REGULATION OF RESPIRATORY ACIDEMIA BY THE AUTONOMIC NERVOUS-SYSTEM (COELOPULSE) IN INSECTS AND TICKS

The respiratory patterns exhibited by diapausing adults of Chrysopa ca rnea (Insecta, Neuroptera) and diapausing adults of Ixodes ricinus (Ac ari, Parasitiformes) have been recorded by means of the scanning micro respirographic method. Both these terrestrial arthropods released the respiratory CO2 in the form of discontinuous pulses with a periodicity of several minutes. In Chrysopa, the periodicity, was 2.1 min, each c ycle lasted 9.5 s, and the amount of CO2 produced in one cycle average d 42.26 nL. In Ixodes, the periodicity was 1.3 min, the CO2 pulses las ted only 7 s, and the amount of CO2 produced in one cycle averaged 26. 13 nL. The described cycles in CO2 production, which are called the Pr ague cycles, are regulated by the autonomic nervous system (the coelop ulse) with the centers located in the thoracic ganglia. Some neurohorm onal centers that could be associated with functions of the coelopulse system are also outlined. The possibility that these structures (peri sympathetic neurohemal organs, H-organ) are involved in regulation of the respiratory acidemia is discussed.