
- Department of Biology, University of Utah, Salt Lake City, Utah, 84112, USA
| | - Elena Arriero
- Department of Zoology and Physical Anthropology, Complutense University of Madrid, E-28040, Madrid, Spain
| | - Jordan M Herman
- Department of Biology, University of Utah, Salt Lake City, Utah, 84112, USA
| | - Emily DiBlasi
- Department of Biology, University of Utah, Salt Lake City, Utah, 84112, USA
| | - Michael Thompson
- Department of Biology, University of Utah, Salt Lake City, Utah, 84112, USA
| | - Jennifer A H Koop
- Department of Biology, University of Utah, Salt Lake City, Utah, 84112, USA
| | - Dale H Clayton
- Department of Biology, University of Utah, Salt Lake City, Utah, 84112, USA
| |
Collapse
|
19
|
Knutie SA. Relationships among introduced parasites, host defenses, and gut microbiota of Galapagos birds. Ecosphere 2018. [DOI: 10.1002/ecs2.2286] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Affiliation(s)
- Sarah A. Knutie
- Department of Ecology and Evolutionary Biology University of Connecticut Storrs Connecticut 06269 USA
| |
Collapse
|
20
|
Mullens BA, Hinkle NC, Fryxell RT, Rochon K. Past, Present, and Future Contributions and Needs for Veterinary Entomology in the United States and Canada. ACTA ACUST UNITED AC 2018. [DOI: 10.1093/ae/tmy006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
| | - Nancy C Hinkle
- Department of Entomology, University of Georgia, Athens, GA
| | - Rebecca Trout Fryxell
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN
| | - Kateryn Rochon
- Department of Entomology, University of Manitoba, Winnipeg, Manitoba
| |
Collapse
|
21
|
McNew SM, Clayton DH. Alien Invasion: Biology of Philornis Flies Highlighting Philornis downsi, an Introduced Parasite of Galápagos Birds. ANNUAL REVIEW OF ENTOMOLOGY 2018; 63:369-387. [PMID: 29058976 DOI: 10.1146/annurev-ento-020117-043103] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The muscid genus Philornis comprises approximately 50 described species of flies, nearly all of which are obligate parasites of nestling birds. Philornis species are native to the Neotropics and widely distributed from Florida to Argentina. Most research on this group has focused on P. downsi, which was introduced to the Galápagos Islands in the late twentieth century. Although Philornis parasitism kills nestlings in several native host species, nowhere do the effects seem more severe than in P. downsi in the Galápagos. Here, we review studies of native and introduced Philornis in an attempt to identify factors that may influence virulence and consider implications for the conservation of hosts in the Galápagos.
Collapse
Affiliation(s)
- Sabrina M McNew
- Department of Biology, University of Utah, Salt Lake City, Utah 84112-0840, USA;
| | - Dale H Clayton
- Department of Biology, University of Utah, Salt Lake City, Utah 84112-0840, USA;
| |
Collapse
|
22
|
Fessl B, Heimpel GE, Causton CE. Invasion of an Avian Nest Parasite, Philornis downsi, to the Galapagos Islands: Colonization History, Adaptations to Novel Ecosystems, and Conservation Challenges. DISEASE ECOLOGY 2018. [DOI: 10.1007/978-3-319-65909-1_9] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
23
|
Abstract
Colonization comprises the physical arrival of a species in a new area, but also its successful establishment within the local community. Oceanic islands, like the Hawaiian and the Galapagos archipelagos, represent excellent systems to study the mechanisms of colonization because of their historical isolation. In this chapter, we first review some of the major mechanisms by which parasites and vectors could arrive to an oceanic island, both naturally or due to human activities, and the factors that may influence their successful establishment in the insular host community. We then explore examples of natural and anthropogenic colonization of the Galapagos Islands by parasites and vectors, focusing on one or more case studies that best represent the diversity of colonization mechanisms that has shaped parasite distribution in the archipelago. Finally, we discuss future directions for research on parasite and vector colonization in Galapagos Islands.
Collapse
Affiliation(s)
- Patricia G. Parker
- Department of Biology, University of Missouri – St. Louis, St. Louis, Missouri USA
| |
Collapse
|
24
|
Knutie SA, Herman JM, Owen JP, Clayton DH. Tri‐trophic ecology of native parasitic nest flies of birds in
T
obago. Ecosphere 2017. [DOI: 10.1002/ecs2.1670] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Sarah A. Knutie
- Department of Biology University of Utah Salt Lake City Utah 84112 USA
| | - Jordan M. Herman
- Department of Biology University of Utah Salt Lake City Utah 84112 USA
| | - Jeb P. Owen
- Department of Entomology Washington State University Pullman Washington 99164 USA
| | - Dale H. Clayton
- Department of Biology University of Utah Salt Lake City Utah 84112 USA
| |
Collapse
|
25
|
Langkilde T, Thawley CJ, Robbins TR. Behavioral Adaptations to Invasive Species. ADVANCES IN THE STUDY OF BEHAVIOR 2017. [DOI: 10.1016/bs.asb.2016.12.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
26
|
Quiroga MA, Monje LD, Arrabal JP, Beldomenico PM. New molecular data on subcutaneous Philornis (Diptera: Muscidae) from southern South America suggests the existence of a species complex. REV MEX BIODIVERS 2016. [DOI: 10.1016/j.rmb.2016.10.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
|
27
|
Cha DH, Mieles AE, Lahuatte PF, Cahuana A, Lincango MP, Causton CE, Tebbich S, Cimadom A, Teale SA. Identification and Optimization of Microbial Attractants for Philornis downsi, an Invasive Fly Parasitic on Galapagos Birds. J Chem Ecol 2016; 42:1101-1111. [PMID: 27744622 DOI: 10.1007/s10886-016-0780-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 09/07/2016] [Accepted: 09/29/2016] [Indexed: 11/28/2022]
Abstract
We investigated the role of olfactory cues from actively fermenting yeast (Saccharomyces cerevisiae) in attraction of adult Philornis downsi and identified two synergistically attractive yeast volatiles. Larvae of this invasive fly parasitize the hatchlings of passerines and threaten the Galapagos avifauna. Gas chromatography coupled with electroantennographic detection (GC-EAD), coupled gas chromatography-mass spectrometry (GC-MS), and field trapping experiments were used to identify volatile compounds from a yeast-sugar solution. EAD responses were consistently elicited by 14 yeast volatiles. In a series of field trapping experiments, a mixture of the 14 EAD-active compounds was similarly attractive to P. downsi when compared to the yeast-sugar solution, and we found that acetic acid and ethanol were essential for attraction. A mixture of 0.03 % acetic acid and 3 % ethanol was as attractive as the 14-component blend, but was not as attractive as the yeast-sugar solution. Philornis downsi showed positive and negative dose-responses to acetic acid in the ranges of 0.01 ~ 0.3 % and 0.3 ~ 9 %, respectively. Further optimization showed that the mixture of 1 % acetic acid and 3 % ethanol was as attractive as the yeast-sugar solution. Both mixtures of acetic acid and ethanol were more selective than the yeast-sugar solution in terms of non-target moths and Polistes versicolor wasps captured. These results indicate that acetic acid and ethanol produced by yeasts are crucial for P. downsi attraction to fermented materials on which they feed as adults and can be used to manage this invasive fly in Galapagos.
Collapse
Affiliation(s)
- Dong H Cha
- College of Environmental Science and Forestry, State University of New York, Syracuse, NY, USA.,USDA-ARS, US Pacific Basin Agricultural Research Laboratory, 64 Nowelo St., Hilo, HI, USA
| | - Alejandro E Mieles
- College of Environmental Science and Forestry, State University of New York, Syracuse, NY, USA
| | - Paola F Lahuatte
- Charles Darwin Foundation for the Galapagos Islands, Puerto Ayora, Santa Cruz Island, Galapagos Islands, Ecuador
| | - Andrea Cahuana
- Charles Darwin Foundation for the Galapagos Islands, Puerto Ayora, Santa Cruz Island, Galapagos Islands, Ecuador
| | - Marie Piedad Lincango
- Charles Darwin Foundation for the Galapagos Islands, Puerto Ayora, Santa Cruz Island, Galapagos Islands, Ecuador.,Facultad de Ciencias Agrícolas, Universidad Central del Ecuador, Quito, Ecuador
| | - Charlotte E Causton
- Charles Darwin Foundation for the Galapagos Islands, Puerto Ayora, Santa Cruz Island, Galapagos Islands, Ecuador
| | - Sabine Tebbich
- Department of Behavioural Biology, University of Vienna, 1090, Vienna, Austria
| | - Arno Cimadom
- Department of Behavioural Biology, University of Vienna, 1090, Vienna, Austria
| | - Stephen A Teale
- College of Environmental Science and Forestry, State University of New York, Syracuse, NY, USA.
| |
Collapse
|
28
|
Darwin's finches treat their feathers with a natural repellent. Sci Rep 2016; 6:34559. [PMID: 27721475 PMCID: PMC5056383 DOI: 10.1038/srep34559] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 09/12/2016] [Indexed: 11/08/2022] Open
Abstract
Darwin's finches are highly innovative. Recently we recorded for the first time a behavioural innovation in Darwin's finches outside the foraging context: individuals of four species rubbed leaves of the endemic tree Psidium galapageium on their feathers. We hypothesised that this behaviour serves to repel ectoparasites and tested the repellency of P. galapageium leaf extracts against parasites that negatively affect the fitness of Darwin's finches, namely mosquitoes and the invasive hematophagous fly Philornis downsi. Mosquitoes transmit pathogens which have recently been introduced by humans and the larvae of the fly suck blood from nestlings and incubating females. Our experimental evidence demonstrates that P. galapageium leaf extracts repel both mosquitoes and adult P. downsi and also inhibit the growth of P. downsi larvae. It is therefore possible that finches use this plant to repel ectopoarasites.
Collapse
|
29
|
Kleindorfer S, Dudaniec RY. Host-parasite ecology, behavior and genetics: a review of the introduced fly parasite Philornis downsi and its Darwin’s finch hosts. BMC ZOOL 2016. [DOI: 10.1186/s40850-016-0003-9] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
|
30
|
Kleindorfer S, Sulloway FJ. Naris deformation in Darwin’s finches: Experimental and historical evidence for a post-1960s arrival of the parasite Philornis downsi. Glob Ecol Conserv 2016. [DOI: 10.1016/j.gecco.2016.05.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
|
31
|
Koop JAH, Kim PS, Knutie SA, Adler F, Clayton DH. An introduced parasitic fly may lead to local extinction of Darwin's finch populations. J Appl Ecol 2016; 53:511-518. [PMID: 26980922 PMCID: PMC4788638 DOI: 10.1111/1365-2664.12575] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Introduced pathogens and other parasites are often implicated in host population level declines and extinctions. However, such claims are rarely supported by rigorous real-time data. Indeed, the threat of introduced parasites often goes unnoticed until after host populations have declined severely. The recent introduction of the parasitic nest fly, Philornis downsi, to the Galápagos Islands provides an opportunity to monitor the current impact of an invasive parasite on endemic land bird populations, including Darwin's finches.In this paper we present a population viability model to explore the potential long-term effect of P. downsi on Darwin's finch populations. The goal of our study was to determine whether P. downsi has the potential to drive host populations to extinction and whether management efforts are likely to be effective.Our model is based on data from five years of experimental field work documenting the effect of P. downsi on the reproductive success of medium ground finch Geospiza fortis populations on Santa Cruz Island. Under two of the three scenarios tested, the model predicted medium ground finches are at risk of extinction within the next century.However, sensitivity analyses reveal that even a modest reduction in the prevalence of the parasite could improve the stability of finch populations. We discuss the practicality of several management options aimed at achieving this goal.Synthesis and applications. Our study demonstrates the predicted high risk of local extinction of an abundant host species, the medium ground finch Geospiza fortis due to an introduced parasite, Philornis downsi. However, our study further suggests that careful management practices aimed at reducing parasite prevalence have the potential to significantly lower the risk of host species extinction.
Collapse
Affiliation(s)
| | - Peter S. Kim
- Mathematics Department, University of Utah, Salt Lake City, UT, USA
| | - Sarah A. Knutie
- Department of Biology, University of Utah, Salt Lake City, UT, USA
| | - Fred Adler
- Department of Biology, University of Utah, Salt Lake City, UT, USA
- Mathematics Department, University of Utah, Salt Lake City, UT, USA
| | - Dale H. Clayton
- Department of Biology, University of Utah, Salt Lake City, UT, USA
| |
Collapse
|
32
|
Banerji A, Duncan AB, Griffin JS, Humphries S, Petchey OL, Kaltz O. Density- and trait-mediated effects of a parasite and a predator in a tri-trophic food web. J Anim Ecol 2015; 84:723-733. [PMID: 25382389 PMCID: PMC4674981 DOI: 10.1111/1365-2656.12317] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 10/30/2014] [Indexed: 11/26/2022]
Abstract
Despite growing interest in ecological consequences of parasitism in food webs, relatively little is known about effects of parasites on long-term population dynamics of non-host species or about whether such effects are density or trait mediated. We studied a tri-trophic food chain comprised of (i) a bacterial basal resource (Serratia fonticola), (ii) an intermediate consumer (Paramecium caudatum), (iii) a top predator (Didinium nasutum) and (iv) a parasite of the intermediate consumer (Holospora undulata). A fully factorial experimental manipulation of predator and parasite presence/absence was combined with analyses of population dynamics, modelling and analyses of host (Paramecium) morphology and behaviour. Predation and parasitism each reduced the abundance of the intermediate consumer (Paramecium), and parasitism indirectly reduced the abundance of the basal resource (Serratia). However, in combination, predation and parasitism had non-additive effects on the abundance of the intermediate consumer, as well as on that of the basal resource. In both cases, the negative effect of parasitism seemed to be effaced by predation. Infection of the intermediate consumer reduced predator abundance. Modelling and additional experimentation revealed that this was most likely due to parasite reduction of intermediate host abundance (a density-mediated effect), as opposed to changes in predator functional or numerical response. Parasitism altered morphological and behavioural traits, by reducing host cell length and increasing the swimming speed of cells with moderate parasite loads. Additional tests showed no significant difference in Didinium feeding rate on infected and uninfected hosts, suggesting that the combination of these modifications does not affect host vulnerability to predation. However, estimated rates of encounter with Serratia based on these modifications were higher for infected Paramecium than for uninfected Paramecium. A mixture of density-mediated and trait-mediated indirect effects of parasitism on non-host species creates rich and complex possibilities for effects of parasites in food webs that should be included in assessments of possible impacts of parasite eradication or introduction.
Collapse
Affiliation(s)
- Aabir Banerji
- Institut für Evolutionsbiologie und Umweltwissenschaften, Universität ZürichWinterthurerstrasse 190, Zürich, CH-8057, Switzerland
| | - Alison B Duncan
- Institut des Sciences de l'Evolution, UMR 5554, Université Montpellier IIPlace Eugène Bataillon, 34095, Montpellier Cedex 05, France
| | - Joanne S Griffin
- Institut des Sciences de l'Evolution, UMR 5554, Université Montpellier IIPlace Eugène Bataillon, 34095, Montpellier Cedex 05, France
| | - Stuart Humphries
- School of Life Sciences, University of LincolnBrayford Pool, Lincoln, Lincolnshire, LN6 7TS, UK
| | - Owen L Petchey
- Institut für Evolutionsbiologie und Umweltwissenschaften, Universität ZürichWinterthurerstrasse 190, Zürich, CH-8057, Switzerland
| | - Oliver Kaltz
- Institut des Sciences de l'Evolution, UMR 5554, Université Montpellier IIPlace Eugène Bataillon, 34095, Montpellier Cedex 05, France
| |
Collapse
|
33
|
Cimadom A, Ulloa A, Meidl P, Zöttl M, Zöttl E, Fessl B, Nemeth E, Dvorak M, Cunninghame F, Tebbich S. Invasive parasites, habitat change and heavy rainfall reduce breeding success in Darwin's finches. PLoS One 2014; 9:e107518. [PMID: 25248092 PMCID: PMC4172424 DOI: 10.1371/journal.pone.0107518] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 08/19/2014] [Indexed: 11/18/2022] Open
Abstract
Invasive alien parasites and pathogens are a growing threat to biodiversity worldwide, which can contribute to the extinction of endemic species. On the Galápagos Islands, the invasive parasitic fly Philornis downsi poses a major threat to the endemic avifauna. Here, we investigated the influence of this parasite on the breeding success of two Darwin's finch species, the warbler finch (Certhidea olivacea) and the sympatric small tree finch (Camarhynchus parvulus), on Santa Cruz Island in 2010 and 2012. While the population of the small tree finch appeared to be stable, the warbler finch has experienced a dramatic decline in population size on Santa Cruz Island since 1997. We aimed to identify whether warbler finches are particularly vulnerable during different stages of the breeding cycle. Contrary to our prediction, breeding success was lower in the small tree finch than in the warbler finch. In both species P. downsi had a strong negative impact on breeding success and our data suggest that heavy rain events also lowered the fledging success. On the one hand parents might be less efficient in compensating their chicks' energy loss due to parasitism as they might be less efficient in foraging on days of heavy rain. On the other hand, intense rainfalls might lead to increased humidity and more rapid cooling of the nests. In the case of the warbler finch we found that the control of invasive plant species with herbicides had a significant additive negative impact on the breeding success. It is very likely that the availability of insects (i.e. food abundance)is lower in such controlled areas, as herbicide usage led to the removal of the entire understory. Predation seems to be a minor factor in brood loss.
Collapse
Affiliation(s)
- Arno Cimadom
- Department of Behavioural Biology, University of Vienna, Vienna, Austria
| | - Angel Ulloa
- Charles Darwin Foundation, Puerto Ayora, Santa Cruz Island, Galápagos, Ecuador
| | - Patrick Meidl
- Institute for Science and Technology, Klosterneuburg, Austria
| | - Markus Zöttl
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Elisabet Zöttl
- Department of Behavioural Biology, University of Vienna, Vienna, Austria
| | - Birgit Fessl
- Charles Darwin Foundation, Puerto Ayora, Santa Cruz Island, Galápagos, Ecuador
| | | | | | | | - Sabine Tebbich
- Department of Behavioural Biology, University of Vienna, Vienna, Austria
- * E-mail:
| |
Collapse
|
34
|
Berkhout BW, Lloyd MM, Poulin R, Studer A. Variation among genotypes in responses to increasing temperature in a marine parasite: evolutionary potential in the face of global warming? Int J Parasitol 2014; 44:1019-27. [PMID: 25066543 DOI: 10.1016/j.ijpara.2014.07.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 07/06/2014] [Accepted: 07/07/2014] [Indexed: 10/25/2022]
Abstract
Climates are changing worldwide, and populations are under selection to adapt to these changes. Changing temperature, in particular, can directly impact ectotherms and their parasites, with potential consequences for whole ecosystems. The potential of parasite populations to adapt to climate change largely depends on the amount of genetic variation they possess in their responses to environmental fluctuations. This study is, to our knowledge, the first to look at differences among parasite genotypes in response to temperature, with the goal of quantifying the extent of variation among conspecifics in their responses to increasing temperature. Snails infected with single genotypes of the trematode Maritrema novaezealandensis were sequentially acclimatised to two different temperatures, 'current' (15°C) and 'elevated' (20°C), over long periods. These temperatures are based on current average field conditions in the natural habitat and those predicted to occur during the next few decades. The output and activity of cercariae (free-swimming infective stages emerging from snails) were assessed for each genotype at each temperature. The results indicate that, on average, both cercarial output and activity are higher at the elevated acclimation temperature. More importantly, the output and activity of cercariae are strongly influenced by a genotype-by-temperature interaction, such that different genotypes show different responses to increasing temperature. Both the magnitude and direction (increase or decrease) of responses to temperature varied widely among genotypes. Therefore, there is much potential for natural selection to act on this variation, and predicting how the trematode M. novaezealandensis will respond to the climate changes predicted for the next century will prove challenging.
Collapse
Affiliation(s)
- Boris W Berkhout
- Department of Zoology, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
| | - Melanie M Lloyd
- Department of Zoology, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
| | - Robert Poulin
- Department of Zoology, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand.
| | - Anja Studer
- Department of Zoology, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
| |
Collapse
|
35
|
Skinner MK, Gurerrero-Bosagna C, Haque MM, Nilsson EE, Koop JAH, Knutie SA, Clayton DH. Epigenetics and the evolution of Darwin's Finches. Genome Biol Evol 2014; 6:1972-89. [PMID: 25062919 PMCID: PMC4159007 DOI: 10.1093/gbe/evu158] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The prevailing theory for the molecular basis of evolution involves genetic mutations that ultimately generate the heritable phenotypic variation on which natural selection acts. However, epigenetic transgenerational inheritance of phenotypic variation may also play an important role in evolutionary change. A growing number of studies have demonstrated the presence of epigenetic inheritance in a variety of different organisms that can persist for hundreds of generations. The possibility that epigenetic changes can accumulate over longer periods of evolutionary time has seldom been tested empirically. This study was designed to compare epigenetic changes among several closely related species of Darwin's finches, a well-known example of adaptive radiation. Erythrocyte DNA was obtained from five species of sympatric Darwin's finches that vary in phylogenetic relatedness. Genome-wide alterations in genetic mutations using copy number variation (CNV) were compared with epigenetic alterations associated with differential DNA methylation regions (epimutations). Epimutations were more common than genetic CNV mutations among the five species; furthermore, the number of epimutations increased monotonically with phylogenetic distance. Interestingly, the number of genetic CNV mutations did not consistently increase with phylogenetic distance. The number, chromosomal locations, regional clustering, and lack of overlap of epimutations and genetic mutations suggest that epigenetic changes are distinct and that they correlate with the evolutionary history of Darwin's finches. The potential functional significance of the epimutations was explored by comparing their locations on the genome to the location of evolutionarily important genes and cellular pathways in birds. Specific epimutations were associated with genes related to the bone morphogenic protein, toll receptor, and melanogenesis signaling pathways. Species-specific epimutations were significantly overrepresented in these pathways. As environmental factors are known to result in heritable changes in the epigenome, it is possible that epigenetic changes contribute to the molecular basis of the evolution of Darwin's finches.
Collapse
Affiliation(s)
- Michael K Skinner
- Center for Reproductive Biology, School of Biological Sciences, Washington State University
| | - Carlos Gurerrero-Bosagna
- Center for Reproductive Biology, School of Biological Sciences, Washington State UniversityPresent address: Department of Physics, Biology and Chemistry (IFM), Linköping University, Sweden
| | - M Muksitul Haque
- Center for Reproductive Biology, School of Biological Sciences, Washington State University
| | - Eric E Nilsson
- Center for Reproductive Biology, School of Biological Sciences, Washington State University
| | - Jennifer A H Koop
- Department of Biology, University of UtahPresent address: Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ
| | | | | |
Collapse
|
36
|
|
37
|
O'Connor JA, Robertson J, Kleindorfer S. Darwin's Finch Begging Intensity Does Not Honestly Signal Need in Parasitised Nests. Ethology 2013. [DOI: 10.1111/eth.12196] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jody A. O'Connor
- School of Biological Sciences; The Flinders University of South Australia; Adelaide SA Australia
| | - Jeremy Robertson
- School of Biological Sciences; The Flinders University of South Australia; Adelaide SA Australia
| | - Sonia Kleindorfer
- School of Biological Sciences; The Flinders University of South Australia; Adelaide SA Australia
| |
Collapse
|
38
|
Knutie SA, Koop JAH, French SS, Clayton DH. Experimental test of the effect of introduced hematophagous flies on corticosterone levels of breeding Darwin's finches. Gen Comp Endocrinol 2013; 193:68-71. [PMID: 23892015 PMCID: PMC4383185 DOI: 10.1016/j.ygcen.2013.07.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 06/12/2013] [Accepted: 07/15/2013] [Indexed: 11/30/2022]
Abstract
Parasites can negatively affect the evolutionary fitness of their hosts by eliciting physiological stress responses. Parasite-induced stress can be monitored by measuring changes in the adrenal steroid hormone corticosterone. We examined the effect of an invasive parasite on the corticosterone concentrations of a common species of Darwin's finch, the medium ground finch (Geospiza fortis). Philornis downsi (Diptera: Muscidae) is a parasitic nest fly recently introduced to the Galapagos Islands, where it feeds on the blood of nestlings and breeding adult female finches. Previous work shows that P. downsi significantly reduces the reproductive success of several species of finches. We predicted that the effect of P. downsi on host reproductive success is mediated by stress responses in breeding female finches. High stress levels could reduce the ability of females to invest in offspring, thus decreasing their reproductive success. To test this hypothesis, we experimentally manipulated the abundance of P. downsi in nests, then measured baseline and acute stress-induced corticosterone levels, body condition, and hematocrit (red blood cell content). Acute stress-induced corticosterone levels increased over baseline levels, but this response did not differ significantly with parasite treatment. There was also no significant difference in the body condition or hematocrit of females from parasitized versus non-parasitized nests. Our results suggest that the lower reproductive success of females from parasitized nests is not mediated by a physiological stress response.
Collapse
Affiliation(s)
- Sarah A Knutie
- Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112, USA.
| | | | | | | |
Collapse
|
39
|
Koop JAH, Owen JP, Knutie SA, Aguilar MA, Clayton DH. Experimental demonstration of a parasite-induced immune response in wild birds: Darwin's finches and introduced nest flies. Ecol Evol 2013; 3:2514-23. [PMID: 24567824 PMCID: PMC3930052 DOI: 10.1002/ece3.651] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 05/10/2013] [Accepted: 05/22/2013] [Indexed: 11/10/2022] Open
Abstract
Ecological immunology aims to explain variation among hosts in the strength and efficacy of immunological defenses. However, a shortcoming has been the failure to link host immune responses to actual parasites under natural conditions. Here, we present one of the first experimental demonstrations of a parasite-induced immune response in a wild bird population. The recently introduced ectoparasitic nest fly Philornis downsi severely impacts the fitness of Darwin's finches and other land birds in the Galápagos Islands. An earlier study showed that female medium ground finches (Geospiza fortis) had P. downsi-binding antibodies correlating with presumed variation in fly exposure over time. In the current study, we experimentally manipulated fly abundance to test whether the fly does, in fact, cause changes in antibody levels. We manipulated P. downsi abundance in nests and quantified P. downsi-binding antibody levels of medium ground finch mothers, fathers, and nestlings. We also quantified host behaviors, such as preening, which can integrate with antibody-mediated defenses against ectoparasites. Philornis downsi-binding antibody levels were significantly higher among mothers at parasitized nests, compared to mothers at (fumigated) nonparasitized nests. Mothers with higher antibody levels tended to have fewer parasites in their nests, suggesting that antibodies play a role in defense against parasites. Mothers showed no behavioral changes that would enhance the effectiveness of the immune response. Neither adult males, nor nestlings, had P. downsi-induced immunological or behavioral responses that would enhance defense against flies. None of the parasitized nests fledged any offspring, despite the immune response by mothers. Thus, this study shows that, while the immune response of mothers appeared to be defensive, it was not sufficient to rescue current reproductive fitness. This study further shows the importance of testing the fitness consequences of immune defenses, rather than assuming that such responses increase host fitness. Host immune responses can protect against the negative fitness consequences of parasitism; however, the strength and effectiveness of these responses vary among hosts. Strong host immune responses are often assumed to correlate with greater host fitness. This study investigates the relationship between host immune response, parasite load, and host fitness using Darwin's finches and an invasive nest parasite. We found that while the immune response of mothers appeared defensive, it did not rescue current reproductive fitness.
Collapse
Affiliation(s)
- Jennifer A H Koop
- Department of Biology, University of Utah Salt Lake City, Utah, 84112
| | - Jeb P Owen
- Department of Entomology, Washington State University Pullman, Washington, 99164
| | - Sarah A Knutie
- Department of Biology, University of Utah Salt Lake City, Utah, 84112
| | - Maria A Aguilar
- Department of Biology, University of Utah Salt Lake City, Utah, 84112
| | - Dale H Clayton
- Department of Biology, University of Utah Salt Lake City, Utah, 84112
| |
Collapse
|
40
|
|
41
|
Introduced parasites in food webs: new species, shifting structures? Trends Ecol Evol 2013; 28:93-9. [DOI: 10.1016/j.tree.2012.08.020] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 08/20/2012] [Accepted: 08/21/2012] [Indexed: 11/21/2022]
|
42
|
Britton JR, Pegg J, Williams CF. Pathological and ecological host consequences of infection by an introduced fish parasite. PLoS One 2011; 6:e26365. [PMID: 22022606 PMCID: PMC3195689 DOI: 10.1371/journal.pone.0026365] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 09/25/2011] [Indexed: 11/18/2022] Open
Abstract
The infection consequences of the introduced cestode fish parasite Bothriocephalus acheilognathi were studied in a cohort of wild, young-of-the-year common carp Cyprinus carpio that lacked co-evolution with the parasite. Within the cohort, parasite prevalence was 42% and parasite burdens were up to 12% body weight. Pathological changes within the intestinal tract of parasitized carp included distension of the gut wall, epithelial compression and degeneration, pressure necrosis and varied inflammatory changes. These were most pronounced in regions containing the largest proportion of mature proglottids. Although the body lengths of parasitized and non-parasitized fish were not significantly different, parasitized fish were of lower body condition and reduced weight compared to non-parasitized conspecifics. Stable isotope analysis (δ15N and δ13C) revealed trophic impacts associated with infection, particularly for δ15N where values for parasitized fish were significantly reduced as their parasite burden increased. In a controlled aquarium environment where the fish were fed ad libitum on an identical food source, there was no significant difference in values of δ15N and δ13C between parasitized and non-parasitized fish. The growth consequences remained, however, with parasitized fish growing significantly slower than non-parasitized fish, with their feeding rate (items s−1) also significantly lower. Thus, infection by an introduced parasite had multiple pathological, ecological and trophic impacts on a host with no experience of the parasite.
Collapse
Affiliation(s)
- J Robert Britton
- Centre for Conservation Ecology and Environmental Change, School of Applied Sciences, Bournemouth University, Poole, Dorset, United Kingdom.
| | | | | |
Collapse
|