Antioxidants in eggs of great tits Parus major from Chernobyl and hatching success

Abstract

Antioxidants are powerful protectors against the damaging eVects of free radicals that constitute the inevitable by-products of aerobic metabolism. Growing embryos are particularly susceptible to the damaging eVects of free radicals produced during rapid growth, and mothers of many species provide protection against such damage by allocating antioxidants to their eggs. Birds living in radioactively contaminated areas use dietary antioxidants to cope with the damaging eVects of radiation, but females also allocate dietary antioxidants to eggs, potentially enforcing a physiological trade-oV between self-maintenance and reproductive investment. Here we tested whether female great tits Parus major breeding in radioactively contaminated study areas near Chernobyl allocated less dietary antioxidants to eggs, and whether such reduced allocation of dietary antioxidants to eggs had Wtness consequences. Concentrations of total yolk carotenoids and vitamins A and E were depressed near Chernobyl compared to concentrations in a less contaminated Ukrainian study area and a French control study area, and all antioxidants showed dose-dependent relationships with all three dietary antioxidants decreasing with increasing level of radiation at nest boxes. These eVects held even when controlling statistically for potentially confounding habitat variables and covariation among antioxidants. Laying date was advanced and clutch size increased at nest boxes with high dose rates. Hatching success increased with increasing concentration of vitamin E, implying that hatching success decreased at boxes with high levels of radiation, eventually eliminating and even reversing the higher potential reproductive output associated with early reproduction and large clutch size. These Wndings are consistent with the hypothesis that radioactive contamination reduced levels of dietary antioxidants in yolks, with negative consequences for hatching success and reproductive success.

Levels of antioxidants in rural and urban birds and their consequences

“…Each observation represents an estimate for an urban and a rural population of a single species. The line shows similar concentrations in the two environments Møller et al (2005Møller et al ( , 2008 showed for birds in Chernobyl that levels of vitamin E were positively correlated with the frequency of sperm with normal morphology and hatching success. Here we tested the prediction that liver antioxidants predicted risk of predation by investigating carotenoids and vitamin E in birds captured by cats and in conspeciWcs that had died for other reasons.…”

Abundance and genetic damage of barn swallows from Fukushima

“…In addition, it suggested that the population decline is due to lower fecundity and/or lower fledging rate, as demonstrated by a decrease in the proportion of juveniles at higher levels of radiation exposure. This result is consistent with the demonstrated decline in fertility, reproductive function and parental care that we have shown in Chernobyl in the barn swallow as well as in other species35404142.…”

Effects of environmental conditions on the egg mass, yolk antioxidant level, eggshell thickness and eggshell spotting patterns of Great Tits (Parus major)

“…3 Relationship between average ambient temperature of a 3-day period preceding laying and egg mass (g) of Great Tits in the Pilis Mountains. Average ambient temperature values were log-transformed 2011), but higher than that found in Great Tit eggs in Sweden (Isaksson et al 2008), France, and Ukraine (Møller et al 2008). Tocopherol concentration was similar to the values found in the Czech population of Great Tits (Remeš et al 2011), but higher than that found in Great Tit eggs in Estonia (Hõrak et al 2002), France, and Ukraine (Møller et al 2008).…”

“…Average ambient temperature values were log-transformed 2011), but higher than that found in Great Tit eggs in Sweden (Isaksson et al 2008), France, and Ukraine (Møller et al 2008). Tocopherol concentration was similar to the values found in the Czech population of Great Tits (Remeš et al 2011), but higher than that found in Great Tit eggs in Estonia (Hõrak et al 2002), France, and Ukraine (Møller et al 2008). These differences show that food and dietary antioxidant availability in different types of habitats may considerably influence the antioxidant concentration of the egg yolks of wild birds.…”