Biology session

The ethology of parasites has not been widely studied despite that not just biochemical and morphological properties help them to adopt to the host. Avian lice (Insecta: Phthiraptera) are permanent obligatory ectoparasites, they predominantly spread during physical contact between hosts, which occurs most frequently during parental care (vertical transmission) in birds. In my study I examined how lice select among offsprings during vertical transmission, how this host preference affects lice distributions in adult birds and how this pattern is passed on to subsequent generations. My study focuses on louse species parasitizing the Red-footed Falcon (Falco vespertinus), a raptor of high international conservation concern. Field work was carried out in Körös-Maros National Park with aid of MME-Birdlife Hungary’s Red-footed Falcon Working Group. The ectoparasites were collected with dust-ruffling. In 2012 I sampled a presumed male and/or female from each nest, their sex was later confirmed with PCR based methods. In 2014 I sampled the male or female member of a given pair in the early breeding season, and later I sampled the entire clutch. The effects of various properties of the host on the quantity of the lice was analysed with generalised linear models. Four lice species were found on the birds out of which one could not be identified exactly, it belongs to the family Menoponidae of suborder Amblycera. We also found a previously undescribed louse on Red-footed Falcons; the Laemobothrion tinnunculi. The most abundant louse species were Colpocephalum subzerafae (feeds on contour feathers, skin and blood), and Degeeriella rufa (only feeding on the material of larger feathers). Host sex had a significant effect on C. subzerafae abundance, while D. rufa abundance depended on wing length (describes the age of the nestlings )in case of nestling birds. The quantity of the C. subzerafae on adult birds depended on parameters describing body size, increased over time during the sampling period and was also significantly higher on female birds. The chance of being infested with D. rufa increased with host body mass and was also higher for female birds. Wiping out the ectoparasites from one of the parents caused a significant decrease in lice prevalence and intensity on their nestlings compared to the control group. However, I did not find any significant difference between the two treatment groups (ectoparasites were removed either from the male or the female parent).

The two most common louse species of Red-footed falcons showed sex dependent infestation patterns; in case of C. subzerafae this pattern was also observable after vertical transmission. The D. rufa presumably uses a different transmission strategy, waiting for the new host to develop as mature plumage as possible. My results indicate that the sex of the host by itself can have an effect on the fitness of parasites and some species show unequal transmission patterns.