Endoparasite Infection Has Both Short- and Long-Term Negative Effects on Reproductive Success of Female House Sparrows, as Revealed by Faecal Parasitic Egg Counts

Abstract

Parasites have the potential to severely reduce host reproductive success. However, the effects of endoparasites on reproductive success have not received the same amount of attention as the effects of parasites on host survival. We investigated the relationship between an avian endoparasite (gapeworm, Syngamus trachea) and both current and future reproductive success of female house sparrows (Passer domesticus) in a population on the coast of Helgeland, northern Norway. We found that the proportion of eggs in a nest that failed to develop into fledglings increased as the faecal parasitic egg count of the mothers increased. We also found that juvenile females with high numbers of parasitic eggs in their faeces had lower lifetime reproductive success as adults. However, we did not find a relationship between maternal parasite infection and clutch size or recruitment rate of offspring. To our knowledge this is the first study to find a relationship between reproductive success of an avian host and faecal egg count of an endoparasite. The present study indicates that infection by an endoparasite may be associated with lower individual reproductive success in both the short-term and long-term in a wild population of hosts.

Sensitivity analysis of effective population size to demographic parameters in house sparrow populations

“…() and Holand et al . (). The pedigrees in tandem with individual capture and observation data provided information on annual survival, fecundity and census population size estimated as the number of adult individuals captured and/or observed before or during breeding season in a given year.…”

“…A blood sample of 25 lL was drawn from the brachial vein underneath the wing and provided the DNA necessary to genotype individuals on 14 unlinked polymorphic microsatellite markers for genetic parentage analyses (Jensen et al 2003). Genetic pedigrees for the populations Handnesøy, Linesøya, Løkta, R anes and Røvass were established (see Table S2 and Parentage analyses, Supporting information), while genetic pedigrees for the remaining populations were already available, see Jensen et al (2003), Billing et al (2012), Jensen et al (2013) and Holand et al (2015). The pedigrees in tandem with individual capture and observation data provided information on annual survival, fecundity and census population size estimated as the number of adult individuals captured and/or observed before or during breeding season in a given year.…”

A comparison of two methods for quantifying parasitic nematode fecundity

“…Accurate measures of nematode fecundity can provide important information for investigating parasite life history evolution (Skorping et al 1991), transmission potential (May and Anderson 1979), and effects on host health Albon et al 2002;Holand et al 2015). This study compared two methods for assessing fecundity of a trichostrongyle nematode, finding that both were good options, although each had its unique advantages and disadvantages.…”

“…Often, the fitness costs of GI nematode infection are a direct result of the number of worms harbored by a host (Hudson et al 1992;Stjernman et al 2008;Benesh 2011). However, fitness costs to the host have also been linked to the number of eggs produced by nematodes, i.e., their total fecundity (Rowe et al 2008;Holand et al 2015). For example, Holand et al (2015) found that the number of gapeworm Syngamus trachea (Montagu, 1811) eggs in the parent bird's feces was negatively correlated with the proportion of successful fledglings in house sparrows (Passer domesticus, Linnaeus, 1758).…”

“…However, fitness costs to the host have also been linked to the number of eggs produced by nematodes, i.e., their total fecundity (Rowe et al 2008;Holand et al 2015). For example, Holand et al (2015) found that the number of gapeworm Syngamus trachea (Montagu, 1811) eggs in the parent bird's feces was negatively correlated with the proportion of successful fledglings in house sparrows (Passer domesticus, Linnaeus, 1758). Quantifying nematode fecundity, in addition to adult worm burdens, can therefore provide valuable insight into the costs of infection, patterns of dissemination in the environment, and the dynamics of local transmission.…”