This is the first report of an ongoing study on arthropofauna of forensic importance in Callao, Peru using a baby pig (Sus scrofa Linneaus, 1758) on land as a model to determine the arthropofauna over 84 days of weekly survey between 17 July and 02 October 2 000. A total of 4,405 specimens were collected belonging to five orders and eight families: Cochliomyia macellaria (Fabricius, 1775) (Diptera, Calliphoridae) (81.62%); Dermestes maculatus (De Geer, 1774) (Coleoptera, Dermestidae) (16.35%); Fannia canicularis (Linnaeus, 1761) (Diptera, Muscidae) (0.04%); Saprinus aeneus (Fabricius, 1775) (Coleoptera, Histeridae) (1.48%); Necrobia rufipes (De Geer, 1775) (Coleoptera, Cleridae) (0.45%); Linepithema humile (Mayr, 1868) (Hymenoptera, Formicidae) (0.02%); Porcellio laevis Latreille, 1804 (Isopoda, Porcellionidae) (0.02%) and Hadruroides lunatus (L. Koch, 1867) (Scorpionida, Iuridae) (0.02%). Larvae accounted for 76%, pupae 14% and adults 10% of the total collected. The arthropods were into three: necrophages (98.01%), predators (1.95%) and omnivorous (0.04%). C. macellaria were significantly higher during the decayed stage; by contrast D. maculatus was much higher in dry remains stage. The highest diversity with the Shannon-Weaver (H') and Pielou (J) index were found during the advanced decayed stage. The absence of species of genus Chrysomyia Robineau-Desvoidy, 1830 is discussed

Se proporciona una lista de verficación de todos los registros válidos publicados de los metazoos parásitos reportados en peces marinos y de agua dulce de Perú. Esta lista incluye los registros de 612 especies diferentes de metazoos parásitos (incluyendo parásitos no identificados) que pertenecen a los siguientes grupos: Platyhelminthes (430 total), incluyendo Monogenea (175), Cestoda (140), y Trematoda (115); Crustacea (99); Nematoda (49); Acanthocephala (16); Myxozoa (14) y Annelida (2). Estos parásitos fueron reportados de 207 especies de peces de Perú (174 teleósteos, 31 elasmobranquios y 2 especies de hospederos no determinados). Los registros de los parásitos no identificados a nivel de especie (182 de 612), representando el 30% de todas las especies, también fueron incluidos. Entre los parásitos de peces reportados de Perú, 391 fueron marinos, 217 de agua dulce y 4 especies se encontraron en ambos ambientes, para un total de 1015 asociaciones parásito-hospedero. Las especies de peces que albergaron el mayor número de parásitos fueron Merluccius gayi peruanus Ginsburg, 1954 (32), seguido de Paralonchurus peruanus (Steindachner, 1875) (31), Scomber japonicus Houttuyn, 1782 (31), Sciaena deliciosa (Tschudi, 1846) (29) y Stellifer minor (Tschudi, 1846) (28), todos ellos son peces marinos. Los parásitos con el mayor número de registros fueron las larvas del cestodo Adenocephalus pacificus Nybelin, 1931 (19), larvas del nematodo Anisakis sp. (18), larvas de Contracaecum sp. (17) y larvas y adultos de Lacistorhynchus tenuis (16), los cuales fueron recuperados de peces marinos, excepto las larvas de Contracaecum sp., las cuales fueron recuperados de ambos ambientes. La diversidad de parásitos en peces peruanos parece estar sesgado por el hospedero muestreado de acuerdo a los intereses del investigador, sino que también está relacionado con las características biológicas de los parásitos y de los hospederos.

The Tocantins–Araguaia basin is one of South America’s largest river systems, across three Brazilian states (Maranhão, Tocantins, and Pará), within the Legal Amazon region. Despite draining extensive Cerrado savanna and rainforest ecosystems, it has suffered significant degradation, notably in the past 40 years. Human activities, including agricultural expansion, deforestation, and the introduction of non-native species, have worsened the environmental damage, which is alarming since many residents and villages along the middle Tocantins River rely on it for water supply, recreation, and fishing. This study assessed the concentration of potentially toxic and essential elements in water samples from four sampling sites distributed along the middle Tocantins River. The monitoring occurred throughout 2023, involving the measurement of parameters both on-site and in the laboratory. Water quality and its health implications were evaluated using the Weighted Arithmetic Water Quality Index (WAWQI), the Water Quality Index (WQI), and the health risk assessment index. The levels of aluminum, copper, iron, magnesium, and selenium exceeded legal standards. Seasonal fluctuations indicate a complex dynamic influenced by climatic or seasonal factors, with February showing the highest values. Site P1, located in urban areas, exhibited elevated mean concentrations for conductivity, total dissolved solids (TDS), and chlorophyll, indicating the need for continuous monitoring. The nitrogen concentrations at P1 raise concerns regarding drinking water quality, which is a concern for the region’s residents who use untreated river water. Despite seasonal variations in element concentrations, the overall WAWQI categorized all sections as “Excellent,” and the WQI rated as “Good.” Human health risk assessments detected no risks, but continuous monitoring and interventions are crucial for sustained water quality improvement.

The lorna drum Sciaena deliciosa is a coastal demersal species and one of the underlying artisanal fisheries in some areas of Peru, and is also a source of protein for Peruvian coastal dwellers. The investigation addresses concern about the environmental impact on this fish species and the potential risks to human health through the consumption of contaminated seafood. This research endeavors to assess the concentration of potentially toxic and essential elements in the muscle and liver tissues of S. deliciosa, in addition to the presence thereof in water and sediment capture areas on the coast of Callao, Peru. The study revealed that, in water samples, Ag, Ni, and Zn exceed Peruvian standards, but were below international standards, and Ba, P, Se, and Sn exceed international standards. In the sediments, As, Cd, Pb, Fe, and Zn were above international standards. In the fish, S. delicious muscle demonstrated As, Hg, and Pb exceeding at least one international standard. In the liver, As, Hg, Pb, and Cu exceed international standards. The study approach increased accuracy in risk assessments, offering crucial insights into the interplay between heavy metal pollution, water quality, and animal health, informing risk management strategies. Future studies can explore the long-term effects of heavy metal exposure on different organisms and consider their cumulative impact on health.

Biological invasions by exotic species impose substantial ecological, economic and social costs worldwide, being a major threat to biodiversity conservation. Because not all individuals introduced in the new environments become successful invaders, the identification of factors underlying variation in invasion success would be essential for evaluating invasion risk. Here, we test several host–parasite hypotheses accounting for invasion success of house sparrowsPasser domesticusin Peru. According to theEnemy Release Hypothesis, invasive house sparrows from Peru showed lower prevalence and genetic diversity of haemosporidian parasites than sparrows from their natural range (Spain), indicating that the release from their natural parasites may have favoured the spread of sparrows in the new area of occurrence. We also showed that Peruvian sparrows had larger uropygial glands and higher anti‐bacterial activity in its secretion than sparrows from Spain, suggesting selection in defensive mechanisms driven by pathogens when colonizing new environments. Finally, we showed that uninfected sparrows had larger uropygial glands and higher anti‐bacterial activity than malaria‐infected house sparrows, implying that uropygial gland secretions may act as a defensive mechanism against haemosporidian infections. Alternatively, a condition‐dependent trade‐off exists between synthesis of uropygial secretion and immune response. These outcomes provide essential information for identifying potential invaders and designing interventions.