HORMONAL-REGULATION OF HEMOLYMPH LIPID-CONCENTRATION IN MONARCH BUTTERFLY, DANAUS-PLEXIPPUS

Selective elevation of hemolymph lipid can be demonstrated in flying Monarch Butterflies. In addition, the low levels of hemolymph lipid characteristic of wild-caught postmigratory Monarchs remain low in winter conditions but are rapidly elevated when winter animals are placed in summer conditions. Abdominal, but not neck, ligatures prevent the elevation of hemolymph lipid characteristic of postmigratory animals placed at summer conditions. Injection of extracts of known cephalic neuroendocrine centers cause specific elevation of hemolymph lipid in both intact animals and isolated abdomens. Hormone-like dose-response and time-course curves and elevation of hemolymph diglycerides occur in response to injection of active extracts. Monarch head, brain, corpora cardiaca-corpora allata, thoracic nerve cord extracts, and Tenebrio head extracts all contain material acting to significantly elevate Monarch hemolymph lipids. By contrast, extracts of Monarch abdominal nerve cords, or Apis or Periplaneta heads, and synthetic crustacean red pigment concentrating hormone are without effect. The active factor in Monarch heads is sensitive to proteolytic enzymes, but resistant to heat and hydrogen peroxide. © 1978.