New Insight Into the Evolutionary Arms Race Between Spider Egg Sac Pseudoparasitoids and Active Maternal Care by the Spiders

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  New Insight Into the Evolutionary Arms Race Between Spider Egg Sac Pseudoparasitoids and Active Maternal Care by the Spiders ABSTRACT Pseudoparasitoids can lead to high mortality in spider egg sacs, and in some cases, they reduce the reproductive success of a spider female to zero. On the other hand, a species that develops within the spider's egg sac uses a limited resource derived from a single egg sac for its larval development. Therefore, the most crucial behaviour that increases the fitness of free-living pseudoparasitoid females is choosing the best host for their offspring. We analysed various points of the counter-adaptations of the spider egg sac pseudoparasitoid and spiders exhibiting active maternal care, utilising the ichneumonid  Hidryta fusiventris  (Thomson, 1873) and the wolf spider  Pardosa lugubris  (Walckenaer, 1802). We showed that the oviposition decision of  H. fusiventris  is based on the spider's egg sac size and that the fema...

Effect of Cover Cropping on the Abundance, Community Composition and Functional Diversity of Ground-Dwelling Arthropods in a Mediterranean Olive Grove

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Effect of Cover Cropping on the Abundance, Community Composition and Functional Diversity of Ground-Dwelling Arthropods in a Mediterranean Olive Grove

Abstract

Cover cropping is increasingly recognized as a biodiversity-friendly practice in Mediterranean agriculture. However, its impact on ground-dwelling arthropods in olive groves remains insufficiently studied. This study assesses the effects of two perennial cover crops, tall fescue (Festuca arundinacea) and white clover (Trifolium repens) on the abundance, community composition, and functional diversity of ground-dwelling arthropods in a traditional olive grove in Crete, Greece. From April to September 2023, arthropods were sampled bi-weekly using pitfall traps and classified by taxonomic identity and functional traits, with particular focus on spiders (Araneae) and ground beetles (Carabidae). Cover cropping significantly increased total arthropod abundance compared to a control, with clover favoring omnivores and saprophages, and fescue promoting predatory taxa. Fescue plots exhibited the highest abundance of spiders and carabids, as well as greater carabid species richness and functional diversity. Although spider beta diversity differed across treatments, their functional diversity remained unchanged. Our findings indicate that perennial cover crops, especially fescue, enhance ground predator diversity and may contribute to natural pest regulation in Mediterranean olive groves, offering a sustainable alternative to conventional management.

Angelioudakis, T., Koliopoulos, G., & Stathakis, T. (2025). Effect of Cover Cropping on the Abundance, Community Composition and Functional Diversity of Ground-Dwelling Arthropods in a Mediterranean Olive Grove. Diversity, 17(9), 621. https://doi.org/10.3390/d17090621