Natural vegetation in and around crops effectively increases predators. Semi-natural habitats (SNHs; non-crop vegetation) surrounding crops provide refuge and resources. However, the function of SNHs may depend on several factors, and the response of natural predators may vary among crops and regions. Here, we examined the spider community in a SNH and at an adjacent vineyard in a semi-arid region of Argentina. We collected spiders in a gradient from an adjacent SNH, towards the vineyard at three distances from the SNH using two techniques: beating and pit-fall traps. We collected spiders in December and February during two consecutive years at two strata: in vegetation and on the ground. In vegetation, spider abundance significantly decreased from SNH towards the interior of the vineyard at 80 m. On the ground, spider abundance was also significantly higher in SNH. However, after decreasing at the 5 and 20 m sites inside the vineyard, the abundance increased at 80 m. For foliage spiders, species richness followed the same pattern as abundance, whereas ground spider richness significantly increased from SNH to the interior of the vineyard. Species composition also showed different tendencies between foliage and ground spiders. The foliage spider community differed between SNH vs. all the vineyard sites. Contrarily, at the ground stratum, SNH was similar in composition to the edge of the vineyard, and they both differed from the other vineyard sites. We found that the adjacent SNH influenced the spider community in the vineyard and that this effect depended on the distance from that habitat and the association of the community to various strata. These results highlight the importance of studying the whole community of spiders when aiming to increase predator abundance to enhance biological control in this kind of crop. In addition, we found species that may act as indicators of native vegetation which has important implications for the management of natural habitats in this region. Natural vegetation in and around crops effectively increases predators. Semi-natural habitats (SNH; non-crop vegetation) surrounding crops provide refuge and resources. Here, we examined the spider community in a SNH and an adjacent vineyard. SNH influenced the spider community in the vineyard, depending on the distance from the habitat and the association of the community to various strata. Hence, studying the whole community of spiders is important when aiming to increase predator abundance in this kind of crop.image

In tarantulas, the reproductive season in their natural habitat is characterized by the presence of walking males. Grammostola vachoni is a tarantula from Argentina, and previous studies have reported that the breeding season occurs only in spring. However, walking males are also observed in other months. Thus, our objectives here were to study the dynamics of G. vachoni in the reproductive season, to compare male activity with climate data and to estimate whether temperature affects male locomotor performance. Two peaks of walking male activity were found (from the end of October to December, and in March). The number of walking females registered was low and was also bimodal. No significant differences between the sexes in activity with regard to temperature and atmospheric pressure were observed, but females were more likely to be observed under the highest humidity conditions. The months of the reproductive season were very similar in their climate characteristics. Male locomotor performance was strongly affected by extreme temperatures, and the optimum experimental temperature was higher than the environmental activity temperature. This study suggests a diplochronous cycle for G. vachoni, which might be a historical constraint or might indicate selection.

We examined egg sac characteristics and oviposition sites of Metepeira calamuchita (Piel, 2001) (Araneidae) at two different habitat types, creosote bush scrub and Prosopis spp. forest patches, at the Ñacuñan Biosphere Reserve located in the Monte Desert of Mendoza, Argentina. At each site, we manually collected egg sacs of M. calamuchita between November and April. We recorded egg sac location, presence of detritus on the egg sac and its colouration. At scrub sites, there was a greater number of egg sacs anchored to the vegetation, while in forest sites most egg sacs were suspended by web threads. In addition, more egg sacs covered with detritus were found at scrub sites, but we did not find an association between egg sac colouration (brown/dark brown) and habitat type. Location of the egg sac and presence of detritus could function as defence strategies in environments with different pressures of egg sac predators and parasitoids.

Maintaining biodiversity in agricultural systems is essential, as it plays a key role in ecosystem services provision. However, it is declining at an unprecedented rate. Several methods can contribute to increasing species diversity in agroecosystems, including the use of artificial microhabitats. Studies focusing on biodiversity in vineyards have been carried out recently, mainly in Europe and North America, but are scarce in South America. In this study, we investigate whether introduced environmental variability and habitat complexity, using corrugated cardboard bands, enhances spider abundance and diversity in vineyards. Spiders were collected from grapevine plants, using two collecting methods (foliage beating and direct collection). Plants with and without cardboard bands (N = 30) were sampled in three different phenological stages of the vineyard (veraison, maturity and postharvest). Overall, we collected 904 spiders belonging to 35 species. We found that spider abundance and species richness significantly increased with cardboard bands. In addition, we identified particular species that prefer cardboard bands to build their shelters. Results suggest that cost-effective habitat manipulation can increase spider abundance in vineyards, which implies higher biodiversity conservation value and potential for improving biological control.

Se presenta el primer registro del género Ocnaea Erichson, 1840 (Díptera, Acroceridae) para la República Argentina y el primer registro de esta familia parasitando una araña del género Catumiri Guadanucci 2004 (Mygalomorphae, Theraphosidae). Se dan a conocer algunas observaciones del ciclo biológico de la mosca y del comportamiento de la tarántula Catumiri argentinense (Mello-Leitão, 1941).

Disturbance is an important factor affecting community composition and biodiversity in natural ecosystems. The Ventania hill system in central Argentina presents several ecosystem disturbances. Spiders are good candidates for studies related to human impact and conservation, as they can be good biological indicators of certain ecosystems. Therefore, we tried to elucidate if the abundance and spatial distribution of the mygalomorph spider Acanthogonatus centralis (Nemesiidae) are affected by different degrees of disturbance in these hilly grasslands. We studied 3 sites with different levels of disturbance located in the Ventania system in southwestern Buenos Aires Province, Argentina. We did not find differences in the mean density of A. centralis among sites. The highest density of this spider species was found in the site with the highest level of disturbance. In addition, the spatial arrangement indicated an aggregate distribution. In conclusion, we found that A. centralis populations are not affected by different levels of disturbances.

In spiders, pheromones are known to be responsible for attracting the opposite sex, eliciting male searching and courtship behaviors, as well as for synchronizing potential mates in space and time. Most spiders are cannibalistic and aggressive. Thus, early recognition of a female as a possible mate is essential for males, who may suffer high energetic or reproductive costs to the extreme of losing all fitness opportunities. In Acanthogonatus centralis Goloboff 1995, a mygalomorph spider, what female signs might be triggering male courtship behavior remain unknown, as well as whether males can discriminate between females. The aims of the present work were (1) establishing whether males can detect the presence of females using airborne and silk-borne signals and (2) determining whether males can discriminate the reproductive status and body condition of females. We found no evidence that airborne pheromones play a role in the sexual communication of A. centralis, but silk-bound contact signals function as a female advertisement. Also, this is the first study that demonstrates that male mygalomorph spiders can discriminate between different signals on silk through direct contact, showing a preference for unmated females.

The genus Homoeomma has thirteen species distributed in Argentina, Brazil, Colombia, Peru and Uruguay. In Argentina, two species are recorded, Homoeomma elegans in Misiones province and H. uruguayense in Buenos Aires, Entre Ríos and Santa Fe provinces. The objective of this work is to provide the first record of Homoeomma uruguayense in the mountainous system of central Argentina, belonging to western record of the genus in this country. In addition, we provide data on natural history of the species, some notes on its sexual behavior and through the species distribution modeling we discussed about the geographic distribu­tion of the species and factors that could led to this pattern.

Gabriel Pompozzi and Sofía Copperi (2018) The family Nemesiidae is the second most diverse family of Mygalomorphae spiders. Acanthogonatus centralis (Nemesiidae) is commonly found in hilly areas of central Argentina. These spiders are considered generalists due to their basal position in the phylogeny, but little is known about the trophic ecology of the species. Therefore, the objectives of this study were to study some of the species' predatory traits, such as feeding frequency and prey acceptance, and to assess its natural diet. In addition, two parameters - attack latency and consumption time - were measured for each accepted prey. We found that A. centralis feeds every two days and accepts almost all prey offered. The most accepted prey items were beetle larvae and termites. In fact, termites were attacked faster than any other prey, suggesting they are a suitable prey for these spiders. In regard to the species' natural diet, we found remains of seven prey items, ants and beetles being the most frequent. In this study, we found that Acanthogonatus centralis is polyphagous since it accepts different kinds of prey.

Scorpions are one of the most important taxa for ecological, conservation, and biogeographic studies. Biodiversity in the pampean grassland hilly environment is relevant because of the high number of native plant and animal taxa. We studied the diversity, abundance and phenology of a scorpion community in a natural reserve from central Argentina. Samples were taken monthly using 10 pitfall traps. Five species of scorpions (269 individuals) were observed in the study site (Bothriuridae). Bothriurus prospicuus was the most abundant species with 40.15% of the total individuals captured. The Shannon index was H '=0.69 and the evenness index was 0.83. Scorpion abundance was significantly different between months and was significantly correlated with monthly mean temperature. The knowledge on the scorpion fauna in Ernesto Tornquist Provincial Park could help in the preservation of natural grassland habitats.

Many adult male spiders have silk glands which are not associated with the spinnerets. They occur on the anterior margin of the genital furrow and are used during the building of the sperm web and sperm droplet induction. These epiandrous glands exit the body through ducts which lead to specialized spigots. In the taxon Mygalomorphae, the presence of epiandrous spigots is just reported for a couple of species but their morphology has not been investigated. In this paper we provide a detailed study of the ultrastructure morphology of eighteen species belonging to eight families using light and scanning electron microscopy (SEM). We describe and present images of the epiandrous spigots above the genital opening. Also, we compare the morphology of spigots between families and describe the epiandrous glands through histology.

This is the first record for the tarantula Vitalius longisternalis Bertani, 2001 in Parana and Araucaria Forests, Misiones province, northeastern Argentina. Specimens were found at Iguazú National Park and Urugua-í Wildlife Reserve. Data on its natural history is provided.Tarantula, Parana, Araucaria Forest, distribution extension

This is the first record for the species Vitalius roseus (Mello- Leitão, 1923) in Argentina. The present study expands the known geographic distribution of the species to western Uruguay River. Data on natural history and sexual behaviour of the species is provided.

En el presente trabajo se analizó la riqueza específica, abundancia y actividad de la comunidad de arañas Mygalomorphae en la Reserva Natural Sierra del Tigre, Buenos Aires, Argentina. Este ecosistema serrano alberga numerosas especies endémicas y es rico en fauna y flora nativa. La abundancia de arañas se muestreó mensualmente desde mayo de 2011 a mayo de 2012, mediante recolección manual y trampas de caída. Las especies registradas en el área de estudio fueron Actinopus sp. 1 (Actinopodidae), Grammostola vachoni Schiapelli y Gerschman, 1960; Plesiopelma longisternale Schiapelli y Gerschman, 1942 y Catumiri argentinense (Mello-Leitão, 1941) (Theraphosidae). Grammostola vachoni resultó la especie dominante en la recolección manual y Actinopus sp. 1 en trampas de caída. Se discuten y analizan la variación estacional, diversidad y abundancia de la comunidad de migalomorfas. Las Mygalomorphae del sistema de Tandilia comprenden un grupo importante de arañas sedentarias y criptozoicas que parecen depender del tipo de ambiente y factores ambientales.

A population of Calathotarsus simoni Schiapelli and Gerschman (1975) was discovered on a hillside in the Ventania system, Argentina. Our objectives were to quantify burrow density, record burrow morphology and door characteristics and describe the micro-habitat. We counted 57 burrows and report a density of 0.01 burrows/m(2). Aggregation indices suggest that burrows are aggregated under some area plots but more evenly distributed on others. The trapdoor is thick and rigid with bevelled edges connected to the entrance rim by a narrow articulated hinge. Two egg sacs from females were obtained and data on eggs and spiderlings are presented. We registered six burrows of an undetermined species of Actinopus. While a few specimens of Actinopus sp. were found inhabiting this hillside, the highest proportion of burrows belonged to C. simoni. Spider diversity on the hillside shows the predominance of Linyphiidae, Nemesiidae and Gnaphosidae. One juvenile of C. simoni was captured using pitfall traps.

The “Ernesto Tornquist” Provincial Park (ETPP) is located inside the Ventania system (Argentina) and was created to protect one of the last relicts of pampean grasslands. Even though many studies have looked at the vertebrate faunal diversity, biology, and conservation in this Park, few studies have been dedicated to arthropods. Among these, spiders have been used as ecological indicators to evaluate nature conservation status, nevertheless, basic information on their distribution and ecology is necessary for their use as indicator taxa in this region. Thus the goal of this study was to present the phenology and demography of the spider Odo bruchi, a cursorial spider present in the ETPP. For this, spiders were sampled bimonthly using pitfall traps between September 2009-2010 (first year), and March 2011-2012 (second year). A total of 10 traps were placed every 10m along a transect of 100m parallel to the longest axis of a grassland slope with native vegetation. Traps were filled with 1 500mL of ethylene glycol, that were examined and refilled every 60 day period. We collected a total of 799 specimens in two years. Juveniles were the most abundant reaching 47.8% of the total, while males corresponded to 27.8% and females 24.4%. We found significant differences in the mean abundance of O. bruchi: the abundance during spring-summer (Nov-Dec-Jan-Feb) was significantly higher than the other periods of the two years period. Moreover, we found an even abundance distribution throughout the year in the entire study. This work represents one of the first contributions to the ecology of this spider family in the area. Also, our results comprise relevant information to encourage future studies on this spider species as a bio-indicator of the conservation status of pampean grasslands.