Abundance and phenology of Pseudoscorpiones (Arachnida) from a mixedwater inundation forest in Central Amazonia, Brazil

Abstract

A total of 675 Pseudoscorpiones, representing nine species, were captured during 12 months in an inundation forest near Manaus, which is covered by several meters of mixedwater for 5-7 months each year. In the terrestrial phase, the average abundance of pseudoscorpions in the soil (0-14 depth) was three times higher during the rainy season (140 ind./m2/month) when compared to the season with less rainfall (48 ind./m2/month). A survival strategy in response to flooding was observed in the terricolous and univoltine Tyrannochthonius amazonicus (Chthoniidae): immature tritonymphs, representing a migrating stage, moved from the soil to the trunk/canopy region where they passed the aquatic phase. Pseudochthonius homodentatus (Chthoniidae) changed from a terricolous mode of life in Central Amazonian upland forests to an arboricolous living in the inundation forest. Six other species, obtained in low numbers predominantly in the trunk/canopy region, are considered arboricolous as well. Our data reconfirm that seasonally inundated forests of the mixedwater type near Manaus represent an ecotone: Pachychernes baileyi (Chernetidae), Tyrannochthonius amazonicus (Chthoniidae), Geogarypus amazonicus (Geogarypidae), Pachyolpium irmgardae (Olpiidae) and Dolichowithius minutus (Withiidae) inhabit blackwater inundation forests in the valley of the Negro River. Parachernes adisi (Chernetidae) was collected from whitewater inundation forests along the lower Solimões River. Paratemnoides minor (Atemnidae) occurs in black- and whitewater inundation forests. Pseudochthonius homodentatus (Chthoniidae) lives in primary and secondary (non-flooded) upland forests of Central Amazonia. The occasionally phoretic Lechytia chthoniiformis (Chthoniidae) is found throughout South America.