Metapopulation dynamics and foraging plasticity in a highly vagile seabird,the southern rockhopper penguin

Population connectivity is driven by individual dispersal potential and modulated by natal philopatry. In seabirds, high vagility facilitates dispersal yet philopatry is also common, with foraging area overlap often correlated with population connectivity. We assess the interplay between these processes by studying past and current connectivity and foraging niche overlap among southern rockhopper penguin colonies of the coast of southern South America using genomic and stable isotope analyses. We found two distinct genetic clusters and detected low admixture between northern and southern colonies. Stable isotope analysis indicated niche variability between colonies, with Malvinas/Falklands colonies encompassing the species entire isotopic foraging niche, while the remaining colonies had smaller, nonoverlapping niches. A recently founded colony in continental Patagonia differed in isotopic niche width and position with Malvinas/Falklands colonies, its genetically identified founder population, suggesting the exploitation of novel foraging areas and/or prey items. Additionally, dispersing individuals found dead across the Patagonian shore in an unusual mortality event were also assigned to the northern cluster, suggesting northern individuals reach southern localities, but do not breed in these colonies. Facilitated by variability in foraging strategies, and especially during unfavorable conditions, the number of dispersing individuals may increase and enhance the probability of founding new colonies. Metapopulation demographic dynamics in seabirds should account for interannual variability in dispersal behavior and pay special attention to extreme climatic events, classically related to negative effects on population trends.     

Molecular identification and morphological variations of Dermacentor albipictus collected from two deer species in northern Mexico

Experimental and Applied Acarology - In total, 57 ticks were collected from six white-tailed deer (Odocoileus virginianus) and three mule deer (O. hemionus) in northern Mexico during the 2017, 2018...     

Development of multi-component non-sex pheromone blends to monitor both sexes of Cydia pomonella (Lepidoptera: Tortricidae)

Nineteen host plant volatiles (HPVs) were screened for attractivity to adult codling moth Cydia pomonella (L.) as a fourth component of core blends (3K) including (E,Z)-2,4-ethyl decadienoate, (E)-4,8-dimethyl-1,3,7-nonatriene and acetic acid. Each new quaternary combination was compared with a previously reported attractive bisexual lure (4K), consisting of the 3K blend plus 6-ethenyl-2,2,6-trimethyloxan-3-ol (pyranoid linalool oxide, pyrLOX). All lure evaluations were conducted in apple, Malus domestica (Borkhausen). Several compounds were found to significantly lower total and/or female catches when added to the 3K blend, including (Z)-3-hexenol, (E)-2-hexanal and hexyl butanoate (female and total moths), and (Z)-3-hexenyl acetate and linalool (female moths). Other compounds when added to the 3K blend did not increase or decrease moth catches, including methyl salicylate, (E)-β-ocimene, limonene, β-caryophyllene, butyl hexanoate, farnesol, terpineol, terpinen-4-ol and α-pinene. A few added compounds significantly increased moth catches compared with the 3K blend, including β-pinene (male moths), (Z)-jasmone (male and total moths), (E)-β-farnesene and β-myrcene (female and total moths), and (E,E)-α-farnesene (male, female, and total moths). In addition, each of these five compounds when added to the 3K core blend performed similarly to the 4K lure (male, females, and total moths). Further studies should expand these results through tests of these and other new blends with a range of component ratios and total loading amounts. Field trials should also be replicated within all host crops of codling moth and across major geographical production regions.     

Recognizing the enemy: do predator cues influence hatching in Neotropical annual killifish?

Annual fish species have evolved complex adaptations to survive in temporary wetlands. The main adaptation of these fish is the ability to produce embryos that survive dry periods. Embryo development of this fish can show variation at multiple levels influenced by many environmental factors, such as photoperiod and temperature. Predator cues are another factor that can influence the embryonic stage. One way in which annual fish could adapt to predators is by using risk-spreading strategies (through bet-hedging). Nonetheless, this strategy depends on the coevolutionary history between predators and preys and on the degree of environmental unpredictability, resulting in different responses across different species. This study investigated the influence of predator cues on the embryonic development and hatching of two Austrolebias species that inhabit ponds that present differences in hydroperiod and the risk of predator presence. The results confirmed a differentiated response between the two annual fish species tested, corroborating the modulation of hatching against the risk of predation by native predatory fish. The authors further showed that development times varied between the two annual fish species, regardless of the presence of predators. They highlight that the variation in embryonic development is strongly affected by different levels of hydroperiod unpredictability faced by the two species. To unravel finer-scale local adaptations in the annual fish embryo development, future studies should focus on a region with greater spatial gradient.     

A phytosociological survey of some serpentine plant communities in the Dominican Republic

This paper presents a floristic and vegetation study of the serpentinised territories of the Dominican Republic, corresponding to the Yamasá and Prieta mountains, Dajabón, Puerto Plata and Gaspar Henández. These sites are very important at a local level as they act as speciation centres and have a specific ultramafic flora with a high endemicity rate. The floristic analysis revealed the existence of 219 species, of which 54 (24.7%) are endemic. Twenty-one plots of vegetation distributed in five areas dominated by serpentines have been analysed in this study. The phytosociological approach is based on the Braun-Blanquet method. The study was combined with statistical techniques such as multivariate analyses. The results revealed three different kinds of forests, one dominated by the endemic Bignoniaceae, Tabebuia berterii (CC.) Britton, which is peculiar to the subhumid–humid environments of the Caribbean-Cibensean territory. The second type of forest is dominated by the serpentinophyte Polygonaceae, Leptogonum buchii Urb. which thrives in the humid ombrotype of the north territory. Finally, the third one adopts the form of the pine forest of Dajabón, dominated by Pinus occidentalis Sw. Four associations and three alliances are proposed as new syntaxa based on statistical and phytosociological analyses.     

Reconstructing Native American Migrations from Whole-Genome and Whole-Exome Data

There is great scientific and popular interest in understanding the genetic history of populations in the Americas. We wish to understand when different regions of the continent were inhabited, where settlers came from, and how current inhabitants relate genetically to earlier populations. Recent studies unraveled parts of the genetic history of the continent using genotyping arrays and uniparental markers. The 1000 Genomes Project provides a unique opportunity for improving our understanding of population genetic history by providing over a hundred sequenced low coverage genomes and exomes from Colombian (CLM), Mexican-American (MXL), and Puerto Rican (PUR) populations. Here, we explore the genomic contributions of African, European, and especially Native American ancestry to these populations. Estimated Native American ancestry is in MXL, in CLM, and in PUR. Native American ancestry in PUR is most closely related to populations surrounding the Orinoco River basin, confirming the Southern America ancestry of the Taíno people of the Caribbean. We present new methods to estimate the allele frequencies in the Native American fraction of the populations, and model their distribution using a demographic model for three ancestral Native American populations. These ancestral populations likely split in close succession: the most likely scenario, based on a peopling of the Americas thousand years ago (kya), supports that the MXL Ancestors split kya, with a subsequent split of the ancestors to CLM and PUR kya. The model also features effective populations of in Mexico, in Colombia, and in Puerto Rico. Modeling Identity-by-descent (IBD) and ancestry tract length, we show that post-contact populations also differ markedly in their effective sizes and migration patterns, with Puerto Rico showing the smallest effective size and the earlier migration from Europe. Finally, we compare IBD and ancestry assignments to find evidence for relatedness among European founders to the three populations.     

Bruton's Tyrosine Kinase (BTK) and Vav1 Contribute to Dectin1-Dependent Phagocytosis of Candida albicans in Macrophages

Phagocytosis of the opportunistic fungal pathogen Candida albicans by cells of the innate immune system is vital to prevent infection. Dectin-1 is the major phagocytic receptor involved in anti-fungal immunity. We identify two new interacting proteins of Dectin-1 in macrophages, Bruton''s Tyrosine Kinase (BTK) and Vav1. BTK and Vav1 are recruited to phagocytic cups containing C. albicans yeasts or hyphae but are absent from mature phagosomes. BTK and Vav1 localize to cuff regions surrounding the hyphae, while Dectin-1 lines the full length of the phagosome. BTK and Vav1 colocalize with the lipid PI(3,4,5)P₃ and F-actin at the phagocytic cup, but not with diacylglycerol (DAG) which marks more mature phagosomal membranes. Using a selective BTK inhibitor, we show that BTK contributes to DAG synthesis at the phagocytic cup and the subsequent recruitment of PKCε. BTK- or Vav1-deficient peritoneal macrophages display a defect in both zymosan and C. albicans phagocytosis. Bone marrow-derived macrophages that lack BTK or Vav1 show reduced uptake of C. albicans, comparable to Dectin1-deficient cells. BTK- or Vav1-deficient mice are more susceptible to systemic C. albicans infection than wild type mice. This work identifies an important role for BTK and Vav1 in immune responses against C. albicans.     

Reconstructing the Population Genetic History of the Caribbean

The Caribbean basin is home to some of the most complex interactions in recent history among previously diverged human populations. Here, we investigate the population genetic history of this region by characterizing patterns of genome-wide variation among 330 individuals from three of the Greater Antilles (Cuba, Puerto Rico, Hispaniola), two mainland (Honduras, Colombia), and three Native South American (Yukpa, Bari, and Warao) populations. We combine these data with a unique database of genomic variation in over 3,000 individuals from diverse European, African, and Native American populations. We use local ancestry inference and tract length distributions to test different demographic scenarios for the pre- and post-colonial history of the region. We develop a novel ancestry-specific PCA (ASPCA) method to reconstruct the sub-continental origin of Native American, European, and African haplotypes from admixed genomes. We find that the most likely source of the indigenous ancestry in Caribbean islanders is a Native South American component shared among inland Amazonian tribes, Central America, and the Yucatan peninsula, suggesting extensive gene flow across the Caribbean in pre-Columbian times. We find evidence of two pulses of African migration. The first pulse—which today is reflected by shorter, older ancestry tracts—consists of a genetic component more similar to coastal West African regions involved in early stages of the trans-Atlantic slave trade. The second pulse—reflected by longer, younger tracts—is more similar to present-day West-Central African populations, supporting historical records of later transatlantic deportation. Surprisingly, we also identify a Latino-specific European component that has significantly diverged from its parental Iberian source populations, presumably as a result of small European founder population size. We demonstrate that the ancestral components in admixed genomes can be traced back to distinct sub-continental source populations with far greater resolution than previously thought, even when limited pre-Columbian Caribbean haplotypes have survived.