Most aphid species carry obligate symbionts in the form of various strains of the bacterium Buchnera aphidicola. The bacteria cannot survive outside the aphid and the aphid relies on them to synthesize various amino acids (usually trypotophan) that it cannot produce for itself. The bacteria are housed in a special cellular organelle, a bacteriocyte, and are inherited vertically - every developing aphid embryo receives symbionts through special processes growing from neighboring maternal bacteriocytes.
Things got more interesting with the discovery of a series of 'secondary' aphid sympbiotes belonging to various other bacterial genera. These are not completely essential for aphid survival, but some provide the aphid with interesting and unique phenotypic abilities (new host range, change in thermal tolerance, etc.). Cytological studies have revealed these bacteria 'piggy-backing' on the bacteriocytes of the primary symbionts to ensure their inheritance, although they are not actually housed within them (yet?) and their inheritance is not as consistent (usually less than 100%).
So my question is, would you consider the vertical inheritance of such symbionts to constitute a valid form of epigenetic inheritance, at least relative to the genome of the aphid ?
I guess we first have to decide whether the symbionts still deserve status as separate organisms, or whether the aphid+symbionte can be considered 'all one organism' at this point, in which case I guess the answer would be 'yes'.