| first record and morphology of myialges caulotoon (acari: epidermoptidae) from galapagos hosts. | hippoboscid flies were collected from wild birds on santiago and fernandina islands, galapagos, ecuador in august 1985. an epidermoptid mite, identified as myialges caulotoon, was found on icosta nigra from galapagos hawks and on olfersia sordida from brown pelicans and a flightless cormorant. this report is the first record of myialges from the 2 birds endemic to galapagos. it is also the first report to provide an identity of a species of myialges from galapagos hosts. | 1998 | 9488365 |
| the kin composition of social groups: trading group size for degree of altruism. | why some social systems form groups composed of kin, while others do not, has gone largely untreated in the literature. using an individual-based simulation model, we explore the demographic consequences of making kinship a criterion in group formation. we find that systems where social groups consist of one-generation breeding associations may face a serious trade-off between degree of altruism and group size that is largely mediated by their kin composition. on the one hand, restricting groups ... | 2004 | 15278839 |
| differences in straggling rates between two genera of dove lice (insecta: phthiraptera) reinforce population genetic and cophylogenetic patterns. | differences in dispersal abilities have been implicated for causing disparate evolutionary patterns between columbicola and physconelloides lice (insecta: phthiraptera). however, no study has documented straggling (when lice are found on atypical hosts) rates within these lineages. we used the fact that the galapagos hawk, buteo galapagoensis (gould) (falconiformes) feeds on the galapagos dove zenaida galapagoensis gould (columbiformes) within an ecologically simplified setting. the galapagos do ... | 2004 | 15380682 |
| effects of host sociality on ectoparasite population biology. | theory predicts a positive relationship between parasite infection intensity and host density. however, this generalization is complicated in natural systems by differences in life history among parasite taxa, e.g., transmissibility. accordingly, predictions relating host density to parasite load should be specific to each parasite taxon. to illustrate this, we studied parasites that differed greatly in life history in the context of the galapagos hawk's (buteo galapagoensis) variably cooperativ ... | 2004 | 15562590 |
| phylogeography of the galápagos hawk (buteo galapagoensis): a recent arrival to the galápagos islands. | galápagos hawks (buteo galapagoensis) are one of the most inbred bird species in the world, living in small, isolated island populations. we used mitochondrial sequence and nuclear minisatellite data to describe relationships among galápagos hawk populations and their colonization history. we sampled 10 populations (encompassing the entire current species range of nine islands and one extirpated population), as well as the galápagos hawk's closest mainland relative, the swainson's hawk (b. swain ... | 2006 | 16376110 |
| disease ecology in the galápagos hawk (buteo galapagoensis): host genetic diversity, parasite load and natural antibodies. | an increased susceptibility to disease is one hypothesis explaining how inbreeding hastens extinction in island endemics and threatened species. experimental studies show that disease resistance declines as inbreeding increases, but data from in situ wildlife systems are scarce. genetic diversity increases with island size across the entire range of an extremely inbred galápagos endemic bird, providing the context for a natural experiment examining the effects of inbreeding on disease susceptibi ... | 2006 | 16618672 |
| cryptic host specificity of an avian skin mite (epidermoptidae) vectored by louseflies (hippoboscidae) associated with two endemic galapagos bird species. | host specificity of vectors is an important but understudied force shaping parasite evolution and the relationship between hosts and parasites. low vector specificity may allow a vectored parasite to invade new host species, whereas high specificity of vectors may reduce the host range of the parasite and favor specialization. the 'generalist' and widely distributed avian skin mite myialges caulotoon speiser (acari: epidermoptidae) is unusual because females require an insect vector to complete ... | 2006 | 17304798 |
| molecular and morphological divergence in a pair of bird species and their ectoparasites. | in an evolutionary context, parasites tend to be morphologically conservative relative to their hosts. however, the rate of neutral molecular evolution across many parasite lineages is faster than in their hosts. although this relationship is apparent at the macroevolutionary scale, insight into the processes underpinning it may be gained through investigations at the microevolutionary scale. birds and their ectoparasitic lice have served as important natural experiments in co-evolution. here, w ... | 2009 | 19655998 |
| island tameness: an altered cardiovascular stress response in galápagos marine iguanas. | island tameness is a widely documented phenomenon in which island species, particularly those that have evolved with no or few natural predators, show a greatly reduced behavioral response when faced with unfamiliar predators. this insufficient anti-predator response has led to widespread population declines among many island species exposed to novel predators, and has become a serious conservation problem. despite its prevalence, the underlying physiology of island tameness is not known. here w ... | 2010 | 20109476 |
| characterization of 10 microsatellite loci in an avian louse, degeeriella regalis (phthiraptera: ischnocera: philopteridae). | we isolated and characterized 10 polymorphic microsatellite loci in an ischnoceran louse, degeeriella regalis, which parasitizes the threatened galápagos hawk (buteo galapagoensis) and other falconiform birds. the loci were screened across 30 individuals from two island populations in the galápagos islands. the number of alleles per locus ranged from two to 28. polymorphic information content ranged from 0.14 to 0.94 and observed heterozygosity ranged from 0 to 0.67. these markers will be valuab ... | 2009 | 21564777 |
| health evaluation of galapagos hawks (buteo galapagoensis) on santiago island, galapagos. | galapagos hawks (buteo galapagoensis), the only endemic, diurnal raptor species in galapagos, are currently distributed on eight galapagos islands having been extirpated from three of the human-inhabited islands. in january 2009, we performed health assessments of 89 galapagos hawks on santiago island, galapagos. four of the 89 galapagos hawks (4%) evaluated had physical abnormalities. blood parameters did not differ between males and females, except for aspartate transaminase values, which were ... | 2012 | 22247372 |
| birds are islands for parasites. | understanding the mechanisms driving the extraordinary diversification of parasites is a major challenge in evolutionary biology. co-speciation, one proposed mechanism that could contribute to this diversity is hypothesized to result from allopatric co-divergence of host-parasite populations. we found that island populations of the galápagos hawk (buteo galapagoensis) and a parasitic feather louse species (degeeriella regalis) exhibit patterns of co-divergence across variable temporal and spatia ... | 2014 | 25099959 |
| reduced mhc and neutral variation in the galápagos hawk, an island endemic. | genes at the major histocompatibility complex (mhc) are known for high levels of polymorphism maintained by balancing selection. in small or bottlenecked populations, however, genetic drift may be strong enough to overwhelm the effect of balancing selection, resulting in reduced mhc variability. in this study we investigated mhc evolution in two recently diverged bird species: the endemic galápagos hawk (buteo galapagoensis), which occurs in small, isolated island populations, and its widespread ... | 2011 | 21612651 |
| eight polymorphic microsatellite markers isolated from the widespread avian louse colpocephalum turbinatum (phthiraptera: amblycera: menoponidae). | we report eight novel microsatellite loci for colpocephalum turbinatum, a parasitic louse of the endangered galápagos hawk (buteo galapagoensis). two island populations of c. turbinatum (n = 30) were genotyped for each locus. we found between two and 12 alleles per locus, polymorphic information content from 0.268 to 0.798, observed heterozygosity from 0.067 to 0.667 and no linkage disequilibrium was detected between loci. these markers will be useful in understanding contemporary gene flow of c ... | 2009 | 21564787 |
| co-phylogeography and comparative population genetics of the threatened galápagos hawk and three ectoparasite species: ecology shapes population histories within parasite communities. | comparative microevolutionary studies of multiple parasites occurring on a single host species can help shed light on the processes underlying parasite diversification. we compared the phylogeographical histories, population genetic structures and population divergence times of three co-distributed and phylogenetically independent ectoparasitic insect species, including an amblyceran and an ischnoceran louse (insecta: phthiraptera), a hippoboscid fly (insecta: diptera) and their endemic avian ho ... | 2007 | 18028178 |
| patterns of parasite abundance and distribution in island populations of galápagos endemic birds. | parasite life-history characteristics, the environment, and host defenses determine variation in parasite population parameters across space and time. parasite abundance and distribution have received little attention despite their pervasive effects on host populations and community dynamics. we used analyses of variance to estimate the variability of intensity, prevalence, and abundance of 4 species of lice (insecta: phthiraptera) infecting galápagos doves and galápagos hawks and 1 haemosporidi ... | 2008 | 18605785 |
| the effect of the thermal environment on the ability of hatchling galapagos land iguanas to avoid predation during dispersal. | during the month of february 1979, several hundred hatchling land iguanas (conolophus pallidus) were observed emerging from their natal burrows in a 2 ha communal nesting area on isla santa fe, galapagos islands. during this emergence, as many as nine galapagos hawks were observed to patrol the nesting area and attack hatchling iguanas.the hypothesis that the ability of hatchling land iguanas to escape predation could be influenced by the interaction of the physiological state of the lizards and ... | 1981 | 28309312 |
| galapagos islands endemic vertebrates: a population genetics perspective. | the organisms of the galapagos islands played a central role in the development of the theory of evolution by charles darwin. examination of the population genetics factors of many of these organisms with modern molecular methods has expanded our understanding of their evolution. here, i provide a perspective on how selection, gene flow, genetic drift, mutation, and inbreeding have contributed to the evolution of 6 iconic galapagos species: flightless cormorant, pink iguana, marine iguana, galap ... | 2019 | 30541084 |