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22 July 2015 Island size predicts the frequency of melanic birds in the color-polymorphic flycatcher Monarcha castaneiventris of the Solomon Islands
J. Albert C. Uy, Luis E. Vargas-Castro
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Observations that similar traits repeatedly evolve across independent taxa on islands—such as loss of flight in birds or reduction of body size in large mammals—suggest that deterministic processes, rather than drift, drive the convergent evolution of these traits. One such repeated pattern on islands that has received little attention is the evolution of entirely black coloration, or “melanism.” In several taxa, including birds, reptiles, and insects, melanism has evolved on islands despite the proximity of mainland populations with different colors. We explored the evolution of melanism on islands by testing how island size predicts the frequency of melanic birds in Monarcha castaneiventris obscurior, a subspecies of flycatcher from the Solomon Islands that is polymorphic for plumage color (i.e. melanic vs. chestnut-bellied). While accounting for potential spatial autocorrelation because some islands are <1 km apart, we found that island size predicted the frequency of melanic birds, with smaller islands having higher frequencies of melanism than larger islands. As with other traits that have repeatedly evolved on islands, this pattern suggests that melanism on small islands is likely mediated by deterministic processes like natural selection.


Island systems have featured prominently in our understanding of key evolutionary and ecological processes (Darwin 1859, Wallace 1864, Mayr 1942, Diamond 1977, MacArthur and Wilson 1963, Kaneshiro 1980, Grant 1986, Losos et al. 1998). For instance, variation among islands inspired Darwin's (1859) and Wallace's (1864) hypothesis that gradual changes among populations driven by natural selection can accumulate to yield large differences that result in new species. Similarly, the universal species–area relationship was largely inspired by patterns observed in tropical archipelagoes from a diverse set of taxa (MacArthur and Wilson 1963). More recently, island systems have provided clear evidence for the operation of natural selection in the wild, including the now classic examples of adaptation to feeding in Darwin's finches (Grant and Grant 2007) and convergent evolution of limb morphology in Caribbean lizards in the genus Anolis (Losos 2011). As such, island systems remain fertile grounds for testing key ecological and evolutionary processes (Losos and Ricklefs 2009).

Island populations are often distinct in behavior and morphology from their continental counterparts, and this has been attributed to the unique biotic and abiotic conditions of islands or to the operation of genetic drift in small populations (Losos and Ricklefs 2009). For instance, loss of flight in birds and insects (McNab 1994), and reduction or increase in body size of large and small mammals, respectively (Lomolino 2005), have evolved repeatedly in oceanic islands, which suggests that deterministic processes like natural selection are driving such convergent changes.

One less explored pattern of convergence is the evolution of entirely black coloration, or “melanism,” on islands. Examples of melanism on islands and in other small, peripheral populations include species of birds, reptiles, spiders, and insects (see Table 1). In these examples, island populations evolved entirely black coloration despite being in proximity to larger populations of a different color, where gene flow could prevent the fixation of melanism on small islands. In a few cases, the possible mechanism seems evident, such as selection for more effective thermoregulation (Theron et al. 2001, Tanaka 2007). However, in the majority of cases, the underlying drivers of the recurring evolution of melanism are poorly understood. Given the repeated evolution of this trait in islands across independent taxa (Table 1), melanism may evolve by deterministic processes and not by drift alone.


Examples of melanism evolving on small islands in birds, reptiles, and invertebrates.


Because color, typically, is either fixed or nearly fixed between island and mainland populations, the general pattern discerned thus far is that some small island populations evolve darker coloration than their mainland counterparts (see Table 1), making it difficult to test how island size, in itself, predicts the frequency of melanism. Taxa with multiple, coexisting color forms (i.e. color polymorphic) would provide a unique test of how the frequency of melanic individuals is predicted by island size. Here, we test the hypothesis that island size predicts the frequency of melanism by taking advantage of a color-polymorphic avian species found in the Solomon Islands. If small islands favor melanism, we predicted a negative relationship between island size and the frequency of melanic birds, even after controlling for spatial autocorrelation because neighboring islands can be <1 km apart.


Study System

In his seminal book on speciation, Ernst Mayr (1942) presented the Monarcha castaneiventris flycatcher complex of the Solomon Islands as a case of incipient speciation (see also Mayr and Diamond 2001). There are at least 6 named subspecies in this complex that differ in body size and plumage color, despite small geographic separation (Mayr 1942, Diamond 2002; Figure 1A). Monarcha castaneiventris are insectivorous leaf-gleaners found primarily in the middle and lower strata of forests (Filardi and Smith 2008). They are socially monogamous, and pairs defend breeding or nesting territories from other breeding pairs (Uy et al. 2009a, 2009b). The subspecies in the Russell Islands, M. c. obscurior, is unique in being the only population that is polymorphic in plumage color (Mayr 1942; see Figure 1). Individuals of this subspecies typically have chestnut bellies and blue-black upperparts; however, melanic birds coexist with chestnut-bellied birds on a few islands (Mayr 1942; Figure 1). In this subspecies, the sexes do not differ significantly in body size and plumage color (Uy et al. personal observation).


Variation in plumage color and distribution of flycatchers in the Monarcha castaneiventris species complex. (A) Geographic variation among subspecies throughout the Solomon Islands. Six subspecies are shown, but in the present study we focused on M. c. obscurior of the Russell Islands, which is the only polymorphic subspecies (green box and islands). (B) Map of the Russell Islands. Asterisks indicate the13 islands sampled in 2011 (Appendix Table 2). (C) The color morphs of M. c. obscurior (from left to right): chestnut-bellied, mostly melanic, and melanic.


Field Survey

The Whitney South Seas Expedition (WSSE), the most expansive collecting expedition in the South Pacific, sampled scores of islands from New Guinea through Pitcairn Island for more than a decade (1921–1932; Chapman 1935). From July 30 to August 7, 1927, the WSSE visited the Russell Islands of the Solomon Islands and collected from the large islands Pavuvu and Banika, and from the smaller islands Moie and Kiomie (detailed in the field journal of one of the collectors on the expedition, F. C. Drowne, courtesy of the American Museum of Natural History; see Figure 1B). On the largest island, Pavuvu, the WSSE collected 13 M. c. obscurior specimens, all with chestnut bellies; on Banika, it collected 1 melanic, 1 mostly melanic, and 11 chestnut-bellied; on Moie, 1 mostly melanic and 3 chestnut-bellied; and on Kiomie, 4 chestnut-bellied specimens. According to Drowne's journal, the WSSE opportunistically collected samples for a few hours on each island, taking birds as they moved from the shore to the interior of the island on trails established by indigenous communities or by workers for large coconut plantations.

We visited the Russell Islands from June 24 through July 1, 2011, sampling the same islands and localities visited by the WSSE (as recorded by Drowne). Similar to the WSSE, we sampled each island by following established trails on the big islands of Banika and Pavuvu, and on the smaller island of Moie, for 4 hr each (0600–1000 hours). We were able to survey the entire islet of Kiomie within 4 hr because of its small size (0.10 km2). We returned to the Russell Islands during October 1–7, 2011, to survey 9 additional islands, for a total of 13 islands surveyed in 2011 (Appendix Table 2). As with the surveys in June, we spent ≥4 hr on each island (0600–1000 hours), either following trails established by indigenous communities (n = 3 large islands) or sampling the entire island (n = 6 islands; see Appendix Table 2). The 9 additional islands visited in October were likewise opportunistically sampled to match the methods of the WSSE and our sampling of 4 islands earlier in June.

To survey each island, a team of observers, which included J.A.C.U. and 3 local field guides, started at the shore and proceeded into the interior of each island, stopping every 10 min to survey birds immediately around the group. Confirmed M. castaneiventris individuals were identified and classified as “chestnut-bellied,” “mostly melanic,” or “melanic” by sighting with binoculars, after complete agreement of the team. Adult M. c. obscurior have blue-black upperparts and light, blue-gray bills. While netting birds for a separate long-term study, we captured several immature individuals with dark bills, light chestnut bellies, and gray instead of black upperparts. We did not capture immature individuals lacking the light chestnut belly (i.e. entirely gray). As such, it remains unclear whether all individuals, regardless of their adult plumage color, started as chestnut-bellied and gray before molting into either a chestnut-bellied or a melanic adult. Further, we do not know when individuals acquired their adult plumage, although preliminary mark–recapture data suggest that this would require at least 2–3 yr. Given that we know little about the transition from immature to adult plumage, immature individuals sighted during the surveys were not included in the test of the predictors of the frequency of melanic birds.

The habitats we surveyed were all similar among islands, consisting primarily of secondary forests and mangroves. Because these forests are relatively open, identification and classification of birds were unambiguous. Further, the assistance of local field guides with intimate knowledge of the islands' flora and fauna and excellent tracking skills ensured that we found all the M. c. obscurior individuals in the vicinity of the group. These included birds that were foraging or not calling. Sampling was conducted only once per island, to avoid counting the same individuals multiple times during subsequent visits.

Establishing a standard transect for the 6 large islands would provide a more unbiased and systematic survey of the relative abundances of chestnut-bellied and melanic M. c. obscurior (as in Smucker et al. 2005). However, given the small size of most of the islands (Appendix Table 2), standardized transects were not feasible. Further, M. castaneiventris is a very abundant and conspicuous species, and so the opportunistic sampling provided an unbiased estimate of the M. c. obscurior color morphs. Note also that some islands had as few as 6 individuals sighted (Appendix Table 2). These numbers may represent a small sample size for statistical tests and be prone to error; however, most of the islets were small, and so the few individuals that we observed likely represented most, if not all, of the birds on that island. That is, we sampled the entire island, and so the sighting of few birds provided a biologically relevant and likely accurate estimate of population composition.

Without knowledge of the genetic basis of melanism, we combined the counts of melanic and mostly melanic birds as a measure of the number of melanic birds, because mostly melanic birds look more like melanic than like chestnut-bellied birds. That is, mostly melanic birds were predominantly black, with a small patch of chestnut at the base of the belly near the cloaca (e.g., see Figure 1C). Frequency of melanic birds was then calculated as the number of melanic birds sighted divided by the total number of birds observed. After digitizing a 1:50,000 scale (1 inch = 1 km) map of the Russell Islands provided by the Ministry of Lands, Housing and Surveys, Solomon Islands, we used SigmaScan Pro version 5.0 (Systat, San Jose, California, USA) to quantify the nearest distance between islands and island area. Island area (km2) was log transformed, and the frequency of melanic birds was arcsine transformed prior to analysis (as recommended by Sokal and Rohlf 1995).

Statistical Analyses

We tested whether island size predicted the frequency of melanism using an ordinary least squares (OLS) regression analysis with log-transformed island size as a predictor and the arcsine transformed frequency of melanic birds as the dependent variable. Given that some islands are <1 km apart and birds are likely to disperse across these short barriers, the OLS regression model's assumption of independently distributed error could be violated by inherent spatial structuring (Lichstein et al. 2002; reviewed by Kissling and Carl 2008). As such, we tested for spatial autocorrelation by calculating global Moran's I (Moran 1950) using the residuals from our OLS regression analysis (as in Kissling and Carl 2008). For calculating Moran's I, we generated a matrix of inverse distance weights from the matrix of pairwise nearest distances between islands measured from the digitized map.

Given the possibility of spatial autocorrelation, we also implemented a simultaneous autoregressive model that accounts for spatial error (SARerr) to concurrently consider spatial structuring and island size as predictors of frequency of melanism across islands (as in Kissling and Carl 2008). The SARerr model assumes that the spatial structuring is in the error term, as in cases where the spatial autocorrelation is not fully explained by the explanatory variable (e.g., by island size alone) and is an inherent property of the response variable (e.g., dispersal ability of birds; for details of analysis and model assumptions, see Kissling and Carl 2008). For the SARerr analysis, we used log transformed island area and the matrix of inverse inter-island distance as explanatory variables, and the arcsine transformed frequency of melanic birds as the dependent variable. We assessed the utility of the OLS regression and the SARerr methods by comparing the maximum model fit for each method (i.e. R2). The R2 value for the SARerr model was calculated using Nagelkerke's (1991) formula (as in Lichstein et al. 2002). Calculation of Moran's I, and the OLS regression and SARerr analyses, were implemented in R (R Development Core Team 2005). Scripts for the SARerr analysis were developed by Kissling and Carl (2008). All tests of hypotheses were 2-tailed.


There was considerable variation in the frequency of melanic birds among the 13 islands sampled across the Russell Archipelago, with some islands having only chestnut-bellied birds while others had as many as one-third of birds with melanic plumage (Appendix Table 2). An OLS regression analysis indicated that island size predicts the frequency of melanic birds (F1, 11 = 7.10, P = 0.022; Figure 2). Exploration of the residuals from the OLS regression analysis indicate a nonsignificant effect of spatial structuring in explaining the frequency of melanism on islands (global Moran's I = 0.196, P = 0.073).


Ordinary least squares regression of frequency of melanic birds (arcsine transformed scale) on island size (log transformed scale).


Because some islands are <1 km apart and the analysis of global Moran's I indicated a near significant trend for spatial autocorrelation, we also performed a SARerr analysis to simultaneously account for spatial autocorrelation while testing for the effect of island size on the frequency of melanic birds. The SARerr model indicated that island size indeed predicts the frequency of melanism (β = −0.469, z value = −4.886, P << 0.001), while accounting for spatial structure. Further, the likelihood ratio (LR) test for the spatial autoregression coefficient (λ) was significant (λ = 0.844, LR = 9.210, P < 0.002), which suggests that the frequency of melanic birds is indeed positively correlated among neighboring islands after accounting for variation explained by island size. As such, the SARerr model, which included the effects of island size and spatial autocorrelation, explained more of the variation in the frequency of melanic birds across islands than the OLS regression model that considered only island size (R2 = 0.508 for SARerr model vs. 0.334 for the OLS regression model).


In the Monarcha castanieventris flycatcher species complex, melanism has evolved independently at least twice, and exclusively on small islands (Uy et al. personal observation). In the Russell Islands, where M. c. obscurior has both melanic and chestnut-bellied forms, we found that island size was a significant predictor of the frequency of melanic birds, even after accounting for spatial autocorrelation. That is, smaller islands had higher frequencies of melanic birds than their larger counterparts, with melanic birds primarily found on small islets ~1 km2 or less in area (Figure 2). In fact, using a spatial autoregressive model that simultaneously considered island size and spatial autocorrelation explained more of the variation in frequency of melanism across islands than an OLS regression. In the Makira Island clade, another melanic subspecies, M. c. ugiensis, is found exclusively on small, satellite islands despite their short distance (approximately 8–10 km) from the large island of Makira, which harbors the chestnut-bellied subspecies M. c. megarhunchus (Mayr 1942, Mayr and Diamond 2001, Uy et al. 2009a, 2009b; see Figure 1A). In this island group, there is substantial gene flow between islands yet the color forms are essentially fixed within islands, indicating strong selection acting on plumage color (Uy et al. 2009b, Uy et al. personal observation). Given the pattern of island size predicting the frequency of melanic birds in the Russells and the observation that selection maintains melanism in the small islands of the Makira clade, deterministic processes are likely driving the convergent evolution and maintenance of melanism on small islands.

In a meta-analysis of birds, melanism was not consistently linked to advantages in reproduction or survival (Meunier et al. 2011), which suggests that selection on melanism is either taxon or trait specific. Given these patterns, what are the factors that dictate the frequency of melanism on the small islands of the Russell Archipelago? There are several hypotheses that could explain the variation in the frequency of melanic forms across islands.

First, melanic birds may simply be more vagile and thus can colonize islands farther away. Small islands tend to be farther from the larger islands of Pavuvu and Banika (Figure 1B), and perhaps melanic birds are better at colonizing these more distant islets. However, given the proximity of islands to each other—the entire archipelago is only ~30 km wide, and many islands are within 1 km of each other—it is unlikely that vagility can explain the higher frequency of melanic birds on smaller islands.

Second, directional selection may favor chestnut-bellied birds, but the efficacy of selection becomes weaker as population size decreases. As such, genetic drift may allow for the persistence of the melanic forms on smaller islands, where selection is less effective. This is a distinct possibility, for drift can have significant effects on the evolution of small island populations (Clegg et al. 2002). However, given that melanism has evolved repeatedly on small islands across independent taxa (Table 1) and we have found that strong selection on plumage color counteracts gene flow in the Makira clade of M. castaneiventris (Uy et al. 2009b, Uy et al. personal observation), it is unlikely that drift alone can mediate the pattern of melanism occurring in higher frequencies on smaller islands in the Russell Archipelago.

Alternatively, selection could favor melanism, either through balancing selection that favors the maintenance of color polymorphism or through directional selection favoring melanism on small islands. In the case of balancing selection, islands may have different optima for the frequency of each morph, depending on their unique biotic and abiotic environment as mediated by island size. Examples of balancing selection favoring color polymorphism in the wild are numerous (reviewed by Gray and McKinnon 2007), and this remains a strong possibility in the Russells clade. In the case of directional selection favoring melanism on small islands, melanic birds should increase in frequency on small islands but perhaps are kept rare by substantial gene flow from neighboring larger islands that are dominated by chestnut-bellied birds (e.g., migration–selection balance). In essence, selection for melanism could be stronger on smaller islands, and the association between island size and frequency of melanism may reflect variation among islands in the balance between selection and gene flow (e.g., different points of equilibria at migration–selection balance). Similarly, the persistence of color polymorphism in island snakes has been attributed to a balance between directional selection for melanism on islands and gene flow from nonmelanic populations on the mainland (King 1993, Bittner and King 2003).

If balancing or directional selection is mediating the frequency of melanism on small islands, what could vary across islands that would generate a variable selective environment? Because islands of the Russell Archipelago are close to each other (Figure 1B), the plant and predator communities are very similar (Uy et al. personal observation). Therefore, it is unlikely that variation per se, in habitat or predators, is driving the association between island size and frequency of melanism. Likewise, because the entire archipelago is ~30 km in width and the islands have similar topography and climate, it is unlikely that selection for more efficient thermoregulation could favor melanism, as has been proposed in island populations of the Bananaquit (Coereba flaveola; Theron et al. 2001), snakes (Tanaka 2007), and spittlebugs (Berry and Willmer 1986). Instead, conditions on small islands may indirectly favor melanism. In several taxa, melanism has been linked to increased aggression, which provides advantages in competitive interactions (Horth 2003, Ducrest et al. 2008, Loehr et al. 2008, McKinnon and Pierotti 2010). This link between melanism and aggression could be due to changes in the melanocortin-1 receptor complex, the major mediator of melanic coloration, which could have pleiotropic effects on other important life history traits (reviewed by Ducrest et al. 2008). Because breeding territories are fewer on small islands (Uy et al. personal observation), selection may favor more aggressive individuals. In support of this hypothesis, our taxidermy-mount and song-playback experiments in the Makira clade revealed that melanic M. c. ugiensis birds were more aggressive than their chestnut-bellied M. c. megarhynchus counterparts (Uy et al. 2009b). Therefore, it is possible that conditions on small islands favor aggression, thereby indirectly favoring melanism—a pattern similarly found in other color-polymorphic taxa (reviewed by McKinnon and Pierotti 2010).

In sum, melanism has evolved multiple times in small peripheral populations across a diverse set of taxa, including at least twice in the M. castaneiventris species complex of the Solomon Islands (Table 1). This recurrent evolution of melanism on small islands suggests that deterministic processes underlie the evolution of this trait. More detailed studies of the ecology of islands and the genetic basis of melanism are needed to more directly elucidate the mechanisms that may favor melanism in small populations.


Permission to work in the Solomon Islands was granted by the Ministry of Education, Solomon Islands. We thank the people of Moie Island for their generous hospitality and help with fieldwork. For helpful discussions, we thank F. Mora-Kepfer Uy and members of the Uy lab.

Funding statement: This work was funded by a National Science Foundation CAREER grant (1137624 to J.A.C.U.), a National Geographic Society CRE grant (9023-11 to J.A.C.U.), and the Aresty Chair in Tropical Ecology.

Ethics statement: Work detailed in this paper adhered to the guidelines of and was approved by the University of Miami's Institutional Animal Care and Use Committee (protocol no. 11-116).



K. Atkinsonand J. V. Briskie (2007). Frequency distribution and environmental correlates of plumage polymorphism in the Grey Fantail Rhipidura fuliginosa. New Zealand Journal of Zoology 34:273–281. Google Scholar


A. J. Berryand P. G. Willmer (1986). Temperature and the colour polymorphism of Philaenus spumarius (Homoptera: Aphrophoridae). Ecological Entomology 11:251–259. Google Scholar


T. D. Bittnerand R. B. King (2003). Gene flow and melanism in garter snakes revisited: A comparison of molecular markers and island vs. coalescent models. Biological Journal of the Linnean Society 79:389–399. Google Scholar


P. M. Brakefield (1990). Genetic drift and patterns of diversity among colour-polymorphic populations of the homopteran Philaenus spumarius in an island archipelago. Biological Journal of the Linnean Society 39:219–237. Google Scholar


J. M. Buades V. Rodríguez B. Terrasa V. Pérez-Mellado R. P. Brown J. A. Castro A. Picornelland M. M. Ramon (2013). Variability of the mc1r gene in melanic and non-melanic Podarcis lilfordi and Podarcis pityusensis from the Balearic Archipelago. PLOS One 8:e53088. Google Scholar


F. M. Chapman (1935). The Whitney South Sea Expedition. Science 81:95–97. Google Scholar


S. M. Clegg S. M. Degnan C. Moritz A. Estoup J. Kikkawaand I. P. F. Owens (2002). Microevolution in island forms: The roles of drift and directional selection in morphological divergence of a passerine bird. Evolution 56:2090–2099. Google Scholar


C. Darwin (1859). On the Origin of Species by Means of Natural Selection. Murray, London, UK. Google Scholar


J. M. Diamond (1977). Continental and insular speciation in Pacific land birds. Systematic Zoology 26:263–268. Google Scholar


J. M. Diamond (2002). Dispersal, mimicry, and geographic variations in northern Melanesian birds. Pacific Science 56:1–22. Google Scholar


S. M. Doucet M. D. Shawkey M. K. Rathburn H. L. Maysand R. Montgomerie (2004). Concordant evolution of plumage colour, feather microstructure and a melanocortin receptor gene between mainland and island populations of a fairy-wren. Proceedings of the Royal Society of London, Series B 271:1663–1670. Google Scholar


A.-L. Ducrest L. Kellerand A. Roulin (2008). Pleiotropy in the melanocortin system, coloration and behavioural syndromes. Trends in Ecology & Evolution 23:502–510. Google Scholar


C. E. Filardiand C. E. Smith (2008). Social selection and geographic variation in two monarch flycatchers from the Solomon Islands. The Condor 110:24–34. Google Scholar


P. R. Grant (1986). Ecology and Evolution of Darwin's Finches. Princeton University Press, Princeton, NJ, USA. Google Scholar


P. R. Grantand B. R. Grant (2007). How and Why Species Multiply: The Radiation of Darwin's Finches. Princeton University Press, Princeton, NJ, USA. Google Scholar


S. M. Grayand J. S. McKinnon (2007). Linking color polymorphism maintenance and speciation. Trends in Ecology & Evolution 22:71–79. Google Scholar


O. Halkka L. Halkkaand K. Roukka (2001). Selection often overrides the effects of random processes in island populations of Philaenus spumarius (Homoptera). Biological Journal of the Linnean Society 74:571–580. Google Scholar


L. Horth (2003). Melanic body colour and aggressive mating behaviour are correlated traits in male mosquitofish (Gambusia holbrooki). Proceedings of the Royal Society of London, Series B 270:1033–1040. Google Scholar


A. W. Jonesand R. S. Kennedy (2008). Plumage convergence and evolutionary history of the island thrush in the Philippines. The Condor 110:35–44. Google Scholar


K. Y. Kaneshiro (1980). Sexual isolation, speciation and direction of evolution. Evolution 34:437–444. Google Scholar


R. B. King (1993). Color-pattern variation in Lake Erie water snakes: Prediction and measurement of natural selection. Evolution 47:1819–1833. Google Scholar


W. D. Kisslingand G. Carl (2008). Spatial autocorrelation and the selection of simultaneous autoregressive models. Global Ecology and Biogeography 17:59–71. Google Scholar


J. W. Lichstein T. R. Simons S. A. Shrinerand K. E. Franzreb (2002). Spatial autocorrelation and autoregressive models in ecology. Ecological Monographs 72:445–463. Google Scholar


J. Loehr J. Carey H. Ylönenand J. Suhonen (2008). Coat darkness is associated with social dominance and mating behaviour in a mountain sheep hybrid lineage. Animal Behaviour 76:1545–1553. Google Scholar


M. V. Lomolino (2005). Body size evolution in insular vertebrates: Generality of the island rule. Journal of Biogeography 32:1683–1699. Google Scholar


J. B. Losos (2011). Lizards in an Evolutionary Tree: Ecology and Adaptive Radiation of Anoles. University of California Press, Berkeley, CA, USA. Google Scholar


J. B. Losos T. R. Jackman A. Larson K. de Queirozand L. Rodríguez-Schettino (1998). Historical contingency and determinism in replicated adaptive radiations of island lizards. Science 279:2115–2118. Google Scholar


J. B. Lososand R. E. Ricklefs (2009). Adaptation and diversification on islands. Nature 457:830–836. Google Scholar


R. H. MacArthurand E. O. Wilson (1963). An equilibrium theory of insular zoogeography. Evolution 17:373–387. Google Scholar


E. Mayr (1942). Systematics and the Origin of Species. Columbia University Press, New York, NY, USA. Google Scholar


E. Mayrand J. M. Diamond (2001). The Birds of Northern Melanesia: Speciation, Ecology, and Biogeography. Oxford University Press, New York, NY, USA. Google Scholar


J. S. McKinnonand M. E. R. Pierotti (2010). Colour polymorphism and correlated characters: Genetic mechanisms and evolution. Molecular Ecology 19:5101–5125. Google Scholar


B. K. McNab (1994). Energy conservation and the evolution of flightlessness in birds. The American Naturalist 144:628–642. Google Scholar


J. Meunier S. Figueiredo Pinto R. Burriand A. Roulin (2011). Eumelanin-based coloration and fitness parameters in birds: A meta-analysis. Behavioral Ecology and Sociobiology 65:559–567. Google Scholar


P. A. P. Moran (1950). Notes on continuous stochastic phenomena. Biometrika 37:17–23. Google Scholar


N. J. D. Nagelkerke (1991). A note on a general definition of the coefficient of determination. Biometrika 78:691–692. Google Scholar


R Development Core Team (2005). R: A Language and Evironment for Statistical Computing. R Foundation for Statistical Computing, Vienna, Austria. Google Scholar


J. M. Ritchie (1978). Melanism in Oedaleus senegalensis and other Oedipodines (Orthoptera, Acrididae). Journal of Natural History 12:153–162. Google Scholar


K. M. Smucker R. L. Huttoand B. M. Steele (2005). Changes in bird abundance after wildfire: Importance of fire severity and time since fire. Ecological Applications 15:1535–1549. Google Scholar


R. R. Sokaland F. J. Rohlf (1995). Biometry: The Principles and Practice of Statistics in Biological Research, third edition. W.H. Freeman, New York, NY, USA. Google Scholar


K. Tanaka (2007). Thermal biology of a colour-dimorphic snake, Elaphe quadrivirgata, in a montane forest: Do melanistic snakes enjoy thermal advantages? Biological Journal of the Linnean Society 92:309–322. Google Scholar


E. Theron K. Hawkins E. Bermingham R. E. Ricklefsand N. I. Mundy (2001). The molecular basis of an avian plumage polymorphism in the wild: A melanocortin-1-receptor point mutation is perfectly associated with the melanic plumage morph of the Bananaquit, Coereba flaveola. Current Biology 11:550–557. Google Scholar


I.-M. Tso P.-L. Tai T.-H. Ku C.-H. Kuoand E.-C. Yang (2002). Colour-associated foraging success and population genetic structure in a sit-and-wait predator Nephila maculata (Araneae: Tetragnathidae). Animal Behaviour 63:175–182. Google Scholar


J. A. C. Uy R. G. Moyleand C. E. Filardi (2009a). Plumage color and song differences mediate species recognition between incipient flycatcher species of the Solomon Islands. Evolution 63:153–164. Google Scholar


J. A. C. Uy R. G. Moyle C. E. Filardiand Z. A. Cheviron (2009b). Difference in plumage color used in species recognition between incipient species is linked to a single amino acid substitution in the melanocortin-1 receptor. American Naturalist 174:244–254. Google Scholar


A. R. Wallace (1864). On the phenomena of variation and geographical distribution as illustrated by the Papilionidae of the Malayan region. Transactions of the Linnean Society of London 25:1–71. Google Scholar




Populations in the Russell Islands sampled for the frequency of chestnut-bellied, melanic, and mostly melanic individuals of the subspecies Monarcha castaneiventris obscurior (see Figure 1B).

© 2015 American Ornithologists' Union
J. Albert C. Uy and Luis E. Vargas-Castro "Island size predicts the frequency of melanic birds in the color-polymorphic flycatcher Monarcha castaneiventris of the Solomon Islands," The Auk 132(4), 787-794, (22 July 2015).
Received: 2 December 2014; Accepted: 1 May 2015; Published: 22 July 2015
color polymorphism
island ecology
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