| 1. |
- Blomqvist, Donald, 1954, et al.
(författare)
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High frequency of extra-pair fertilisations in the moustached warbler, a songbird with a variable breeding system
- 2005
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Ingår i: Behaviour. - : Brill. - 0005-7959 .- 1568-539X. ; 142:8, s. 1133-1148
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Tidskriftsartikel (refereegranskat)abstract
- We examined the genetic mating system of the moustached warbler Acrocephalus melanopogon, a multi-brooded songbird that sometimes breeds in trios (one female and two males). The second male, which appears relatively late in the breeding cycle, participates in all forms of parental care but provides less care than the pair male. DNA fingerprinting revealed a high frequency of extra-pair paternity: 39% (7/18) of the broods contained extra-pair young, comprising 27% (12/44) of the chicks. An additional 7 broods contained at least 9 chicks (out of 20) that were not sired by the resident male. We were able to assign paternity for 11 (52%) of the extra-pair young. Of these, 7 (64%) were sired by secondary males and 4 (36%) by close neighbours (nesting within 50 m). Consistently, pairs with extra-pair young had more close neighbours, and they also tended to have a secondary male at the nest. Caring for nestlings that they might have sired through extra-pair copulations may be a way for secondary males to salvage their reproductive effort. They may also provide parental care because of the possibility of pairing with the female in future breeding attempts. Our results suggest that female moustached warblers obtain direct benefits (i.e., help with brood care) from extra-pair copulations. However, a skewed fertilisation pattern implies that genetic compatibility between mates and copulation partners may also influence female extra-pair behaviour in this species.
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| 2. |
- Dudaniec, Rachael, et al.
(författare)
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Genetic and morphological divergence in island and mainland birds: Informing conservation priorities
- 2011
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Ingår i: Biological Conservation. - : Elsevier BV. - 1873-2917 .- 0006-3207. ; 144:12, s. 2902-2912
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Tidskriftsartikel (refereegranskat)abstract
- Evolutionary processes can complicate conservation efforts for species with uncertain taxonomic classifications and discrete geographic populations. Discordant morphological and genetic patterns across the geographic range of species further calls for the identification of evolutionary significant units for conservation. Using island and mainland populations of a small Australian passerine (the superb fairy-wren, Malurus cyaneus), we examine the relationship between morphological and genetic divergence among two subspecies, M. c. ashbyi (Kangaroo Island, South Australia) and M. c. leggei (South Australia, mainland), using eight microsatellite markers. Island birds showed clear evidence for morphological divergence, with a larger body size and thinner bill compared to mainland birds. Two genetic clusters were found using Bayesian methods, comprising mainland and island regions. Estimates of recent migration rates between all sites were very low (<2%). Morphological and genetic differentiation between island and mainland sites correlated significantly, but not when controlling for isolation by distance. Genetic and morphological substructure was evident with three distinct genetic clusters in each region. Males, the highly sedentary sex, appeared to drive correlations between morphological and genetic differentiation. Our study provides evidence that the subspecies classification of M. cyaneus in island and mainland regions encapsulates two independently diverging populations that can be recognised in conservation planning.
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| 3. |
- Kleindorfer, Sonia, et al.
(författare)
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Changes in Philornis infestation behavior threaten Darwin's finch survival
- 2014
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Ingår i: Current Zoology. - 1674-5507. ; 60:4, s. 542-550
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Tidskriftsartikel (refereegranskat)abstract
- The conservation behavior framework is useful to identify key linkages between behavior and conservation practice. We apply this framework to a novel host-parasite system on the Galapagos Islands and ask if there have been changes in parasite oviposition behavior and host mortality patterns across the first decade (2004-2013) of its known association. The Dipteran parasite Philornis downsi was first discovered in Darwin's finch nests in 1997 and is the biggest threat to the survival of Galapagos land birds. Host mortality has increased over the past decade. In Dipterans, pupation and pupae size are determined by access to host resources. Here, we test the hypothesis that P. downsi flies are laying eggs in finch nests earlier in the nestling phase to maximize larval feeding time and therefore chance of pupation success before host death. The results show fewer 1st instar larvae later in the host nesting cycle in support of earlier egg laying behavior by female flies. Between 2004 and 2013, parasite intensity increased from similar to 28 to similar to 48 parasites per nest, host mortality increased from similar to 50% to similar to 90%, and host age at death decreased from similar to 11 to similar to 5 days. The earlier age at host death was correlated with fewer pupae (from similar to 50% to similar to 20%) and smaller pupae size (similar to 10% decrease). Changes in parasite behavior reveal new fitness costs to both the parasite and Darwin's finches. These findings underscore the need for urgent conservation action to save Darwin's finches from extinction due to a novel, lethal and introduced parasite
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| 4. |
- Kleindorfer, Sonia, et al.
(författare)
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Species Collapse via Hybridization in Darwin's Tree Finches
- 2014
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Ingår i: American Naturalist. - : University of Chicago Press. - 0003-0147 .- 1537-5323. ; 183:3, s. 325-341
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Tidskriftsartikel (refereegranskat)abstract
- Species hybridization can lead to fitness costs, species collapse, and novel evolutionary trajectories in changing environments. Hybridization is predicted to be more common when environmental conditions change rapidly. Here, we test patterns of hybridization in three sympatric tree finch species (small tree finch Camarhynchus parvulus, medium tree finch Camarhynchus pauper, and large tree finch: Camarhynchus psittacula) that are currently recognized on Floreana Island, Galaapagos Archipelago. Genetic analysis of microsatellite data from contemporary samples showed two genetic populations and one hybrid cluster in both 2005 and 2010; hybrid individuals were derived from genetic population 1 (small morph) and genetic population 2 (large morph). Females of the large and rare species were more likely to pair with males of the small common species. Finch populations differed in morphology in 1852--1906 compared with 2005/2010. An unsupervised clustering method showed (a) support for three morphological clusters in the historical tree finch sample (1852--1906), which is consistent with current species recognition; (b) support for two or three morphological clusters in 2005 with some (19%) hybridization; and (c) support for just two morphological clusters in 2010 with frequent (41%) hybridization. We discuss these findings in relation to species demarcations of Camarhynchus tree finches on Floreana Island.
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| 5. |
- Odom, Karan J., et al.
(författare)
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Sex role similarity and sexual selection predict male and female song elaboration and dimorphism in fairy-wrens
- 2021
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Ingår i: Ecology and Evolution. - : John Wiley & Sons. - 2045-7758. ; 11:24, s. 17901-17919
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Tidskriftsartikel (refereegranskat)abstract
- Historically, bird song complexity was thought to evolve primarily through sexual selection on males; yet, in many species, both sexes sing and selection pressure on both sexes may be broader. Previous research suggests competition for mates and resources during short, synchronous breeding seasons leads to more elaborate male songs at high, temperate latitudes. Furthermore, we expect male-female song structure and elaboration to be more similar at lower, tropical latitudes, where longer breeding seasons and year-round territoriality yield similar social selection pressures in both sexes. However, studies seldom take both types of selective pressures and sexes into account. We examined song in both sexes in 15 populations of nine-fairy-wren species (Maluridae), a Southern Hemisphere clade with female song. We compared song elaboration (in both sexes) and sexual song dimorphism to latitude and life-history variables tied to sexual and social selection pressures and sex roles. Our results suggest that song elaboration evolved in part due to sexual competition in males: male songs were longer than female songs in populations with low male survival and less male provisioning. Also, female songs evolved independently of male songs: female songs were slower paced than male songs, although only in less synchronously breeding populations. We also found male and female songs were more similar when parental care was more equal and when male survival was high, which provides strong evidence that sex role similarity correlates with male-female song similarity. Contrary to Northern Hemisphere latitudinal patterns, male and female songs were more similar at higher, temperate latitudes. These results suggest that selection on song can be sex specific, with male song elaboration favored in contexts with stronger sexual selection. At the same time, selection pressures associated with sex role similarity appear to favor sex role similarity in song structure.
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| 6. |
- Wemer, Laura, et al.
(författare)
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Reduced ectoparasite load, body mass and blood haemolysis in Eurasian kestrels (Falco tinnunculus) along an urban–rural gradient
- 2021
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Ingår i: Science of Nature. - : Springer Science and Business Media LLC. - 0028-1042 .- 1432-1904. ; 108:5
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Tidskriftsartikel (refereegranskat)abstract
- Urbanisation is proceeding at an alarming rate which forces wildlife to either retreat from urban areas or cope with novel stressors linked to human presence and activities. For example, urban stressors like anthropogenic noise, artificial light at night and chemical pollution can have severe impacts on the physiology of wildlife (and humans), in particular the immune system and antioxidant defences. These physiological systems are important to combat and reduce the severity of parasitic infections, which are common among wild animals. One question that then arises is whether urban-dwelling animals, whose immune and antioxidant system are already challenged by the urban stressors, are more susceptible to parasitic infections. To assess this, we studied nestlings of Eurasian kestrels (Falco tinnunculus) in Vienna, Austria, during 2015 and 2017. We measured biomarkers of innate immune function, oxidative stress and body mass index and ectoparasite infection intensity in 143 nestlings (from 56 nests) along an urban gradient. Nestlings in more urbanised areas had overall fewer ectoparasites, lower haemolysis (complement activity) and lower body mass index compared to nestlings in less urbanised areas. None of the other immune or oxidative stress markers were associated with the urban gradient. Despite some non-significant results, our data still suggest that kestrel nestlings experience some level of reduced physiological health, perhaps as a consequence of exposure to more urban stressors or altered prey availability in inner-city districts even though they had an overall lower ectoparasite burden in these heavily urbanised areas.
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