Browsing by Subject "Panama"

Now showing 1 - 5 of 5
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    Differential introgression of a female competitive trait in a hybrid zone between sex-role reversed species.
    (Evolution; international journal of organic evolution, 2019-02) Lipshutz, Sara E; Meier, Joana I; Derryberry, Graham E; Miller, Matthew J; Miller, Matthew J; Seehausen, Ole; Derryberry, Elizabeth P
    Mating behavior between recently diverged species in secondary contact can impede or promote reproductive isolation. Traditionally, researchers focus on the importance of female mate choice and male-male competition in maintaining or eroding species barriers. Although female-female competition is widespread, little is known about its role in the speciation process. Here, we investigate a case of interspecific female competition and its influence on patterns of phenotypic and genetic introgression between species. We examine a hybrid zone between sex-role reversed, Neotropical shorebird species, the northern jacana (Jacana spinosa) and wattled jacana (J. jacana), in which female-female competition is a major determinant of reproductive success. Previous work found that females of the more aggressive and larger species, J. spinosa, disproportionately mother hybrid offspring, potentially by monopolizing breeding territories in sympatry with J. jacana. We find a cline shift of female body mass relative to the genetic center of the hybrid zone, consistent with asymmetric introgression of this competitive trait. We suggest that divergence in sexual characteristics between sex-role reversed females can influence patterns of gene flow upon secondary contact, similar to males in systems with more typical sex roles.
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    Food for Thought: The Effectiveness of Inpatient Malnutrition Treatment in the Case of Nutre Hogar in Panama
    (2009-12) Chou, Julia
    A nonprofit nongovernmental organization named Nutre Hogar was founded in 1988 to address the high prevalence of child malnutrition in Panama. Given the context specific nature of malnutrition treatment models, this paper evaluates whether or not Nutre Hogar’s inpatient treatment model is suited to the Panamanian context and whether an alternative model might be more effective. Quantitative data about physical outcomes of treatment were collected from a Nutre Hogar logbook, and interviews with parents of patients and Nutre Hogar staff members were conducted to gather qualitative data on community perceptions of Nutre Hogar. While children gained weight throughout their stay, they left the center still moderately malnourished, raising concerns about the efficacy of treatment. Recommendations include incorporating elements of other malnutrition treatment protocols into Nutre Hogar’s current program, as well as focusing on sustainable solutions for preventing malnutrition in children under five years of age in Panama.
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    Genetic and phenotypic characterization of a hybrid zone between polyandrous Northern and Wattled Jacanas in Western Panama.
    (BMC evolutionary biology, 2014-11) Miller, Matthew J; Lipshutz, Sara E; Smith, Neal G; Bermingham, Eldredge

    Background

    Hybridization provides a unique perspective into the ecological, genetic and behavioral context of speciation. Hybridization is common in birds, but has not yet been reported among bird species with a simultaneously polyandrous mating system; a mating system where a single female defends a harem of males who provide nearly all parental care. Unlike simple polyandry, polyandrous mating is extremely rare in birds, with only 1% of bird species employing this mating system. Although it is classically held that females are "choosy" in avian hybrid systems, nearly-exclusive male parental care raises the possibility that female selection against heterospecific matings might be reduced compared to birds with other mating systems.

    Results

    We describe a narrow hybrid zone in southwestern Panama between two polyandrous freshwater waders: Northern Jacana, Jacana spinosa and Wattled Jacana, J. jacana. We document coincident cline centers for three phenotypic traits, mtDNA, and one of two autosomal introns. Cline widths for these six markers varied from seven to 142 km, with mtDNA being the narrowest, and five of the six markers having widths less than 100 km. Cline tails were asymmetrical, with greater introgression of J. jacana traits extending westward into the range of J. spinosa. Likewise, within the hybrid zone, the average hybrid index of phenotypic hybrids was significantly biased towards J. spinosa. Species distribution models indicate that the hybrid zone is located at the edge of a roughly 100 km wide overlap where habitat is predicted to be suitable for both species, with more westerly areas suitable only for spinosa and eastward habitats suitable only for J. jacana.

    Conclusion

    The two species of New World jacanas maintain a narrow, and persistent hybrid zone in western Panama. The hybrid zone may be maintained by the behavioral dominance of J. spinosa counterbalanced by unsuitable habitat for J. spinosa east of the contact zone. Although the two parental species are relatively young, mitochondrial cline width was extremely narrow. This result suggests strong selection against maternally-inherited markers, which may indicate either mitonuclear incompatibilities and/or female choice against heterospecific matings typical of avian hybrid systems, despite jacana sex role reversal.
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    Measuring protected areas’ impact on deforestation in Panama
    (2010-12-10) Haruna, Akiko
    Throughout the last century, protected areas (PAs) have been the major policy instrument for forest conservation worldwide, as well as in the Republic of Panama. The country has strived to lower the decline in its tropical forest cover which is rich in biodiversity. The importance of evaluating existing forest policies has been increasing, especially with emergence of financial incentives given to mitigation of deforestation. Few studies, however, have examined the effectiveness of forest policies in Panama, including the adoption of PAs. This study evaluates the impact of PAs on deforestation rates in Panama through the use of matching methods. The methods are used to adjust observable selection bias of PAs location. The conventional evaluation methods for protected areas failed to consider such bias, thus results using matching methods were expected to give less distorted estimates of the impact. Two types of matching methods were applied to obtain the estimated impacts of PAs, namely propensity score matching and covariate matching. The results were compared with those from the conventional evaluation methods. Countrywide forested plots in two time periods, 1992-2000, and 2000-2005 were examined. The results indicated positive effects of PAs on prevention of deforestation. They also revealed that conventional evaluation methods overestimated the impact of PAs. Such results agree with the previous matching analysis done for other geographic regions. It seems that the magnitude of the impact was enhanced in areas where high deforestation pressure existed. There was an indication of a geographical shift of deforestation frontiers toward remote areas with time. Bias-adjusted estimates for evaluation of PAs will be critical for formulation of future policy. With PAs being effective in avoiding deforestation, the future focus should be on where to put major resources for protection. As deforestation drivers make the deforestation frontier shift geographically, PAs will need to meet needs of covering forests under large threat in the present and the future.
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    The genomic consequences of adaptive divergence and reproductive isolation between species of manakins.
    (Mol Ecol, 2013-06) Parchman, TL; Gompert, Z; Braun, MJ; Brumfield, RT; McDonald, DB; Uy, JAC; Zhang, G; Jarvis, ED; Schlinger, BA; Buerkle, CA
    The processes of adaptation and speciation are expected to shape genomic variation within and between diverging species. Here we analyze genomic heterogeneity of genetic differentiation and introgression in a hybrid zone between two bird species (Manacus candei and M. vitellinus) using 59 100 SNPs, a whole genome assembly, and Bayesian models. Measures of genetic differentiation (FST) and introgression (genomic cline center [α] and rate [β]) were highly heterogeneous among loci. We identified thousands of loci with elevated parameter estimates, some of which are likely to be associated with variation in fitness in Manacus populations. To analyze the genomic organization of differentiation and introgression, we mapped SNPs onto a draft assembly of the M. vitellinus genome. Estimates of FST, α, and β were autocorrelated at very short physical distances (< 100 bp), but much less so beyond this. In addition, average statistical associations (linkage disequilibrium) between SNPs were generally low and were not higher in admixed populations than in populations of the parental species. Although they did not occur with a constant probability across the genome, loci with elevated FST, α, and β were not strongly co-localized in the genome. Contrary to verbal models that predict clustering of loci involved in adaptation and isolation in discrete genomic regions, these results are consistent with the hypothesis that genetic regions involved in adaptive divergence and reproductive isolation are scattered throughout the genome. We also found that many loci were characterized by both exceptional genetic differentiation and introgression, consistent with the hypothesis that loci involved in isolation are also often characterized by a history of divergent selection. However, the concordance between isolation and differentiation was only partial, indicating a complex architecture and history of loci involved in isolation.