Anatomy of the Feather-Winged Beetles Acrotrichis montandoni and Ptilium myrmecophilum (Coleoptera, Ptiliidae)

摘要

The internal morphology of adults and larvae of Acrotrichis montandoni and adults of Ptilium myrmecophilum is described on the basis of the study of LM and TEM of serial sections and total preparations. Specific structural traits related to miniaturization are revealed, the most essential ones are the absence of midgut muscles, reduction of two Malpighian tubules, absence of heart, general reduction of the circulatory system (which is replaced by the fat body), absence of tracheal system in the larval abdomen, strong oligomerization and concentration of the nervous system in the adu reduced size and number of nerve cells; and reduction of the right testis and ovary. The possible factors limiting the further miniaturization in Ptiliidae are the egg size and the volume occupied by the nervous system.