Arthropod parasites of Antarctic and Subantarctic birds and pinnipeds: A review of host-parasite associations

Reighardia sternae Infection and Associated Lesions in a Yellow-Legged Gull (Larus michahellis) in Italy

Reighardia sternae is a pentastomid parasitising the respiratory system of larids and skuas, the pathological significance of which is still poorly understood. In this study, pentastomes found in the interclavicular air sac of a deceased and necropsied yellow-legged gull (Larus michahellis) were identified by parasitological and molecular methods and associated gross and histopathological lesions were evaluated. After morphological evaluation and molecular characterisation, the species R. sternae was identified. This is the first report of R. sternae infecting L. michahellis in Italy. Gross pathology showed generalised aerosacculitis, parabronchial edema, and enlargement of the heart, liver, and spleen. The systemic lesions found at histopathological examination were indicative of chronic cardiocirculatory failure, which led to the death of the gull. Moreover, inflammation was present throughout the lungs and air sacs in the form of some granulomas and diffuse small nodular aggregates rich in lymphocytes. The remnants of a parasite were observed within a granulomatous lesion in the lung, suggesting a primary host response to the parasite. These latter findings may suggest that the migration of R. sternae was the cause of the pathological granulomatous pictures in the examined yellow-legged gull.

Advances and shortfalls in knowledge of Antarctic terrestrial and freshwater biodiversity

Antarctica harbors many distinctive features of life, yet much about the diversity and functioning of Antarctica's life remains unknown. Evolutionary histories and functional ecology are well understood only for vertebrates, whereas research on invertebrates is largely limited to species descriptions and some studies on environmental tolerances. Knowledge on Antarctic vegetation cover showcases the challenges of characterizing population trends for most groups. Recent community-level microbial studies have provided insights into the functioning of life at its limits. Overall, biotic interactions remain largely unknown across all groups, restricted to basic information on trophic level placement. Insufficient knowledge of many groups limits the understanding of ecological processes on the continent. Remedies for the current situation rely on identifying the caveats of each ecological discipline and finding targeted solutions. Such precise delimitation of knowledge gaps will enable a more aware, representative, and strategic systematic conservation planning of Antarctica.

Entomopathogenic Fungi as Alternatives to Chemical Acaricides: Challenges, Opportunities and Prospects for Sustainable Tick Control

Entomopathogenic fungi (EPFs) can infect and kill a diverse range of arthropods, including ticks (Acari: Ixodidae) that can transmit various diseases to animals and humans. Consequently, the use of EPFs as a biocontrol method for managing tick populations has been explored as an alternative to chemical acaricides, which may have harmful effects on the environment and non-target species. This review summarizes studies conducted on EPFs for tick control between 1998 and 2024, identifying 9 different EPF species that have been used against 15 different species of ticks. One of the most well-known and widely researched EPFs used against ticks is Metarhizium anisopliae, a fungus known for its ability to infect and kill various arthropods. When applied to tick-infested areas, M. anisopliae spores attach to the tick's cuticle, germinate, and penetrate through the cuticle, leading to the eventual death of the tick due to the fungal infection. Whilst a number of studies support the potential of this and other EPF species against ticks, this review suggests that limitations to their effective use may include factors such as heat, humidity, and ultraviolet light (UV-A and UV-B). This comprehensive review aims to provide an overview of the literature on the potential of EPFs in tick control, focusing on their mode of action, previous field successes/failures, advantages, potential applications, and prospects for future practical developments.

Feather mites (Acariformes, Astigmata) from marine birds of the Barton Peninsula (King George Island, Antarctica), with descriptions of two new species

We report on the first investigation of feather mites associated with birds living on the Barton Peninsula (King George Island, Antarctica). We found seven feather mite species of the superfamily Analgoidea from four host species. Two new species are described from two charadriiform hosts: Alloptes (Sternalloptes) antarcticussp. nov. (Alloptidae) from Stercorariusmaccormicki Saunders (Stercorariidae), and Ingrassiachionissp. nov. (Xolalgidae) from Chionisalbus (Gmelin) (Chionidae). Additionally, we provide partial sequences of the mitochondrial cytochrome c oxidase subunit I (COI), which was utilized as a DNA barcode, for all seven feather mite species.