Jan. 8, 2013 — In mam mals such as rodents that raise their young as a group, infants will nurse from their mother as well as other females, a dynamic known as allo suck ling. Ecol o gists have long hypoth e sized that allo suck ling lets new borns stock pile anti bod ies to var ious dis eases, but the exper imen tal proof has been lacking until now.
An in-press report in the jour nalMam malian Biol ogy found that infant Mon go lian ger bils that suck led from females given sep a rate vac cines for two dif fer ent dis eases wound up with anti bod ies for both illnesses.
The find ings not only demon strate the poten tial pur pose of allo suckling, but also pro vide the first framework for fur ther study ing it in the wild by using trace able anti bod ies, said first author Romain Gar nier, a postdoc toral researcher in Prince ton University’s Depart ment of Ecol ogy and Evo lu tion ary Biol ogy. Gar nier con ducted the research with Syl vain Gan don and Thierry Boulin ier of the Cen ter for Func tional and Evo lu tionary Ecol ogy in France, and with Yan nick Chaval and Nathalie Charbon nel at the Cen ter for Biol ogy and Man age ment of Pop u la tions in France.
Gar nier and his coau thors admin istered an influenza vac cine to one group of female ger bils, and a vaccine for Bor re lia burgdor feri — the bac te r ial agent of Lyme dis ease — to another group. Once impreg nated, female ger bils from each vac cine group were paired and, as the gerbils do in nature, kept sep a rate from the male ger bils to birth and rear their young. In the wild, females can choose which young to nurse and infant ger bils can like wise choose which female to suckle. In the typ i cal lab, how ever, one male, one female and their young are housed together, the researchers wrote.
When screened upon birth, all the infant ger bils had no detectable anti bod ies against influenza while one had antibod ies against B. burgdor feri, accord ing to the paper. But after eight days of nurs ing, all the infants con tained high lev els of anti bod ies for both influenza and B. burgdor feri, sug gest ing that the females nursed the young — their own and those of the other female — evenly. These results sug gest that allosuck ling is indeed intended to expose new born ani mals to a host of antibodies.
This ben e fit sheds light on a pecu liar arrange ment in coop er ative mam mals that ecol o gists have puz zled over, the authors wrote. In social species, females usu ally fall into dom i nant or sub or di nate groups with the sub or di nate females typ i cally involved in tend ing to the young pro duced by dom i nant females. Yet, in many cases, sub or di nate females are “allowed” to breed. Gar nier and his col leagues sug gest that the poten tially larger anti body pool avail able through nurs ing might be one of the rea sons why.
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- Romain Garnier, Sylvain Gandon, Yannick Chaval, Nathalie Charbonnel, Thierry Boulinier. Evidence of cross-transfer of maternal antibodies through allosuckling in a mammal: Potential importance for behavioral ecology. Mammalian Biology – Zeitschrift für Säugetierkunde, 2012; DOI:10.1016/j.mambio.2012.11.004