The present invention relates to a gel used as a source of water and/or nutrients for rearing insects. The gel comprises 90 to 99.6% by weight of an aqueous substrate comprising at least 25% by weight, of the total weight of the aqueous substrate, of a liquid coproduct from agro-industry, 0.3 to 2% by weight of a gelling agent, and 0.1 to 5% by weight of a preservative, the percentages by weight of aqueous substrate, gelling agent and preservative being expressed over the total weight of the gel.