Ground-dwelling Spider Communities Respond to Changes in Riparian Vegetation Widths.

Spiders play a key role in the ecological dynamics in riparian habitats. However, most studies on the effects of changes in riparian habitats on spider communities have focused on the conversion of riparian forest to other land uses rather than on a gradient of forest widths. We assessed the community structure of ground-dwelling spiders in riparian vegetation fragments with varying widths in Southern Brazil. We selected four fragments with different riparian vegetation widths (> 40 m; < 30 m; < 15 m; < 5 m). In each fragment, spiders were seasonally collected using pitfall traps. We tested the effects of riparian vegetation widths and environmental variables (litter height, litter cover and canopy openness) on the taxonomic and guild composition of spider communities. The taxonomic and guild composition of ground-dwelling spiders varied among the widest (> 40 and < 30 m) and narrower riparian widths (< 15 m and < 5 m). While hunting spiders were associated with the narrower widths, web-building spiders were associated with the wider widths. Spider composition was influenced by the leaf litter height in the widest widths (> 40 and < 30 m) and by canopy openness in the narrowest width (< 15 m). Reductions in riparian vegetation were associated with significant changes in the community structure of ground-dwelling spiders, likely through top-down mechanisms associated with the higher litter input in wider fragments. In summary, the fragmentation of the riparian forests of Sothern Brazil are negatively associated with web-building spiders.

New species and records of cunaxid mites (Acari: Cunaxidae) from soil in Southern Brazil.

Neocunaxoides promatae sp. nov., Bonzia flechtmanni sp. nov. and Dactyloscirus multiscutus sp. nov. are described from soil and leaf litter in Atlantic rainforest and Atlantic Araucaria forest in natural environments in São Francisco de Paula municipality, Rio Grande do Sul State, Brazil. In addition, the species Pulaeus quadrisolenidius Castro & Den Heyer 2009 and Lupaeus lectus Castro & Den Heyer (2009) are registered for the first time in this State.

Tydeid and triophtydeid mites (Acari: Tydeoidea) associated with grapevine (Vitaceae: Vitis spp.) in Brazil, with the descriptions of species of Prelorryia (André, 1980) and Tydeus Koch, 1835.

We report on the Tydeidae and Triophtydeidae associated with grapevine (Vitis labrusca L. and Vitis vinifera L.) in Rio Grande do Sul State, Brazil, and describe a new species of Prelorryia, Prelorryia labrusca sp. nov., and two new species of Tydeus, Tydeus manoi sp. nov. and Tydeus riopardensis sp. nov. Brachytydeus formosa (Cooreman), B. podocarpa (Baker), Neolorryia pandana (Baker), Tydeus californicus (Banks), Pretydeus henriandrei Kazmierski and Triophtydeus lebruni (André) are recorded and illustrated. A key to species of Tydeidae and Triophtydeidae from Brazil is provided. 

A new genus and species of phytoseiid mite (Acari: phytoseiidae) from the Brazilian Atlantic Forest.

A new genus, Ingaseius nov. gen., and a new species, Ingaseius silvaticus nov. sp., Phytoseiidae, collected from Inga edulis Martius and Inga marginata Wild. (Fabaceae) are described from the Brazilian Atlantic Forest. This species is unique in the following characteristics: females and males with few teeth on fixed cheliceral digit and short Jv5, without J2, Z1 and leg macrosetae. In addition, females lack Jv3 and Zv3, and have a reduced ventrianal shield. 

First new species of the Phytoseius horridus group (Acari: Phytoseiidae) described from Brazil, with a key to the Brazilian species of Phytoseius.

Phytoseius litoralis n. sp., a member of the horridus species group, is described from the State of Rio Grande do Sul, in southern Brazil, based on specimens collected on Psidium guajava, Solanum concinnum and Cecropia pachystachya. This is the first species of the horridus group described from Brazil. A key to species of Phytoseius reported from Brazil is provided.

A new species of Scutopalus (Acari: Cunaxidae: Cunaxoidinae) from Rio Grande do Sul State, Brazil with a key to world species.

Scutopalus tomentosus sp. nov. is described and illustrated from Plantago tomentosa Lam. (Plantaginaceae) in a vineyard agroecosystem at Dois Lajeados county, State of Rio Grande do Sul, Brazil. This is the first species of this genus described from the Americas. A key to world species is included.