Climate variability affects the impact of parasitic flies (Philornis torquans Nielsen 1913) on Argentinean forest birds

ANTONIAZZI, LEANDRO; MANZOLI, DARIO; ROHRMANN, DAVID; SARAVIA PIETROPAOLO, MARIA JOSÉ; SILVESTRI, LEONARDO JOSÉ; BELDOMENICO, PABLO

JOURNAL OF ZOOLOGY

Zoological Society of London

Lugar: London; Año: 2011 vol. 283 p. 126 - 134

0022-5460

The genus Philornis (Diptera: Muscidae) comprises Neotropical parasitic flies that parasitize bird nestlings while in their larval stage. The ecology of most species of these parasitic flies is largely unknown. Here, we contribute with data that shed some light on the environmental factors that are associated with variations in parasitism intensity of Philornis torquans, and examine whether increased intensity is followed by greater probability of mortality or reduced nestling growth. Intensive examination of nestlings of the bird community present in a 30 ha area was carried out weekly along two breeding seasons in Santa Fe, Argentina. Some nestlings of the most frequently parasitized bird species were followed twice a week, from hatching to fledging, to assess the impact of the parasites. High average maximum temperature and increased rainfall were significantly positively correlated with mean Philornis intensity. In turn, heavily parasitized nestlings were more likely to die: 10 larvae doubled the chances of mortality, and growth was affected in those that survived. The greater precipitation and warmer weather predicted for some areas of South America pose a potential impact on nestlings via this parasitism, and consequently on the population dynamics of native birds.