Morphometric changes of corpora allata in Morimus funereus müls. (Cerambycidae) larvae during thermal stress

thesize and release juvenile hormones (JHs). Together with the corpora cardiaca, they also represent a neurohemal organ (S a k a k i b a r a and F u g o, 1990). The activity of CA is regulated by numerous hormonal factors, primarily by allatotropin (stimulatory) and allatostatin (inhibitory) neuropeptides. These allatoregulatory neuropeptides may reach the CA via the hemolymph and/or via nervous connections (S t a y, 2000; G ä d e and H o f f m a n, 2005). Morphometric and ultrastructural studies demonstrate that fluctuations in JH production always accompany changes in CA gland volume, cell size and quantity of cellular components (C h i a n g et al., 1998; P s z c z o l k o w s k i and C h i a n g, 2000; C h a n g et al., 2005). The CA undergo cyclic volumetric changes during the period between two larval ecdyses (N e n a d o v i ć et al., 1993) and during ovarian cycles (C h i a n g and S c h a l, 1994).