Philornis retrasa el crecimiento de pichones de Troglodytes aedon y el parasitismo aumenta en bosques exóticos

MONGES VIRGINIA; CHIRAMBERRO ANA PAULA; MARIA CECILIA EZQUIAGA; SEGURA LUCIANO

Gramado

Congreso; II Congreso de Ornitología de las Américas; 2023

Larvae of the Neotropical genus Philornis (Diptera: Muscidae) are subcutaneous parasites that infect nestling birds, causing a direct (nestling death) or indirect (growth retardation) effect on nestlings. Using non-linear mixed-effects models, we evaluated the effect of parasitism on nestling growth of the House Wren Troglodytes aedon in forested areas of central-eastern Argentina, during the breeding season 2022-2023. Also, we evaluated whether the prevalence of parasitism was associated with forest composition (comparing native forest patches with forested areas invaded with exotic trees). We monitored 11 nests (modal number of nestlings per nest = 4) in each sector. We found that the mean intensity per infected nestling was ~9 larvae. Nestlings fledged at ~14 days of age with a mass of ~14 g and a wing-flattened length of ~39 mm. Philornis parasitism did not affect nestling size at the time of fledging, but delay the timing of growth (both for body mass and wing-flattened length. The prevalence of parasitized nests was higher in the forested areas invaded with exotic trees (2 of 11 nests in native patches; 9 of 11 nests in exotic patches). The invasion of exotic trees creates denser forest corridors in relation to native forests. Our results are particularly relevant because of the increasing invasion of exotic trees in these forests, which favored the prevalence of Philornis. We suggest actions that tend to conserve the native forest, for example, through the creation of protected areas, or/and regulation of exotic tree species populations.