Insulin the simplest unicellular eukaryotes. Apart from animals, insulin-like proteins are also known to exist in the Fungi and Protista kingdoms. Insulin is produced by beta cells of the pancreatic islets in most vertebrates and by the Brockmann body in some teleost fish. Cone snails "Conus geographus" and "Conus tulipa", venomous sea snails that hunt small fish, use modified forms of insulin in their venom cocktails. The insulin toxin, closer in structure to fishes' than to snails' native insulin, slows down the prey fishes by lowering their blood glucose levels. The preproinsulin precursor of insulin is encoded by the "INS" gene.
Insulin resistance a socio-ecological adaptation with insulin being the means for differentiating energy allocation to various components of the body and insulin sensitivity an adaptation to manipulate where the energy is diverted to. The Behavioral Switch Hypothesis posits that insulin resistance results in two methods to alter reproductive strategies and behavioral methods. The two strategies are coined as “r to K” and “soldier to diplomat.” The r to K strategy involves diverting insulin via placenta to the fetus. This has demonstrated weight gain in the fetus, but not the mother indicating a method of increased parental investment (K strategy). In the “soldier