French Guiana Research Articles

Monitoring the threatened Harttiella (Siluriformes, Loricariidae) with environmental DNA: A comparison between metabarcoding and targeted digital PCR

Abstract Environmental DNA has emerged as an efficient alternative to traditional sampling methods. A standard multispecies or a targeted single‐species approach can be used for analysing environmental DNA samples. The costs, benefits, and drawbacks associated with these two approaches are quite different. Here, a comparison between standard multispecies metabarcoding and targeted species assay using digital PCR (dPCR) for two threatened Harttiella species occurring in French Guiana (Harttiella lucifer and H. nsp. “Makwali”) was performed. Samples were collected in 11 sites of the upper Maroni River drainage basin and located in the Galbao mountain range, known to host the targeted species. The “Teleo” primer was used for the metabarcoding approach. To implement a new dPCR assay, specific primers and probes for the two targeted Harttiella species were developed. This targeted dPCR assay detected Harttiella in seven sites. All of these sites were also positive for metabarcoding detection, and the habitat characteristics were favourable for the species. This study demonstrated that both targeted (dPCR) and multispecies (metabarcoding) approaches can be used for the monitoring of the threatened H. lucifer and H. nsp. “Makwali” species. From a conservation point of view, we recommend to use the metabarcoding approach to update the spatial distribution of the species, while the dPCR method can be used for a temporal follow‐up of known Harttiella populations.

The Saucer Bugs (Hemiptera: Heteroptera: Naucoridae) of French Guiana

Northeastern South America has been historically undersampled across most biota.  Surveys conducted for aquatic insects in French Guiana during the past 14 years have resulted in the collection of 16 species of Naucoridae, of which 10 are new country records.  Of these 16 species, 10 are in the subfamily Ambrysinae, one in Ilyocorinae, and five in Limnocorinae.  At least six of these species are considered rare, as very few specimens are known.  A checklist, annotated list, distribution maps, and an illustrated key to identify adults of these species are presented.

Climate anomalies and neighbourhood crowding interact in shaping tree growth in old‐growth and selectively logged tropical forests

Abstract Climate extremes and biotic interactions at the neighbourhood scale affect tropical forest dynamics with long‐term consequences for biodiversity, global carbon cycling and climate change mitigation. However, forest disturbance may change crowding intensity, and thus the relative contribution of climate extremes and neighbourhood interactions on tree growth, thereby influencing tropical forest resistance and resilience to climate change. Here, we aim to evaluate the separate and interactive effects of climate and neighbours on tree growth in old‐growth and disturbed tropical forests. We used 30 years of growth measurements for over 300 tropical tree species from 15 forest plots in French Guiana to investigate the separate and interactive effects of climate anomalies (in solar radiation, maximum temperature, vapour pressure deficit and climatic water deficit) and neighbourhood crowding on individual tree growth. Contrasting old‐growth and selectively logged forests, we also examined how disturbance history affects tree growth sensitivity to climate and neighbours. Finally, for the most abundant 100 species, we evaluated the role of 12 functional traits pertaining to water relations, light and carbon use in mediating tree growth sensitivity to climate anomalies, neighbourhood crowding and their interactions. Climate anomalies tied to heat and drought stress and neighbourhood crowding independently reduced tree growth, and showed positive interactive effects which attenuated their separate effects on tree growth. Their separate and interactive effects were stronger in disturbed than undisturbed forests. Fast‐growing species (i.e. higher intrinsic growth rates) were more abundant in disturbed forests and more sensitive to climate anomalies and neighbourhood crowding. Traits related to water relations, light and carbon use captured species sensitivities to different climate anomalies and neighbourhood crowding levels but were weak predictors of their interactions. Synthesis: Our results demonstrate that climate anomalies and neighbourhood crowding can interact to shape tropical tree growth, suggesting that considering the biotic context may improve predictions of tropical forest dynamics facing altered climate regimes. Furthermore, species traits can capture tree growth sensitivity to the separate effects of climate and neighbours, suggesting that better representing leading functional dimensions in tropical tree strategies offers a promising way towards a better understanding of the underlying ecological mechanisms that govern tropical forest dynamics.

Three New Species of Microsphecodes s.str. (Hymenoptera: Halictidae) with an updated key to species of the subgenus.

We diagnose, describe and illustrate three new species of Microsphecodes Eickwort and Stage, all from the nominate subgenus: M. peckorum Graham and Packer n. sp. from Venezuela, M. fernandoi Graham and Packer n. sp. from French Guiana, and M. septentrionalis Graham and Packer n. sp. from Guatemala. The latter extends the known range of the subgenus further north by approximately 500 km. We provide an updated, illustrated, key to the species of Microsphecodes s.str.

Molecular detection and characterization of Bartonella spp. in small mammals in the Amazonia and Cerrado biomes, midwestern Brazil

Although Bartonella spp. have been worldwide described in rodents and bats, few studies have reported these agents in marsupials. The present work aimed to investigate the occurrence and genetic diversity of Bartonella in small mammals (rodents, marsupials, and bats) and associated ectoparasites in two ecoregions (Amazonia and Cerrado biomes) in midwestern Brazil. For this purpose, DNA samples from 378 specimens of small mammals (128 rodents, 111 marsupials, and 139 bats) and 41 fleas (Siphonaptera) were screened for the Bartonella genus employing a quantitative real-time PCR assay (qPCR) based on the nuoG (nicotinamide adenine dinucleotide dehydrogenase gamma subunit) gene. Then, positive samples in qPCR were submitted to conventional PCR (cPCR) assays targeting the gltA, ftsZ, and rpoB genes. One (0.78 %) rodent, 23 (16.54 %) bats, and 3 (7.31 %) fleas showed positive results in the qPCR for Bartonella sp. After cPCR amplification and sequencing, 13 partial Bartonella DNA sequences of the following genes were obtained only from bats´ blood samples: 9 gltA (citrate synthase), 3 ftsZ (cell division protein), and 1 rpoB (RNA polymerase beta subunit). The maximum likelihood inference based on the gltA gene positioned the obtained sequences in three different clades, closely related to Bartonella genotypes previously detected in other bat species and bat flies sampled in Brazil and other countries from Latin America. Similarly, the ftsZ sequences clustered in two different clades with sequences described in bats from Brazil, other countries from Latin America, and Georgia (eastern Europe). Finally, the Bartonella rpoB from a specimen of Lophostoma silvicolum clustered with a Bartonella sp. sequence obtained from a Noctilio albiventris (KP715475) from French Guiana. The present study provided valuable insights into the diversity of Bartonella genotypes infecting bats from two ecoregions (Amazonia and Cerrado) in midwestern Brazil and emphasized that further studies should be conducted regarding the description and evaluation of different lineages of Bartonella in wild small mammals and their ectoparasites in different Brazilian biomes.

A transposon-based genetic marker for conspecific identity within the Bactrocera dorsalis species complex.

Here we describe a molecular approach to assess conspecific identity that relies on the comparison of an evolved mutated transposable element sequence and its genomic insertion site in individuals from closely related species. This was explored with the IFP2 piggyBac transposon, originally discovered in Trichoplusia ni as a 2472bp functional element, that was subsequently found as mutated elements in seven species within the Bactrocera dorsalis species complex. In a B. dorsalis [Hendel] strain collected in Kahuku, Hawaii, a degenerate 2420bp piggyBac sequence (pBacBd-Kah) having ~ 94.5% sequence identity to IFP2 was isolated, and it was reasoned that common species, or strains within species, should share the same evolved element and its precise genomic insertion site. To test this assumption, PCR using primers to pBacBd-Kah and adjacent genomic sequences was used to isolate and compare homologous sequences in strains of four sibling species within the complex. Three of these taxa, B. papayae, B. philippinensis, and B. invadens, were previously synonymized with B. dorsalis, and found to share nearly identical pBacBd-Kah homologous elements (> 99% nucleotide identity) within the identical insertion site consistent with conspecific species. The fourth species tested, B. carambolae, considered to be a closely related yet independent species sympatric with B. dorsalis, also shared the pBacBd-Kah sequence and insertion site in one strain from Suriname, while another divergent pBacBd-Kah derivative, closer in identity to IFP2, was found in individuals from French Guiana, Bangladesh and Malaysia. This data, along with the absence of pBacBd-Kah in distantly related Bactrocera, indicates that mutated descendants of piggyBac, as well as other invasive mobile elements, could be reliable genomic markers for common species identity.

Intestinal protozoa in returning travellers: a GeoSentinel analysis from 2007 to 2019.

Prolonged diarrhoea is common among returning travellers and is often caused by intestinal protozoa. However, the epidemiology of travel-associated illness caused by protozoal pathogens is not well described. We analysed records of returning international travellers with illness caused by Giardia duodenalis, Cryptosporidium spp., Cyclospora cayetanensis, or Cystoisospora belli, reported to the GeoSentinel Network during January 2007-December 2019. We excluded records of travellers migrating, with an unascertainable exposure country, or from GeoSentinel sites that were not located in high-income countries. There were 2517 cases, 82.3% giardiasis (n = 2072), 11.4% cryptosporidiosis (n = 287), 6.0% cyclosporiasis (n = 150), and 0.3% cystoisosporiasis (n = 8). Overall, most travellers were tourists (64.4%) on long trips (median durations: 18-30days). Cryptosporidiosis more frequently affected people < 18years (13.9%) and cyclosporiasis affected people ≥40years (59.4%). Giardiasis was most frequently acquired in South-Central Asia (45.8%) and Sub-Saharan Africa (22.6%), cryptosporidiosis in Sub-Saharan Africa (24.7%) and South-Central Asia (19.5%), and cyclosporiasis in South East Asia (31.3%) and Central America (27.3%). and cystoisosporiasis in Sub-Saharan Africa (62.5%). Cyclosporiasis cases were reported from countries of uncertain endemicity (e.g. Cambodia) or in countries with no previous evidence of this parasite (e.g. French Guiana). The time from symptom onset to presentation at a GeoSentinel site was the longest among travellers with giardiasis (median: 30days). Over 14% of travellers with cryptosporidiosis were hospitalized. This analysis provides new insights into the epidemiology and clinical significance of 4 intestinal protozoa that can cause morbidity in international travellers. These data might help optimize pretravel advice and post-travel management of patients with travel-associated prolonged gastrointestinal illnesses. This analysis reinforces the importance of international travel-related surveillance to identify sentinel cases and areas where protozoal infections might be undetected or underreported.

Contrasting responses of fine root biomass and traits to large‐scale nitrogen and phosphorus addition in tropical forests in the Guiana shield

Fine roots mediate plant nutrient acquisition and growth. Depending on soil nutrient availability, plants can regulate fine root biomass and morphological traits to optimise nutrient acquisition. Little is known, however, about the importance of these parameters influencing forest functioning. In this study, we measured root responses to nutrient additions to gain a mechanistic understanding of plant adaptations to nutrient limitation in two tropical forests in French Guiana, differing twofold in their soil nutrient statuses. We analysed the responses of root biomass, mean root diameter (RD), specific root length (SRL), specific root area (SRA), root tissue density (RTD) and carbon (C), nitrogen (N) and phosphorus (P) concentrations in roots down to 15 cm soil depth after three years of N and P additions. At the lower‐fertility site Paracou, no changes in root biomass or morphological traits were detected with either N or P addition, although P concentrations in roots increased with P addition. In the higher fertility site, Nouragues, root biomass and P concentrations in roots increased with P addition, with no changes in morphological traits. In contrast, N addition shifted root traits from acquisitive to more conservative by increasing RTD. A significant interaction between N and P in Nouragues pointed to stronger responses to P addition in the absence of N. Our results suggest that the magnitude and direction of root biomass and trait expression were regulated by soil fertility, corroborated by the response to N or P additions. At low fertility sites, we found lower plasticity in root trait expression compared to more fertile conditions, where N and P additions caused stronger and antagonistic responses. Identifying the exact role of mechanisms affecting root nutrient uptake in Amazon forests growing in different soils will be crucial to foresee if and how rapid global changes can affect their carbon allocation.

Contrasted life trajectories: reconstituting the main population exposomes in French Guiana.

In French Guiana, life expectancy is between 2 and 3 years below that of France, reflecting differences in mortality rates that are largely sensitive to primary healthcare and thus preventable. However, because poverty affects half of the population in French Guiana, global measurements of life expectancy presumably conflate at least two distinct situations: persons who have similar life expectancies as in mainland France and persons living in precariousness who have far greater mortality rates than their wealthier counterparts. We thus aimed to synthesize what is known about statistical regularities regarding exposures and sketch typical French Guiana exposomes in relation to health outcomes. We conducted a narrative review on common exposures in French Guiana and made comparisons between French Guiana and mainland France, between rich and poor in French Guiana, and between urban and rural areas within French Guiana. The most striking fact this panorama shows is that being a fetus or a young child in French Guiana is fraught with multiple threats. In French Guiana, poverty and poor pregnancy follow-up; renouncing healthcare; wide variety of infectious diseases; very high prevalence of food insecurity; psychosocial stress; micronutrient deficiencies; obesity and metabolic problems; and frequent exposure to lead and mercury in rural areas constitute a stunningly challenging exposome for a new human being to develop into. A substantial part of the population's health is hence affected by poverty and its sources of nutrition.

Understanding transmission risk and predicting environmental suitability for Mayaro Virus in Central and South America.

Mayaro virus (MAYV) is a mosquito-borne Alphavirus that is widespread in South America. MAYV infection often presents with non-specific febrile symptoms but may progress to debilitating chronic arthritis or arthralgia. Despite the pandemic threat of MAYV, its true distribution remains unknown. The objective of this study was to clarify the geographic distribution of MAYV using an established risk mapping framework. This consisted of generating evidence consensus scores for MAYV presence, modeling the potential distribution of MAYV in select countries across Central and South America, and estimating the population residing in areas suitable for MAYV transmission. We compiled a georeferenced compendium of MAYV occurrence in humans, animals, and arthropods. Based on an established evidence consensus framework, we integrated multiple information sources to assess the total evidence supporting ongoing transmission of MAYV within each country in our study region. We then developed high resolution maps of the disease's estimated distribution using a boosted regression tree approach. Models were developed using nine climatic and environmental covariates that are related to the MAYV transmission cycle. Using the output of our boosted regression tree models, we estimated the total population living in regions suitable for MAYV transmission. The evidence consensus scores revealed high or very high evidence of MAYV transmission in several countries including Brazil (especially the states of Mato Grosso and Goiás), Venezuela, Peru, Trinidad and Tobago, and French Guiana. According to the boosted regression tree models, a substantial region of South America is suitable for MAYV transmission, including north and central Brazil, French Guiana, and Suriname. Some regions (e.g., Guyana) with only moderate evidence of known transmission were identified as highly suitable for MAYV. We estimate that approximately 58.9 million people (95% CI: 21.4-100.4) in Central and South America live in areas that may be suitable for MAYV transmission, including 46.2 million people (95% CI: 17.6-68.9) in Brazil. Our results may assist in prioritizing high-risk areas for vector control, human disease surveillance and ecological studies.

Mortality Trend of Severe COVID-19 in Under-Vaccinated Population Admitted to ICU in French Amazonia.

(1) Background: Until December 2021, French Guiana (FG), located in South America, faced four consecutive COVID-19 epidemic waves. This study sought to analyze the mortality trend of severe COVID-19 patients admitted to the referral ICU of FG. (2) Methods: We conducted a prospective, observational, and non-interventional study in ICU at Cayenne Hospital. We included 383 patients older than 18 admitted with SARS-CoV-2-related pneumonia hospitalized from May 2020 to December 2021. The study covers three periods. Period 1 (Waves 1 and 2, original variant), period 2 (Wave 3, Gamma variant), and period 3 (Wave 4, Delta variant). (3) Results: The median age was 63 years (52-70). Frailty was diagnosed in 36 patients over 70 (32.4%). Only 4.8% of patients were vaccinated. The median ICU LOS was 10 days (6-19). Hospital mortality was 37.3%. It was 30.9% in period 1, 36.6% in period 2 (p = 0.329 vs. period 1), and 47.1% in period 3 (0.015 vs. period 1). In multivariate analysis, independent factors associated with hospital mortality included age greater than 40 years (]40-60 years] OR = 5.2, 95%CI: 1.4-19.5; (]60-70 years] OR = 8.5, 95%CI: 2.2-32; (]70+ years] OR = 17.9, 95%CI: 4.5-70.9), frailty (OR = 5.6, 95%CI: 2.2-17.2), immunosuppression (OR = 2.6, 95%CI: 1.05-6.7), and MV use (OR = 11, 95%CI: 6.1-19.9). This model had an overall sensitivity of 72%, a specificity of 80.4%, a positive predictive value of 68.7%, and a negative predictive value of 82.8%. (4) Conclusions: The mortality of severe COVID-19 patients in French Amazonia was higher during the Delta variant wave. This over-death could be explained by the virulence of the responsible SARS-CoV-2 variant and the under-vaccination coverage of the studied population.

Thirty years of HIV pregnancies in French Guiana: prevention successes and remaining obstetrical challenges.

In a context of high HIV prevalence, poor pregnancy follow-up, frequent poverty, preeclampsia, and preterm delivery, we aimed to describe the characteristics and outcomes of pregnancies among women living with HIV in French Guiana. A retrospective cohort study was conducted on HIV-infected pregnancies enrolled between January 1st 1992 to 31st July 2022. Overall, there were 1,774 pregnancies in 881 women living with HIV. For 75.1% of pregnancies, the HIV diagnosis was already known before pregnancy and in 67.6% of women, HIV follow-up predated pregnancy. Nearly half of women, 49.6%, only had one pregnancy since having been diagnosed with HIV. Although most women received antiretroviral therapy during pregnancy, for those with the available information we found only 48.5% had an undetectable viral load at delivery. Overall, 15.3% of pregnancies ended with an abortion. There were a total of 110 newborns infected with HIV representing an overall transmission rate of 6.2% (110/1,771). Between 1993 and 2002, the transmission rate was 34%, between 2003 and 2012 it was 1.3%, and between 2013 and 2022 it was 0.7%. Overall, in Cayenne, since 2008, 106 of 581 HIV-infected pregnancies (18.2%) with available information were premature before 37 weeks of pregnancy; of these, 33 (5.7%) were very preterm deliveries and 73 (13.3%) were late preterm deliveries. Over time, in Cayenne, preterm delivery declined significantly. The present study emphasizes that, despite spectacular progress in reducing mother to child transmission, pregnancy outcomes among women living with HIV are still preoccupying with high incidence of preterm delivery and low birth weight. Teasing out what fraction is linked to HIV and what fraction is linked to social precariousness and poor follow-up was not possible in this study. Despite the high incidence of very preterm delivery recent progress suggests that coordination efforts to improve follow-up may also have improved obstetrical outcomes.

Across the Atlantic: morbidity, geography, and the eighteenth-century French Atlantic slave trade

ABSTRACT In 1765, enslaved Africans boarded the Roi Guinguin in Badagry as part of a restitution agreement between a Nantesian slave trading company and an African ruler. These captive Africans endured treacherous journeys from West Africa’s interior to Badagry, then Príncipe, then toward Saint Domingue before being rerouted to Cayenne in Guyane (French Guiana), and then the Îles du Salut for a smallpox quarantine. The captain of the Roi Guinguin and French imperial officials’ fears of smallpox outbreaks and other contagious diseases prompted them to halt and reroute the voyage to refreshment centers and quarantines along the West African and South American coasts. The African captives took these stopovers as opportunities to flee and otherwise resist their enslavement. The enslaved Africans felt West African and European imperialism and commerce come to bear on and in their bodies as slave traders and colonial officials exploited the African and South American coastal geography.

Multi-locus sequence analysis unveils a novel genus of filarial nematodes associated with ticks in French Guiana.

Filarial nematodes of the Dipetalonema lineage include tick-borne filarioids that infect both domestic and wild vertebrate hosts, but they remain understudied in many cases. In this study, we conducted a molecular characterization of a Dipetalonema-like filarioid (DLF) recently identified in two tick species in French Guiana, South America. While the cox1 mitochondrial gene was the sole marker initially sequenced for describing DLF, its classification and phylogenetic relationship with other members of the Dipetalonema lineage were unclear. Therefore, we better characterized DLF through the sequencing of six additional gene markers and conducted phylogenetic analyses. Based on this multi-locus typing scheme, DLF exhibited significant divergence from known genera and species of filarioids, or other sequences available in public databases, suggesting its potential classification as a novel genus within the Dipetalonema lineage. Phylogenetic analyses further unveiled a close evolutionary relationship between DLF and all other filarioids associated with Acari (ticks and mites) within a robust monophyletic subclade in the Dipetalonema lineage. Overall, these findings confirm the existence of a specialized, Acari-borne group of filarioids and underscore the need for comprehensive investigations into their epidemiology and potential impact on animal health.

Estimation of the number of tree species in French Guiana by extrapolation of permanent plots richness

Abstract The biodiversity of tropical rainforest is difficult to assess. Yet, its estimation is necessary for conservation purposes, to evaluate our level of knowledge and the risks faced by the forest in relation to global change. Our contribution is to estimate the regional richness of tree species from local but widely spread inventories. We reviewed the methods available, which are nonparametric estimators based on abundance or occurrence data, log-series extrapolation and the universal species–area relationship based on maximum entropy. Appropriate methods depend on the scale considered. Harte’s self-similarity model is suitable at the regional scale, while the log-series extrapolation is not. GuyaDiv is a network of forest plots installed over the whole territory of French Guiana, where trees over 10 cm DBH are identified. We used its information (1315 species censused in 68 one-hectare plots) to estimate the exponent of the species–area relationship, assuming Arrhenius’s power law. We could then extrapolate the number of species from three local, wide inventories (over 2.5 km2). We evaluated the number of tree species around 2200 over the territory.

The Singular Epidemiology of Plasmacytoma and Multiple Myeloma in French Guiana.

The objective was to review a decade of plasmacytoma (PC) and multiple myeloma (MM) data from French Guiana, and to study its spatial and temporal trends. This was a retrospective study of MM and PC between January 2005 and December 2014 using cancer registry data, including age-standardized incidence and mortality rates. There were 110 cases of PC and MM (62 women and 48 men), representing the eighth most frequent malignancy in French Guiana. PC and MM were much more common in females. In men, 79% of cases occurred at ≥55 years, and in women, 90% of cases occurred at ≥50 years. The median age at diagnosis was 60 years for men and 66 years for women, while it was 72 years for men and 75 years for women in mainland France. The incidence rate standardized to the world population was 5.9 patients of PC and MM per 100,000 men/year and 7.8 per 100,000 women/year. In our territory, the incidence of PC and MM was higher and patients were diagnosed at a substantially younger age than in mainland France. Women had a greater incidence than men, and there was an increasing temporal trend of incidence among women. African ancestry and the frequency of obesity, notably among women, could have contributed to this observation.

Geographically variable mate preferences shed light on the processes maintaining inversion polymorphism

Abstract An important question in evolution is to understand the mechanisms that maintain phenotypic diversity, despite selection that should drive homogeneity. For example, selection by predators may promote the convergence of colour patterns among defended prey, resulting in the formation of mimetic communities. However, certain aposematic species, such as the Neotropical butterfly Heliconius numata, are polymorphic. In H. numata, wing pattern polymorphism, which is associated with chromosomal inversions, may be maintained via disassortative mating preferences, thought to favour the co-occurrence of individuals with different mimicry phenotypes in Peru. To test whether environmental variation due to geography influences mate choice, here we investigate the occurrence of disassortative mating among the two coexisting forms of H. numata in French Guiana, and its potential role in the maintenance of this polymorphism. Our experimental approach demonstrates that the two forms display weak and slightly asymmetrical disassortative mate preferences. Modelling and simulations suggest that this pattern of mate preference alone is not sufficient to maintain polymorphism, and predict the loss of the choosiest form, unless this form enjoys a survival advantage. In this aposematic species, such an advantage could arise from mimicry, but further studies into the benefits of mimicry and predator generalization are needed to test this hypothesis. More importantly, our results suggest that the balance between selective forces influencing polymorphism may vary across geographical and ecological contexts, and this warrants further study.

Population genetic structure and demographic history of the timber tree Dicorynia guianensis in French Guiana

Population genetic structure and demographic history of the timber tree Dicorynia guianensis in French Guiana

Natural durability of 8 tropical species suitable for structural roundwood: laboratory screening tests for resistance to fungi and termites

Knowledge of the wood properties of tropical tree species is still relatively limited, so timber extraction focuses on a few abundant, large-diameter species. Very little is known about small-diameter trees, although they could be used directly as roundwood for construction. The aim of this study was to determine the natural durability of 8 candidate species for use as structural roundwood in French Guiana: Goupia glabra, Licania alba, Hymenopus heteromorphus, Lecythis persistens, Oxandra asbeckii, Pouteria bangii, Simarouba amara, Tachigali melinonii and Virola surinamensis. Samples of their wood were exposed to white rot (European and tropical), brown rot (European), and European subterranean termites (using non-choice and multi-choice tests) in laboratory conditions and subjected to screening tests adapted from European standards. Only two species were classified as durable against both fungi and termites: L. alba and P. bangii, which means they can be used without treatment as building material in tropical or temperate climates. The other species tested were classified (1) as durable but with notable differences observed in their resistance to fungi and termites respectively (G. glabra, L. persistens, O. asbeckii), (2) moderately durable (H. heteromorphus), (3) low durability to sensitive (T. melinonii, S. amara, V. surinamensis), meaning actual European standards would not let use these last species in outdoor structures without protection, despite their use by local population in traditional building. However, they could be used for building purposes with appropriate protection systems (including wood protection). The results we obtained for resistance to wood decay provide essential information to assess the potential of these eight tree species in French Guiana’s construction sector.

Mosquitoes (Diptera: Culicidae) of the Amazonian savannas of French Guiana with a description of two new species.

Amazonian savannas are among the most noteworthy landscape components of the coastal plain of French Guiana. Although they cover only 0.22% of the territory, they bring together a large part of the animal and plant diversity of this overseas region of France. This article outlines the results of the first study dedicated to mosquitoes (Diptera: Culicidae) of Amazonian savannas. Samplings were conducted in eight independent savannas evenly distributed along a transect of 170 km on the coastal plain of French Guiana. A total of 50 mosquito species were recorded, which is about 20% of the culicid fauna currently known in French Guiana. Among them, Culex (Melanoconion) organaboensis sp. nov. and Cx. (Mel.) zabanicus sp. nov. are newly described based on both morphological features of the male genitalia and a DNA barcode obtained from type specimens. Diagnostic characters to assist their identification are provided and their placement within the infrasubgeneric classification of the subgenus Melanoconion is discussed.