The neonicotinoid imidacloprid impairs the predatory performance and functional response of the jumping spider Helpis minitabunda (Araneae, Salticidae)

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  The neonicotinoid imidacloprid impairs the predatory performance and functional response of the jumping spider Helpis minitabunda (Araneae, Salticidae) Abstract The neonicotinoid imidacloprid can cause lethal and sublethal effects in non-target organisms, including impaired behavior, reduced fertility, disrupted locomotion, and reduced predatory performance in arthropods. Spiders are among the most abundant arthropod predators in terrestrial ecosystems, including agricultural ecosystems, yet the effects of neonicotinoids on the predatory function of jumping spiders remain poorly understood. The functional response of a predator describes how predation rates change with prey density and is key to understanding predator–prey dynamics. We tested whether acute exposure to a commercial formulation of imidacloprid at field-recommended concentrations alters the functional response of the Aussie bronze jumping spider, Helpis minitabunda (L. Koch, 1880). We compared the predation of treat...

First record of Tropicosa thorelli (Araneae: Lycosidae) attacking the dragonfly Rhionaeschna marchali (Odonata: Aeshnidae)

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First record of Tropicosa thorelli (Araneae: Lycosidae) attacking the dragonfly Rhionaeschna marchali (Odonata: Aeshnidae)

Abstract 

This study records thirteen predation attempts by the wolf spider Tropicosa thorelli (Keyserling) on males of the aeshnid dragonfly Rhionaeschna marchali (Rambur) in a protected area of the Colombian Andes. All events occurred on macrophyte vegetation near the shoreline of the Tominé Reservoir, at the locality of Club Náutico El Muña. For each event, we recorded perch height, time of occurrence, attack duration, and ambient temperature. The observations took place between 11:01 and 11:47 h during the dry season, under temperatures ranging from 21.2 to 23.7 °C. The mean duration of attack events was 12.72 ± 2.41 min. In all cases, the attacks were interrupted by the arrival of R. marchali males, although the mechanisms underlying this behavior remain unclear. These observations suggest that perch characteristics, particularly perch height, may influence the vulnerability of R. marchali males to predation by sit-and-wait spiders. 

Palacino Rodríguez, F., & Palacino-Penagos, D. A. (2026). Primer registro de Tropicosa thorelli (Araneae: Lycosidae) atacando a la libélula Rhionaeschna marchali (Odonata: Aeshnidae). Biota Colombiana, 27, e1300. https://doi.org/10.21068/2539200X.1300