Feeding, energy flow and soil turnover in the desert isopod, Hemilepistus reaumuri

Abstract

The desert woodlouse Hemilepistus reaumuri is one of the most abundant macroscopic invertebrates in North Africa, the Arabian steppes, semi-desert and desert, and the Negev desert Israel.The main purposes of our study were: 1. To investigate the feeding behaviour of H. reaumuri in the field and the laboratory, with special attention to the importance of soil and perennials in the isopods' diet. 2. To estimate annual energy flow and soil turnover by the isopods and to relate it to the role of isopods in the desert ecosystem. The results of field observations and feeding experiments in the laboratory show: a) That desert isopods are saprovores, herbivores and microbivores. b) That in order to survive the isopod should include soil particles and or soil minerals when feeding on vegetation. c) Annual ingestion was 10.3-38.6 kcals/m, 3-12% of the available dead organic matter, and soil turnover 28.5-105.7 g/m. It was hypothesized that by ingestion and defaecation of organic matter and inorganic soil particles, H. reaumuri alters the structure of the decomposition substrate and increase the rate of decomposition in the desert ecosystem.

Some aspects of the regional variation in the amount of available sediment produced by isopods and porcupines, northern negev, israel

“…Study of the spatial distribution of the biological activity was carried out in September 1974 at the end of the summer period. Previous studies (Schahak et al (1976)) have shown that by this time the porcupines and especially the isopods have already produced 90-95 per cent of the yearly amount of available sediment and that at this stage the distinction between successful and unsuccessful isopod burrows is very easy to make. The field survey consisted in counting the number of porcupine digging points in each plot, unsuccessful and successful isopod borrows at each of the intersections of the grid system.…”

Phenology, activity and regulation of radiation load in the desert isopod, Hemilepistus reaumuri

“…This limits its ability to fully utilize environmental resources. Thus, H. reaumuri is inactive during winter months when water availability is maximal and its foraging period is limited to 8 months, despite food availability throughout the year (Shachak et al, 1976).…”

Effects of Local-Scale Disturbance on Biocrusts

“…Zaady et al examined the effects of mountain bicycles on cyanobacterial crusts on loess soils in the Zin Valley, Negev Desert highlands (E. Zaady, unpublished). The results suggested that, although it took up to 3 years for biocrusts to recover, the major damage was to the organisms that rely on the cyanobacterial crusts (Shachak and Steinberger 1980;Shachak et al 1976). The cyanobacterial crusts comprise the basis for the ecological system in the Negev Desert.…”