Maize (Zea mays L.) is one of the main staples in the Peruvian Andes. Phenotypic diversity is extremely high in terms of plant morphology, grain colour, grain size and uses. However, little is known about the genetic component of the Peruvian maize. Genotyping-by-sequencing was used, for the first time, to infer the genetic diversity and population structure of 25 accessions of maize collected from two ecoregions of the departments of the Peruvian highlands, Cajamarca and Huancavelica, to provide a basis for the conservation and breeding of this crop genetic resource. A total of 29,332 single-nucleotide polymorphisms were identified along all 10 chromosomes of maize. STRUCTURE analysis revealed two clusters (open-pollinated cultivars and landraces). Principal coordinate analysis and our dendrogram showed that these accessions of Peruvian maize do not group based on their geographic origin but on their improvement status, however, this is weakly supported. Average genetic diversity was very high (0.35). Analysis of molecular variance showed a reduced variation between populations (2.85%) and indicated that variability within populations is 97.15%. The lowest population divergence was zero for populations of Colcabamba versus Pichos and Daniel Hernandez versus Colcabamba and the highest population divergence (0.041) was observed for population Cajamarca versus Santiago de Tucuma. As expected, FIS values were positive. Additional samples from other Andean and west coast Peruvian localities are needed to provide a better understanding of the genetic components of this important crop aiming to develop a modern breeding programme of maize in Peru.

Fleas have great medical relevance as vectors of the causative agents of several diseases in animals and humans and rodents are the principal reservoirs for these pathogens. Argentinian Patagonia has the highest diversity of rodent fleas in South America. However, parasitism rates of rodents by fleas, the factors that influence them and the ecological aspects that modulate geographical distributions of flea–host association remain unknown for this region. This is the first study to record the diversity, prevalence, abundance, geographical distributions and host ranges of fleas in Argentinian Patagonia. It also compares parasitism rates among Patagonian ecoregions and host species. We captured 438 rodents belonging to 13 species, which harboured 624 fleas from 11 species and subspecies (P = 46%; mean abundance = 1.44). The high parasitism rates obtained were consistent with previous records for other arid regions, suggesting that Patagonia favours the survival and development of Siphonaptera. Host geographic range and abundance were related to the parasitological indexes: host species with high-density populations had the highest mean flea abundance and prevalence, whereas widely distributed hosts had the highest richness and diversity of flea species. Our results contribute to the knowledge of the flea–host–environment complex. Our analysis of flea distributions and parasitism rate in Central Patagonia may be useful in epidemiological studies of flea-borne diseases and provide a basis for implementing surveillance systems for better risk assessment of emerging zoonoses in the region.