Do parasites and antioxidant availability affect begging behaviour, growth rate and resistance to oxidative stress?

Abstract

Early-life trade-offs faced by developing offspring can have long-term consequences for their future fitness. Young offspring use begging displays to solicit resources from their parents and have been selected to grow fast to maximize survival. However, growth and begging behaviour are generally traded off against self-maintenance. Oxidative stress, a physiological mediator of life-history trade-offs, may play a major role in this trade-off by constraining, or being costly to, growth and begging behaviour. Yet, despite implications for the evolution of life-history strategies and parent-offspring conflicts, the interplay between growth, begging behaviour and resistance to oxidative stress remains to be investigated. We experimentally challenged wild great tit (Parus major) offspring by infesting nests with a common ectoparasite, the hen flea (Ceratophyllus gallinae), and simultaneously tested for compensating effects of increased vitamin E availability, a common dietary antioxidant. We further quantified the experimental treatment effects on offspring growth, begging intensity and oxidative stress. Flea-infested nestlings of both sexes showed reduced body mass during the first half of the nestling phase, but this effect vanished short before fledging. Begging intensity and oxidative stress of both sexes were unaffected by both experimental treatments. Feeding rates were not affected by the experimental treatments, but parents of flea-infested nests fed nestlings with a higher proportion of caterpillars, the main source of antioxidants. Additionally, female nestlings begged significantly less than males in control nests, whereas both sexes begged at similar rates in vitamin E-supplemented nests. Our study shows that a parasite exposure does not necessarily affect oxidative stress levels or begging intensity, but suggests that parents can compensate for negative effects of parasitism by modifying food composition. Furthermore, our results indicate that the begging capacity of the less competitive sex is constrained by antioxidant availability.

Blue tit Cyanistes caeruleus males increase their reproductive effort when subject to a flea experimental manipulation

“…Thus, as the nestling adaptive immune system matures, the costs of flea parasitism may be reduced and a larger proportion of the food provided by the parents can be allocated to growth. Interestingly, in our study, these differences had vanished at the age of 14 days mirroring results from other studies on flea manipulation of great and blue tits (Tripet et al 2002, Maronde et al 2018). As our flea manipulation was confined to the incubation phase, natural population dynamics (including immigration and emigration) might have evened out the differences late in the nestling cycle.…”

“…Thus, as the nestling adaptive immune system matures, the costs of flea parasitism may be reduced and a larger proportion of the food provided by the parents can be allocated to growth. Interestingly, in our study, these differences had vanished at the age of 14 days mirroring results from other studies on flea manipulation of great and blue tits (Tripet et al 2002, Maronde et al 2018).…”

Subtle short-term physiological costs of an experimental augmentation of fleas in wild Columbian ground squirrels

“…This may reflect a poorer capacity of parasitized females to buffer reproduction-associated oxidative increases or a potential delayed effect of parasites. Generally, similar flea infestation studies have largely found no results of parasites on oxidative stress (Devevey et al, 2008;Maronde et al, 2018;Wegmann et al, 2015). That said, our finding of an interaction between parasitism and oxidative stress where others have found no relationship is not surprising given the multifaceted and non-linear relationship between the two (Costantini and Møller, 2009).…”

Is there a role for aromatic plants in blue tit (Cyanistes caeruleus) nests? Results from a correlational and an experimental study

“…Larcombe et al (2008) showed that the yellow plumage colouration in blue tit nestlings was positively related with lipid peroxidation levels, suggesting that colouration reflected the oxidative damage rather than resistance to oxidative stress. In our study, nests with added grass had more fleas, which has been related to increased oxidative stress in female great tit (Parus major) nestlings (De Coster et al (2012) but see Maronde et al (2018)). Hence, stronger carotenoid-based colouration in nestling' flanges could reflect oxidative damage as a consequence of flea infestation and related inflammation processes (Owen et al 2010).…”