Demographic history and genetic diversity in West Indian Coereba flaveola populations

The bananaquit (Coereba flaveola) has been well studied throughout the Caribbean region from a phylogenetic perspective. However, data concerning the population genetics and long-term demography of this bird species are lacking. In this study, we focused on three populations within the Lesser Antilles and one on Puerto Rico and assessed genetic and demographic processes, using five nuclear and two mitochondrial markers. We found that genetic diversity of bananaquits on Puerto Rico exceeds that on the smaller islands (Dominica, Guadeloupe and Grenada); this might reflect either successive founder events from Puerto Rico to Grenada, or more rapid drift in smaller populations subsequent to colonization. Population growth rate estimates showed no evidence of rapid expansion and migration was indicated only between populations from the closest islands of Dominica and Guadeloupe. Overall, our results suggest that a "demographic fission" model, considering only mutation and drift, but without migration, can be applied to these bananaquit populations in the West Indies.     

Distribution anomalies in avian haemosporidian parasites in the southern Lesser Antilles

We compared the haemosporidian parasite faunas (Plasmodium and Haemoproteus) of small land birds on the islands of St Lucia, St Vincent and Grenada in the southern Lesser Antilles. The islands differ in distance from the South American source of colonists, proximity to each other, and similarity of their avifaunas. On each island, we obtained 419–572 blood samples from 22–25 of the 34–41 resident species. We detected parasite infection by PCR and identified parasite lineages by sequencing a portion of the mitochondrial cytochrome b gene. Parasite prevalence varied from 31% on St Lucia to 22% on St Vincent and 18% on Grenada. Abundant parasite lineages differed between the three islands in spite of the similarity in host species. As in other studies, the geographic distributions of the individual parasite lineages varied widely between local endemism and broad distribution within the West Indies, including cases of long‐distance disjunction. St Vincent was unusual in the near absence of Plasmodium parasites, which accorded with low numbers of suitable mosquito vectors reported from the island. Parasites on St Vincent also tended to be host specialists compared to those on St Lucia and Grenada. Similarity in parasite assemblages among the three islands varied in parallel with host assemblage similarity (but not similarity of infected hosts) and with geographic proximity. Parasite prevalence increased with host abundance on both St Lucia and St Vincent, but not on Grenada; prevalence did not vary between endemic and more widespread host species. In addition, the endemic host species harbored parasites that were recovered from a variety of non‐endemic species as well. These results support the individualistic nature of haemosporidian parasite assemblages in evolutionarily independent host populations.     

Origin of the green iguana (Iguana iguana) invasion in the greater Caribbean Region and Fiji

Invasive populations of green iguanas (Iguanidae: Iguana iguana) are widely established beyond their native Central, South American, and Lesser Antillean range in various islands of the Pacific, Florida USA, and in the Greater Caribbean Region. Although widespread, information about these invasions is scarce. Here we determine the origin of invasive populations of green iguanas in Puerto Rico, Fiji, The Caymans, Florida USA, The Dominican Republic, the US Virgin Islands (USVI) of St. Thomas and St. Croix, and a U.S.A pet store. We sampled 120 individuals from these locations and sequenced one mitochondrial (ND4) and two nuclear (PAC and NT3) loci. We also include a preliminary characterization of population structure throughout Puerto Rico using six microsatellite loci to genotype individuals across 10 sampling sites. Comparing the genealogical relationships of all our samples to published sequencing data from the native range, we found that sampled populations were largely a product of populations from Colombia and El Salvador; two countries with multiple, industrial-size pet iguana farming operations. Notably, we found that haplotypes detected exclusively in the USVI and Puerto Rico’s outlying island of Vieques are closely linked to green iguanas native to Saba and Montserrat (Lesser Antilles); a clade not reported in the pet trade. Our population genetic analyses did not reveal isolation among sampling sites in Puerto Rico, rather the evidence supported admixture across the island. This study highlights the roles of the pet trade and lack of regulation in the spread of green iguanas beyond their native range.

     

Recent radiation of endemic Caribbean Drosophila of the dunni subgroup inferred from multilocus DNA sequence variation

Studies of island endemism provide a unique opportunity to elucidate fundamental mechanisms of speciation. Here we examine intra- and interspecific DNA sequence variation at four unlinked genetic loci among populations of the Drosophila dunni subgroup to provide a detailed genealogical portrait of the process of speciation among these island endemic species. Our data indicate two major rounds of diversification that have shaped the D. dunni subgroup. The first occurred 1.6-2.6 million years ago and separated three major lineages, one in Puerto Rico and the Virgin Islands, a second in the northern Lesser Antilles and Barbados, and a third in St. Vincent and Grenada. A second round of diversification occurred in the last 96,000 years in the northern Lesser Antilles and Barbados. The four distinct species that resulted from this recent round of diversification maintain relatively high amounts of genetic variation, similar to that of a closely related mainland species, and share extensive ancestral polymorphism. These data suggest a minimal role for population bottlenecks linked to founder events in the history of the D. dunni subgroup. Further, the recent divergence of these island populations highlights the extremely rapid development of reproductive isolation and distinct patterns of abdominal pigmentation that has occurred in these species.     

Rickettsia africae in Amblyomma variegatum and domestic ruminants on eight Caribbean islands

We used PCRs with omp A primers to determine if spotted fever group rickettsiae occurred in Amblyomma variegatum from 6 Caribbean islands. Positive amplicons were obtained from ticks from the U.S. Virgin Islands (9/18; 50%), Dominica (39/171; 30%), Montserrat (2/5; 40%), Nevis (17/34; 50%), St. Kitts (46/227; 20%), and St. Lucia (1/14; 7%). Sequences for a convenience sample of reaction products obtained from A. variegatum on St. Kitts (7), American Virgin Islands (4), Montserrat (2), and St. Lucia (1) were 100% homologous with that of Rickettsia africae , the agent of African tick-bite fever. To determine if transmission of R. africae occurred, we used Rickettsia rickettsii antigen in IFA tests and found positive titers (≥ 1/80) with sera from cattle, goats, and sheep from Dominica (24/95 [25%], 2/136 [2%], 0/58 [0%]), Nevis (12/45 [27%], 5/157 [3%], 0/90 [0%]), St. Kitts (2/43 [5%], 1/25 [4%), 1/35 [3%]), and St. Lucia (6/184 [3%] cattle), respectively. No seropositive animals were found in Grenada (0/4, 0/98/, 0/86), Montserrat (0/12, 0/26, 0/52), or Puerto Rico (0/80 cattle). Our study indicates that R. africae and African tick-bite fever are widespread in the Caribbean.     

Colonization history and genetic diversity: adaptive potential in early stage invasions

The introduction of Anolis cristatellus from the multiple species anole community of Puerto Rico in the Greater Antilles to the island of Dominica in the Lesser Antilles, with its solitary endemic anole, provides an example of a very recent, timed, single colonization. We investigate the geographic origin and adaptive potential of the Dominican population using a range of methods including mtDNA phylogeography, nuclear microsatellite variation and multiple paternity studies, as well as heritability estimates, common garden experiments and comparative geographic studies of quantitative scalation traits. Phylogeographic analysis of NADH2 and microsatellite studies suggests that the Dominican population arose from a set of individuals from the central west area of Puerto Rico within their endemic range. The multiple‐individual inoculation, together with sperm storage and evidence of multiple paternity indicate genetic variability and suggest the potential for adaptation by natural selection. Estimates of heritability, common garden experiments and broad sense Q_ST/F_ST ratios, linked to replicated comparisons along elevational transects go some way to suggesting that the invasive populations may be adapting by natural selection, in parallel with the endemic anole, in the brief period since their introduction.     

St Lucia Whiptail Lizard Cnemidophorus vanzoi (Sauria: Teiidae) microsatellite primers

Eight polymorphic microsatellite loci have been characterized for the endangered St Lucia Whiptail Lizard Cnemidophorus vanzoi. Endemic to two small islets, Maria Major and Maria Minor, off the coast of St Lucia, Lesser Antilles, the world population is estimated at < 1000 individuals. However, representatives of the systematically complex genus Cnemidophorus, containing sexual species and parthenogenetic allopolyploids, are distributed widely in North, Central and South America, and on several islands in the Caribbean Sea. These microsatellite markers are being used to monitor the genetic structure of a population of St Lucia Whiptails, recently founded through translocation, on the nearby Praslin Island.     

Phylogeography of the frog Leptodactylus validus (Amphibia: Anura): Patterns and timing of colonization events in the Lesser Antilles

The frog Leptodactylus validus occurs in northern South America, Trinidad and Tobago, and the southern Lesser Antilles (Grenada and St. Vincent). Mitochondrial DNA sequences were used to perform a nested clade phylogeographic analysis (NCPA), to date colonization events, and to analyze colonization patterns using on a relaxed molecular clock and coalescent simulations. L. validus originated on the mainland and first colonized Trinidad with subsequent independent colonizations of Tobago and the Lesser Antilles from Trinidad. The NCPA suggests a historical vicariant event between populations in Trinidad and Tobago from those in the Lesser Antilles. The colonization of Trinidad occurred 1 million years ago (mya) and the colonization of the Lesser Antillean islands occurred 0.4 mya. The coalescent approach supported the scenario where L. validus dispersed from Trinidad to St. Vincent and from there to Grenada, a dispersal event that could have been mediated by human introduction as recent as 1600 years ago.     

Molecular phylogeny and biogeography of West Indian frogs of the genus Leptodactylus (Anura, Leptodactylidae)

Three endemic species of the aquatic-breeding frog genus Leptodactylus are recognized from the West Indies: Leptodactylus albilabris (Puerto Rico and the Virgin Islands), Leptodactylus dominicensis (Hispaniola), and Leptodactylus fallax (Lesser Antilles). DNA sequences were obtained from several mitochondrial genes to resolve taxonomic questions involving these species and to provide insights into their origin and distribution in the islands. We found low levels of sequence divergence between L. dominicensis and L. albilabris, supporting morphological evidence that the former species is a junior synonym of the latter species. Phylogenetic analysis supported previous species-group allocations, finding that L. albilabris is a member of the fuscus group and L. fallax is a member of the pentadactylus group. Molecular time estimates for the divergence of L. albilabris from its closest relative in South America (24-58 million years ago, Ma) and for L. fallax from its closest relative in South America (23-34Ma) indicate that they colonized the West Indies independently by over-water dispersal in the mid-Cenozoic. The absence of detectable sequence divergence between the two extant populations of L. fallax (Dominica and Montserrat), a species used for human food and now critically endangered, suggests that one or both arose by human introduction from an island or islands where that species originated. The relatively minor genetic differentiation of populations of L. albilabris can be explained by vicariance and dispersal in the Pleistocene and Holocene, although human introduction of some populations cannot be ruled out.     

Multiple origins and incursions of the Atlantic barnacle Chthamalus proteus in the Pacific

Chthamalus proteus, a barnacle native to the Caribbean and western Atlantic, was introduced to the Pacific within the last few decades. Using direct sequencing of mitochondrial DNA (COI), we characterized genetic variation in native and introduced populations and searched for genetic matches between regions to determine if there were multiple geographical sources and introduction points for this barnacle. In the native range, we found great genetic differences among populations (max. F_ST = 0.613) encompassing four lineages: one endemic to Panama, one endemic to Brazil, and two occurring Caribbean-wide. All four lineages were represented in the Pacific, but not equally; the Brazilian lineage was most prevalent and the Panamanian least common. Twenty-one individuals spread among nearly every island from where the barnacle is known in the Pacific, exactly matched six haplotypes scattered among Curaçao, the Netherlands Antilles; St John, US Virgin Islands; Puerto Rico; and Brazil, confirming a multigeographical origin for the Pacific populations. Significant genetic differences were also found in introduced populations from the Hawaiian Islands (F_CT = 0.043, P < 0.001), indicating introduction events have occurred at more than one locality. However, the sequence, timing and number of arrival events remains unknown. Possible reasons for limited transport of this barnacle through the Panama Canal are discussed. This and a preponderance of Brazilian-type individuals in the Pacific suggest an unexpected route of entry from around Cape Horn, South America. Unification in the Pacific of historically divergent lineages of this barnacle raises the possibility for selection of ‘hybrids’ with novel ecological adaptations in its new environment.     

Colonisation and Diversification of the Zenaida Dove (Zenaida aurita) in the Antilles: Phylogeography,Contemporary Gene Flow and Morphological Divergence

Caribbean avifaunal biogeography has been mainly studied based on mitochondrial DNA. Here, we investigated both past and recent island differentiation and micro-evolutionary changes in the Zenaida Dove (Zenaida aurita) based on combined information from one mitochondrial (Cytochrome c Oxydase subunit I, COI) and 13 microsatellite markers and four morphological characters. This Caribbean endemic and abundant species has a large distribution, and two subspecies are supposed to occur: Z. a. zenaida in the Greater Antilles (GA) and Z. a. aurita in the Lesser Antilles (LA). Doves were sampled on two GA islands (Puerto Rico and the British Virgin Islands) and six LA islands (Saint Barthélemy, Guadeloupe, Les Saintes, Martinique, Saint Lucia and Barbados). Eleven COI haplotypes were observed that could be assembled in two distinct lineages, with six specific to GA, four to LA, the remaining one occurring in all islands. However, the level of divergence between those two lineages was too moderate to fully corroborate the existence of two subspecies. Colonisation of the studied islands appeared to be a recent process. However, both phenotypic and microsatellite data suggest that differentiation is already under way between all of them, partly associated with the existence of limited gene flow. No isolation by distance was observed. Differentiation for morphological traits was more pronounced than for neutral markers. These results suggest that despite recent colonisation, genetic drift and/or restricted gene flow are promoting differentiation for neutral markers. Variation in selective pressures between islands may explain the observed phenotypic differentiation.     

Mitochondrial DNA polymorphism in three Antillean island populations of the fruit bat, Artibeus jamaicensis

The Neotropical fruit bat, Artibeus jamaicensis, occurs throughout Latin America and on many islands in the Caribbean. Populations from Jamaica (in the Greater Antilles) to Barbados (in the Lesser Antilles) have been classified as a subspecies (A.j. jamaicensis) separate from that on the Lesser Antillean island of St. Vincent (A.j. schwartzi). Mitochondrial DNA (mtDNA) was isolated from 54 individuals collected on these islands, analyzed by digestion with restriction endonucleases, and the restriction sites were mapped. Three different mtDNA genotypes (16,000 +/- 200 bp) were identified: J-1 (16 animals from Jamaica, one from St. Vincent, 15 from Barbados), J-2 (two animals from Jamaica), and SV-1 (18 animals from St. Vincent, two from Barbados). The J-1 and J-2 genotypes were estimated to differ from each other by only 0.4%, but the SV-1 genotype differed from J-1 and J-2 by 8.1%-10.5%. The estimated sequence divergence between SV-1 and J-1 is unusually large for mammals that are regarded as conspecific. Restriction mapping showed that the differences among the genotypes (presence or absence of particular restriction sites) were located throughout the genome. The presence of the J-1 mtDNA genotype on Jamaica and on St. Vincent and Barbados (1,400 km away) demonstrates that maternal lineages in these bats are not necessarily confined to single islands or limited geographic regions. The presence of the J-1 mtDNA genotype within the A. j. schwartzi population on St. Vincent and the presence of the SV-1 genotype in two specimens of A. j. jamaicensis from Barbados document genetic exchange between subspecific populations on these islands, which are separated by 180 km of open water.     

Revealing the geographic origin of an invasive lizard: the problem of native population genetic diversity

The brown anole, Anolis sagrei, is one of the most widespread and successful colonisers of the diverse Anolis genus, which comprises c. 400 species occurring naturally in Central and South America and the Caribbean. Based on extensive between and within population sampling from a previously published study (334 mitochondrial DNA sequences) and sampling for this study (37 mtDNA sequences), we reconstruct a phylogeny and produce a haplotype network to assign a recently introduced population in St Vincent, Lesser Antilles to its geographic origin. A single haplotype was present in the St Vincent population, which was identical to a haplotype from Tampa, FL. We show that genetic diversity within native range populations, combined with low frequencies of introduced haplotypes in native ranges, may impair attempts to identify source populations, even despite intensive sampling effort. The absence of mtDNA haplotype diversity suggests a significant genetic founder effect within the St Vincent population.     

Genetic diversity in Puerto Rico and its implications for the peopling of the Island and the West Indies

Puerto Rico and the surrounding islands rest on the eastern fringe of the Caribbean's Greater Antilles, located less than 100 miles northwest of the Lesser Antilles. Puerto Ricans are genetic descendants of pre‐Columbian peoples, as well as peoples of European and African descent through 500 years of migration to the island. To infer these patterns of pre‐Columbian and historic peopling of the Caribbean, we characterized genetic diversity in 326 individuals from the southeastern region of Puerto Rico and the island municipality of Vieques. We sequenced the mitochondrial DNA (mtDNA) control region of all of the samples and the complete mitogenomes of 12 of them to infer their putative place of origin. In addition, we genotyped 121 male samples for 25 Y‐chromosome single nucleotide polymorphism and 17 STR loci. Approximately 60% of the participants had indigenous mtDNA haplotypes (mostly from haplogroups A2 and C1), while 25% had African and 15% European haplotypes. Three A2 sublineages were unique to the Greater Antilles, one of which was similar to Mesoamerican types, while C1b haplogroups showed links to South America, suggesting that people reached the island from the two distinct continental source areas. However, none of the male participants had indigenous Y‐chromosomes, with 85% of them instead being European/Mediterranean and 15% sub‐Saharan African in origin. West Eurasian Y‐chromosome short tandem repeat haplotypes were quite diverse and showed similarities to those observed in southern Europe, North Africa and the Middle East. These results attest to the distinct, yet equally complex, pasts for the male and female ancestors of modern day Puerto Ricans. Am J Phys Anthropol 155:352–368, 2014. © 2014 Wiley Periodicals, Inc.     

The Assembly of an Island Fauna by Natural Invasion: Sources and Temporal Patterns in the Avian Colonization of Barbados

By virtue of their isolation and depauperate faunas, oceanic islands offer unique opportunities to characterize the historical development of ecological communities derived from both natural and anthropogenic invasions. Barbados, an outlying island in the Lesser Antilles, was formed approximately 700,000 YBP by tectonic uplift and was then colonized by birds via natural invasion from the much older volcanic islands in the main Lesser Antillean arc. We investigated the timing and sources of the avian invasion of Barbados by determining levels of mitochondrial DNA (mtDNA) divergence between populations of eight bird species from Barbados and those on the nearby putative source islands of St. Lucia and St. Vincent. Although all Barbados populations appeared to be young relative to the geological age of the island, we found differences among species in their inferred times of colonization and we identified at least two sources of immigrants to Barbados. In contrast to these historical differences across species and populations, our characterization of the mitochondrial genotypes of 231 individual birds suggests that each island population represents the descendants of a single founding maternal lineage. Considered in concert, the results of this molecular survey indicate that the Barbados bird community is composed of species with different invasion histories, which in turn suggests that the island's community composition has changed repeatedly over its 700,000 year history.     

The management of Insular Caribbean mangroves in relation to site location and community type

Mangrove ecosystems occupy different locations on Caribbean island coasts, ranging from open bays (fringe mangals) to totally enclosed salt ponds and salinas. On geomorphologically active coastlines, such as south Jamaica, systems are at varying degrees of maturity and productivity. Furthermore, because of system variability, the interactions between mangroves and associated marine systems, such as coral reefs and seagrass beds, are developed to different degrees.Community structure and productivity of a range of mangals on different islands of the Greater and Lesser Antilles are discussed. Forcing functions and levels of interaction with the marine environment are identified.The rational choice of management options must be based on the range of goods and services provided by the different systems; and a good understanding of their ecology is essential when choosing sites for protection, waste disposal, landfill, marina development and fisheries enhancement. Examples are given from current studies in Jamaica, St. Lucia, the British Virgin Islands and Trinidad, of a flexible management response to mangrove ecosystem diversity.     

Sea level,topography and island diversity: phylogeography of the Puerto Rican Red‐eyed Coquí, Eleutherodactylus antillensis

Quaternary climatic oscillations caused changes in sea level that altered the size, number and degree of isolation of islands, particularly in land‐bridge archipelagoes. Elucidating the demographic effects of these oscillations increases our understanding of the role of climate change in shaping evolutionary processes in archipelagoes. The Puerto Rican Bank (PRB) (Puerto Rico and the Eastern Islands, which comprise Vieques, Culebra, the Virgin Islands and associated islets) in the eastern Caribbean Sea periodically coalesced during glaciations and fragmented during interglacial periods of the quaternary. To explore population‐level consequences of sea level changes, we studied the phylogeography of the frog Eleutherodactylus antillensis across the archipelago. We tested hypotheses encompassing vicariance and dispersal narratives by sequencing mtDNA (c. 552 bp) of 285 individuals from 58 localities, and four nuDNA introns (totalling c. 1633 bp) from 173 of these individuals. We found low support for a hypothesis of divergence of the Eastern Islands populations prior to the start of the penultimate interglacial c. 250 kya, and higher support for a hypothesis of colonization of the Eastern Islands from sources in eastern Puerto Rico during the penultimate and last glacial period, when a land bridge united the PRB. The Río Grande de Loíza Basin in eastern Puerto Rico delineates a phylogeographic break. Haplotypes shared between the PRB and St. Croix (an island c. 105 km south‐east of this archipelago) likely represent human‐mediated introductions. Our findings illustrate how varying degrees of connectivity and isolation influence the evolution of tropical island organisms.     

A review of the net-winged midges (Diptera: Blephariceridae) of the West Indies,with description of a new species from Puerto Rico

ABSTRACT

The Caribbean blepharicerid fauna comprises three described species: Paltostoma palominoi Hogue and Garces, 1990, found in eastern Cuba; P. agyrocincta Curran, 1927, widespread in Puerto Rico; and P. schineri Williston, 1896, which occupies most major islands of the Lesser Antilles. In this paper, we describe P. portoricensis Hogue and Courtney, sp. n., a second species from Puerto Rico. We also provide keys to adults, pupae, and larvae of known Caribbean species, re-describe P. argyrocincta and P. schineri, and present a brief discussion of the bionomics and phylogenetic affinities of the net-winged midge fauna.     

A MORPHOLOGIC AND GENETIC STUDY OF THE ISLAND FOX,UROCYON LITTORALIS

The Island Fox, Urocyon littoralis, is a dwarf form found on six of the Channel Islands located 30–98 km off the coast of southern California. The island populations differ in two variables that affect genetic variation: effective population size and duration of isolation. We estimate that the effective population size of foxes on the islands varies from approximately 150 to 1,000 individuals. Archeological and geological evidence suggests that foxes likely arrived on the three northern islands minimally 10,400–16,000 years ago and dispersed to the three southern islands 2,200–4,300 years ago. We use morphometrics, allozyme electrophoresis, mitochondrial DNA (mtDNA) restriction-site analysis, and analysis of hypervariable minisatellite DNA to measure variability within and distances among island fox populations. The amount of within-population variation is lowest for the smallest island populations and highest for the mainland population. However, the larger populations are sometimes less variable, with respect to some genetic measures, than expected. No distinct trends of variability with founding time are observed. Genetic distances among the island populations, as estimated by the four techniques, are not well correlated. The apparent lack of correspondence among techniques may reflect the effects of mutation rate and colonization history on the values of each genetic measure.