1) Host species | 2) Island | 3) Year of study | 4) Sample size | 5) P. downsi prevalence | 6) Mean number of P. downsi per nest (range) | 7) In-nest mortality (%) | 8) Effects on host | 9) Comments | 10) Type of Study | 11) Exp. (E) versus Obs. (O) study | 12) Reference |
---|---|---|---|---|---|---|---|---|---|---|---|
9 species | Santa Cruz | 1998 | 63 | 97 % | N/A | First study to describe P. downsi in bird nests on Santa Cruz Island | Ecology | O | Fessl, Couri, Tebbich 2001 [29] | ||
12 species | Santa Cruz | 1998–2000 | 177 | 97 % | 15.7 ± 7.4–49.8 ± 31.2 (0–182) | 27 % | Number of larvae increased with nestling age; P. downsi not found in nests during incubation | Intensity compared for nestling age <8 days vs. >8d; species differed in intensity | Ecology | O | Fessl, Tebbich 2002 [28] |
3 Darwin’s finch species | Santa Cruz | 2000, 2004, 2005 | 63 | 100 % | −32.4–95.2 % | Damage to nestling nasal cavities; calculated 18–55 % overnight blood loss in nestlings due to parasitism | Identify two stage life cycle of P. downsi with 1st instar within nestling nares and 2nd and 3rd instar feeding externally | Ecology | O | Fessl, Sinclair, Kleindorfer 2006 [42] | |
2 Darwin’s finch species | Santa Cruz | 2000, 2004 | 27 | 100 % | 18.4 ± 2.4–23.2 ± 4.2 | 66 % | Parasitized nestlings had 61 % lower survival, 56 % lower body mass, 28 % lower hemoglobin concentration | 11 nests prayed with 1 % permethrim (~1 P. downsi left per nest; range 0–5 larvae) | Ecology | E | Fessl, Kleindorfer, Tebbich 2006 [41] |
Darwin’s finches | All islands | P. downsi given highest risk ranking for invasive species that negatively impact endemic fauna | 23 % (around 463 species) of Galapagos invertebrate species are introduced of which 6 are confirmed to be highly invasive and harmful to endemic species | Ecology | Causton, Peck, Sinclair, Roque-Albelo, Hodgson, Landry 2006 [26] | ||||||
Small ground finch | Santa Cruz, Floreana, Isabela | 2004 | 24 | 92 % | 23 ± 6 (0–90) | 2 % lower hemoglobin concentration per additional larva | Effect of clutch size on P. downsi number per nestling | Ecology | O | Dudaniec, Kleindorfer, Fessl 2006 [44] | |
6 Darwin’s finch species | Santa Cruz | 1998–2005 | 131 | 100 % | 30.2 ± 4–66.8 ± 7.6 | 55 % | Positive association between P. downsi intensity and rainfall (eight year study); same intensity across habitats on Santa Cruz | Species differences in intensity | Ecology | O | Dudaniec, Fessl, Kleindorfer 2007 [33] |
Darwin’s finches | 13 islands | 1998–2005 | 515 | 27.0 (1–182) | P. downsi was found on 11 of 13 islands sampled (absent from flat arid islands); more parasites in highland nests on elevated islands | Lowland nests on elevated islands had more P. downsi than lowland nests on flat islands | Ecology | O | Wiedenfeld, Jiménez, Fessl, Kleindorfer, Valarezo 2007 [39] | ||
5 Darwin’s finch species | Santa Cruz, Floreana, Isabela | 2004–2006 | 64 | 100 % | High gene flow between islands; some genetic differentiation of P. downsi on Floreana; evidence for genetic bottleneck | Sequenced CO1 mitochondrial gene fragments | Genetics, Ecology | O | Dudaniec, Gardner, Donnellan, Kleindorfer 2008 [40] | ||
Medium ground finch | Santa Cruz | 2004–2006 | 63 | 64–98 % | (0–200) | 16–37 % | Number of P. downsi per nestling (but not per nest) predicted survival; no effect of P. downsi on nestling size | Nests earlier in the breeding season had more P. downsi per nest | Ecology | O | Huber 2008 [34] |
Small ground finch | Santa Cruz | 2008 | 623 | 36.3 % of adult birds had malformed beaks with enlarged naris (likely caused by P. downsi during the nestling phase) | Ecology | O | Galligan, Kleindorfer 2009 [48] | ||||
5 Darwin’s finch species | Santa Cruz | 2000–2004 | 43 | 100 % | 23.0 ± 3–57.0 ± 4 | Larger finches built larger nests; within species, larger nests had more P. downsi | Behavior | O | Kleindorfer, Dudaniec 2009 [90] | ||
Small ground finch | Floreana | 2004–2006 | 39 | 94 % | 8.0 ± 1.6–39.3 ± 4.6 (0–78) | 3–33.4 % | Arid lowland nests had 80 % fewer P. downsi and 91 % lower in-nest mortality than highland nests | Ecology | O | O’Connor, Dudaniec, Kleindorfer 2010 [89] | |
Medium ground finch | Santa Cruz, Daphne Major | 2008 | 67 | More Philornis-specific antibodies in females than males, and more during the nesting period | No P. downsi found on Daphne Major | Ecology, Behavior | O | Huber, Owen, Koop, King, Grant, Grant, Clayton 2010 [46] | |||
3 Darwin’s finch species | Santa Cruz, Floreana | 2008 | 11 | 89 % | 27.1 ± 8.5 (0–74) | 79.2 % | Multiple P. downsi entries into the nest during incubation and feeding; nestlings stood on top of each other presumably to avoid larvae; adults preened nestling nares and nest base; nestling consumed larva | In-nest video; altered time budgets and behavior in heavily parasitized nests; adults removed dead nestling from nest | Behavior, Ecology | O | O’Connor, Robertson, Kleindorfer 2010 [49] |
5 Darwin’s finch species | Santa Cruz, Floreana | 2004–2006 | 57 | 100 % | 30.8 ± 16.5 (5–65) | Genetic relatedness among P. downsi within nests was 57 % lower on Santa Cruz than on Floreana Island; between 1–6 different females laid their eggs per finch nest; each female mated with ~2 different males; each female laid ~5 eggs per finch nest with a maximum of 24 from one female | Genetics, Ecology, Behavior | O | Dudaniec, Gardner, Kleindorfer 2010 [117] | ||
Medium tree finch | Floreana | 2006, 2008 | 30 | 100 % | 43.1 ± 10.7–65.6 ± 8.5 (8–96) | 20–38 % total brood loss; 53 % of nests with partial or total brood loss | Parasite intensity did not predict fledging success; parasitized nestlings had grossly enlarged nares and tissue loss | Highest P. downsi intensity in critically endangered medium tree finch | Ecology | O | O’Connor, Sulloway, Robertson, Kleindorfer 2010 [38] |
Mangrove finch | Isabela | 2006–2009 | 15 | 100 | 40.8 ± 15.3 sd | 14 % | Less rat predation after rat control (30 % predation after control versus 54 % predation before); P. downsi explained 14 % nestling mortality | Before and after rat control | Ecology | O + E | Fessl, Young, Young, Rodríguez-Matamoros, Dvorak, Tebbich 2010 [63] |
Medium ground finch | Santa Cruz | 2008 | 48 | 90 % | 37.5 ± 4.9 | 96 % | Parasitized nestlings had ~30 % shorter primary feather length and 88 % lower fledging success | Nylon stocking placed over wire hoop as barrier to P. downsi; reduced parasite intensity to ~21 larvae per nest | Ecology, Behavior | E | Koop, Huber, Laverty, Clayton 2011 [63] |
Darwin’s finches | All islands | 2012-present | Summary of known P. downsi biology and impacts on endemic land birds | Launch of the P. downsi Action Plan | Ecology, Behavior, Genetics | Causton, Cunninghame, Tapia 2013 [72] | |||||
Medium ground finch | Santa Cruz | 2010 | 30 (15 control, 15 exp.) | 44.7 ± 6 (5–79) | No effect of P. downsi on attending female corticosterone level, body condition or hematocrit level | 15 nests sprayed with 1 % permethrin (~0 per nest) | E | Knutie, Koop, French, Clayton 2013 [102] | |||
Medium ground finch | Santa Cruz | 2010 | 43 (22 control,21 exp) | 100 % | 38.5 ± 5.1 | 100 % | Compared with fumigated nests, females at parasitized nests had more P. downsi-specific antibodies, spent 42 % less time brooding and 74 % more time standing erect in the nest | 14 females and 10 males from fumigated nests, 15 females and 10 males from parasitized nests | Behavior | E | Koop, Owen, Knutie, Aguilar, Clayton 2013 [47] |
Medium ground finch | Santa Cruz | 2009 | 13 (7 control, 6 exp.) | 83 % | 30.5 ± 7.5 | 86 % | No effect of rainfall on P. downsi intensity (two year study) | 6 nests sprayed with 1 % permethrin (zero P. downsi) | Ecology | E | Koop, Le Bohec, Clayton 2013 [88] |
Small ground finch | Floreana | 2010 | 14 (7 control, 7 exp.) | 100 % | 22.7 ± 3.9 (12–60) | 100 % | In-nest video; heavily parasitized nestlings had weak begging; parents only fed strongly begging nestlings | 7 nests sprayed with 1 % permethrin (zero P. downsi) | Behavior | E | O’Connor, Robertson, Kleindorfer 2014 [100] |
4 Darwin’s finch species | Floreana | 2004–2013 | 238 | 100 % | 27.5 ± 4.6 (2004) to 48.4 ± 6.5 (2013) | 50–90 % | Across the decade, P. downsi intensity increased (~28 to ~48), in-nest mortality increased (~50 to ~90 %), nestlings died younger (~11 to ~5 days after hatching); pupa size got 10 % smaller (~10 mm to ~9 mm) | Compared with other finches, small ground finch nests had more P. downsi pupae, which indicates higher fly reproductive success | Ecology | O | Kleindorfer, Peters, Custance, Dudaniec, O’Connor 2014 [37] |
3 Darwin’s tree finch species | Floreana | 2005, 2010 | 201 | 100 % | 25 ± 3–65 ± 18 | Hybrid finch nests had 50–79 % fewer P. downsi than medium tree finch (2005, 2010) | Contemporary hybridization in Darwin’s tree Finches; evidence for hybrid fitness | Behavior, Genetics, Ecology | O | Kleindorfer, O’Connor, Dudaniec, Myers, Robertson, Sulloway 2014 [7] | |
2 Darwin’s finch species | Santa Cruz | 2010, 2012 | 82 | 100 % | 25, 38 | 37–56 % | Extreme weather events and number of P. downsi influenced nesting success | Species differences in P. downsi intensity | Ecology | O | Cimadom, Ulloa, Meidl, Zöttl, Zöttl, Fessl, Nemeth, Dvorak, Cunninghame, Tebbich 2014 [36] |
4 Darwin’s finch species | Santa Cruz | 2013 | 37 (17 control, 20 exp.) plus 26 nests checked for treated cotton | 17 ± 3.9 | 46 % | Parasitized nests had 35 % lower fledging success | Permethrin-treated cotton from dispensers in 22 nests; 20 nests sprayed with 1 % permethrin (zero P. downsi) | Ecology | E | Knutie, McNew, Bartlow, Vargas, Clayton 2014 [70] | |
Small ground finch | Floreana | 2010 | 14 (8 control, 6 exp.) | 100 % | 24.2 ± 2.7 | Parasitized nestlings had larger relative (39 %) and absolute (3.3 mm) naris size compared with parasite-free nestlings (20.2 %, 1.6 mm) | 6 nests sprayed with 1 % permethrin (zero P. downsi); museum specimens had normal naris size suggesting post 1960s arrival of P. downsi | Ecology, Morphology | E | Kleindorfer, Sulloway 2016 [30] | |
3 Darwin’s finch species | Floreana | 2004–2014 | 582 | 100 % | 17.7 ± 3.3–87.8 ± 19.5 | Higher fly traps caught more female P. downsi; higher finch nests had more P. downsi | 28 McPhail traps placed at 1 m–7 m to test for fly sex ratio at different trapping heights | Behavior, Ecology | E | Kleindorfer, Peters, Hohl, Sulloway 2016 [71] | |
Medium ground finch, mockingbird | Santa Cruz | 2012, 2013 | 127 | P. downsi density (grams per nestling g) predicted finch but not mockingbird mortality; no P. downsi antibodies in nestlings; parasitized mockingbird but not finch nestlings begged more | 32 finch nests and 34 mockingbird nests prayed with 1 % permethrin | Behavior, Ecology | E | Knutie, Owen, McNew, Bartlow, Arriero, Herman, DiBlasi, Thompson, Koop, Clayton 2016 [105] |