Scorpion Group 1 discovered in the venom of Anuroctonus phaiodactylus

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  Scorpion Group 1 discovered in the venom of Anuroctonus phaiodactylus Abstract Scorpion Group 1 (SG1) represents a novel, highly divergent lineage of symbiotic bacteria within the class Mollicutes (phylum Mycoplasmatota). Currently, SG1’s distribution remains restricted - it has been identified exclusively within the scorpion family Vaejovidae, specifically in the genera Vaejovis and Mesomexovis . To date, SG1 has not been detected in other major scorpion families, suggesting a specialized host-symbiont relationship. In this study, we utilized the long-read capabilities of Oxford Nanopore Technology to sequence the 16S rRNA gene from the venom of two scorpion species: Paruroctonus becki (family Vaejovidae) and Anuroctonus phaiodactylus (family Anuroctonidae). We aimed to uncover cryptic microbial diversity, such as SG1, that may have been overlooked by previous short-read sequencing platforms. Our results revealed SG1 was indeed present in A. phaiodactylus but its presence wa...

Aversive conditioning and memory in the harvester Mischonyx squalidus (Arachnida: Opiliones)

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Aversive conditioning and memory in the harvester Mischonyx squalidus (Arachnida: Opiliones)

Abstract

Aversive conditioning is a form of associative learning. Here, we investigated learning and memory capacity of the harvester Mischonyx squalidus (Roewer, 1913), to examine the formation of short (STM) and long-term memories (LTM). First, we trained harvesters to associate an aversive stimulus (shock) with a neutral stimulus (tea odor). Each subject went through three consecutive trials, in which pairings between the stimuli lasted for 3s, with intervals of 1 (STM) and 30 (LTM) min. Subsequently, to test memory, we introduced the subjects in a choice arena where they could choose between staying in either of two areas: impregnated with tea chemicals or blank. We did this immediately after the conditioning phase or 24h after it. Both protocols were successful for STM within the same-day test, but not for LTM on the following day. In summary, we provide a new method to train aversive conditioning in harvesters and evidence for short-term memory.

Guilherme Ferreira Pagoti, Marina Costa Rodrigues, Gabriel Pimenta Murayama, Rodrigo Hirata Willemart "Aversive conditioning and memory in the harvester Mischonyx squalidus (Arachnida: Opiliones)," The Journal of Arachnology, 53(1), 26-29, (20 June 2025)