Distributional Notes on Three Wolf Spider Species (Araneae: Lycosidae) Recorded for the First Time in Diyala Province, Iraq

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  Distributional Notes on Three Wolf Spider Species (Araneae: Lycosidae) Recorded for the First Time in Diyala Province, Iraq Abstract This study presents new distributional data for three wolf spider species (Araneae: Lycosidae) from Diyala Province in eastern Iraq. Specimens were gathered from different districts and habitats between July 2025 and June 2026. The species Arctosa tbilisiensis Mcheidze, 1946, Lycosa piochardi Simon, 1876, and Wadicosa fidelis (O. Pickard-Cambridge, 1872) are recorded for the first time in Diyala, extending their known ranges within Iraq. The paper describes key diagnostic morphological features and includes information about the examined specimens and their local distributions. These findings improve knowledge of the distribution of Iraqi Lycosidae and reveal that Diyala Province, despite its habitat variety, remains insufficiently studied. The records serve as a valuable baseline for future taxonomic, faunistic, and ecological research on spiders i...

Ants offset bottom-up control of spiders in Amazonian savanna trees

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Ants offset bottom-up control of spiders in Amazonian savanna trees

Abstract

Community trophic structure is shaped by concurrent bottom-up (resources) and top-down effects (predators), but the extent to which they interact remains uncertain. The Exploitation Ecosystems Hypothesis predicts that predators should offset increases in herbivore abundance with plant productivity, which is supported by data. However, the extent to which interactions within trophic levels (e.g. competition, intraguild predation) have similar effects is less clear. Ants and spiders are abundant in vegetation and consume similar arthropod prey (occasionally each other) and plant exudates, with ants generally showing competitive dominance over spiders. We tested whether ants could shape the trophic structure of tree-dwelling macroarthropod communities by offsetting increases in spider abundance with insect prey. We performed three surveys of the macroarthropod community of 97 trees from two sites in the savanna of Northern Amazonia. Together, ants and spiders represented 74% of the sampled individuals per tree. Insect prey abundance increased with tree crown volume and crown flower cover, consistent with bottom-up limitation. Likewise, both ants and spiders increased with insect prey abundance, with ant abundance also varying with tree species, suggesting reliance on both animal and plant resources. However, as predicted, the positive relationship between spider abundance and insect prey abundance disappeared as ant abundance increased. Our results suggest that agonistic interactions within trophic levels can strongly shape community structure and size by modifying bottom-up effects as much as interactions across trophic levels.

Pedro A.C.L. Pequeno, Ciro Campos, Reinaldo Imbrozio Barbosa, Ants offset bottom-up control of spiders in Amazonian savanna trees, Acta Oecologica, Volume 121, 2023, 103955, ISSN 1146-609X, https://doi.org/10.1016/j.actao.2023.103955.

(https://www.sciencedirect.com/science/article/pii/S1146609X2300067X)