Anti-parasite treatment removes negative effects of environmental pollutants on reproduction in an Arctic seabird.
Recent studies have shown that the detrimental effects of anthropogenic pollutants may be worse if organisms are exposed to natural stress. In this study, we examined whether negative effects of organochlorines (OCs) could be influenced by parasites. In two breeding seasons, we administered an anti-helminthic drug to groups of breeding glaucous gulls (Larus hyperboreus), whereas control groups were placebo treated. In all birds, blood residues of the most important OCs in the study population (hexachlorobenzene, oxychlordane, p,p'-dichlorodiphenyldichloroethylene and polychlorinated biphenyl), were measured. The relationships between OCs and fitness components (i.e. nesting success and return rate between breeding seasons) were then compared between the birds receiving anti-parasite treatment and the controls. Among untreated males, higher blood residues of OCs were associated with lowered nesting success, while in males receiving anti-parasite treatment, there was no detrimental effect of OCs on fitness. Return rate was not affected by treatment or OCs. Our findings suggest that parasites may be an important factor in triggering reproductive effects of such pollutants, and that relatively low levels of OCs may have serious reproductive consequences in natural populations when stress from other sources is high.
Bustnes
Jan O
JO
Norwegian Institute for Nature Research, The Polar Environmental Centre, 9296 Tromsø, Norway. jan.o.bustnes@nina.no
Erikstad
Kjell E
KE
Hanssen
Sveinn A
SA
Tveraa
Torkild
T
Folstad
Ivar
I
Skaare
Janncehe U
JU
D000818:Animals; D000871:Anthelmintics / Q000494:pharmacology*; D001110:Arctic Regions; D001947:Breeding; D046091:Charadriiformes / Q000469:parasitology / Q000502:physiology*; D002706:Chlordan / Q000031:analogs & derivatives / Q000097:blood; D052284:Clutch Size / Q000187:drug effects; D003633:Dichlorodiphenyl Dichloroethylene / Q000097:blood; D004785:Environmental Pollutants / Q000097:blood*; D005260:Female; D006581:Hexachlorobenzene / Q000097:blood; D006702:Homing Behavior / Q000187:drug effects; D006843:Hydrocarbons, Chlorinated / Q000097:blood*; D008297:Male; D009425:Nesting Behavior / Q000187:drug effects; D011078:Polychlorinated Biphenyls / Q000097:blood; D012098:Reproduction / Q000187:drug effects*
D000871:Anthelmintics; D004785:Environmental Pollutants; D006843:Hydrocarbons, Chlorinated; D002706:Chlordan; C008743:oxychlordane; D003633:Dichlorodiphenyl Dichloroethylene; D006581:Hexachlorobenzene; D011078:Polychlorinated Biphenyls