Analysis of extra‐pair paternity and conspecific brood parasitism in mallards Anas platyrhynchos using non‐invasive techniques

Abstract

A method that was based on non‐invasive sampling of genetic material was used to determine the rates of extra‐pair paternity (EPP) and conspecific brood parasitism (CBP) in mallards. Maternal and offspring DNA were extracted from feathers in nest material and hatched eggshell membranes. Using 8 microsatelite loci, extra‐pair offspring were detected in 48% of nests and accounted for 9.3% of all offspring. In addition, 10.1% of the offspring were confirmed to result from CBP, and 24% of all nests contained at least 1 offspring from CBP. Rates of conspecific nest parasitism were higher than those of related species, which might have been due to higher breeding densities at our study site. The incidence of EPP was distributed randomly (i.e. did not deviate from bionomial distribution) throughout the population, indicating that variations in pre‐copulatory (e.g. female choice, mate guarding) or post‐copulatory processes (e.g. sperm competition, cryptic female choice) do not affect the distribution of EPP among breeding pairs markedly. Yet, our data provide evidence of variation in the risk of being parasitized among breeding females. The occurrence of CBP and EPP was unaffected by the timing of the breeding attempt or breeding synchrony.

Eggshell coloration reflects both yolk characteristics and dietary carotenoid history of female mallards

“…However, mallard females engage in intraspecific brood parasitism, with almost one quarter of all nests experiencing egg dumping (Kreisinger et al . ). Thus, the high repeatability of eggshell coloration within females suggests that females could use inter‐individual differences in eggshell coloration to increase likelihood of detection of brood parasites.…”

Kin grouping is insufficient to explain the inclusive fitness gains of conspecific brood parasitism in the common eider

“…Microsatellite methods require DNA, which has been sampled invasively by blood draws (Tiedemann et al, ) and noninvasively from nest bowls in the form of feathers, hatch membranes and eggshells (Kreisinger et al, ). We found success with both feathers and hatch membranes in this project, but we did not find eggshells to be reliable even though previous work has shown that eggshells contain nuclear DNA (Egloff, Labrosse, Hebert, & Crump, ).…”

“…From feathers, we used a portion of the calamus, targeting the superior umbilicus indicated by a red dot where blood commonly clots (Figure ; Horvath, Martinez‐Cruz, Negro, Kalmar, & Godoy, ). For hatch membranes, we used ~25 mg of hatch membrane targeting chorionic vessels containing embryonic DNA (Figure ; Kreisinger, Munclinger, Javukova, & Albrecht, ). For eggshells, we used ~70 mg of eggshell removed from hatch membrane carefully to avoid cross contamination from hatch membrane.…”

Development of microsatellite markers for a diving duck, the common pochard (Aythya ferina)

“…Microsatellite genotyping of samples derived non-invasively from bird nests is effective in addressing these issues with minimal adverse effects on populations (e.g. Pearce et al 1997;Kreisinger et al 2010). This method allows estimations of renesting rates, breeding fidelity and research on alternative reproductive strategies such as conspecific brood parasitism (CBP) or extra pair paternity (EPP).…”