A pseudoscorpion clinging to a cave salamander: phoresy or failed predation?

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  A pseudoscorpion clinging to a cave salamander: phoresy or failed predation? Abstract Pseudoscorpions are well known for phoretic associations with arthropods, but interactions with amphibians are rarely documented. Here we report a pseudoscorpion attached to the left palpebral region of an adult male Italian cave salamander, Speleomantes italicus , observed during a visual survey in a karst cave in Tuscany, Italy. The pseudoscorpion, assigned on the basis of visible morphology and locality to Chthonius cf. elongatus , was grasping a minute cutaneous fold on the lower margin of the left upper eyelid with one chela while the salamander moved slowly over the rock surface. No handling was performed and the initial contact between the two animals was not observed. The event therefore cannot be interpreted unambiguously, but may represent opportunistic phoresy or defensive attachment following a failed predation attempt. To our knowledge, this is the first published observation of a ...

The agrobiont wolf spider, Tigrosa helluo (Araneae: Lycosidae), has broad thermal limits and displays consistent temperature preferences in laboratory trials

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The agrobiont wolf spider, Tigrosa helluo (Araneae: Lycosidae), has broad thermal limits and displays consistent temperature preferences in laboratory trials

Abstract

The arthropod species that invade and persist in disturbed habitats, such as agricultural fields, likely have adaptations that allow individuals to tolerate and/or respond to abiotic extremes. We hypothesized that the agribiont wolf spider, Tigrosa helluo (Walckenaer, 1837) (Araneae, Lycosidae), would have a broad thermal tolerance range and be able to actively select favorable sites within an open landscape. We documented the reactions of juveniles and adult females when released in a hostile arena at low (4 to 7 °C), high (77 to 80 °C), or room temperatures (23 to 26 °C) and recorded the temperature where they settled as a measure of thermal preference. All individuals commenced moving in less than a minute and repeatedly relocated to regions with more amenable temperatures (≈ 20 °C) regardless of their starting point. We also determined the critical thermal maxima (CTmax) and minima (CTmin) of the subjects. The CTmax for adults was between 37 to 48 °C which was significantly higher than the values of 27 to 46 °C obtained for juveniles. The CTmin for adults was 2 to 6 °C which was significantly lower than we recorded for juveniles (between 2 and 7 °C). Taken together, the broad tolerance range, quick reactions to temperature extremes, and consistent thermal preferences displayed by T. helluo likely contribute to their success in disturbed agroecosystems. Both adult females and juveniles can withstand the thermal environment for much of the year and counter extreme temperatures through behavior.


Sperry, M., Shannon, H. C., & Rypstra, A. L. The agrobiont wolf spider, Tigrosa helluo (Araneae: Lycosidae), has broad thermal limits and displays consistent temperature preferences in laboratory trials. Environmental Entomology. https://doi.org/10.1093/ee/nvaf053


Acknowledgment: I sincerely thank Leif Cash (@leifcollectsbugs) for generously providing the in situ image of Tigrosa helluo.