What do larvae of fleas primarily feed on?

Larvae of fleas primarily feed on dried blood found in the feces of adult fleas. As adult fleas feed on the blood of their hosts, they excrete a portion of that blood, which the larvae then consume. This diet is particularly important for their development as they require the nutrients found in blood to grow and eventually pupate. The use of dried blood in feces as a food source is a unique adaptation that allows flea larvae to thrive in environments where adult fleas are present, ensuring that they have access to the necessary nutrients for their growth lifecycle.

Other options, while they may seem plausible as food sources, do not align with the specific dietary needs of flea larvae. Food crumbs and carpet fibers do not provide the essential nutrients required for larval development, and while pet food could theoretically offer some nutritional value, it is not the primary source of sustenance for flea larvae. Thus, the correct focus is on the dried blood found in the feces of adult fleas as their main food source.