AGE DYNAMICS OF THE HELMINTH FAUNA OF THE HERRING GULL (LARUS ARGENTATUS) IN THE KOLA BAY, BARENTS SEA

The influence of host age on the helminth fauna of the herring gull (Larus argentatus) captured in breeding colonies in the Kola Bay, Barents Sea was studied. Birds were grouped into flightless chicks, fledglings, and adults (June and September). 27 helminth species were recorded: 11 trematodes, 10 cestodes, five nematodes, and one acanthocephalan, with 15 worm species found in chicks, 22 species in fledglings, 20 species in adults during June, and 13 species in adults during September. All three bird groups shared nine species of parasitic worms. Chicks lacked the parasites circulating in freshwater ecosystems, as well as species whose life cycles were realized in marine coastal environments with the participation of invertebrates with hard covers as intermediate hosts. The chicks were infested by some nonspecific helminths usually parasitic in other birds, but did not occur in adult gulls. The greatest diversity of the helminth fauna was observed in the fledglings that had switched to independent feeding. Their parasitic fauna included almost all species found in adult birds, as well as some chick worms. The most probable reasons for the differences observed between were the gull parents collecting food separately from the chicks, low resistance of young birds to invasions by nonspecific helminths, a varied efficiency of foraging by young and adult birds, and seasonal availability of some food resources. A certain influence on the composition and dynamics of the helminth fauna of gulls differing in age was also revealed in birds capable of using garbage as food.

Automated summary

The study found that the host age had an influence on the helminth fauna of herring gulls, with chicks lacking certain parasites found in other ecosystems and fledglings having the highest diversity of parasitic fauna. The differences observed were likely due to factors such as separate feeding behavior of gull parents and varying foraging efficiency between young and adult birds.