Feldmann, P. | Search bioRxiv

bioRxiv2024

Contrasting patterns of differentiation among three taxa of the rapidly diversifying orchid genus Ophrys sect. Insectifera (Orchidaceae) where their range overlap

In rapidly diversifying groups, taxa defined on the basis of typological criteria can be difficult to support with genetic data. The diversity observed in the insect-mimicking orchid genus Ophrys perfectly illustrates this situation; among 400 described species only 9-10 lineages are detectable by genetic markers such as nrITS. The three taxa described in the Ophrys insectifera group: O. insectifera, O. subinsectifera and O. aymoninii, can be clearly distinguished by their flowers, which have evolved different phenotypes as a result of adaptation to specific pollinator insect species from three different families. However, genetic differentiation between these three taxa has never been really supported by population genetic data and their taxonomic status is still debated. Using population genomic approaches, we found a clustering consistent with the existence of three genetic entities where the geographic distributions of the three taxa overlap. Two of these clusters correspond to France populations of the widespread O. insectifera and the micro-endemic O. aymoninii. However, the last cluster grouped together all the Iberian individuals, suggesting that individuals phenotypically identified as either O. insectifera or O. subinsectifera are genetically weakly differentiated there. Populations of the two pairs of taxa thus may have experienced different patterns of inter-specific gene flow.

evolutionary biology↗

bioRxiv2020

Habitat selection by the Ringed Kingfisher (Megaceryle torquata stictipennis) in Basse-Terre, Guadeloupe: Possible negative association with chlordecone pollution

In the Lesser Antilles the Ringed Kingfisher Megaceryle torquata stictipennis is found on Martinique, Dominica and Guadeloupe. On Martinique and Guadeloupe, farmers growing bananas have made massive use of chlordecone from 1973 until 1993. Chlordecone is a remnant organochlorine insecticide which bioaccumulates in organisms easily. We carried out a survey of the Ringed Kingfisher in 2009 on Basse-Terre, Guadeloupe, traveling 270 km on 44 rivers to assess the effects of chlordecone on its habitat selection behaviour. We recorded 47 encounters of Ringed Kingfishers over the survey. A habitat selection analysis revealed that the Ringed Kingfishers were located mainly in sections of rivers flowing through the ombrophilous forest, but absent on the ocean shoreline or in the lower parts of rivers. The Ringed Kingfishers distribution on Guadeloupe could be negatively associated with areas heavily polluted by the chlordecone. We propose that the widespread use of chlordecone in banana plantations on Guadeloupe between 1973 and 1993 has adverse ecological consequences, and may be responsible for the absence of Ringed Kingfishers in lowland habitat on the island. ResumeDans les Petites Antilles, le Martin-pecheur a ventre roux Megaceryle torquata stictipennis ne vit que sur trois iles: Martinique, Dominique et Guadeloupe. En 2009, nous avons effectue un recensement en Guadeloupe, sur 270 km parcourus dans 44 rivieres. Douze territoires de Martin-pecheur a ventre roux ont ete trouves, et la taille totale de la population est estimee a 54-64 individus. Une analyse de la selection de lhabitat montre que le Martin-pecheur a ventre roux se trouvait principalement sur les rivieres dans la foret ombrophile et non pas sur le bord de locean ni dans la partie basse des rivieres. En Guadeloupe, le Martin -pecheur a ventre roux est negativement associe avec les surfaces hautement polluees par un insecticide organochlore, la chlordecone. Nous suggerons que lepandage massif de la chlordecone de 1973 a 1993, dans les bananeraies de Guadeloupe, doit etre grandement responsable de labsence du Martin-pecheur a ventre roux dans les habitats de basses altitudes de lile. ResumenEn las Antillas Menores, el Martin Gijante Neotropical Megaceryle torquata stictipennis solo vive en tres islas: Martinica, Santo Domingo y Guadalupe. En 2001, realizamos un censo en Guadalupe sobre 270 km recorridos en 44 rios. Doce territorios de Martin Gijante Neotropical han sido registrados, y el volumen total de la poblacion se estima a 54-64 individuales. Un analisis de la seleccion del habitat muestra que el Martin Gijante Neotropical se encontraba principalmente en los rios en el bosque lluvioso y no a la orilla del mar tampoco en la parte baja de los rios. En Guadalupe, el Martin Gijante Neotropical esta negativamente asociado con las superficies muy poluadas por un insecticida organicloro, la chlordecona. Sugeremos que la difusion masiva de la chlordecona entre 1973 y 1993, en las plantaciones de platanos de Guadalupe, debe de ser altamente responsable de la aucencia del Martin Gijante Neotropical en los habitats de baja altitud en la isla.

ecology↗