Wolf spiders (Araneae: Lycosidae) in the genus Schizocosa Chamberlin, 1904 show a diverse array of male courtship behaviors, signaling modes and morphological traits, and have been the subject of extensive study. Although S. saltatrix (Hentz, 1844) is not as well-studied as some of its congeners, this species occupies a phylogenetic position basal to the well-studied ocreata clade within the genus. Here, we present a detailed analyses of its courtship and provide some insights about multimodal signals in the genus Schizocosa. Male and female S. saltatrix were collected from the field and raised to maturity in the lab, then paired randomly for mating trials, in which courtship and mating behaviors were recorded. Male courtship displays consist of vibratory signals coupled with leg-raising visual signals, suggesting that males apparently use complex (multimodal) signals in courtship despite assumptions from other studies. While the overall amplitude of vibratory signals is not related to mating success, rates and amplitude of some individual components (leg strikes) appear to play a role. Female responses show that variation in visual and vibratory signals is associated with receptivity and mating success, although signal information content (e.g., body condition) is unclear. Although visual displays may serve as attention-altering signals and attract female attention, vibratory signals are more important to receptivity. Recent phylogenies suggest that while leg decorations, extensive leg pigmentation and visual signals have likely been secondarily lost, visual displays are retained in S. saltatrix, perhaps as attention-altering signals.

The reproductive phenology of a species of phalangiid harvestmen, Odiellus aspersus, was studied at Maruyama Park, Sapporo, Hokkaido, for the difference in adult emergence between males and females. At the timepoint in which 50% of the population had matured to adulthood, more females were represented than males, and adult females developed about 10 days earlier on average than males. There was no difference in adult body size between males that had matured earlier and males that were collected later in the season. This fact would conflict with a plausible hypothesis that males should mature slowly to attain larger body size in this species. Elongation of spermatheca in females of the species may explain the marked difference in the adult emergence in the species, by enhancing sperm priority of the males that copulated with females last.

The reproductive phenology of Himalphalangium spinulatum (Roewer, 1911) (Eupnoi: Phalangiidae), which overwinter as juveniles and mature in early summer, was surveyed at a riparian forest on the Sendai River, Tottori City, Honshu, Japan. Females became adults about 3–4 days earlier than males. The body weight of females and males and the number of mature eggs retained in females were highest at the age about a week after the final molting, suggesting a shorter time is needed to commence mating and oviposition in this species. This might be the reason for the shorter time lag in maturation between females and males in this species compared to other species of protogynous harvestmen.

Net-casting spiders (Deinopidae) are cribellate spiders that spin a rectangular, sticky net that is held stretched between the claws of their first two pairs of legs. Deinopids produce eight distinct silk types, but knowledge of the silk-producing morphologies is mostly limited to the spigots associated with different fibers. As there have been no studies of deinopid silk gland structure, we dissected all the silk glands from Deinopis spinosa Marx, 1889 and document their number and morphology. We found silk gland position and morphology consistent with the type and number of silk spigots described for Deinopidae. Notably, for the first time, we describe the silk glands associated with cribellate silk: paracribellate, pseudoflagelliform, and cribellar silk glands. Our findings support the homology of pseudoflagelliform glands with araneoid flagelliform glands and will have importance for informing our understanding of spider web evolution.

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.

Mexico boasts the highest number of known ricinuleid species worldwide, however the diversity from North America is still poorly known. Herein, we evaluate Pseudocellus pelaezi (Coronado-Gutiérrez, 1970), a dimorphic species distributed in San Luis Potosí and Tamaulipas, northeastern Mexico. This species represents the first known dimorphic species of ricinuleids, well-documented based on morphology, ultrastructure, and genetic distance. The average intraspecific genetic distance (p-distance) at the mitochondrial cytochrome c oxidase subunit 1 (CO1) within P. pelaezi was 4.1%, whereas a much higher value of 14.6% was found between analyzed species of Pseudocellus Platnick, 1980. Although the genetic distance within the species is .4%, the morphology of primary sexual structures such as the male copulatory apparatus of leg III and the female spermathecae were strongly conserved across all the specimens. However, the morphology of a secondary sexual structure, male femora II, showed variation, with some males possessing a thin femora II (morpho 1-M1) (homeomorphic) and others with a wide femora II (morpho 2-M2) (heteromorphic). This male dimorphism, even within the same population of P. pelaezi, might be considered as a direct effect of sexual competition among males to mate with females, however more studies are needed to test this in ricinuleids. This could be done by studying and evaluating the sexual behavior in combination with the genetic evidence from specimens across several populations, offering insight into whether such dimorphism and/or genetic variation is correlated with sexual competition or represents underestimated diversity yet to be described.

Harvestmen are generally considered to be omnivores. In contrast to most other arachnids that are fluid feeders, harvestmen are capable of ingesting solid food particles and may consume invertebrates, small vertebrates, plant tissues, fungi, and detritus. However, for most species, quantitative diet data are lacking. Stable nitrogen isotope analysis provides a means to measure the contribution of these materials to the diet over the time scale of tissue turnover, and thus quantify trophic position. Examination of fecal material can provide additional evidence of recent feeding, which can further complement field observations and isotopic analyses. We investigated the diet of Erginulus clavotibialis (F.O. Pickard-Cambridge, 1905) (Arachnida, Opiliones, Cosmetidae) in western Belize, using stable isotope analysis and scanning electron microscopy of fecal samples. We also examined nitrogen isotopic ratios for carnivores (scorpions and spiders), herbivores (grasshoppers and katydids), and preliminary measures for two other harvestmen species, ants, and termites. Erginulus clavotibialis had δ¹⁵N signatures similar to scorpions and spiders, indicating carnivory. Nymphs and adults (females and males) of E. clavotibialis did not differ significantly in their trophic level despite possessing chelicerae and pedipalps that differ substantially in relative size and morphology. Fecal samples contained considerable evidence of arthropod consumption, as fragments of legs and exoskeleton were evident. Our study provides an initial quantification of harvestman diet and documents that E. clavotibialis is primarily carnivorous.

Sticky spiral construction behavior in orb-weaving spiders is strikingly flexible: 10 to 16 different cues influence the hundreds of decisions that a spider makes while building the sticky spiral in an orb. Several variables that are influenced by radial tensions, including the frequencies and amplitudes of vibrations and the extensibility and tensions of the radii, have been repeatedly mentioned as possible cues guiding sticky spiral placement. Nevertheless, previous studies have suggested that radius tensions do not affect sticky spiral spacing. These tests were complicated, however, by the tight correlations between variables due to the highly regular geometry of orbs, possible context-dependent variation in the use of cues, and the intrinsic difficulty of demonstrating the absence of an effect. Greater certainty regarding tension-dependent cues is crucial for understanding the cues guiding orb construction, so this study extends these experiments, examining the effects of both increasing and decreasing radius tension, and of different sequences and magnitudes of changes. The results confirm previous findings: changes in radius tensions did not influence sticky spiral spacing decisions in consistent ways and generally failed to produce statistically significant effects. I argue that the likely reason why spiders do not use tension-dependent variables to guide sticky spiral placement is that such cues are unreliable because the spider's own weight substantially alters the tensions on nearby web lines in complex and variable ways.

During a study of the pseudoscorpion fauna of caves in northeastern Brazil, a new species of the genus Neoallochernes Hoff, 1947 was discovered. Morphological analysis suggests that the new species, named Neoallochernes catimbauensis sp. nov., is closely related to N. cubanus Muchmore, 1992. Neoallochernes catimbauensis can be distinguished from other congeners by its spermathecae morphology, trichobothria ib and ist positioned subbasally, trichobothrium isb located subdistally to the middle of the finger and proximal to est. Femur length/width ratios were 2.83× (♀) and 2.42–2.62× (♂); patella width ratios were 2.34× (♀) and 2.29–2.31× (♂); and chela (without pedicel) ratios were 3.34× (♀) and 3.18–3.21× (♂). In addition, ecological observations, distribution maps including past and present records, and a taxonomic identification key are provided.