The attractive effect of dung on coprophagous beetle communities and their role in dung degradation are well-known phenomena. However, little research has been conducted on the recruitment capacity of this substrate for other arthropods, especially those inhabiting the soil. With the aim of beginning to recognize general patterns in these relationships, the influence of the structure and origin of dung from invasive exotic mammals on the recruitment of microarthropods was investigated in two meadows within Nahuel Huapi National Park in southwestern Argentina. Abundance, richness and diversity of microarthropod communities collected on invasive mammal dung were studied. A total of 2478 microarthropods were collected and 52 species were identified. Recruitment of microarthropods on dung of two invasive coprophagic herbivores, the rabbit, Oryctolagus cuniculus and the hare, Lepus europaeus, were compared with two invasive non-coprophagic mammals, one herbivorous, the red deer, Cervus elaphus and one omnivorous, the wild boar, Sus scrofa. Pellets of S. scrofa showed the highest microarthropod abundance and richness while diversity was greatest on pellets of C. elaphus. Pygmephorid and oribatid mites and springtails were the most abundant. Liposcelis psocopterans and oribatid mites were more abundant on S. scrofa dung. Low similarity was observed when comparing dung of invasive mammals from different sites revealing spatial variability regarding species composition. Based on its more diverse diet, we conclude that S. scrofa dung exerts a strong influence on microarthropod communities by recruiting a greater number of individuals and species than the dung of the remaining invasive mammals.

The spotted wing drosophila, Drosophila suzukii Matsumura, is native to Southeast Asia and has become a serious pest of soft-skinned fruits worldwide. Several control methods are being tested worldwide as part of an integrated pest management approach. Biological control is a promising alternative tactic that can be used to manage D. suzukii populations, especially in unmanaged areas. This study aimed at exploring the diversity of resident hymenopteran parasitoids of drosophilids in northwestern Patagonia, where D. suzukii is considered an important pest. The survey also aimed to investigate possible associations between parasitoids and D. suzukii in several crops and non-crop fruits, and to determine D. suzukii fruits infestation levels. Fourteen sites with mainly berry crops were sampled biweekly using cider vinegar traps and collecting fresh fruits from a variety of crop and non-crop fruit plants. We identified five species of hymenopteran parasitoids, obtained from the baited traps, that have the potential to associate with D. suzukii : Leptopilina heterotoma Thomson, Ganaspis brasiliensis Ihering, Hexacola hexatoma Hartig (Figitidae), Pachycrepoideus vindemmiae Rondani (Pteromalidae), and Spalangia endius Walker (Spalangiidae). Leptopilina heterotoma is reported for the first time in Argentina. High numbers of D. suzukii adults were recovered from baited traps and field-collected fruits. However, no parasitoid emerged from D. suzukii pupae recovered from fruits, nor were any dead parasitoids recorded inside D. suzukii pupae. Overall infestation levels of D. suzukii on field-collected fruits did not differ significantly between species/varieties. The results are discussed with emphasis on the possible functionality and perspectives of using these species as biological control agents.

Phidon abismus sp. nov. is described from north-western Patagonian forests in Argentina. The specimens were collected under dead tree bark of Austrocedrus chilensis, Nothofagus dombeyi and Nothofagus pumilio. A detailed description of the male including abdominal apex, genitalia, tegmen and wing venation and front femur armament type B2 is provided as well as a description of the A type oviparity. The genus Phidon is recorded from Argentina for the first time. The key of Rehn (1933) for the known males of the genus is updated.

Belowground biodiversity loss from anthropogenic causes is far less addressed and quantified than aboveground biodiversity loss. Soil fauna supports soil productivity and biogeochemical cycles, and their decline needs further research. We tested the effects of a woodland harvest gradient (0, 30, 50, and 70% biomass removal) on litterfall, mesofauna density, and Oribatida diversity in three sites of northwestern Patagonia (Argentina). Sites contrasted in plant community structure and productivity. Acari from litter and soil were compared. Annual litter production showed a 58% decline at the highest harvest intensity level, which was constant across sites. Litter structural α- diversity decreased with the highest intensity harvest only at the high productivity site. The density of soil-inhabiting Acari did not change with increasing harvest intensity, while the density of Acari inhabiting the litter decreased by 65% at the highest harvest intensity. Within Acari, Oribatida inhabiting the litter had the most significant density decline with increasing harvest intensity. Oribatida richness and α- diversity only differed among sites, suggesting resistance to increasing biomass removal despite shifts in litter production and litter structural diversity. Prostigmata did not respond to increasing biomass removal either in soil or litter. Our study is the first to assess Acari response to an aboveground biomass removal gradient in southern woodlands. Applying high biomass removal to low productivity sites can compromise micro detritivore density and thus, impair its functional role. Site productivity should be considered in management plans entailing conservation of soil fauna in southern woodlands.

All active stages of Tanytydeus nothofagi n. sp. are described from northwestern Patagonian forests in Argentina where it was collected on bare tree bark of Nothofagus dombeyi. The genus Tanytydeus is recorded from South America for the first time.

The weevil Mythapion adesmiae, previously known from Chilean Patagonia (Aysén and Magallanes regions) and the province of Santa Cruz in Argentina, is recorded for the first time for the province of Río Negro, above the treeline, between 1744-1850 m a.s.l. on Cerro Challhuaco associated with Adesmia corymbosa, which is a new plant association. The known records suggest an extensive distribution along the Patagonian Andes of Chile and Argentina.

The information about the diversity of the Phylum Tardigrada in Argentina and particularly in the Patagonian region is fragmented and dispersed. In this contribution, keys for the identification of the 23 genera and 49 species of limnoterrestrial tardigrades registered up to now in the area of the Nahuel Huapi National Park and surroundings are presented

Leptoglossus occidentalis Heidemann is a conifer seed bug, native to North America. This species is considered invasive and has reached several countries in the Northern Hemisphere and most recently Chile in South America. This work reports the first detection of this species in Argentina, with specimens from the Rio Negro province, in 2017. Ecological traits and its potential rapid spread were also discussed.

During an examination of the parasite fauna of the Red-gartered Coot Fulica armillata from the Mari Menuco lake in the Northwestern Argentinean Patagonia, nasal mite specimens belonging to Rallinyssus caudistigmus were found. This is the southernmost record of R. caudistigmus in F. armillata as a new host.

During an examination of the parasite fauna of the Red-gartered Coot Fulica armillata from the Mari Menuco lake in the Northwestern Argentinean Patago- nia, nasal mite specimens belonging to Rallinyssus caudistigmus were found. This is the southernmost record of R. caudistigmus in F. armillata as a new host.

The relation of particular species of Acari with soil functions regarding organic matter decomposition and nutrient recycling is not clear. Furthermore it is not known if distinguishable Acari species are more efficient to lead to an increase in the rate of mass loss of leaf litter or to favour the development of the microflora on leaf litter. We tackled this dilemma by growing selected mites on defaunated leaf litter of Austrocedrus chilensis. We tested for changes in the biomass of leaf litter in the presence or the absence of the mites. We used four species of oribatid mites which are usual inhabitants of the leaf litter of Austrocedrus chilensis in forests of Argentina's Northwestern Patagonia: Anderemaeus magellanis, Cosmochthonius semifoveolatus, Lanceoppia kovacsi and Nothrus peruensis. After 3 months, the development of fungal growth in the presence of mites was evident. Containers with only C. semifoveolatus and L. kovacsi showed greater development of fungal biomass than those with A. magellanis or N. peruensis, evidencing specific differences in the enhancement effect. In the presence of C. semifoveolatus, mycelial diversity diminished with respect to the blank favoring only the development of septate brown hyphae of Ascomycota. We found no significant differences between the fungal growth enhancement provoked by L. kovacsi and C. semifoveolatus. Entanglement of fragments and propagules of fungi among the branched setae of C. semifoveolatus could account for the enhancement of fungal growth. Repeated contact of faster L. kovacsi specimens with mycelia and adherence of mycelial fragments and fungi propagules on mite bodies could account for the effect. Mite size was also related to the fungal growth enhancement as smaller mites were more efficient in fungal growth enhancement. Our results showed that fungal growth is more intensive in the presence of mites than in their absence and that oribatid mites have a role in shaping the communities of fungi in soil.

During a three-year survey of oribatid mites in soil and leaf litter of Andean North patagonian forests, specimens belonging to the genus Oxyoppia were collected. Even though the specimens could be recognized by the use of previous descriptions and existing keys as being close to Oxyoppia (Oxyoppiella) suramericana, morphological analyses suggest enough differences to propose a new species Oxyoppia mustaciata n. sp. A new identification key to species of Oxyoppiinae from Argentina is provided.

Megastigmus aculeatus Sweden's (Hymenoptera: Chalcidoidea) infest Rosa species seeds both at the origin and invasion areas. The wasp larvae develop by consuming the entire seed. The M. aculeatus infestation was analyzed at different Rosa canina L. and Rosa rubiginosa L. populations and at isolated plants of Rosa multiflora Thunb. at Norwestern Patagonian natural areas of Argentina. In R. rubiginosa, the most abundant species, we studied the wasp infestation prevalence and success and the possible infestation effect on fruit size. In this paper we registered the first records of R. canina and R. rubiginosa as host plants for M. aculeatus in wild areas of Argentina and we verified the absence of the wasp in R. multiflora fruits. In R. canina the percentage of infected fruits by M. aculeatus was low (0-1 % per site) not being probably a conditioning factor of its actual reduced spread. In R. rubiginosa, the percentage was high (31-75 % of infested fruits per sites), but only the 2-8 % of achenes were infected. Considering the analyzed sites, the distribution of M. aculeatus infestation at regional level in rose studied species was reduced. The fruit size was not affected by the insect infestation. The results of this work show a low actual impact of M. aculeatus in the control of rose invasion at Andean region of Argentina. However, since M. aculeatus populations could be affect by the temperature, a change of this variable could increase the seeds infestation prevalence in the medium and long term.

The genus Paroppia comprises four species, none of which occur in South America. Here a new species, P. patagonica, is described from adult specimens collected in Nothofagus forests of Northwestern Patagonia. Paroppia patagonica differs from other species in this genus by the shape of the aciculated fusiform sensillus, the size and position of inter-lamellar sigillae, the position of notogastral and genital setae, and the small thick notogastral c2 and exobothridial setae. Classification and description of leg setae and solenidia according to Grandjean is given. An identification key to known species of Paroppia is proposed. Morphological characters shared between Paroppia and Taiwanoppia senegalensis are briefly discussed.

Our study investigated the diet of the southernmost gecko in the world, Homonota darwini. Fifty-three specimenswere captured during spring and summer in four locations in Patagonia, Argentina. The stomach contents of the specimens wereidentified, and we found that prey consisted of six main groups: Coleoptera, Hymenoptera, Homoptera and Araneae, and theadults and larvae of moth Lepidoptera. Lepidoptera was the major dietary component. The presence of ants and moths as commonprey suggests an ambush feeding strategy. In spring, females consumed more ants than males although no other dietary differencesbetween males and females were evident. We found nine geckos with empty stomachs and six parasitized by nematodes.Presence of empty stomachs corroborates previous observations of other nocturnal geckos and non-gecko lizards. Reduced foragingsuccess of nocturnal lizards could be due to difficulty in prey detection due to dim light, reduced or erratic activity of insectprey at night, or shorter activity times of geckos relative to diurnal success. Sex and season were not associated with the incidenceof empty stomachs. Principal component analysis showed that four food alternatives correlated with season. The constraint ofnocturnality, coupled with low night-time temperatures restricting feeding to only a few hours after sunset, appear to have causeda generality of diet which may limit energy acquisition. We conclude that H. darwini is an arthropod generalist and likely an ambushforager, as are many other nocturnal gekkonids

Forest sites in Northwestern Argentinean Patagonia were surveyed to determine the oribatid mite fauna. A taxonomic inventory of oribatid mites was carried out in Northwestern Argentinean Patagonia to establish the taxonomic diversity, for increasing the knowledge of their distribution, detecting new species and assessing environmental effects on the oribatid mite community. Eleven sampling sites in nearly pure forests of Austrocedrus chilensis, Nothofagus dombeyi, Nothofagus antarctica were selected as these are among the most recurrent arboreal species found in this region. Samples of leaf litter, soil and pitfall traps contents were taken from each forest. Fifty-five oribatid species, belonging to 46 genera in 28 families, were found. Nine species are new records for Argentina and one for continental Argentina. Thirty-two species were recorded in A. chilensis forests, 35 in N. dombeyi forests and 20 in N. antarctica forests. Fifty species were found in leaf litter, 35 in soil and eight in pitfall traps. Fourteen species were recorded exclusively in leaf litter, one in soil and four in pitfall traps. A high level of endemism is confirmed as nearly 62 % of collected species have previously been found only in Southern Andes supporting the existence of an associated autochthonous oribatid fauna.