Matías J. Cafaro

First survey of arthropod gut fungi and associates from Vieques, Puerto Rico.

This is the first survey of trichomycetes for Vieques, Puerto Rico. Several types of arthropods, including millipedes, crabs, mosquitoes, bloodworms, amphipods and isopods, were collected from marine, freshwater and terrestrial habitats and their guts examined for the presence of trichomycetes. A new species of Enterobryus, which was found attached to the gut of the millipede Anadenobolus arboreus (Diplopoda), is described as Enterobryus viequensis sp. nov. We report the presence of Smittium culisetae in mosquito larvae and also provide information on two eccrinids associated with the fiddler crabs Uca rapax and U. burgersi and an amphipod.

Presence of Multiparasite Infections Within Individual Colonies of Leaf-Cutter Ants

ABSTRACT Host—parasite dynamics can be altered when a host is infected by multiple parasite genotypes. The different strains of parasite are expected to compete for the limited host resources, potentially affecting the survival and reproduction of the host as well as the infecting parasites. Fungus-growing ants, including the well-known leaf-cutters, are an emerging model system for studying the evolution and ecology of symbiosis and host-parasite dynamics. We examine whether the fungus gardens of leaf-cutter ants can be simultaneously infected by multiple strains of the fungal pathogen Escovopsis. Intensive sampling of Escovopsis was conducted from individual gardens, as well as between different garden chambers within individual colonies of leaf-cutting ants. Isolates obtained were genotyped by DNA sequencing. We found that, minimally, 67% of the individual colonies of the leaf-cutter ant genera Atta and Acromyrmex and 50% of the At. colombica garden chambers studied were simultaneously infected by multiple distinct Escovopsis strains. Experimental challenges showed that different Escovopsis strains do not exhibit obvious antagonism toward each other, suggesting that coinfecting strains of the parasite do not engage in interference competition, although interactions were not studied at the cellular level. Further research is needed to understand interparasite interactions between coinfecting Escovopsis strains and to understand the impact of multiparasite infections on the survival of leaf-cutter ant gardens.

Seasonality and prevalence of the protistan trichomycete Enterobryus halophilus (Ichthyosporea: Eccrinales) in the mole crab Emerita portoricensis

In Puerto Rico the protist Enterobryus halophilus (Ichthyosporea: Eccrinales) has been reported associated with a new host, Emerita portoricensis (Malacostraca: Hippidae). A study on prevalence and abundance in populations of E. halophilus was conducted during 18 mo to determine whether sex-dependent infection exists in Em. portoricensis, as suggested (1958) for the original description of E. halophilus in Em. talpoida. Individuals (1440) of Em. portoricensis were collected and their guts dissected on microscope slides. The thalli of E. halophilus were counted under a microscope with random grid squares. A factorial ANOVA with interaction revealed that the prevalence and the abundance of E. halophilus do not depend on the sex of its host. Furthermore the data indicate that E. halophilus populations undergo seasonal variations in infestation following the population dynamics of the host.

Dipteran-associated Harpellales from lowland and submontane tropical rain forests of Veracruz (Mexico)

We report on the species of Harpellales found in dipteran hosts during two surveys (32 field d) in the state of Veracruz, Mexico. One new morphospecies, Genistellospora dorsicaudata, is described with particular attention to the position of the terminal cell associated with fully developed fertile thalli bearing sexual spores. We emend the description of G. guanacastensis to include morphometrics on the zygospores, based on discovery of the sexual spores for that species in our collections. Thirteen other previously described species, which are new for Mexico, include G. homothallica, Pennella montana, Simuliomyces microsporus, Smittium aciculare, S. brasiliense (in a new host type), S. culisetae, S. dipterorum, S. microsporum, S. simulii and the unbranched species Harpella melusinae, H. tica, Stachylina grandispora and S. paucispora. Some species have been described but not named, specifically one each of Harpella, Pennella and Smittium. All taxa are identified morphologically, illustrated and additional details on their ecology are provided.

Paratrechina longicornis ants in a tropical dry forest harbor specific Actinobacteria diversity

The diversity of Actinobacteria associated with Paratrechina longicornis, an ant species that prefers a high protein diet, in a subtropical dry forest (Guánica, Puerto Rico) was determined by culture methods and by 16S rDNA clone libraries. The results of both methodologies were integrated to obtain a broader view of the diversity. Streptomyces, Actinomadura, Nocardia, Ornithinimicrobium, Tsukamurella, Brevibacterium, Saccharopolyspora, Nocardioides, Microbacterium, Leifsonia, Pseudonocardia, Corynebacterium, Geodermatophilus, Amycolatopsis, and Nonomuraea were found associated with the ants. The genera Streptomyces and Actinomadura were the most abundant. Also, the diversity of Actinobacteria associated with the soil surrounding the nest was determined using 16S rDNA clone libraries. In total, 27 genera of Actinobacteria were associated with the nest soils. A dominant genus was not observed in any of the soil samples. We compared statistically the Actinobacteria communities among P. longicornis nests and each nest with its surrounding soil using the clone libraries data. We established that the communities associated with the ants were consistent and significantly different from those found in the soil in which the ants live.