Food is a serious business, for humans, for non-human animals, and for plants. Humans are the only animals that have monetised and trade food, although some spiders, crickets, and birds engage in nuptial gifts of food to facilitate mating. In crickets, males offer food produced from special glands to feed females; spider males themselves form the tasty morsel during the mating process, and birds offer favoured fruit or insects to females in courtship rituals. Plants make their own food, for which they need access to light.