Long-term effects of infant malnutrition on the behaviour of adult meadow voles, Microtus pennsylvanicus

Several studies on laboratory mice and rats have shown that malnutrition during infancy has a variety of long-term effects extending into adulthood. These effects are manifested in reproduction, including reduced litter sizes, reduced growth rates of the young, and skewed sex ratios, and in behaviour, including increased nervousness, decreased problem-solving ability, and reduced pup retrieval to the nest by the mother. This study investigated the effects of early malnutrition on behaviour in adult meadow voles, Microtus pennsylvanicus. Experimental animals received a standard diet diluted with pure cornstarch (1 part standard diet to 2 parts pure cornstarch) through their mothers during lactation and directly for 3 weeks postweaning. Control individuals always received the standard diet ad libitum. The cumulative duration of 13 behaviours was measured in 10-min trial periods and compared between experimental and control animals. Experimental females differed from control females in a number of behaviours, especially those involving high activity levels, whereas experimental and control males showed little difference in the behaviours performed. The behaviour profile of previously malnourished females was similar to those of both control and experimental males. Increased activity, resulting from poor nutrition, may have consequences for dispersal and spacing behaviour.