Ctenidae of French Guiana

undescribed species of Ctenus, similar to Ctenus amphora

Ctenus dubius, type species of the genus

Ctenus dubius, epigyne of female

Ctenus dubius, male palp, ventral

venter of Ctenus villasboasi

species of Enoploctenus

French Guiana holds an impressive species richness or biodiversity, of which large parts are still unknown, especially when looking at the invertebrate arthropods.

To list the insects of French Guiana is an aim of a current project of the Société Entomologique Antilles Guyane (SEAG). So far approximately 14,000 species were recorded, the estimated number based on this research is more than 80,000 species. Since several years, several projects not only tried to make close to complete inventories, but also to contribute to scientific knowledge on the geographical distribution of species and the community structures, including the different trophic levels. BREGA and DIADEMA, both funded by ANR (Agence Nationale de Recherche) via the Labex CEBA (2013-2015) are such projects. They aim to evaluate the beta-diversity of tropical rainforest of the Guiana shield by investigating geographical and environmental gradients. These studies are innovative in including a quantitative characterization of the diversity of several groups of organisms: plants, fungi, earthworms, arthropods, amphibians, fishes and the “big fauna” (birds and mammals) in tropical forests at the country level. Another long term objective of these projects is to initiate collections and databases for a future Biodiversity Office of French Guiana (OBAG).

One of the key groups in tropical forests are the spiders (Order: Araneae), due to their species richness and higher position in the food web as predators. Particularly noticeable are the wandering spiders of the family Ctenidae – the tropical wolf spiders, due to their commonness, abundance and not least by the impressive size of some species. They play a significant role as predators of the extremely system-relevant epigeic meso- and macrofauna in Neotropical rainforests, but also as prey for a multitude of invertebrate (e.g. ants) and vertebrate species (e.g. frogs, lizards, mammals).

In the frame of the two mentioned projects, several sites were sampled with a standardized and optimized sampling protocol (Vedel & Lalagüe 2013), repeated in space and in time. Several sampling methods were used during day and night, such as beating tray, sweep net, pitfall traps or nocturnal hand collecting, in order to collect efficiently at all (lower) strata. The protocol was applied widely across vegetational, geographical and altitudinal gradients (e.g. flooded forest, slopes, hill tops). All specimens collected were sorted to morphospecies and send to specialists for identification.

The Ctenid spiders were sorted and identified by Vincent Vedel and Hubert Höfer in 2015 at the museum in Karlsruhe (SMNK), profiting from a voucher collection from the Brazilian Amazon region. Photographs for morpho-specification were taken by the student trainee Lena Enderle. The material contains new records for French Guiana expanding the list published by Vedel et al. 2013 and also new species, which will be described in the future. Till then, observations and species records will be presented on the website Wandering Spiders of the Amazon.

Selected Publications

Vedel V., Cerdan A., Martinez Q., Baraloto C., Petitclerc F., Orivel J. & Fortunel C. (2015):
Day-time vs. night-time sampling does not affect estimates of spider diversity across a land use gradient in the Neotropics (short communication). Journal of Arachnology. 43: 413
Vedel V., Hadrien L. (2013):
Standardized sampling protocol for spider community assessment in the Neotropical rainforest. Journal of Entomology and Zoology Studies. 1: 18-35  PDF-Download of the publication
Vedel V., Rheims C.A., Murienne J., Brescovit A.D. (2013):
Biodiversity baseline of the French Guiana spider fauna. SpringerPlus. 2: 1-19  PDF-Download of the publication