I was thinking about how bees can produce honey and human can eat it. After that I came up with question. What are the smallest animal that can produce food for human?
It would depend on what you consider food, but if you consider things that contribute to food substances (e.g. food dyes) then cochineal scale mites are only about 5 mm (0.2 in) long and produce a red dye that is commonly used as a food colorant.
There are also several ant species of similar size that are eaten as food sources. For example, Liometopum apiculatum (6-7 mm adult) grubs are/were harvested as a food source in parts of the USA and Mexico.
$\begingroup$ I cannot find the size of Chaoborus edulis but they might be a contender: Kunga cake. $\endgroup$– RolandJan 16 at 8:07
$\begingroup$ @Roland I knew of that one, but didn't know the name or which region of Africa it was from, so I didn't try to find it. You should write your own answer based on this. Bugguide.net suggests 8-10 mm for the genus. $\endgroup$– bob1Jan 16 at 9:04
$\begingroup$ I'll throw in my 2 cents and say fungi, especially yeast (or other fungi used for blue-cheese etc.), typically measuring 3–4 µm in diameter and could be perceived as 'producer' since it's converting sugars via fermentation.. $\endgroup$ Jan 16 at 12:42
3$\begingroup$ @iLuvLogix That's not an animal as OP requested. $\endgroup$– bob1Jan 16 at 19:07
$\begingroup$ @bob1 Thanks for pointing that out - a quick search revealed that they seem to have a seperate kingdom of their own (besides plants and animals) - my bad.. $\endgroup$ Jan 17 at 15:31