Chemical Secretion Use Varies Among Species but Lacks a Straightforward Relationship With Other Defenses in Neotropical Opiliones

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  Chemical Secretion Use Varies Among Species but Lacks a Straightforward Relationship With Other Defenses in Neotropical Opiliones ABSTRACT Chemical secretion deployment is a widespread defensive strategy in arthropods, typically aimed at surviving encounters with predators. However, the ecological forces shaping variation in its use across species remain unclear. We quantified chemical secretion behavior in 11 sympatric species of Prionostemma within the understudied arachnid order Opiliones. We surveyed species in two distinct forests in Costa Rica and tested their secretion propensity when stimulated, and whether these differences correlate with interspecific variation in morphology, leg-loss levels, or social behavior. We found that species varied in their tendency to release chemical secretions, forming a continuous gradient from taxa that rarely secreted to those that secreted in nearly all encounters. However, this variation was not explained by body size or leg loss. Spec...

An Example of Chromosomal Study in Chelicerates: Haplodrassus ovtchinnikovi Ponomarev, 2008 (Gnaphosidae: Araneae)

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An Example of Chromosomal Study in Chelicerates: Haplodrassus ovtchinnikovi Ponomarev, 2008 (Gnaphosidae: Araneae)

Abstract

Chelicerates constitute a broad group of arthropods that include scorpions, mites, spiders, horseshoe crabs, sea spiders, and ticks. Among them, spiders are a species-rich order that has adapted to terrestrial in the world. In this study, it was aimed to determine the cytological characteristics of Haplodrassus ovtchinnikovi Ponomarev, 2008, a species belonging to the family Gnaphosidae. The specimens used in the study were collected from the central district of Nevşehir province between March and May 2024. In this study, where actively dividing tissues were used, the standard plate spreading preparation method was applied. For this purpose, gonads dissected from specimens were treated respectively with hypotonic solution, fixatives, and acetic acid solution, followed by preparation of spreading slides. Preparations with best chromosome spreads in mitotic and meiotic stages were selected for staining. The preparations were examined under the microscope, and metaphase stages for the karyotype, as well as meiotic division stages for division behavior, were identified and photographed. Karyotype results revealed that the species has a diploid chromosome number and sex chromosome system of 2n♂=22(X1X2). A gradual decrease in chromosome lengths was observed. Considering the cytogenetic characteristics of previously studied species within the family Gnaphosidae, the meiotic stages showed a high degree of conserved features. In particular, the sex chromosomes were observed to stain more intensely during meiosis I, while in meiosis II they stained at levels equivalent to the autosomes. Additionally, the species was found to conform to the chiasmatic meiosis model.

Kumbıçak, Ü., & Kumbıçak, Z. (2026). An Example of Chromosomal Study in Chelicerates: Haplodrassus ovtchinnikovi Ponomarev, 2008 (Gnaphosidae: Araneae). Commagene Journal of Biology, 10(1). https://doi.org/10.31594/commagene.1928136