Biology and predation capacity of Parasitus bituberosus (Acari: Mesostigmata: Parasitidae) on Frankliniella occidentalis (Thysanoptera: Thripidae), and free-living nematodes as its complementary prey.

BACKGROUND: Parasitus bituberosus is common in rose fields and nearby vegetation around Bogotá. In rearing units, it is often aggregated, feeding on Frankliniella occidentalis edaphic phases. Preliminary observations suggested predator immatures can not reach adulthood if isolated. The objectives were to evaluate the suitability of F. occidentalis as prey for P. bituberosus, to evaluate free-living nematodes as complementary food, and to confirm the aggregation effect on predator biology. Aggregation types: (1) isolated mites, (2) mites paired only as deutonymphs and early adulthood, and (3) mites always paired. Diets: thrips (T), nematodes (N) and thrips + nematodes (NT). RESULTS: Parasitus bituberosus juveniles did not feed on live F. occidentalis, but developed and oviposited on nematodes. Approximately 77% of the isolated mites died as immatures. Mortality was low (21-23%) when predators were paired at least in the deutonymph and the early adult phase. Female daily predation rates were comparable to other predators on F. occidentalis (≥2.5). Continuously paired mites had high biotic potential, especially when the diet included nematodes (rm  ≥ 0.33; Ro  ≥ 33.90; daily oviposition rate ≥ 10.9). CONCLUSION: The results of this study warrant further investigation of this predator, to evaluate methods for its mass production, inclusion in conservation biocontrol programs and performance against the pest at a larger scale. © 2019 Society of Chemical Industry.

Ascidae, Blattisociidae and Melicharidae (Acari: Mesostigmata): zoogeographic analyses based on newly available databases.

Until recently, species of the families Ascidae Voigts Oudemans, Blattisociidae Garman and Melicharidae Hirschmann were considered to belong to a single family, Ascidae, based on their similarity in external morphology. Databases on the distribution and biology of species in those families have been collected are now freely available. This information allows the first zoogeographic analysis of these groups. Almost 2200 records obtained from about 820 publications were entered into the databases, which are periodically updated. The countries with the highest known diversity of mites of these groups are: Ascidae-Russia (56), United States of America (42), China (37) and Poland (36); Blattisociidae-China (47), United States of America (41), Ecuador (38), India (33) and Poland (32); Melicharidae-United States of America (46), Brazil (23), Ecuador (20) and Poland and Germany (15). No species of these families have been reported from about 44% of the countries, most probably because of inadequate sampling effort. Comparing the species composition of the different regions, Jaccard similarity indexes were low, being higher between the Palaearctic and Saharo-Arabian regions for the ascids (0.15), between the same regions for the blattisociids (0.19) and between the Neotropical and Panamanian regions for the melicharids (0.18). These data are compatible with the results of parsimony analyses of endemicity (PAE), in which those pairs of regions constituted distinct clades. The analyses suggest that Ascidae probably originated in the Palaearctic region, whereas Blattisociidae and Melicharidae probably originated somewhere in the Neotropical or Panamanian regions.

Soil mites of the families Ascidae, Blattisociidae and Melicharidae (Acari: Mesostigmata) from mountainous areas of Colombia.

Soil mites of the Ascidae sensu Lindquist & Evans (1965) are poorly known in Colombia. This group, presently represented by the families Ascidae sensu stricto, Blattisociidae and Melicharidae, contains species known to prey on small arthropods and nematodes, thus having the potential to be used for the control of soil pests. The aim of this study was to identify species of this group from a fragment of Andean forest and a nearby grassland at the municipality of La Calera, Cundinamarca Department, Colombia, at about 2800 m of elevation. Nine species were found, including five new species, namely Gamasellodes andinus sp. nov., Gamasellodes intermedius sp. nov., Protogamasellus caleraensis sp. nov., Cheiroseius mesae sp. nov. and Proctolaelaps colombianus sp. nov. Morphological characterisation of all the species and relevant soil characteristics of the sites where the mites were collected are presented.

DISTRIBUCIÓN ESPACIAL, COMPOSICIÓN Y DENSIDAD DE EDAFOFAUNA EN HOJARASCA DE BOSQUE Y CAFETAL (MONTENEGRO, COLOMBIA) / Spatial Distribution, Composition and Density of the Leaflitter Edaphofauna in Forest and Coffee Plantation (Montenegro, Colombia)

Se determinaron los cambios en composición, densidad y distribución espacial de la edafofauna de hojarasca entre dos usos de suelo (cafetal y bosque subandino) para entender el efecto del uso de suelo. Asimismo, se establecieron las relaciones entre las variables de la edafofauna y atributos de la hojarasca. Se colectaron muestras de hojarasca superficial durante la época seca y se extrajo la edafofauna, manualmente y mediante embudos Berlese modificados. Esta se identificó hasta el menor nivel taxonómico posible y se clasificó en grupos funcionales. La composición faunística fue diferente entre los usos de suelo. La similitud en la composición fue menor al 50 % en dos de los tres grupos funcionales encontrados, pero la densidad total no presentó diferencias. En general hubo coeficientes de variación altos en la densidad faunística intermuestral para los diferentes grupos taxonómicos y, en consecuencia, una baja detectabilidad del patrón espacial. Sin embargo, se detectó un patrón espacial en la abundancia para Coleoptera, larvas de Diptera y biomasa de hojarasca, en el cafetal. La estructura fue más difícil de detectar en bosque, por los pequeños parches en este. La varianza de la abundancia fue mayor en el cafetal, para todos los grupos, excepto Acaridida y Formicidae. La densidad de Formicidae aumentó al hacerlo la humedad de la hojarasca, pero solo en cafetal. Se concluye que el establecimiento del cafetal afecta de manera diferencial a taxones y grupos funcionales de la edafofauna. Esto sienta las bases para definir los efectos del cambio de uso de suelo y los factores ambientales asociados con la distribución espacial de la edafofauna.

Changes in composition, density and spatial distribution on the litter edaphic fauna between two land uses (a coffee plantation and a tropical Andean forest) were established, in order to understand the soil use effects. Also, the relationships between the biotic variables and some litter features were evaluated. Superficial litter samples were collected during dry season. The edaphic fauna was extracted manually and with modified Berlese funnels; it was identified up to the lower taxonomic level and classified in functional groups. Differences in fauna composition were observed between the two land uses. Composition similarity was lower than 50 % for almost all functional groups found, but total density did not differ between the land uses. In general, there was a high variation in density among samples resulting in higher coefficients of variation for different taxonomic groups and consequently low detectability of spatial pattern. However a spatial pattern was detected only for Coleoptera, Diptera larvae and litter biomass in the coffee plantation. The structure in forest was more difficult to detect, due to the smaller patches on it. The variance of abundance was significantly higher in the coffee plantation for all groups, except Acaridida and Formicidae. Density of Formicidae increased with the enhancement of litter moisture, but only in the coffee plantation. In conclusion, the establishment of coffee plantation differentially affects taxa and functional groups of soil fauna. This is the basis for establishing the effects of soil change use, and the environmental factors associated with spatial distribution of edaphic fauna.

Mites of the superfamily Rhodacaroidea (Acari: Mesostigmata) from Colombia, with a key for the world species of Desectophis Karg (Ologamasidae).

Three species of Rhodacaroidea are reported from soil in Colombia. Desectophis anthuriumsetis n. sp. (Ologamasidae) and Multidentorhodacarus colombianus n. sp. (Rhodacaridae) are described from newly-collected material. Multidentorhodacarus triramulus (Karg, 1998) is redescribed from the holotype and adult females collected in this study. A key for the separation of females of the five recognisable world species of Desectophis Karg is provided.