Postembryonic development of leucokinin I‐producing neurons in the brain of insectSpodoptera litura

Abstract

Antisera against the myotropic neuropeptide leucokinin I, originally isolated from head extracts of the cockroach Leucophaea maderae, have been used to investigate the distribution of the leucokinin I‐immunoreactive (LK I‐IR) neurons in the brain of the common cutworm, Spodoptera litura, during postembryonic development. The LK I‐IR neurons are found at the larval stages (excluding first instar larval stage), pupal stages, and adult stage, of which the brains have been examined in this experiment. The number of the LK I‐IR neurons in the brain increases from the second instar larva to the fifth instar larva which has about 32, the largest number in all postembryonic stages. Thereafter, the LK I‐IR neurons begin to decrease in number. During the pupal stages, smaller number of LK I‐IR neurons persist in the brains; 6 or 4. At adult stage the brain contains 8 LK I‐IR neurons. The LK I‐IR cell bodies are distributed in each dorsal cortex of both cerebral hemispheres in the second instar larva and through all...