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...

Chalcochares hirsutifemur (Banks) (Hymenoptera: Pompilidae: Pompilinae), a probable obligate parasitoid of Aptostichus Simon (Araneae: Mygalomorphae: Euctenizidae) in California

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Chalcochares hirsutifemur (Banks) (Hymenoptera: Pompilidae: Pompilinae), a probable obligate parasitoid of Aptostichus Simon (Araneae: Mygalomorphae: Euctenizidae) in California


Abstract


Size equivalence, seasonal synchronicity, geospatial sympatry, habitat specificity, and host-search­ing behavior implicate the spider wasp Chalcochares hirsutifemur (Banks) (Hymenoptera: Pompilidae: Pompilinae) as an obligate parasitoid on species of the wafer-lid spider genus Aptostichus Simon (Araneae: Mygalomorphae: Euctenizidae) on coastal sandy back dunes in San Luis Obispo and Santa Barbara coun­ties, CA. This is substantiated by 2010–2022 macrophotographs, videos, and field observations. Such host evidence supports recent unpublished phylogenomic studies that place Chalcochares as a sister genus of the spider wasp tribe Aporini, in which all species are known obligate parasitoids on trapdoor spiders and related Mygalomorphae. Chalcochares hirsutifemur and C. engleharti (Banks) are separated based on morphological, geographic, and probable host spider differences. Resource partitioning on the coastal sand dunes between C. hirsutifemur and three species of smaller Aporus Spinola is proposed.


Kurczewski FE, Abela AJ, Shimizu A. 2023. Chalcochares hirsutifemur (Banks) (Hymenoptera: Pompilidae: Pompilinae), a probable obligate parasitoid of Aptostichus Simon (Araneae: Mygalomorphae: Euctenizidae) in California. Insecta Mundi 1004: 1–13.