Why does my 10-month-old want to nurse more?

Last month we had it down to 2 feedings per day -- and she could have skipped one of those. Now she seems to want to nurse several times in the day, and several times at night -- and it doesn't seem to be hunger or thirst, she doesn't want food or drink, she just seems to need the sucking. (Doesn't suck a finger or take a pacifier) She gets all wistful when she sees my , which she never did before. Could she be not getting enough of some nutrient in the solid food I feed her? Is it normal for demand to increase with growth periods or something like that? Maybe she is feeling more insecure lately? I just wonder what you think the most likely explanation is, and if this is common. Thanks