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  • Larvae eating chick (Photo: Jody O Connor, Biological Sciences - Flinders University, jody.oconnor@flinders.edu.au)
  • Adult fly (Photo: Jody O Connor, Biological Sciences - Flinders University, jody.oconnor@flinders.edu.au)
  • Philornis downsi pupa (Photo: Jody O Connor, Biological Sciences - Flinders University, jody.oconnor@flinders.edu.au)
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Common name
Synonym
Similar species
Philornis deceptiva, Philornis seguyi, Philornis carinatus
Summary
Adult Philornis downsi flies feed on fruit, but larvae are semi-haematophagous (blood and tissue-feeding) parasites of birds. P. downsi larvae were first discovered in finch nests on Santa Cruz Island in 1997, although retrospective examination of insect collections show that the fly was present in the Galapagos Islands as early as 1964. Since then the parasite has spread to 12 of the 13 main Galapagos Islands and its larvae have been found in 64-100% of Darwin’s finch nests. The blood sucking larvae cause mortality in up to 76% of nestlings. For this high impact, it is given the highest risk ranking amongst introduced insects and amongst diseases/parasites.
Species Description
Eggs: approximately the shape of a rice grain, 2-3mm in length, elongated oval shaped, creamy white in colour. Larvae:1st, 2nd and 3rd instar phases vary in size and development. Creamy colour, soft-bodied, segmented along thoracic region, mouth hooks and other sensory/feeding apparatus at anterior end, spiracles (for breathing) present at posterior and anterior region (anterior spiracles in 2nd and 3rd instar only). Pupae: Light to dark brown in colour depending on duration, elongated barrel-shaped cocoon tapering towards anterior and posterior ends, rounded on one end and with a with cuff-like margin on the other. Adult fly: Similar in size to common house fly, generally dark in colour though colour varies according to size of individual.
For full description of developmental stages see Fessl et al. 2006
Lifecycle Stages
Female flies lay eggs in the nasal cavities of nestlings or in the nesting material. Larvae pass through 3 instar phases and are principally ectoparasitic feeding on blood and tissue fluids. First and early second instars tend to be subcutaneous feeders, feeding within the nostril of bird nestlings. Later instars are semi-haemotophagous and are free-living within the nest. The larval period in the nest is approximately 5-6 days. Third instar larvae drop to the bottom of the nest where they pupate (Fessl et al, 2006a). Philornis flies are known to emerge from pupae after approximately 2 weeks (Dodge, 1971).
Habitat Description
In the Galapagos, Philornis downsi occurs in most habitat types, including both arid lowland and humid highland zones. No information is available from Brazil and Trinidad
Reproduction
Adult fly mating behaviour is currently unknown though has not been observed in the nest. Females have been observed depositing eggs in the nesting material (O'Connor, unpublished data) and are known to mate with up to 5 males per laying event (Dudaniec et al, 2008). Captive breeding experiments are currently being carried out at Charles Darwin Research Station.
Nutrition
The adult Philornis downsi fly is vegetarian; its larvae feed on the blood and body fluids of bird nestlings. In Galapagos, documented hosts include Passeriformes and Cuculiformes: Mangove finch (Cactospiza heliobates), Woodpecker finch, (Cactospiza pallida), Warbler Finch (Certhidea olivacea), Small Ground Finch (Geospiza fuliginosa), Medium Ground Finch (Geospiza fortis), Cactus Finch (Geospiza scandens), Small Tree Finch (Camarhynchus parvulus), Medium Tree Finch (Camarhynchus pauper), Large Tree Finch (Camarhynchus psittacula) (Emberizidae); Galapagos Flycatcher (Myiarchus magnirostris), Vermilion Flycatcher (Pyrocephalus rubinus) (Fringillidae); Chatham mocking bird (Mimus melanotis), Galapagos mockingbird (Nesomimus parvulus), Floreana Mockingbird (Nesomimus trifasciatus) (Mimidae), Yellow Warbler (Dendroica petechia) (Parulidae); Dark-billed Cuckoo (Coccyzus melacoryphus), Smooth-billed ani (Crotophaga ani) (Cuculidae). In Brazil, documented hosts include: Rufous-capped Antshrike (Thamnophilus ruficapillus) (Thamnophilidae). In Trinidad documented hosts include: Cocoa Thrush (Turdus fumigatus) (Turdidae); Southern House-wren (Troglodytes musculus) (Troglodytidae); Palm Tanager (Thraupis palmarum) (Thraupidae); Gray-breasted Martin (Progne chalybea) (Hirundinidae); Shiny Cowbird (Molothrus bonariensis), Yellow-rumped Cacique (Cacicus cela) (Icteridae); Tropical Mockingbird (Mimus gilvus) (Mimidae); Piratic Flycatcher (Legatus leucophaius), Tropical Kingbird (Tyrannus melancholicus), Great Kiskadee (Pitangus sulfuratus) (Tyrannidae); Bananaquit (Coereba flaveola) (Coerebidae); Rufous-tailed Jacamar (Galbula ruficauda) (Galbulidae); Smooth-billed Ani (Crotophaga ani) (Cuculidae); Silver-beaked Tanager (Ramphocelus carbo) (Thraupidae); Bare-eyed Thrush (Turdus nudigenis) (Turdidae). (Galapagos references: Fessl and Tebbich, 2002; Fessl et al, 2001, Fessl et al, 2006a, Fessl et al, 2006b, Dudaniec et al, 2007; Wiedenfeld et al, 2007; O’Connor et al, in prep. Brazil reference: Mendonca and Couri, 1999. Trinidad reference: Dodge and Aitkin, 1968).
Pathway
Philornis downsi was accidentally introduced from mainland South America. Probably via fruit importation or in nesting material with pigeons

Principal source:

Compiler: Jody O'Connor, PhD Candidate School of Biological Sciences, Flinders University of South Australia. Adelaide, Australia & IUCN SSC Invasive Species Specialist Group (ISSG)

Review: R. Dudaniec, PhD, Post-doctoral Fellow, University of British Columbia, Vancouver, BC, Canada; B. Fessl, PhD, Mangrove Finch Project, Charles Darwin Foundation, Santa Cruz, Gal�pagos; C. Causton, PhD, Adjunct Researcher Charles Darwin Foundation for the Galapagos Islands (CDF); S. Kleindorfer, PhD, Senior lecturer Flinders University, Collaborating Scientist (CDRS)

Publication date: 2008-08-05

Recommended citation: Global Invasive Species Database (2016) Species profile: Philornis downsi. Downloaded from http://www.iucngisd.org/gisd/species.php?sc=1400 on 27-07-2016.

General Impacts
In the Galapagos Islands, known Philornis downsi fitness costs to Darwin's finches include: high nestling blood loss (18-55%), multiple body wounds and infections, grossly deteriorated nasal openings (Fessl et al, 2006a), reduced haemoglobin levels (Dudaniec et al 2006) and reduced growth rates (Fessl and Tebbich, 2002). Consequently, it is not surprising that P. downsi parasitism has been linked with high brood mortality: 16% to 95% (Fessl and Tebbich, 2002; Fessl et al, 2006a; Huber, 2008), and reduced fledging success (Dudaniec et al, 2007). Species with small clutch sizes, e.g. tree finch species are higher impacted than species with bigger clutch sizes (Fessl and Tebbich, 2002). As well, parasite intensity is higher in islands with highlands (Wiedenfeld et al, 2007).

Impacts of P. downsi parasitism especially threaten small remaining populations of the 'Critically Endangered (CR)' mangrove finch (see Camarhynchus heliobates in IUCN Red List of Threatened Species) with an approximate population of 100 individuals; the 'Critically Endangered (CR)' Floreana mockingbird (see Mimus trifasciatus in IUCN Red List of Threatened Species), and the the 'Critically Endangered (CR)' medium tree finch (see Camarhynchus pauper in IUCN Red List of Threatened Species). The Darwin's medium tree finch \r\nhas recently been uplisted from 'Vulnerable (VU)' to 'Critically Endangered (CR)'. Recent estimates put the total population at not more than 1,660 individuals, and it has recently begun declining rapidly owing to the effects of P. downsi (BirdLife International, 2009). No information is available to our knowledge on impacts of P.downsi on other places.

Management Info
Preventative measures: Quarantine measures to reduce introduction and dispersal (health standards for importing live birds, inspections of cargo).

Chemical: Charles Darwin Research Station (CDRS) and collaborators are trialing fly traps and lures for short term control. Accessible bird nests can be successfully liberated from parasites by applying a 1% Pyrethrin solution to the inside of the nest (without spraying directly on the nestlings, of course) (Fessl et al. 2006b). Currently, CDRS researchers are collecting more biological data on Philornis (e.g. life history, mating behaviour, fly distribution over the year and in different zones). They are also trying to breed the flies in the lab in order to evaluate the possibility of using sterile insect techniques to control the fly.

Countries (or multi-country features) with distribution records for Philornis downsi
ALIEN RANGE
NATIVE RANGE
Informations on Philornis downsi has been recorded for the following locations. Click on the name for additional informations.
Lorem Ipsum
Location Status Invasiveness Occurrence Source
Details of Philornis downsi in information
Status
Invasiveness
Arrival date
Occurrence
Source
Introduction
Species notes for this location
Location note
Management notes for this location
Impact
Mechanism:
Outcome:
Ecosystem services:
Impact information
In the Galapagos Islands, known Philornis downsi fitness costs to Darwin's finches include: high nestling blood loss (18-55%), multiple body wounds and infections, grossly deteriorated nasal openings (Fessl et al, 2006a), reduced haemoglobin levels (Dudaniec et al 2006) and reduced growth rates (Fessl and Tebbich, 2002). Consequently, it is not surprising that P. downsi parasitism has been linked with high brood mortality: 16% to 95% (Fessl and Tebbich, 2002; Fessl et al, 2006a; Huber, 2008), and reduced fledging success (Dudaniec et al, 2007). Species with small clutch sizes, e.g. tree finch species are higher impacted than species with bigger clutch sizes (Fessl and Tebbich, 2002). As well, parasite intensity is higher in islands with highlands (Wiedenfeld et al, 2007).

Impacts of P. downsi parasitism especially threaten small remaining populations of the 'Critically Endangered (CR)' mangrove finch (see Camarhynchus heliobates in IUCN Red List of Threatened Species) with an approximate population of 100 individuals; the 'Critically Endangered (CR)' Floreana mockingbird (see Mimus trifasciatus in IUCN Red List of Threatened Species), and the the 'Critically Endangered (CR)' medium tree finch (see Camarhynchus pauper in IUCN Red List of Threatened Species). The Darwin's medium tree finch \r\nhas recently been uplisted from 'Vulnerable (VU)' to 'Critically Endangered (CR)'. Recent estimates put the total population at not more than 1,660 individuals, and it has recently begun declining rapidly owing to the effects of P. downsi (BirdLife International, 2009). No information is available to our knowledge on impacts of P.downsi on other places.

Red List assessed species 5: CR = 3; EN = 1; VU = 1;
Locations
Mechanism
[1] Parasitism
Outcomes
[1] Environmental Species - Population
  • [1] Plant/animal health
Management information
Preventative measures: Quarantine measures to reduce introduction and dispersal (health standards for importing live birds, inspections of cargo).

Chemical: Charles Darwin Research Station (CDRS) and collaborators are trialing fly traps and lures for short term control. Accessible bird nests can be successfully liberated from parasites by applying a 1% Pyrethrin solution to the inside of the nest (without spraying directly on the nestlings, of course) (Fessl et al. 2006b). Currently, CDRS researchers are collecting more biological data on Philornis (e.g. life history, mating behaviour, fly distribution over the year and in different zones). They are also trying to breed the flies in the lab in order to evaluate the possibility of using sterile insect techniques to control the fly.

Locations
Management Category
Control
Bibliography
32 references found for Philornis downsi

Managment information
BirdLife International, 2009. Species factsheet: Camarhynchus pauper.
Summary: Available from: http://www.birdlife.org/datazone/species/index.html?action=SpcHTMDetails.asp&sid=9609&m=0 [Accessed 12 August 2009]
Causton, C. E; S. B. Peck; B. J. Sinclair; L. Roque-Albelo; C. J. Hodgson, & B. Landry., 2006. Alien Insects: Threats and Implications for Conservation of Gala�pagos Islands. Ann. Entomol. Soc. Am. 99(1): 121�143 (2006)
Galapagos Conservation Trust (GCT) ., December 2002. Response from CDF to article on parasites in Darwin s finches
Summary: Available from: http://www.gct.org/dec02_3.html [Accessed 5 August 2008]
Wiedenfeld, David A & Gustavo A. Jimenez-Uzcategui., 2008. Critical problems for bird conservation in the Galapagos islands. Cotinga 29 (2008): 22-27
Summary: Available from: http://www.neotropicalbirdclub.org/articles/29/Galapagos.pdf [Accessed 5 August 2008]
General information
Arendt, W.J.1985a. Philornis ectoparasitism of Pearly-eyed thrashers. I. Impact on growth and devlopment of nestlings. The Auk. 102: 270-280
Arendt, W.J.1985b. Philornis ectoparasitism of Pearly-eyed thrashers. II. Effect on adults and reproduction. The Auk. 102: 281-292
BirdLife International 2004. Camarhynchus heliobates. In: IUCN 2007. 2007 IUCN Red List of Threatened Species.
Summary: Available from: http://www.iucnredlist.org/search/details.php/3663/all [Accessed 5 August 2008]
BirdLife International 2004. Camarhynchus pauper. In: IUCN 2007. 2007 IUCN Red List of Threatened Species.
Summary: Available from: http://www.iucnredlist.org/search/details.php/3664/all [Accessed 5 August 2008]
BirdLife International, 2008. Species factsheet: Camarhynchus heliobates.
Summary: Available from: http://www.birdlife.org/datazone/species/index.html?action=SpcHTMDetails.asp&sid=9612&m=0 [Accessed 5 August 2008]
BirdLife International, 2008. Species factsheet: Camarhynchus pauper.
Summary: Available from: http://www.birdlife.info/wbdbwebstaging/SpcHarnessDetails.asp?sid=9609&m=0 [Accessed 5 August 2008]
Couri, M.S., Rabuffette, F.L., Reboreda, J.C. 2005. New data on Philornis seguyi Garcia (1952) (Diptera), Muscidae
Dodge, H.R. 1971. Revisional study of flies of the genus Philornis Meinert. Studia Entomologica. 14: 458-459
Dodge, H.R. and Aitkin, T.H.G. 1968. Philornis flies from Trinidad (Diptera:Muscidae). Journal of Kansas Entomological Society. 41:134-154
Dudaniec, Rachael Y., Sonia Kleindorfer and and Birgit Fessl., 2006. Effects of the introduced ectoparasite Philornis downsi on haemoglobin level and nestling survival in Darwin�s Small Ground Finch (Geospiza fuliginosa). Austral Ecology (2006) 31, 88�94
Dudaniec, R.Y. Fessl, B., Kleindorfer, S. 2007. Interannual amd interspecific variation in intensity of the parasitic fly, Philornis downsi, in Darwin s finches. Biological Conservation. 139:325-332
Dudaniec R.Y, Gardner M.G, Donellan S, Kleindorfer S., 2008. Genetic variation in the invasive avian parasite, Philornis downsi (Diptera, Muscidae) on the Gal�pagos archipelago. BMC Ecology: 8
Dudaniec R.Y, Gardner M.G, Kleindorfer S., 2008. Isolation, characterisation and multiplex PCR of novel microsatellite loci for the avian parasite, Philornis downsi (Diptera: Muscidae). Molecular Ecology Resources. 8: 142-144.
Dudaniec, R.Y, Gardner M.G, Kleindorfer, S., 2009. Offspring genetic structure reveals multiple mating and nest infestation behaviour of an invasive parasitic fly (Philornis downsi) of Galapagos birds. Biological Invasions. DOI: 10.1007/s10530-009-9464-x
Dudaniec, R.Y. & Kleindorfer. S. 2006. The effects of the parasitic flies Phlornis (Diptera, Muscidae) on birds. Emu. Aust. Ornith. 106:13-20
Encyclopedia of Life (EOL)., 2008. Philornis downsi
Summary: Available from: http://www.eol.org/taxa/16313523 [Accessed 5 August 2008]
Fessl, B., Couri, M.S., Tebbich, S. 2001. Philornis downsi Dodge and Aitkin, new to the Galapagos Islands (Diptera, Muscidae). Studia Dipterologic. 8:317-322
Fessl, Birgit & Sabine Tebbich., 2002. Philornis downsi � a recently discovered parasite on the Gal�pagos archipelago � a threat for Darwin�s finches? Ibis (2002), 144, 445�451
Fessl, B; R. J. Sinclair and S. Kleindorfer., 2006. The life-cycle of Philornis downsi (Diptera: Muscidae) parasitizing Darwin s finches and its impacts on nestling survival. Parasitology, Volume 133, Issue 06, December 2006, pp 739-747
Fessl, B; S. Kleindorfer and S. Tebbich., 2006. An experimental study on the effects of an introduced parasite in Darwin�s finches . Biological Conservation Volume 127, Issue 1, January 2006, Pages 55-61
Huber, K Sarah., 2008. Effects of the introduced parasite Philornis downsi on nestling growth and mortality in the medium ground finch (Geospiza fortis). Short Communication Biological Conservation Volume 141, Issue 2, February 2008, Pages 601-609
ITIS (Integrated Taxonomic Information System), 2005. Online Database Philornis
Summary: An online database that provides taxonomic information, common names, synonyms and geographical jurisdiction of a species. In addition links are provided to retrieve biological records and collection information from the Global Biodiversity Information Facility (GBIF) Data Portal and bioscience articles from BioOne journals. Available from: http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=150620 [Accessed 5 August 2008]
Kleindorfer S, Dudaniec R Y., 2009. Love thy Neighbour? Ectoparasite intensity varies with social nesting pattern and nest size in Darwin�s finches. Behavioural Ecology and Sociobiology. 63: 731-739
Mendoca, E.C. & Couri, M.S. 1999. New associations between Philornis Meinert (Diptera, Muscidae) and Thamnophilidae (Aves, Passeriformes). Revista Basiliera de Zoologia. 16: 1223-1225
Uhazy and Arendt, W.J. 1986. Pathogenesis associated with Philornid myiasis (Diptera, Muscidae) on pearly-eyed thrashers (Aves: Mimidae) in the Luquillo Rainforest, Puerto Rico. Journal of Wildlife Diseases. 22. 224-237
Wiedenfeld, David A; Jimenez U, Gustavo A; Fessl, Birgit; Kleindorfer, Sonia; Valarezo, Juan Carlos., 2007. Distribution of the introduced parasitic fly Philornis downsi (Diptera, Muscidae) in the Galapagos Islands. Pacific Conservation Biology. 13(1). MAR 2007. 14-19.
Summary: Abstract: The avifauna of the Galapagos Islands is characterized by a small number of endemic species, including the 13 species of Darwin s finches. The introduced fly parasite Philornis downsi reduces nestling survival and growth rate of altricial birds, and can cause mortality and morbidity of the nestlings. We examined the occurrence of Philornis downsi among islands and at different elevations. The parasite was found in nests from 11 of 13 islands sampled. The two islands on which P downsi was not found were Espa (n) over tilde ola and Genovesa, both and islands with no humid highlands and distant from the centre of the archipelago. Parasite infection intensity was greater in nests at higher elevations, and on islands that have moist highlands, which may serve as a reservoir for the flies. A full understanding of the fly s ecology may permit the development of eradication or control methods, or at least mitigation of its effects on the birds.
Young, B. E. 1993. Effects of the parasitic botfly Philornis carinatus on nestling house wrens, Troglodytes aedon, in Costa Rica. Oecologia 93, 256�262. doi:10.1007/BF00317679
Contact
The following 4 contacts offer information an advice on Philornis downsi
Causton,
Charlotte
Organization:
Adjunct Researcher with the Charles Darwin Foundation for the Galapagos Islands (CDF)
Address:
Charles Darwin Research Station, A.P. 17-01-3891, Quito, Ecuador
Phone:
+593 5 2526 146
Fax:
+593 5 2526 147
Dudaniec,
Rachael
Organization:
Post-doctoral Research Fellow Department of Forest Sciences
Address:
3041 - 2424 Main Mall University of British Columbia Vancouver, BC, Canada, V6T 1Z4
Phone:
604-818-1742
Fax:
Kleindorfer,
Sonia
Organization:
School of Biological Sciences Flinders University of South Australia
Address:
GPO Box 2100 Adelaide 5001
Phone:
(08) 8201-5232
Fax:
(08) 8201-3015
O Connor,
Jody
Jody O�Connor is an Australian PhD student working on Philornis downsi parasitism in Darwin�s finches (Galapagos Islands). Her project focuses on the conservation of Darwin�s finches by quantifying finch nesting success, prevalence and impacts of P. downsi parasites, studying the host-parasite interaction (including behavioural and life-history adaptations), conducting avian population surveys, and using video surveillance in parasitised nests. The project is based primarily on Floreana Island, where the only existing population of Darwin�s medium tree finches are severely threatened by P. downsi parasitism, introduced predators, and habitat destruction.
Organization:
PhD candidate, Biological Sciences, Flinders University
Address:
GPO Box 2100 Adelaide SA 5001
Phone:
(08) 82012450
Fax: