First winter record of Latrodectus mirabilis (Araneae: Theridiidae) in arid Patagonia: A consequence of climate change and urbanization?

Cases of araneism reported in the province of Chubut (Argentina) have tripled in the last two decades, and almost 80 % of them involve Latrodectus mirabilis (Holmberg) (Araneae: Theridiidae). According to descriptions of the life cycle of this species in Argentina, the low temperatures typical of autumn-winter cause the death of all adult spiders, so that no adult specimens of L. mirabilis are observed in winter. Field samplings, observations by the Grupo de Entomología Patagónica (GENTPAT, IPEEC CCT CENPAT CONICET), and citizen reports for more than 15 years suggested a similar cycle in northeastern Patagonia. However, for the last three consecutive years, we have recorded adult females in the field throughout the Patagonian winter. Some of these individuals even survived the winter and were alive the following spring. The purpose of this note is to report the field presence of adult female specimens of L. mirabilis in the outskirts of the city of Puerto Madryn (Chubut, Argentina) during the last three consecutive winters corresponding to the years 2021, 2022 and 2023; and to note that at least two of them survived the winter, arriving alive (and in good condition) the following spring. Given the medical importance of this spider, the publication of this information, the context of the findings, and their ecological implications will help to prevent its spread and reduce the likelihood of accidents.

Species diversity of Tenebrionidae (Coleoptera) in mountaintops of extra-Andean volcanoes of Payunia (Argentina), with descriptions of two new species.

The north of Neuquén province shares with the south of Mendoza province the subprovince Payunia of the biogeographical province of Patagonic steppe, which is characterized by the presence of approximately 800 volcanoes. Although we have conducted several samplings in volcanoes of Mendoza in past years to recognize the biodiversity of tenebrionids, it is still pending which is the role that these mountains have in the biota of tenebrionids in Neuquén. In this work we reported the results of two consecutive years of prospection in two volcanoes separated by 120 km between each other, Tromen and Auca Mahuida which have 3978 and 2215 meters above sea level respectively. We found that Auca Mahuida harbours a total diversity of 10 tenebrionid species and Tromen 9, but these communities were significantly different between them. From these prospections two new endemic species of Tenebrionidae are described: Scotobius aucamahuidensis Silvestro sp. nov. (Tenebrioninae: Scotobiini) from Auca Mahuida and Psectrascelis tromensis Flores sp. nov. (Pimeliinae: Nycteliini) from Tromen. Photographs for these two new species are included, with comparisons to other known species of these genera. Based on these results we discuss the role of different factors that influence tenebrionid diversity and their implications to conserve biodiversity.

Distribution and environmental determinants of darkling beetles assemblages (Coleoptera: Tenebrionidae) in Península Valdés (Argentinean Patagonia).

Arid lands provide several products and services to humankind, but human activities affect this environment, increasing the extinction risk of the native species. Thus, to successfully conserve the biodiversity of these ecosystems, it is necessary to identify which environmental factors influence the spatial distribution of the organisms that offer these benefits. Darkling beetles play a relevant role on the functioning of deserts. Although these insects are among the most abundant and diverse in these environments, there is no agreement on the relative importance that different environmental factors have as determinants of their spatial distribution. In this work, we assessed the role of climate, vegetation, and soil variables as factors that determine distribution patterns of darkling beetles within the Natural Protected Area Península Valdés (Northeastern Patagonia). Five groups of environmental units were identified, each one with an exclusive tenebrionid species assemblage and different species diversity. The most influential environmental variables were temperature, precipitations, and soil texture. Results suggest that the magnitude of several ecosystem processes may vary among the groups of environmental units. We recommend prioritizing the conservation of the five groups of environmental units and incorporating the darkling beetles-environment relationship in future conservation strategies for arid Patagonia.

Two new species of Nyctelia Latreille (Coleoptera: Tenebrionidae) from Argentinean Patagonia with zoogeographical and ecological remarks.

Two new species of the genus Nyctelia Latreille (Pimeliinae: Nycteliini) from Argentinean Patagonia, N. sulcogranata sp. nov. and N. recteplicata sp. nov., are described. Distributional maps, habitus, photographs and illustrations of genitalic features for these two new species are included, with comparisons to other known species of the genus. A discussion is presented on distributional habitat records and biogeography.

A Tenebrionid beetle's dataset (Coleoptera, Tenebrionidae) from Peninsula Valdés (Chubut, Argentina).

The Natural Protected Area Peninsula Valdés, located in Northeastern Patagonia, is one of the largest conservation units of arid lands in Argentina. Although this area has been in the UNESCO World Heritage List since 1999, it has been continually exposed to sheep grazing and cattle farming for more than a century which have had a negative impact on the local environment. Our aim is to describe the first dataset of tenebrionid beetle species living in Peninsula Valdés and their relationship to sheep grazing. The dataset contains 118 records on 11 species and 198 adult individuals collected. Beetles were collected using pitfall traps in the two major environmental units of Peninsula Valdés, taking into account grazing intensities over a three year time frame from 2005-2007. The Data quality was enhanced following the best practices suggested in the literature during the digitalization and geo-referencing processes. Moreover, identification of specimens and current accurate spelling of scientific names were reviewed. Finally, post-validation processes using DarwinTest software were applied. Specimens have been deposited at Entomological Collection of the Centro Nacional Patagónico (CENPAT-CONICET). The dataset is part of the database of this collection and has been published on the internet through GBIF Integrated Publishing Toolkit (IPT) (http://data.gbif.org/datasets/resource/14669/). Furthermore, it is the first dataset for tenebrionid beetles of arid Patagonia available in GBIF database, and it is the first one based on a previously designed and standardized sampling to assess the interaction between these beetles and grazing in the area. The main purposes of this dataset are to ensure accessibility to data associated with Tenebrionidae specimens from Peninsula Valdés (Chubut, Argentina), also to contribute to GBIF with primary data about Patagonian tenebrionids and finally, to promote the Entomological Collection of Centro Nacional Patagónico (CENPAT-CONICET) and its associated biodiversity data. For these reasons, we believe that this information will certainly be useful for future faunistic, ecological, conservational and biogeographical studies.

Efficient sampling of ground-dwelling arthropods using pitfall traps in arid steppes

Pitfall trapping is probably the most frequently used method for sampling grounddwelling arthropods. While the capture of specimens in pitfall traps largely depends on the number of individuals in the sampled area, trap design and trapping effort for a given environment, can also affect sampling success. The aim of this study was to determine the best pitfall trapping design for collecting ground-dwelling arthropods in the wind-blown and cold arid steppe areas of Patagonia. We tested four designs of traps, six types of preservative and different times of activation as well as the quantity of traps. Both preservation attributes and sampling efficiency differed between different trap designs and fluids compared. We conclude that in order to obtain reliable data on the structure of a community of ground-dwelling arthropods in Patagonia, at least three pitfall traps per experimental unit are required. In addition, traps should be opened for a minimum of 10 days filled with 300 ml of 30 percent ethylene glycol. We also suggested the use of a simple trap design (i. e. without funnel or roof). We believe these findings will contribute to more appropriate sampling of the ground dwelling fauna of Patagonia as well as other arid areas, leading to more reliable diversity studies.

The ground-dwelling arthropod community of Península Valdés in Patagonia, Argentina.

This is the first study based on a planned and intensive sampling effort that describes the community composition and structure of the ground-dwelling arthropod assemblage of Península Valdés (Patagonia). It was carried out using pitfall traps, opened for two weeks during the summers of 2005, 2006 and 2007. A total of 28,111 individuals were caught. Ants(Hymenoptera: Formicidae) dominated this community, followed by beetles (Coleoptera) and spiders (Araneae). The most abundant species were Pheidole bergi Mayr (Hymenoptera:Formicidae) and Blapstinus punctulatus Solier (Coleoptera: Tenebrionidae). Two new species were very recently described as new based on specimens collected during this study: Valdesianacuriosa Carpintero, Dellapé & Cheli (Hemiptera, Miridae) and Anomaloptera patagonica Dellapé& Cheli (Hemiptera, Oxycarenidae). The order Coleoptera was the most diverse taxa. The distribution of abundance data was best described by the logarithmic series model both at the family and species levels, suggesting that ecological relationships in this community could be controlled by a few factors. The community was dominated by predators from a trophic perspective. This suggests that predation acts as an important factor driving the distribution and abundances of surface-dwelling arthropods in this habitat and as such serves as a key element in understanding desert, above-ground community structure. These findings may also be useful for management and conservation purposes in arid Patagonia.

Efficient sampling of ground-dwelling arthropods using pitfall traps in arid steppes.

Pitfall trapping is probably the most frequently used method for sampling ground-dwelling arthropods. While the capture of specimens in pitfall traps largely depends on the number of individuals in the sampled area, trap design and trapping effort for a given environment, can also affect sampling success. The aim of this study was to determine the best pitfall trapping design for collecting ground-dwelling arthropods in the wind-blown and cold arid steppe areas of Patagonia. We tested four designs of traps, six types of preservative and different times of activation as well as the quantity of traps. Both preservation attributes and sampling efficiency differed between different trap designs and fluids compared. We conclude that in order to obtain reliable data on the structure of a community of ground-dwelling arthropods in Patagonia, at least three pitfall traps per experimental unit are required. In addition, traps should be opened for a minimum of 10 days filled with 300 ml of 30% ethylene glycol. We also suggested the use of a simple trap design (i. e. without funnel or roof). We believe these findings will contribute to more appropriate sampling of the ground dwelling fauna of Patagonia as well as other arid areas, leading to more reliable diversity studies.

Una aproximación experimental a la preferencia alimentaría de Nyctelia circumundata (Coleoptera: Tenebrionidae) en el Noreste de la Patagonia / An experimental approach of feeding preferences of Nyctelia circumundata (Coleoptera: Tenebrionidae) in Northeastern Patagonia / UMa aproximaÇÃO experimental a prefErÊncia alimentÁria de Nyctelia circumundata (ColeÓptera: Tenebrionidae) NO Noreste da Patagonia

Los coleópteros constituyen el orden de insectos más diverso, presentando una gran variedad de hábitos alimentarios. La familia Tenebrionidae, considerada típicamente como detritívora, es la más abundante de la fauna de coleópteros epigeos en el nordeste patagónico, siendo Nyctelia circumundata una de las especies más representativas. Con el objetivo de conocer los principales componentes de su dieta, preferencia relativa y posible consumo de la especie vegetal introducida Diplotaxis tenuifolia, se realizaron ensayos en laboratorio utilizando test de preferencia simple y de presentación simultánea de ítems pareados. Se hallaron diferencias significativas en las preferencias de especies vegetales nativas: Senecio filaginoides y Lycium chilense fueron los ítems más preferidos, Sporobolus rigens y Atriplex lampa los menos, y Schinus johnstonii y Grindelia chiloensis en un orden intermedio. Al mismo tiempo, N. circumundata incorporó en su dieta a la especie introducida D. tenuifolia, resultando ser el ítem más consumido. Los resultados modifican el concepto clásico sobre N. circumundata, al demostrar que es un activo consumidor de biomasa vegetal en pie y exponer un claro patrón de preferencias relativas a los diferentes ítems, patrón de selección que podría deberse a una interacción compleja entre atributos energéticos de las plantas, su palatabilidad y los requerimientos metabólicos del coleóptero. El hecho que D. tenuifolia constituya el ítem alimentario preferido arroja luz sobre la conformación de nuevas interacciones entre especies nativas e invasoras, con desconocidas implicaciones ecológicas y aplicadas.

Coleopteran is the most diverse order of insects, and as such it includes a broad variety of feeding habits. The Tenebrionidae family, typically considered as composed of scavengers, is the most abundant family found in Northeastern Patagonia. In turn, Nyctelia circumundata is one of its most representative Tenebrionidae in the region. In order to know the most important components of its diet, as well as its feeding preferences and the possible consumption of the foreign specie Diplotaxis tenuifolia, two different laboratory assays were carried out: simple preference tests and paired choice tests. Clear preferences were found, being Senecio filaginoides and Lycium chilense the most preferred items, and Sporobolus rigens and Atriplex lampa the less preferred, and Schinus johnstonii and Grindelia chiloensis, intermediate. N. circumundata consumed the exotic species D. tenuifolia, turning out to be the most consumed item. The results modify the classical concept about N. circumundata, showing that it feeds on green plant parts and exhibits a defined feeding preference pattern. This preference could be the consequence of a complex interaction between plant energetic attributes, palatability and metabolic requirements. The fact that D. tenuifolia was the preferred item suggests the development of a new interaction between native insects and an invasive plant, which may bring about ecological and application consequences.

Os coleópteros constituem a ordem de insetos mais diverso, apresentando uma grande variedade de hábitos alimentários. A família Tenebrionidae, considerada tipicamente como detritívora, é a mais abundante da fauna de coleópteros epígeos no nordeste patagônico, sendo Nyctelia circumundata uma das espécies mais representativas. Com o objetivo de conhecer os principais componentes da sua dieta, preferência relativa e possível consumo da espécie vegetal introduzida Diplotaxis tenuifolia, se realizaram ensaios em laboratório utilizando teste de preferência simples e de apresentação simultânea de itens pareados. Acharam-se diferenças significativas nas preferências de espécies vegetais nativas: Senecio filaginoides e Lycium chilense foram os itens mais preferidos, Sporobolus rigens e Atriplex lampa os menos, e Schinus johnstonii e Grindelia chiloensis em uma ordem intermediária. Ao mesmo tempo, N. circumundata incorporou na sua dieta a espécie introduzida D. tenuifolia, resultando ser o item mais consumido. Os resultados modificam o conceito clássico sobre N. circumundata, ao demonstrar que é um ativo consumidor de biomassa vegetal em pé e ao expor um claro padrão de preferências relativas aos diferentes itens, padrão de seleção que poderia dever-se a uma interação complexa entre atributos energéticos das plantas, sua palatabilidade e os requerimentos metabólicos do coleóptero. O fato de que D. tenuifolia constitua o item alimentário preferido, joga luz sobre a conformação de novas interações entre espécies nativas e invasoras, com desconhecidas implicações ecológicas e aplicadas.

Preferencia alimentaria de arañas Misumenops pallidus (Araneae: Thomisidae) sobre potenciales insectos presa de cultivos de alfalfa / Feeding preferences of the spider Misumenops pallidus (Araneae: Thomisidae) on potential prey insects from alfalfa crops

The spider Misumenops pallidus (Thomisidae) is commonly found in alfalfa crops. We studied its predatory preferences on potential insect prey, particularly regarding agroecosystems pests. Two kinds of tests were done under normal laboratory conditions: simultaneous presentation of prey (n = 215) and alternative prey test (n = 45). The spiders preferred insects that were mobile, small, without defensive glands and with thin exoskeletons. According to the amount of prey consumed, we established four predation levels: high (> 55%, on adult Drosophila melanogaster flies); intermediate (30%-55% on the defoliator larvae of Rachiplusia nu and adult heteropterans: Horciasinus argentinus and Halticus spegazzinii); and low (10%-30% on the chrysomelids Colapsis sp. and Diabrotica speciosa). The pentatomid Piezodorus guildinii, the curculionid Naupactus sp. and the aphid Acyrthosiphom pisum were not accepted as food. Once the spider captured a prey item it did not accept another, independently of prey item species (82% of trials).

Se analizó la preferencia alimentaria de la araña Misumenops pallidus frente a diferentes potenciales insectos presas, algunos de los cuales son plaga en cultivos agrícolas. Se efectuaron pruebas de presentación simultánea de presas (n= 215) y de presa alternativa (n= 45), en condiciones normales de laboratorio. M. pallidus mostró predilección por insectos móviles, pequeños, de exoesqueleto delgado y sin glándulas repelentes. Se establecieron cuatro niveles de depredación. El grado máximo (> 55%) correspondió a las moscas adultas Drosophila melanogaster. Hubo depredación intermedia (30%-55%) de larvas desfoliadoras (Rachiplusia nu) y heterópteros adultos (Horciasinus argentinus y Halticus spegazzinii); y depredación mínima (10%-30%) de los crisomélidos Colaspis sp. y Diabrotica speciosa. Los pentatómidos Piezodorus guildinii, los curculiónidos Naupactus sp. y los áfidos Acyrthosiphom pisum, no fueron depredados. En el 82% de los casos, una vez que M. pallidus logra cazar su presa, no la cambia por otra (independientemente del tipo de presa considerada).

[Feeding preferences of the spider Misumenops pallidus (Araneae: Thomisidae) on potential prey insects from alfalfa crops]. / Preferencia alimentaria de arañas Misumenops pallidus (Araneae: Thomisidae) sobre potenciales insectos presa de cultivos de alfalfa.

The spider Misumenops pallidus (Thomisidae) is commonly found in alfalfa crops. We studied its predatory preferences on potential insect prey, particularly regarding agroecosystems pests. Two kinds of tests were done under normal laboratory conditions: simultaneous presentation of prey (n = 215) and alternative prey test (n = 45). The spiders preferred insects that were mobile, small, without defensive glands and with thin exoskeletons. According to the amount of prey consumed, we established four predation levels: high (> 55%, on adult Drosophila melanogaster flies); intermediate (30%-55% on the defoliator larvae of Rachiplusia nu and adult heteropterans: Horciasinus argentinus and Halticus spegazzinii); and low (10%-30% on the chrysomelids Colapsis sp. and Diabrotica speciosa). The pentatomid Piezodorus guildinii, the curculionid Naupactus sp. and the aphid Acyrthosiphom pisum were not accepted as food. Once the spider captured a prey item it did not accept another, independently of prey item species (82% of trials).