Incorporation of the 15N-labeled simulated arthropod rain in the soil food web.

Direct trophic links between aboveground and belowground animal communities are rarely considered in food web models. Most invertebrate animals inhabiting aboveground space eventually become prey of soil predators and scavengers forming a gravity-driven spatial subsidy to detrital food webs, but its importance remains unquantified. We used laboratory-grown 15N-labeled Collembola to trace the incorporation of arthropod rain into soil food webs. Live or euthanized Collembola were supplemented once to field mesocosms in the amount equivalent to the mean daily input of the arthropod rain (19 mg d.w. m-2). After the addition of live Collembola, the isotopic label was found most often in predatory Trombidiformes (83% of samples) and Mesostigmata mites (85%), followed by Araneae (58%), Chilopoda (45%), and Coleoptera (29%). Among non-predatory groups, the isotopic label was recorded in Thysanoptera (27%), Collembola (24%), and Oribatida (18%). The 15N-label was also detected in Symphyla, Formicidae, Diplura, Diplopoda, Opiliones, Diptera, Hemiptera, Oligochaeta, and Nematoda. There was a positive correlation between natural 15N abundance and the frequency of the isotopic label among predators, but not among decomposers. In the non-replicated treatment, in which dead collembolans were added, the label was found in predators and decomposers in approximately equal proportions (21-25%). Unlike other forms of the aboveground subsidy (such as leaf litter, frass, or honeydew) that are primarily processed by microorganisms, arthropod rain is assimilated directly by the animals. The high frequency of consumption of the aboveground subsidy suggests that it plays a significant role in maintaining the abundance of soil predators.

Taxonomic diversity and abundance of enchytraeids (Annelida, Clitellata, Enchytraeida) in the Northern Palaearctic. 1. Asian part.

Background: Enchytraeids, or potworms, are tiny oligochaetes that are distributed worldwide in many terrestrial, freshwater and marine ecosystems. Despite their key role in the functioning of ecosystems, the diversity and abundance of Enchytraeidae are rarely studied due to the laborious process of species identification. The present study addresses this gap and sheds some light on the distribution and abundance of enchytraeids in the lands of the Northern Palearctic. The provided dataset constitutes the latest and comprehensive field sampling of enchytraeid assemblages across the Asiatic part of the Northern Palearctic, encompassing an original set of soil samples systematically collected throughout the region from 2019 to 2022. New information: The dataset includes occurrences from 131 georeferenced sites, encompassing 39 species and 7,074 records. This represents the first dataset providing species-specific information about the distribution and abundance of terrestrial enchytraeids across an extensive geographic area covering the Asian sector of the Northern Palaearctic. The compiled dataset is the key for exploring and understanding local and regional enchytraeid diversity. It may also serve as a valuable resource for monitoring and conserving the entire soil biodiversity.

Ontogenetic instars of the oribatid mite Tyrphonothrus digeluensis sp. nov. (Acari, Oribatida, Malaconothridae) from Ethiopia.

A new species of the genus Tyrphonothrus (Oribatida, Malaconothridae) is described from Ethiopia, based on adult and juvenile instars; it is collected from mosses on the swamp at the top of the mountain in Arsi Mountains National Park. Tyrphonothrus digeluensis sp. nov. differs from the related species Tyrphonothrus obesus (Yamamoto & Coetzee, 2004) and T. rectus (Yamamoto & Coetzee, 2004) by the pubescence of exobothridial, epimeral, anoadanal, and some notogastral setae. Comparison between juvenile instars of the new species and the known juveniles of Malaconothridae is presented.