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Common LK, Kleindorfer S, Colombelli-Négrel D, Dudaniec RY. Genetics reveals shifts in reproductive behaviour of the invasive bird parasite Philornis downsi collected from Darwin’s finch nests. Biol Invasions 2022. [DOI: 10.1007/s10530-022-02935-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
AbstractDue to novel or dynamic fluctuations in environmental conditions and resources, host and parasite relationships can be subject to diverse selection pressures that may lead to significant changes during and after invasion of a parasite. Genomic analyses are useful for elucidating evolutionary processes in invasive parasites following their arrival to a new area and host. Philornis downsi (Diptera: Muscidae), the avian vampire fly, was introduced to the Galápagos Islands circa 1964 and has since spread across the archipelago, feeding on the blood of developing nestlings of endemic land birds. Since its discovery, there have been significant changes to the dynamics of P. downsi and its novel hosts, such as shifting mortality rates and changing oviposition behaviour, however no temporal genetic studies have been conducted. We collected P. downsi from nests and traps from a single island population over a 14-year period, and genotyped flies at 469 single nucleotide polymorphisms (SNPs) using restriction-site associated DNA sequencing (RADSeq). Despite significant genetic differentiation (FST) between years, there was no evidence for genetic clustering within or across four sampling years between 2006 and 2020, suggesting a lack of population isolation. Sibship reconstructions from P. downsi collected from 10 Darwin’s finch nests sampled in 2020 showed evidence for shifts in reproductive behaviour compared to a similar genetic analysis conducted in 2004–2006. Compared with this previous study, females mated with fewer males, individual females oviposited fewer offspring per nest, but more unique females oviposited per nest. These findings are important to consider within reproductive control techniques, and have fitness implications for both parasite evolution and host fitness.
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2
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Kleindorfer S, Colombelli‐Négrel D, Common LK, O’Connor JA, Peters KJ, Katsis AC, Dudaniec RY, Sulloway FJ, Adreani NM. Functional traits and foraging behaviour: avian vampire fly larvae change the beak and fitness of their Darwin’s finch hosts. Funct Ecol 2022. [DOI: 10.1111/1365-2435.14061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Sonia Kleindorfer
- College of Science and Engineering Flinders University Adelaide Australia
- Konrad Lorenz Research Center for Behavior and Cognition and Department of Behavioral and Cognitive Biology University of Vienna Vienna Austria
| | | | - Lauren K. Common
- College of Science and Engineering Flinders University Adelaide Australia
| | | | - Katharina J. Peters
- College of Science and Engineering Flinders University Adelaide Australia
- Evolutionary Genetics Group, Department of Anthropology University of Zurich Zurich Switzerland
- School of Earth and Environment Christchurch New Zealand
| | - Andrew C. Katsis
- College of Science and Engineering Flinders University Adelaide Australia
| | | | | | - Nicolas M. Adreani
- Konrad Lorenz Research Center for Behavior and Cognition and Department of Behavioral and Cognitive Biology University of Vienna Vienna Austria
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Kleindorfer S, Common LK, O'Connor JA, Garcia-Loor J, Katsis AC, Dudaniec RY, Colombelli-Négrel D, Adreani NM. Female in-nest attendance predicts the number of ectoparasites in Darwin's finch species. Proc Biol Sci 2021; 288:20211668. [PMID: 34905711 PMCID: PMC8670954 DOI: 10.1098/rspb.2021.1668] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 11/19/2021] [Indexed: 11/12/2022] Open
Abstract
Selection should act on parental care and favour parental investment decisions that optimize the number of offspring produced. Such predictions have been robustly tested in predation risk contexts, but less is known about alternative functions of parental care under conditions of parasitism. The avian vampire fly (Philornis downsi) is a myasis-causing ectoparasite accidentally introduced to the Galápagos Islands, and one of the major mortality causes in Darwin's finch nests. With an 11-year dataset spanning 21 years, we examine the relationship between parental care behaviours and number of fly larvae and pupae in Darwin's finch nests. We do so across three host species (Camarhynchus parvulus, C. pauper, Geospiza fuliginosa) and one hybrid Camarhynchus group. Nests with longer female brooding duration (minutes per hour spent sitting on hatchlings to provide warmth) had fewer parasites, and this effect depended on male food delivery to chicks. Neither male age nor number of nest provisioning visits were directly associated with number of parasites. While the causal mechanisms remain unknown, we provide the first empirical study showing that female brooding duration is negatively related to the number of ectoparasites in nests. We predict selection for coordinated host male and female behaviour to reduce gaps in nest attendance, especially under conditions of novel and introduced ectoparasites.
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Affiliation(s)
- Sonia Kleindorfer
- College of Science and Engineering, Flinders University, Adelaide 5001, Australia
- Konrad Lorenz Research Center for Behavior and Cognition and Department of Behavioral and Cognitive Biology, University of Vienna, Vienna 1090, Austria
| | - Lauren K. Common
- College of Science and Engineering, Flinders University, Adelaide 5001, Australia
| | | | - Jefferson Garcia-Loor
- Konrad Lorenz Research Center for Behavior and Cognition and Department of Behavioral and Cognitive Biology, University of Vienna, Vienna 1090, Austria
- Charles Darwin Research Station, Galápagos, Ecuador
| | - Andrew C. Katsis
- College of Science and Engineering, Flinders University, Adelaide 5001, Australia
| | - Rachael Y. Dudaniec
- Department of Biological Sciences, Macquarie University, Sydney 2109, Australia
| | | | - Nico M. Adreani
- Konrad Lorenz Research Center for Behavior and Cognition and Department of Behavioral and Cognitive Biology, University of Vienna, Vienna 1090, Austria
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4
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Temporal and spatial variation in sex-specific abundance of the avian vampire fly (Philornis downsi). Parasitol Res 2021; 121:63-74. [PMID: 34799771 PMCID: PMC8748338 DOI: 10.1007/s00436-021-07350-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 10/12/2021] [Indexed: 10/26/2022]
Abstract
Understanding the range and behaviour of an invasive species is critical to identify key habitat areas to focus control efforts. Patterns of range use in parasites can differ temporally, across life stages and between sexes. The invasive avian vampire fly, Philornis downsi, spends the larval stage of its life within bird nests, feeding on developing nestlings and causing high levels of mortality and deformation. However, little is known of the ecology and behaviour of the non-parasitic adult fly life stage. Here, we document sex-specific temporal and spatial patterns of abundance of adult avian vampire flies during a single Darwin's finch breeding season. We analyse fly trapping data collected across 7 weeks in the highlands (N = 405 flies) and lowlands (N = 12 flies) of Floreana Island (Galápagos). Lowland catches occurred later in the season, which supports the hypothesis that flies may migrate from the food-rich highlands to the food-poor lowlands once host breeding has commenced. Fly abundance was not correlated with host nesting density (oviposition site) but was correlated with distance to the agricultural zone (feeding site). We consistently caught more males closer to the agricultural zone and more females further away from the agricultural zone. These sex differences suggest that males may be defending or lekking at feeding sites in the agricultural zone for mating. This temporal and sex-specific habitat use of the avian vampire fly is relevant for developing targeted control methods and provides insight into the behavioural ecology of this introduced parasite on the Galápagos Archipelago.
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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.
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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
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6
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Common LK, Sumasgutner P, Dudaniec RY, Colombelli-Négrel D, Kleindorfer S. Avian vampire fly (Philornis downsi) mortality differs across Darwin's finch host species. Sci Rep 2021; 11:15832. [PMID: 34349147 PMCID: PMC8338931 DOI: 10.1038/s41598-021-94996-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 07/19/2021] [Indexed: 12/03/2022] Open
Abstract
In invasive parasites, generalism is considered advantageous during the initial phase of introduction. Thereafter, fitness costs to parasites, such as host-specific mortality, can drive parasites towards specialism to avoid costly hosts. It is important to determine changes in host specificity of invasive populations to understand host-parasite dynamics and their effects on vulnerable host populations. We examined changes in mortality in the introduced avian vampire fly (Philornis downsi) (Diptera: Muscidae), a generalist myasis-causing ectoparasite, between 2004 and 2020 on Floreana Island (Galápagos). Mortality was measured as the proportion of immature larvae found upon host nest termination. Over the time period, the avian vampire fly was most abundant and had low mortality in nests of the critically endangered medium tree finch (Camarhynchus pauper) and had the highest mortality in nests of hybrid tree finches (Camarhynchus spp.). Low larval mortality was also found in small tree (Camarhynchus parvulus) and small ground finch (Geospiza fuliginosa) nests. Selection could favour avian vampire flies that select medium tree finch nests and/or avoid hybrid nests. Overall, the finding of differences in avian vampire fly survival across host species is parsimonious with the idea that the introduced fly may be evolving towards host specialisation.
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Affiliation(s)
- Lauren K Common
- College of Science and Engineering, Flinders University, Bedford Park, SA, 5001, Australia
| | - Petra Sumasgutner
- Department of Behavioral and Cognitive Biology, Konrad Lorenz Research Center, Core Facility for Behavior and Cognition, University of Vienna, Vienna, Austria
| | - Rachael Y Dudaniec
- Department of Biological Sciences, Macquarie University, Sydney, NSW , 2109, Australia
| | | | - Sonia Kleindorfer
- College of Science and Engineering, Flinders University, Bedford Park, SA, 5001, Australia. .,Department of Behavioral and Cognitive Biology, Konrad Lorenz Research Center, Core Facility for Behavior and Cognition, University of Vienna, Vienna, Austria.
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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.
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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
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Tebbich S, Schwemhofer T, Fischer B, Pike C. Darwin’s finches habitually anoint their feathers with leaves of the endemic tree
Psidium galapageium
during the non‐breeding season. Ethology 2021. [DOI: 10.1111/eth.13153] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Sabine Tebbich
- Department of Behavioural and Cognitive Biology University of Vienna Vienna Austria
| | - Timo Schwemhofer
- Department of Behavioural and Cognitive Biology University of Vienna Vienna Austria
| | - Barbara Fischer
- Department of Evolutionary Biology Unit for Theoretical Biology University of Vienna Vienna Austria
| | - Courtney Pike
- Department of Behavioural and Cognitive Biology University of Vienna Vienna Austria
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9
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Jose PA, Ben-Yosef M, Lahuatte P, Causton CE, Heimpel GE, Jurkevitch E, Yuval B. Shifting microbiomes complement life stage transitions and diet of the bird parasite Philornis downsi from the Galapagos Islands. Environ Microbiol 2021; 23:5014-5029. [PMID: 33587780 DOI: 10.1111/1462-2920.15435] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 02/12/2021] [Indexed: 01/04/2023]
Abstract
Domestication disconnects an animal from its natural environment and diet, imposing changes in the attendant microbial community. We examine these changes in Philornis downsi (Muscidae), an invasive parasitic fly of land birds in the Galapagos Islands. Using a 16S rDNA profiling approach we studied the microbiome of larvae and adults of wild and laboratory-reared populations. These populations diverged in their microbiomes, significantly more so in larval than in adult flies. In field-collected second-instar larvae, Klebsiella (70.3%) was the most abundant taxon, while in the laboratory Ignatzschineria and Providencia made up 89.2% of the community. In adults, Gilliamella and Dysgonomonas were key members of the core microbiome of field-derived females and males but had no or very low representation in the laboratory. Adult flies harbour sex-specific microbial consortia in their gut, as male core microbiomes were significantly dominated by Klebsiella. Thus, P. downsi microbiomes are dynamic and shift correspondingly with life cycle and diet. Sex-specific foraging behaviour of adult flies and nest conditions, which are absent in the laboratory, may contribute to shaping distinct larval, and adult male and female microbiomes. We discuss these findings in the context of microbe-host co-evolution and the implications for control measures.
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Affiliation(s)
- Polpass Arul Jose
- Faculty of Agriculture Food and Environment, The Hebrew University of Jerusalem, Rehovot, 7612001, Israel
| | - Michael Ben-Yosef
- Department of Entomology, Agricultural Research Organization, Gilat Center, M. P. Negev, 85280, Israel
| | - Paola Lahuatte
- Charles Darwin Research Station, Charles Darwin Foundation, Puerto Ayora, Galapagos, 200350, Ecuador
| | - Charlotte E Causton
- Charles Darwin Research Station, Charles Darwin Foundation, Puerto Ayora, Galapagos, 200350, Ecuador
| | - George E Heimpel
- Department of Entomology, University of Minnesota, 1980 Folwell Avenue, MN, 55108, USA
| | - Edouard Jurkevitch
- Faculty of Agriculture Food and Environment, The Hebrew University of Jerusalem, Rehovot, 7612001, Israel
| | - Boaz Yuval
- Faculty of Agriculture Food and Environment, The Hebrew University of Jerusalem, Rehovot, 7612001, Israel
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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.
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11
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Common LK, O'Connor JA, Dudaniec RY, Peters KJ, Kleindorfer S. Evidence for rapid downward fecundity selection in an ectoparasite (Philornis downsi) with earlier host mortality in Darwin's finches. J Evol Biol 2020; 33:524-533. [PMID: 31961983 PMCID: PMC7217188 DOI: 10.1111/jeb.13588] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 01/09/2020] [Accepted: 01/15/2020] [Indexed: 01/05/2023]
Abstract
Fecundity selection is a critical component of fitness and a major driver of adaptive evolution. Trade‐offs between parasite mortality and host resources are likely to impose a selection pressure on parasite fecundity, but this is little studied in natural systems. The ‘fecundity advantage hypothesis’ predicts female‐biased sexual size dimorphism whereby larger females produce more offspring. Parasitic insects are useful for exploring the interplay between host resource availability and parasite fecundity, because female body size is a reliable proxy for fecundity in insects. Here we explore temporal changes in body size in the myiasis‐causing parasite Philornis downsi (Diptera: Muscidae) on the Galápagos Islands under conditions of earlier in‐nest host mortality. We aim to investigate the effects of decreasing host resources on parasite body size and fecundity. Across a 12‐year period, we observed a mean of c. 17% P. downsi mortality in host nests with 55 ± 6.2% host mortality and a trend of c. 66% higher host mortality throughout the study period. Using specimens from 116 Darwin's finch nests (Passeriformes: Thraupidae) and 114 traps, we found that over time, P. downsi pupae mass decreased by c. 32%, and male (c. 6%) and female adult size (c. 11%) decreased. Notably, females had c. 26% smaller abdomens in later years, and female abdomen size was correlated with number of eggs. Our findings imply natural selection for faster P. downsi pupation and consequently smaller body size and lower parasite fecundity in this newly evolving host–parasite system.
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Affiliation(s)
- Lauren K Common
- College of Science and Engineering, Flinders University, Adelaide, SA, Australia
| | - Jody A O'Connor
- College of Science and Engineering, Flinders University, Adelaide, SA, Australia.,Department for Environment and Water, Government of South Australia, Adelaide, SA, Australia
| | - Rachael Y Dudaniec
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Katharina J Peters
- College of Science and Engineering, Flinders University, Adelaide, SA, Australia
| | - Sonia Kleindorfer
- College of Science and Engineering, Flinders University, Adelaide, SA, Australia.,Konrad Lorenz Research Center for Behaviour and Cognition and Department of Behavioural and Cognitive Biology, University of Vienna, Vienna, Austria
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12
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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.
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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
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13
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Ursino CA, De Mársico MC, Reboreda JC. Brood parasitic nestlings benefit from unusual host defenses against botfly larvae (Philornis spp.). Behav Ecol Sociobiol 2019. [DOI: 10.1007/s00265-019-2751-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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14
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Kleindorfer S, Custance G, Peters KJ, Sulloway FJ. Introduced parasite changes host phenotype, mating signal and hybridization risk: Philornis downsi effects on Darwin's finch song. Proc Biol Sci 2019; 286:20190461. [PMID: 31185871 DOI: 10.1098/rspb.2019.0461] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Introduced parasites that alter their host's mating signal can change the evolutionary trajectory of a species through sexual selection. Darwin's Camarhynchus finches are threatened by the introduced fly Philornis downsi that is thought to have accidentally arrived on the Galapagos Islands during the 1960s. The P. downsi larvae feed on the blood and tissue of developing finches, causing on average approximately 55% in-nest mortality and enlarged naris size in survivors. Here we test if enlarged naris size is associated with song characteristics and vocal deviation in the small tree finch ( Camarhynchus parvulus), the critically endangered medium tree finch ( C. pauper) and the recently observed hybrid tree finch group ( Camarhynchus hybrids). Male C. parvulus and C. pauper with enlarged naris size produced song with lower maximum frequency and greater vocal deviation, but there was no significant association in hybrids. Less vocal deviation predicted faster pairing success in both parental species. Finally, C. pauper males with normal naris size produced species-specific song, but male C. pauper with enlarged naris size had song that was indistinguishable from other tree finches. When parasites disrupt host mating signal, they may also facilitate hybridization. Here we show how parasite-induced naris enlargement affects vocal quality, resulting in blurred species mating signals.
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Affiliation(s)
- Sonia Kleindorfer
- 1 College of Science and Engineering, Flinders University , Adelaide 5001 , Australia.,2 Konrad Lorenz Research Station and Department of Behavioural Biology, University of Vienna , Vienna , Austria
| | - Georgina Custance
- 1 College of Science and Engineering, Flinders University , Adelaide 5001 , Australia
| | - Katharina J Peters
- 1 College of Science and Engineering, Flinders University , Adelaide 5001 , Australia
| | - Frank J Sulloway
- 3 Department of Psychology, University of California , 2121 Berkeley Way, Room 3302, 4125 Tolman Hall, Berkeley, CA 94720 , USA
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15
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Peters KJ, Evans C, Aguirre JD, Kleindorfer S. Genetic admixture predicts parasite intensity: evidence for increased hybrid performance in Darwin's tree finches. ROYAL SOCIETY OPEN SCIENCE 2019; 6:181616. [PMID: 31183118 PMCID: PMC6502384 DOI: 10.1098/rsos.181616] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 03/07/2019] [Indexed: 06/09/2023]
Abstract
Hybridization can increase adaptive potential when enhanced genetic diversity or novel genetic combinations confer a fitness advantage, such as in the evolution of anti-parasitic mechanisms. Island systems are especially susceptible to invasive parasites due to the lack of defence mechanisms that usually coevolve in long-standing host-parasite relationships. We test if host genetic admixture affects parasite numbers in a novel host-parasite association on the Galápagos Islands. Specifically, we compare the number of Philornis downsi in nests with offspring sired by Darwin's small tree finch (Camarhynchus parvulus), Darwin's medium tree finch (C. pauper) and hybrids of these two species. The number of P. downsi decreased with an increasing genetic admixture of the attending male, and nests of hybrid males had approximately 50% fewer parasites than C. parvulus nests, and approximately 60% fewer parasites than C. pauper nests. This finding indicates that hybridization in this system could be favoured by selection and reveal a mechanism to combat an invasive parasite.
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Affiliation(s)
- Katharina J. Peters
- College of Science and Engineering, Flinders University, Adelaide, Australia
- School of Natural and Computational Sciences, Massey University, Auckland, New Zealand
| | - Christine Evans
- College of Science and Engineering, Flinders University, Adelaide, Australia
- School of Natural and Computational Sciences, Massey University, Auckland, New Zealand
| | - J. David Aguirre
- School of Natural and Computational Sciences, Massey University, Auckland, New Zealand
| | - Sonia Kleindorfer
- College of Science and Engineering, Flinders University, Adelaide, Australia
- Konrad Lorenz Research Station and Department of Behavioural Biology, University of Vienna, Austria
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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.
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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
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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
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18
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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.
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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;
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Filek N, Cimadom A, Schulze CH, Jäger H, Tebbich S. The impact of invasive plant management on the foraging ecology of the Warbler Finch ( Certhidea olivacea) and the Small Tree Finch ( Camarhynchus parvulus) on Galápagos. JOURNAL OF ORNITHOLOGY 2018; 159:129-140. [PMID: 31998596 PMCID: PMC6956869 DOI: 10.1007/s10336-017-1481-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 07/16/2017] [Accepted: 07/18/2017] [Indexed: 05/17/2023]
Abstract
In recent decades, arboreal Darwin's Finches have suffered from a dramatic population decline, which has been attributed to parasitism by the invasive botfly Philornis downsi. However, changes to their primary habitat caused by invasive plant species may have additionally contributed to the observed population decline. The humid cloud forest on Santa Cruz Island is a stronghold of arboreal Darwin's Finches but has been invaded by blackberry (Rubus niveus). In some areas, manual control and herbicide application are used to combat this invasion, both causing a temporary removal of the entire understory. We hypothesized that the removal of the understory reduces the availability of arthropods, which are a main food source during chick rearing. We compared the foraging behaviour of Warbler Finches (Certhidea olivacea) and Small Tree Finches (Camarhynchus parvulus) at three study sites that varied in the degree of R. niveus invasion and the length of time since the last herbicide application. We used prey attack rate and foraging success as an index for food availability and predicted a lower attack rate and foraging success in areas that had recently been sprayed with herbicides. We found that both the invasion and the management of R. niveus influenced microhabitat use, foraging substrate and prey choice in both species. Contrary to our hypothesis, we did not find a lower attack rate or foraging success in the area with recent herbicide application. This may be explained by the finding that both species mainly foraged in the canopy but also used dead plant structures of the understory of the recently controlled area that resulted from the invasive plant management.
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Affiliation(s)
- Nikolaus Filek
- Department of Behavioural Biology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - Arno Cimadom
- Department of Behavioural Biology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
| | - Christian H. Schulze
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030 Vienna, Austria
| | - Heinke Jäger
- Charles Darwin Foundation, Puerto Ayora, Santa Cruz, Galápagos Ecuador
| | - Sabine Tebbich
- Department of Behavioural Biology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
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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]
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21
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Ben-Yosef M, Zaada DSY, Dudaniec RY, Pasternak Z, Jurkevitch E, Smith RJ, Causton CE, Lincango MP, Tobe SS, Mitchell JG, Kleindorfer S, Yuval B. Host-specific associations affect the microbiome ofPhilornis downsi, an introduced parasite to the Galápagos Islands. Mol Ecol 2017; 26:4644-4656. [DOI: 10.1111/mec.14219] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 05/25/2017] [Accepted: 06/13/2017] [Indexed: 01/08/2023]
Affiliation(s)
- Michael Ben-Yosef
- Department of Entomology; Faculty of Agriculture Food and Environment; The Hebrew University of Jerusalem; Rehovot Israel
| | - Doron S. Y. Zaada
- Department of Entomology; Faculty of Agriculture Food and Environment; The Hebrew University of Jerusalem; Rehovot Israel
| | - Rachael Y. Dudaniec
- Department of Biological Sciences; Macquarie University; Sydney NSW Australia
| | - Zohar Pasternak
- Department of Microbiology and Plant Pathology; Faculty of Agriculture Food and Environment; The Hebrew University of Jerusalem; Rehovot Israel
| | - Edouard Jurkevitch
- Department of Microbiology and Plant Pathology; Faculty of Agriculture Food and Environment; The Hebrew University of Jerusalem; Rehovot Israel
| | - Renee J. Smith
- School of Biological Sciences; Flinders University; Adelaide SA Australia
| | - Charlotte E. Causton
- Charles Darwin Foundation; Puerto Ayora Santa Cruz Island Galápagos Islands Ecuador
| | - Maria Piedad Lincango
- Charles Darwin Foundation; Puerto Ayora Santa Cruz Island Galápagos Islands Ecuador
- Facultad De Ciencias Agrícolas; Universidad Central Del Ecuador; Quito Pichincha Ecuador
| | - Shanan S. Tobe
- School of Biological Sciences; Flinders University; Adelaide SA Australia
- Department of Chemistry and Physics; Arcadia University; Glenside PA USA
| | - James G. Mitchell
- School of Biological Sciences; Flinders University; Adelaide SA Australia
| | - Sonia Kleindorfer
- School of Biological Sciences; Flinders University; Adelaide SA Australia
| | - Boaz Yuval
- Department of Entomology; Faculty of Agriculture Food and Environment; The Hebrew University of Jerusalem; Rehovot Israel
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22
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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.
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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
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Lahuatte PF, Lincango MP, Heimpel GE, Causton CE. Rearing Larvae of the Avian Nest Parasite, Philornis downsi (Diptera: Muscidae), on Chicken Blood-Based Diets. JOURNAL OF INSECT SCIENCE (ONLINE) 2016; 16:iew064. [PMID: 27493240 PMCID: PMC4973507 DOI: 10.1093/jisesa/iew064] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 06/27/2016] [Indexed: 06/06/2023]
Abstract
Captive rearing of insect pests is necessary to understand their biology and to develop control methods. The avian nest fly, Philornis downsi Dodge and Aitken, is a blood-sucking parasite during its larval stage and a serious threat to endemic birds in the Galapagos Islands where it is considered invasive. In order to procure large numbers of flies for biological studies, rearing media and diets were trialed for rearing the larval stage of P. downsi under controlled conditions in the absence of its avian host. P. downsi eggs were obtained from field-caught female flies, and once eggs hatched they were reared on chicken blood for the first 3 d. Following this, three diets were tested on second- and third-instar larvae: 1) chicken blood only; 2) chicken blood, hydrolyzed protein and dried milk powder; and 3) chicken blood, hydrolyzed protein and brewer's yeast. Out of 385 P. downsi larvae tested, we were able to rear 50 larvae to the adult stage. The highest level of mortality was found in the first-instar larvae. Survivorship of second- and third-instar larvae was similar irrespective of diet and diet did not significantly influence larval or pupal development times; though larvae fed the diet with brewer's yeast developed marginally faster. Pupal weights were similar to those of larvae that had developed on bird hosts in the field. To our knowledge, this is the first effective protocol for rearing a hematophagous parasitic avian fly from egg to adult in the absence of a living host.
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Affiliation(s)
- Paola F Lahuatte
- Carrera De Ciencias Biológicas Y Ambientales, Sector El Dorado, Quito-Ecuador, Universidad Central Del Ecuador, Iquique N14-121 Y Sodiro-Itchimbía Charles Darwin Foundation, Santa Cruz Island, Galapagos Islands, Ecuador
| | - M P Lincango
- Charles Darwin Foundation, Santa Cruz Island, Galapagos Islands, Ecuador Facultad De Ciencias Agrícolas, Universidad Central Del Ecuador, Quito, Ecuador
| | - G E Heimpel
- Department of Entomology, University of Minnesota, St. Paul MN, USA
| | - C E Causton
- Charles Darwin Foundation, Santa Cruz Island, Galapagos Islands, Ecuador
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25
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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
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26
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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.
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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
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27
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Interactions between the Avian Parasite, Philornis downsi (Diptera: Muscidae) and the Galapagos Flycatcher, Myiarchus magnirostris Gould (Passeriformes: Tyrannidae). J Wildl Dis 2015; 51:907-10. [PMID: 26267462 DOI: 10.7589/2015-01-025] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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28
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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.
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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:
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29
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Kleindorfer S, O’Connor JA, Dudaniec RY, Myers SA, Robertson J, Sulloway FJ. Species Collapse via Hybridization in Darwin’s Tree Finches. Am Nat 2014; 183:325-41. [DOI: 10.1086/674899] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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30
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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
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31
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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.
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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
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32
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Villa SM, Le Bohec C, Koop JAH, Proctor HC, Clayton DH. Diversity of feather mites (Acari: Astigmata) on Darwin's finches. J Parasitol 2013; 99:756-62. [PMID: 23691947 DOI: 10.1645/12-112.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Feather mites are a diverse group of ectosymbionts that occur on most species of birds. Although Darwin's finches are a well-studied group of birds, relatively little is known about their feather mites. Nearly 200 birds across 9 finch species, and from 2 locations on Santa Cruz Island, Galápagos, were dust-ruffled during the 2009 breeding season. We found 8 genera of feather mites; the most prevalent genus was Mesalgoides (53-55%), followed by Trouessartia (40-45%), Amerodectes and Proctophyllodes (26-33%), Xolalgoides (21-27%), Analges and Strelkoviacarus (0-6%), and Dermoglyphus (2-4%). There was no evidence for microclimatic effects (ambient temperature and relative humidity) on mite diversity. Host body mass was significantly correlated with mean feather mite abundance across 7 of 8 well-sampled species of finches. Certhidea olivacea, the smallest species, did not fit this pattern and had a disproportionately high number of mites for its body mass.
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Affiliation(s)
- Scott M Villa
- Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, Utah 84112
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Monitoring Western Snowy Plover Nests with Remote Surveillance Systems in San Francisco Bay, California. JOURNAL OF FISH AND WILDLIFE MANAGEMENT 2012. [DOI: 10.3996/062011-jfwm-036] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Abstract
The western snowy plover Charadrius nivosus nivosus is listed as threatened under the U.S. Endangered Species Act of 1973 due to long-term population declines related, in part, to nest predation and human disturbance. In San Francisco Bay, California, numbers of predators of western snowy plovers and the potential for recreation-based human disturbances have increased during the past few decades and will likely increase for the foreseeable future. In an attempt to increase the reproductive success of western snowy plovers, managers have dedicated considerable resources to management practices including predator removal and habitat enhancement projects in San Francisco Bay. The unequivocal identification of western snowy plover nest predators and information regarding the behavioral responses of nesting plovers to human disturbance would inform management practices for this species. Therefore, we examined the efficacy of using a digital video surveillance system to identify nest predators of western snowy plovers in former salt evaporation ponds in San Francisco Bay and to assess its potential for use in behavioral studies. This system was designed to minimize disturbance to nesting plovers and limit predator bias at breeding sites that had little or no cover to camouflage or protect the equipment. The system included a small camera with infrared lights placed approximately 20 m from nests and a continuously operating recording unit and power supply that was positioned up to 300 m from nests. The system could be deployed within 20 min, run continuously for up to 5 d, and data could be retrieved without disturbing nesting birds. During a 2-y study period, we recorded six species depredating plover eggs and chicks: red-tailed hawk Buteo jamaicensis, common raven Corvus corax, California gull Larus californicus, northern harrier Circus cyaneus, ruddy turnstone Arenaria interpres, and gray fox Urocyon cinereoargenteus. Our results suggest that this surveillance system was effective for identifying western snowy plover nest predators, and the presence of the camera did not influence nesting success of monitored nests. This system could be integrated into conservation programs intended to improve reproductive success of this species and could be useful for conducting behavioral studies of western snowy plovers and other species.
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Distribution and abundance of Darwin’s finches and other land birds on Santa Cruz Island, Galápagos: evidence for declining populations. ORYX 2011. [DOI: 10.1017/s0030605311000597] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
AbstractPopulation monitoring is a vital tool for conservation management and for testing hypotheses about population trends in changing environments. Darwin’s finches on Santa Cruz Island in the Galápagos archipelago have experienced habitat alteration because of human activity, introduced predators, parasites and disease. We used point counts to conduct systematic quantitative surveys of Darwin’s finches and other land birds between 1997 and 2010. The temporal analysis revealed that six of the nine species investigated declined significantly and that this decline was most pronounced at higher elevations in humid native forest and agricultural areas; the highland areas have been most affected by introduced species or direct human impact. Five of the six declining species are insectivorous, which suggests that changes in insect abundance or insect availability are a critical factor in the declines. Further study is required to test this idea. Other factors including habitat alteration and introduced parasites or pathogens may be contributing to the observed declines.
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Koop JAH, Huber SK, Laverty SM, Clayton DH. Experimental demonstration of the fitness consequences of an introduced parasite of Darwin's finches. PLoS One 2011; 6:e19706. [PMID: 21589659 PMCID: PMC3092749 DOI: 10.1371/journal.pone.0019706] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Accepted: 04/14/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Introduced parasites are a particular threat to small populations of hosts living on islands because extinction can occur before hosts have a chance to evolve effective defenses. An experimental approach in which parasite abundance is manipulated in the field can be the most informative means of assessing a parasite's impact on the host. The parasitic fly Philornis downsi, recently introduced to the Galápagos Islands, feeds on nestling Darwin's finches and other land birds. Several correlational studies, and one experimental study of mixed species over several years, reported that the flies reduce host fitness. Here we report the results of a larger scale experimental study of a single species at a single site over a single breeding season. METHODOLOGY/PRINCIPAL FINDINGS We manipulated the abundance of flies in the nests of medium ground finches (Geospiza fortis) and quantified the impact of the parasites on nestling growth and fledging success. We used nylon nest liners to reduce the number of parasites in 24 nests, leaving another 24 nests as controls. A significant reduction in mean parasite abundance led to a significant increase in the number of nests that successfully fledged young. Nestlings in parasite-reduced nests also tended to be larger prior to fledging. CONCLUSIONS/SIGNIFICANCE Our results confirm that P. downsi has significant negative effects on the fitness of medium ground finches, and they may pose a serious threat to other species of Darwin's finches. These data can help in the design of management plans for controlling P. downsi in Darwin's finch breeding populations.
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Affiliation(s)
- Jennifer A H Koop
- Biology Department, University of Utah, Salt Lake City, Utah, United States of America.
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