Experimental and molecular approximation to microbial niche: trophic interactions between oribatid mites and microfungi in an oligotrophic freshwater system.

Mite-fungal interactions play a key role in structuring core ecosystem processes such as nutrient dynamics. Despite their ecological relevance, these cross-kingdom interactions remain poorly understood particularly in extreme environments. Herein, we investigated feeding preferences of a novel genetic lineage of aquatic oribatids obtained from an oligotrophic freshwater system in the Cuatro Ciénegas Basin (CCB) within the Chihuahuan Desert, Mexico. During in vitro diet preference bioassays, transient aquatic microfungi (Aspergillus niger, Talaromyces sp., and Pleosporales sp.) recovered from the same mesocosm samples were offered individually and simultaneously to mites. Gut content was analyzed using classic plating and culture-independent direct PCR (focusing on the fungal barcoding region) methods. Our results indicated that oribatids fed on all tested fungal isolates, yet the profusely developing A. niger was preferentially consumed with all fungal components being digested. This feeding habit is particularly interesting since A. niger has been reported as an unsuitable dietary element for population growth, being consistently avoided by mites in previous laboratory experiments. It is possible that our mites from the CCB have adapted to exploit available resources within this oligotrophic site. This work confirms the trophic relationship between microfungi and mites, two rarely investigated major components of the microbial community, shedding light on the niche dynamics under low-nutrient conditions.

Two new synanthropic species of Anyphaena Sundevall (Araneae: Anyphaenidae) associated to houses in Mexico City.

The family Anyphaenidae is composed by 56 genera and 542 species worldwide (World Spider Catalog 2015). These spiders, known as "ghost spiders", are wandering hunters living in a variety of environments, from forests to deserts, and can be quite abundant in different crops such as cotton, sorghum and rice (Brescovit 1996; Young & Edwards 1990; Taylor & Pfannenstiel 2008). They typically live on vegetation, among dead leaves or under loose bark and rocks (Richman & Ubick 2005) but synanthropic associations have been reported for a few species (Jiménez 1998; Guarisco 1999; Durán-Barrón et al. 2009). The genus Anyphaena has 81 species widely distributed in Asia, Central Europe, North America and Mexico (Brescovit 1996; Richman & Ubick 2005; World Spider Catalog 2015). The species from Noth America and Mexico were revised by Platnick (1974) who recognized four species groups (accentuata, celer, pectorosa and pacifica). Platnick (1977), Platnick & Lau (1975) and Brescovit & Lise (1989) complemented the revision of the genus in Central America. Presently, there are 27 species of Anyphaena recorded in Mexico (World Spider Catalog 2015), 24 of them from the celer group. Here, two new species of Anyphaena are described based in material collected during an inventory of spiders associated to houses in Mexico City, carried out by Durán-Barrón et al. (2009). Both species have the diagnostic characters of the members of the pacifica group as defined by Platnick (1974), such as the lack of leg coxal spurs and the presence of a lightly sclerotized atrium in the female epigynum. These species represent the first record of the pacifica group in Mexico. The occurrence of Anyphaenidae associated to houses was reported in Mexico by Durán-Barrón et al. (2009), who recorded Anyphaena obregon Platnick & Lau, 1975 and Hibana futilis (Banks, 1898) as frequent inhabitants inside houses. The species herein described are reported solely from urban areas and can be also characterized as frequent in these anthropic environments.

Coadaptación entre los ácaros (Arachnida: Klinckowstroemiidae) y coleópteros Passalidae (Insecta: Coleoptera) / Co-adaptation between mites (Arachnida: Klinckowstroemiidae) and Passalidae beteles (Insecta: Coleoptera)

Co-adaptation between mites (Arachnida: Klinckowstroemiidae) and Passalidae beteles (Insecta: Coleoptera). Mites of the family Klinckowstroemiidae establish an association with beetles of the family Passalidae known as phoresy. In order to obtain information about this association, we analyzed the relationship between mites of the family Klinckowstroemiidae and beetles of the family Passalidae, as adult mites have been exclusively collected from host beetles. We examined 1 150 beetles collected in seven states of the Mexican Republic, and found 19 species of klinckowstroemiid mites associated with 168 passalids, that belong to 28 different species in 15 genera. Host specificity between species of both groups does not exist, as one species of passalid beetle can have several different symbionts; conversely, a given mite species can associate with passalid beetles of different species and even of different genera. This way, Odontotaenius zodiacus has been found associated with mites of seven species of the genus Klinckowstroemia. Besides, Klinckowstroemia valdezi is associated with five species of passalids. Furthermore, two and even three different species of mites have been found on one host beetle (synhospitality). The lack of congruence between the phylogenies of the mites and that of the beetles indicates that a process of co-adaptation by colonization is going on, because the association is due to the resources that passalid beetles can offer to the mites, like transportation, food and refuge. Since these resources are not host-specific, the klinckowstroemiid mites can climb onto virtually any species of passalid beetles occurring on the same habitat. Rev. Biol. Trop. 60 (2): 599-609. Epub 2012 June 01.

Realizamos un análisis de la relación que existe entre los ácaros Klinckowstroemiidae y los coleópteros Passalidae, puesto que los ácaros adultos se recolectaron exclusivamente sobre pasálidos (huéspedes). Asimismo, examinamos 1 150 coleópteros recolectados en siete estados de la República Mexicana, y encontramos 19 especies de ácaros klinckowstroémidos asociados con 168 de ellos, pertenecientes a 28 diferentes especies de 15 géneros distintos. Estos táxones establecen una relación simbiótica llamada foresia. No existe una especificidad entre las especies de ambos grupos, debido a que una especie de pasálido puede tener varios forontes, y una especie de ácaro puede asociarse a pasálidos de diferentes géneros y especies. Un ejemplo es Odontotaenius zodiacus que presentó a siete especies de Klinckowstroemia asociadas, y por otro lado, Klinckowstroemia valdezi se encuentra asociada a cinco especies de pasálidos. Además, dos o hasta tres especies de ácaros se encontraron sobre un coleóptero huésped (synhospitality). La falta de congruencias entre la filogenia de los ácaros con la de los pasálidos nos indica que se está produciendo un proceso de coadaptación por colonización, y que ésta asociación se debe a los recursos que le brindan los pasálidos a los ácaros: transporte, refugio y alimento. Como estos recursos no son específicos para algún huésped los klinckowstroémidos se suben a cualquier especie de pasálido.

[Co-adaptation between mites (Arachnida: Klinckowstroemiidae) and Passalidae beetles (Insecta: Coleoptera)]. / Coadaptación entre los ácaros (Arachnida: Klinckowstroemiidae) y coleópteros Passalidae (insecta: Coleoptera).

Mites of the family Klinckowstroemiidae establish an association with beetles of the family Passalidae known as phoresy. In order to obtain information about this association, we analyzed the relationship between mites of the family Klinckowstroemiidae and beetles of the family Passalidae, as adult mites have been exclusively collected from host beetles. We examined 1 150 beetles collected in seven states of the Mexican Republic, and found 19 species of klinckowstroemiid mites associated with 168 passalids, that belong to 28 different species in 15 genera. Host specificity between species of both groups does not exist, as one species of passalid beetle can have several different symbionts; conversely, a given mite species can associate with passalid beetles of different species and even of different genera. This way, Odontotaenius zodiacus has been found associated with mites of seven species of the genus Klinckowstroemia. Besides, Klinckowstroemia valdezi is associated with five species of passalids. Furthermore, two and even three different species of mites have been found on one host beetle (synhospitality). The lack of congruence between the phylogenies of the mites and that of the beetles indicates that a process of co-adaptation by colonization is going on, because the association is due to the resources that passalid beetles can offer to the mites, like transportation, food and refuge. Since these resources are not host-specific, the klinckowstroemiid mites can climb onto virtually any species of passalid beetles occurring on the same habitat.

Ácaros asociados al coleóptero Passalus cognatus (Coleoptera: Passalidae) de Los Tuxtlas, Veracruz, México

Mites associated to the Coleopteran Passalus cognatus (Coleoptera:Passalidae) from Los Tuxtlas, Veracruz, Mexico. There are few records of mites associated with the tropical coleopterans of Mexico. We examined 35 passalid beetles (bessbugs) Passalus cognatus from Los Tuxtlas region in Veracruz State, Mexico. Twenty of them had a total of 245 mites (representing eight species, eight genera, eight families and three suborders). The most abundant species were Uroobovella californiana Wisniewski & Hirschmann (35%), Euzercon hyatti Hunter & Rosario (20%), and Uropoda sp. (17.5%). The preferred attachment areas were the coxae; followed by the mesosternum and the humeri. Each beetle had 1 to 40 mites (average: 12); and we found 1-4 mite species per beetle. Rev. Biol. Trop. 56 (3): 1261-1268. Epub 2008 September 30.

Se revisaron 35 ejemplares de Passalus cognatus Truqui recolectados en Los Tuxtlas, Veracruz, México. En 20 de ellos se encontraron 245 ácaros pertenecientes a ocho especies, ocho géneros, ocho familias y tres subórdenes. Las especies de acáros más abundantes fueron Uroobovella californiana Wisniewski y Hirschmann (35%), Euzercon hyatti Hunter y Rosario (20%) y Uropoda sp. (17.5%). Las zonas de fijación preferidas por los ácaros fueron las coxas; en menor proporción el mesoesternón y los húmeros. Los pasálidos infestados presentaron de 1 a 40 ácaros, con un promedio de 12. El número de especies de ácaros por pasálido infestado fue de 1 a 4.

[Mites associated to the Coleopteran Passalus cognatus (Coleoptera:Passalidae) from Los Tuxtlas, Veracruz, Mexico]. / Acaros asociados al coleóptero Passalus cognatus (Coleoptera: Passalidae) de Los Tuxtlas, Veracruz, México.

There are few records of mites associated with the tropical coleopterans of Mexico. We examined 35 passalid beetles (bessbugs) Passalus cognatus from Los Tuxtlas region in Veracruz State, Mexico. Twenty of them had a total of 245 mites (representing eight species, eight genera, eight families and three suborders). The most abundant species were Uroobovella californiana Wisniewski & Hirschmann (35%), Euzercon hyatti Hunter & Rosario (20%), and Uropoda sp. (17.5%). The preferred attachment areas were the coxae; followed by the mesosternum and the humeri. Each beetle had 1 to 40 mites (average: 12); and we found 1-4 mite species per beetle.

Application of ITS-2 sequences as markers for identification and phylogenetic inference within the genus Geomylichus (Acari: Listrophoridae).

Phylogenetic relationships among 18 samples from nine nominal species of Geomylichus (Acari: Listrophoridae), were analyzed based on internal transcribed spacer 2 (ITS 2) sequences, Prolistrophorus sp. was used as an outgroup. Maximum likelihood and neighbor-joining analyses indicated that Geomylichus is formed by at least three internal clades. Genetic distance among Prolistrophorus and Geomylichus was 27.8-35.5%, and among species, populations, and infrapopulations of Geomylichus it was 0.4-21.8%, 0.8-2.4%, and 0.8-1.2%, respectively. Differences between the results of this analysis with conventional taxonomy of the group, as well as the overlapping of genetic distances among species, populations, and infrapopulations, suggest that the definition of species within Geomylichus deserves reconsideration. For example, the recognition of inconsistencies among G. texanus populations associated to different host species, resulting from the molecular analysis, led us to collect new morphological evidence now suggesting that this taxon represents more than one species.