Definition of the concordis species group of the genus Euseius (Acari: Phytoseiidae), with a morphological reassessment of the species included.

Phytoseiidae (Acari) is the best known family of predatory mites. Within this family, Euseius Wainstein is one of the largest genera. The species of this genus have generalist feeding behavior, including in their diet mites and pollen. Some studies have demonstrated the potential of certain Euseius species to control pest mites. Euseius concordis (Chant) has been mentioned in the literature as potentially useful for the control of the tomato russet mite, Aculops lycopersici (Tryon) (Eriophyidae). Several other American species are morphologically similar to E. concordis; the morphological variation of these species is poorly understood. The objective of this study was a taxonomic re-evaluation of E. concordis and of the world species most similar to it. Measurements of species collected in this study and a taxonomic key to separate the species of this group are provided. Morphological evaluations confirmed that Euseius flechtmanni Denmark & Muma is a junior synonym of E. concordis, and determined that Euseius caseariae De Leon is also a junior synonym of E. concordis, that Euseius ho (De Leon) and Euseius brazilli (El-Banhawy) are junior synonyms of Euseius mesembrinus (Dean) and that Euseius vivax (Chant & Baker) is not a junior synonym of Euseius fructicolus (Gonzalez & Schuster), as previously thought.

Allometric relations of neotropical small rodents (Sigmodontinae) in anthropogenic environments.

The present study aims at assessing allometric relationships in the Sigmodontinae rodents (Calomys tener, Akodon cf. montensis, Necromys lasiurus, Oligoryzomys flavescens, and Oligoryzomys nigripes), and morphological variation among different habitats in human-dominated environments in Southeastern Brazil. We captured rodents using pitfall traps placed in Eucalyptus plantations, abandoned pastures, and remnants of secondary native vegetation, and took the following measurements: body mass, total length, body length, left hind foot length, and left ear length. Males were usually larger than females, except in N. lasiurus. There was no intraspecific difference in body condition among habitats, suggesting that Eucalyptus may not have a deleterious effect upon its residents. However, A. cf montensis from Eucalyptus plantations had longer feet than those from other vegetation associations, suggesting a possible adaptive response to the lower cover in the plantation environment, and its consequent higher predation risk, or alternatively that only individuals with greater dispersal ability are found in Eucalyptus plantations. Future studies should investigate a possible co-evolutionary predator-prey relationship, including rapid evolution by Sigmodontinae rodents in anthropogenic landscapes.