Notes on the parasitoids found within the nests of Delta dimidiatipenne (Hymenoptera, Vespidae)

An examination of parasitoids that had completed their development but were trapped within Delta dimidiatipenne nests revealed 15 species of insect parasitoids, belonging to eight families under two orders. A new association of Miltogramminae (Diptera: Sarcophagidae) with this wasp is also reported

Parasitoid Abundance and Community Composition in Desert Vineyards and Their Adjacent Natural Habitats

Parasitoids are important natural enemies of many agricultural pests. Preserving natural habitats around agricultural fields may support parasitoid populations. However, the success of such an approach depends on the ability of parasitoids to utilize both crop and natural habitats. While these aspects have been studied extensively in temperate regions, very little is known about parasitoid communities in desert agroecosystems. We took one step in this direction by sampling parasitoids in six vineyards and their surrounding natural desert habitat in a hyper-arid region of the Negev Desert Highlands, Israel. We predicted that due to the high contrast in environmental conditions, parasitoid abundance and community composition would differ greatly between the crop and the natural desert habitats. We found that parasitoid abundance differed between the habitats; however, the exact distribution pattern depended on the time of year—with higher numbers of parasitoids in the natural habitat at the beginning of the vine growth season and higher numbers in the vineyard at the middle and end of the season. Although parasitoid community composition significantly differed between the vineyard and desert habitats, this only accounted for ~4% of the total variation. Overall, our results do not strongly support the notion of distinct parasitoid communities in the crop vs. the desert environment, suggesting that despite environmental contrasts, parasitoids may move between and utilize resources in both habitats

Failure and Collapse of Ancient Agricultural Stone Terraces: On-Site Effects on Soil and Vegetation

Ancient agricultural stone terraces, dated to the Roman and Byzantine ages, are prevalent across the Negev drylands of Southern Israel. The goal of these structures was to reduce hydrological connectivity by harvesting water runoff and controlling soil erosion, thus allowing cultivation of cereals. Land abandonment and the lack of maintenance have led to the failure and collapse of many of these stone terraces. The objective of this study was to assess the effect of failure and collapse of terraces on the on-site (on-field) geo-ecosystem functioning, as determined by vegetation cover and soil quality parameters. This was achieved by studying vegetal and soil properties in shrubby vegetation patches and inter-shrub spaces of intact-terrace plots and collapsed-terrace plots, as well as in the surrounding ‘natural’ lands. Mean cover of both shrubby and herbaceous vegetation was highest in intact terraces, intermediate in ‘natural’ lands, and lowest in collapsed terraces. The overall soil quality followed the same trend as the vegetation cover. Additionally, this study shows that the anthropogenic impact on geo-ecosystem functioning can be either beneficial or detrimental. While well maintained stone terraces benefit the soil and vegetation, abandoned and unmaintained terraces may result in accelerated soil erosion and land degradation

The Impact of Terrestrial Oil Pollution on Parasitoid Wasps Associated With Vachellia (Fabales: Fabaceae) Trees in a Desert Ecosystem, Israel

Oil is a major pollutant of the environment, and terrestrial oil spills frequently occur in desert areas. Although arthropods account for a large share of animal diversity, the effect of oil pollution on this group is rarely documented. We evaluated the effects of oil pollution on parasitoid wasps associated with Vachellia (formerly Acacia) tortilis (Forssk.) and Vachellia raddiana (Savi) trees in a hyper-arid desert that was affected by two major oil spills (in 1975 and 2014). We sampled the parasitoid populations between 2016 and 2018 in three sampling sites and compared their abundance, diversity, and community composition between oil-polluted and unpolluted trees. Parasitoid abundance in oil-polluted trees was lower in one of the sites affected by the recent oil spill, but not in the site affected by the 1975 oil spill. Oil-polluted trees supported lower parasitoid diversity than unpolluted trees in some sampling site/year combinations; however, such negative effects were inconsistent and pollution explained a small proportion of the variation in parasitoid community composition. Our results indicate that oil pollution may negatively affect parasitoid abundances and diversity, although the magnitude of the effect depends on the tree species, sampling site, and the time since the oil spill.Israel Nature and Parks Authority (INPA); Jacob Blaustein Center for Scientific Cooperation.info:eu-repo/semantics/publishedVersio