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...

Disparity among venom components, and morphometrics in Centruroides baergi Hoffmann, 1932, a medically relevant scorpion species from Mexico

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Disparity among venom components, and morphometrics in Centruroides baergi Hoffmann, 1932, a medically relevant scorpion species from Mexico

Abstract

Centruroides baergi is a scorpion species distributed in the biogeographical province of the Balsas Basin in Mexico. Health officials have reported acute envenomation in human populations living on the western side of this scorpion's range, but none in the eastern region. This disparity in toxicity suggested that there may be two distinct species. We used two different approaches, including venom analysis and morphometric specimens from both regions, to test our hypothesis. We performed chromatographic, electrophoretic, and mass spectrometry analysis to identify the known β-toxins involved in the intoxication. The most remarkable finding was the absence of Cb3 β-toxin in the eastern population. Consequently, the LD50 of the eastern population was lower than that of the western population. We analyzed linear and ratio body measurements with parametric and nonparametric statistics to test species limits. These analyses indicated that all putative populations of C. baergi are significantly similar, suggesting that they may represent a single species. Unexpectedly, the population of scorpions in the center of the study area, Suchixtlahuaca, previously identified as C. baergi, showed significant morphological and venom composition differences. We provided empirical evidence of an abrupt change of highly toxic peptides around the 98th meridian that limits populations of Centruroides baergi to the east of Mexico.
Bejarano-Mendoza, F. O., Gómez-Ramírez, I. V., Cortés Guzmán, A. J., Becerril, B., Possani, L. D., Cid Uribe, J. I., & González-Santillán, E. (2025). Disparity among venom components, and morphometrics in Centruroides baergi Hoffmann, 1932, a medically relevant scorpion species from Mexico. Toxicon, 108370. https://doi.org/10.1016/j.toxicon.2025.108370