Stayin’ Alive: Endocrinological Stress Responses in Insects

Most stress-related hormones are secreted by specialized neurons as opposed to glandular tissue. In this chapter, the authors use the term hormone regardless of whether the source is a neurosecretory cell or a gland. There is evidence that dopamine is also released as a hormone, although the source neurons are less well studied than the OAergic dorsal unpaired median neurons, and may be species-specific. The peptide adipokinetic hormone is released from the corpora cardiaca by neurosecretory cells. Juvenile hormone and ecdysteroids are critical for development and reproduction, and as such, are well placed to coordinate changes in growth and fecundity in response to stress. Tachykinin-related peptides (TRPs) may be released as hormones during fight-or-flight stress. TRPs are released from neurons and may also be released from the midgut as a circulating hormone in the locust Locusta migratoria and the cockroach Leucophaea maderae.