ABSTRACT
There are three major ways that microbes play a role in insect rearing: (1) they may be symbionts that live in or on the bodies of insects in a neutral relationship (sometimes known as commensalism) or in a way that is mutually benecial to themselves and their insect hosts (a partnership relationship known as mutualism), (2) they may occur as parasites or pathogens of the insects that we are trying to rear, and (3) they may occur as contaminants of the diets or other rearing materials in our cultures. In the rst type, the symbionts may be essential to the well-being of the insects, most often in a nutritionally benecial relationship where the microbe guest repays its host’s hospitality by synthesizing an otherwise unavailable or poorly available nutrient. Termites and their microbes are excellent examples of such a mutualism as are cockroaches and their symbionts and most homopterans and their microbes. In using articial diets for insects that rely on such relationships, the danger is not in contamination but rather in the disruption of the relationship by inadvertent removal of the microbe or of its means of gaining entry in or access to the host. Even with the so-called commensals, it is possible that there is a cryptic benet (i.e., a hidden mutualism) that we may disrupt by our rearing efforts. These relationships are further discussed in Chapter 7.
