Horizontal transmission maintains host specificity and codiversification of symbionts in a brood parasitic host.

In host-symbiont systems, interspecific transmissions create opportunities for host switches, potentially leading to cophylogenetic incongruence. In contrast, conspecific transmissions often result in high host specificity and congruent cophylogenies. In most bird-feather mite systems, conspecific transmission is considered dominant, while interspecific transmission is supposedly rare. However, while mites typically maintain high host specificity, incongruent cophylogenies are common. To explain this conundrum, we quantify the magnitude of conspecific vs. interspecific transmission in the brood parasitic shiny cowbird (Molothrus bonariensis). M. bonariensis lacks parental care, allowing the assessment of the role of horizontal transmission alone in maintaining host specificity. We found that despite frequent interspecific interactions via foster parental care, mite species dispersing via conspecific horizontal contacts are three times more likely to colonize M. bonariensis than mites transmitted vertically via foster parents. The results highlight the previously underappreciated rate of transmission via horizontal contacts in maintaining host specificity on a microevolutionary scale. On a macroevolutionary scale, however, host switches were estimated to have occurred as frequently as codivergences. This suggests that macroevolutionary patterns resulting from rare events cannot be easily generalized from short-term evolutionary trends.

Taxonomic contribution to the knowledge of Galumnidae (Acari, Oribatida, Galumnidae) from Cuba.

The present study is based on galumnid mites (Oribatida, Galumnidae) collected from leaf litter of two mixed forests in Cuba; six species from three genera are identified. Three new species-Pergalumna (Pergalumna) cienfuegosensis sp. nov., P. (P.) foveolatostriata sp. nov. and Galumna (G.) gigantea sp. nov.-are described. Allogalumna brevisetosa (Bayartogtokh & Weigmann, 2005) is recorded in the Neotropical region for the first time; P. (P.) obvia (Berlese, 1914) is recorded in Cuba for the first time.

Phylogenetic position of the house dust mite subfamily Guatemalichinae (Acariformes: Pyroglyphidae) based on integrated molecular and morphological analyses and different measures of support.

Based on multilocus phylogenetic analyses (18S, 28S, EF1-α, SRP54, HSP70, CO1, 10 860 nt aligned), we show that the house dust mite subfamily Guatemalichinae is nested within non-onychalgine pyroglyphid mites and forms the sister group to the genus Sturnophagoides (bootstrap support 100, posterior probability 1.0). Because high bootstrap support values may be misleading in the presence of incongruence, we evaluate robustness of the Guatemalichinae+Sturnophagoides clade using: (1) internode certainty indices to estimate the frequency of conflicting bipartitions in maximum-likelihood bootstrap trees, (ii) consensus networks to investigate conflict among different loci; and (iii) statistical hypothesis testing based on information theory, both multi-scale and regular bootstrap. Results suggest that this grouping is very well supported given the data. The molecular analyses were integrated with detailed morphological study using scanning electron and light microscopy. We suggest that the subfamilial status of Guatemalichinae should be reconsidered, and this lineage should be placed within the subfamily Dermatophagoidinae. The latter subfamily is currently accepted in the literature as a monophyletic group but was here inferred as paraphyletic and was not supported by any morphological synapomorphy. The paraphyly involved the most species-rich and medically important genus, Dermatophagoides. Our findings suggest the need for a comprehensive revision of the higher-level relationships of pyroglyphid house dust mites using both DNA sequences and morphology coupled with a broad taxonomic sampling.

Tachornithoglyphus gen. nov.--a new genus of nidicolous Pyroglyphidae (Acariformes: Astigmata).

Tachornithoglyphus gen. nov. (Acariformes: Pyroglyphidae) is established for Tachornithoglyphus tachornis (Cruz, Cuervo and Dusbabek, 1984), comb. nov. (transferred from Guatemalichus), collected from nests of the Antillean palm swift, Tachornis phoenicobia (Apodiformes: Apodidae) in Cuba. The new genus differs from the other four genera of the subfamily Guatemalichinae, Guatemalichus Fain and Wharton, 1970, Pottocola Fain, 1971, Fainoglyphus Atyeo and Gaud, 1977, and Capitonocoptes Fain and Gaud, 1984, mainly by having the length of solenidion σ1 of genu I less than one-third that of the segment (vs. solenidion σ1I at least half as long as genu I), by the absence of famulus ε on tarsus I (vs. present), and by coxal apodemes Ia separated from each other and contiguous to the lateral parts of the epigynal arch (vs. posterior tips of apodemes Ia fused to each other and with the median part of the epigynal arch, or separated and contiguous to or fused with the median part of the epigynal arch). A detailed redescription of adults and tritonymphs of T. tachornis is provided.

Biological activity of the mite Sancassania sp. (Acari: Acaridae) from bat guano associated with the pathogenic fungus Histoplasma capsulatum.

Mites and the mammal pathogenic fungus Histoplasma capsulatum are the major components of bat guano microbiota. Interactions between mites and H. capsulatum were evaluated under laboratory conditions. Acarid mites, mainly Sancassania sp., were the most abundant microarthropod in the sampled guano of the Mexican bat Tadarida brasiliensis mexicana and, based on its morphology, Sancassania sp. was similar to the cosmopolitan species Sancassania sphaerogaster. The mycophagous and vectoring activities of this mite were tested for H. capsulatum and two other fungal species, Sporothrix schenckii (pathogenic) and Aspergillus sclerotiorum (non-pathogenic). S. ca. sphaerogaster was able to reproduce in H. capsulatum and S. schenckii colonies, multiplying in great numbers under controlled fungal mycelial-phase culture conditions. H. capsulatum colonies were completely destroyed after 14 days of in vitro interaction with mites. In contrast, S. ca. sphaerogaster did not reproduce in A. sclerotiorum cultures. S. ca. sphaerogaster was found vectoring H. capsulatum, but not the two other fungal species studied.

Biological activity of the mite Sancassania sp. (Acari: Acaridae) from bat guano associated with the pathogenic fungus Histoplasma capsulatum

Mites and the mammal pathogenic fungus Histoplasma capsulatum are the major components of bat guano microbiota. Interactions between mites and H. capsulatum were evaluated under laboratory conditions. Acarid mites, mainly Sancassania sp., were the most abundant microarthropod in the sampled guano of the Mexican bat Tadarida brasiliensis mexicana and, based on its morphology, Sancassania sp. was similar to the cosmopolitan species Sancassania sphaerogaster. The mycophagous and vectoring activities of this mite were tested for H. capsulatum and two other fungal species, Sporothrix schenckii (pathogenic) and Aspergillus sclerotiorum (non-pathogenic). S. ca. sphaerogaster was able to reproduce in H. capsulatum and S. schenckii colonies, multiplying in great numbers under controlled fungal mycelial-phase culture conditions. H. capsulatum colonies were completely destroyed after 14 days of in vitro interaction with mites. In contrast, S. ca. sphaerogaster did not reproduce in A. sclerotiorum cultures. S. ca. sphaerogaster was found vectoring H. capsulatum, but not the two other fungal species studied.