For example, among coleopterans pre-oral digestion is carried out by enzymes from the midgut (Cheeseman and Gillott, 1987 and Colepicolo-Neto et al., 1986) and at least in the case of the elaterid Pyrearinus www.selleckchem.com/products/abt-199.html termitilluminans (Coleoptera: Elateridae) ( Colepicolo-Neto et al., 1986), pre-oral digestion includes initial and intermediate digestion. Pre-oral digestion among hemipterans is reported to occur under the action of salivary enzymes and

trypsin in Zellus renardii (Heteroptera: Reduviidae) ( Cohen, 1993) is frequently cited as the main enzyme. Accordingly, a trypsin gene was found to be active in the salivary gland of Lygus lineolaris (Heteroptera: Miridae) ( Zeng et al., 2002). In spite of this, there is evidence of the presence of a cysteine proteinase (probably

a cathepsin L-like proteinase) in salivary glands of L. lineolaris ( Zeng et al., 2002 and Zhu et al., 2003) and Podisus maculiventris (Heteroptera: Pentatomidae) ( Bell et al., 2005). Although both works concluded that serine is more important than cysteine proteinase, their assay conditions do not favor cysteine proteinase action (no activators like cysteine see more were added). Furthermore, the finding that a part of the proteolytic activity in salivary glands of P. maculiventris is inhibited by EDTA ( Bell et al., 2005) deserves further investigation. The inhibition was misinterpreted as due to carboxypeptidases which are not significantly active on intact protein molecules. It is, therefore, more probable that the enzyme inhibited was the metallopeptidase collagenase. This paper was undertaken to evaluate the digestive enzymes in the salivary glands and midgut, as well as the role of a collagenase in pre-oral digestion in a predaceous hemipteran, Podisus nigrispinus (Heteroptera: Pentatomidae), and to provide evidence that pre-oral digestion in this case is actually a pre-oral dispersion of food and that digestion is carried out in midgut, essentially as described before for other non-predaceous

hemipterans. P. nigrispinus was chosen in this study because it is an important predator of agricultural pests worldwide ( De Clercq, 2000), next including in Brazil ( Zanuncio et al., 1994), and because the first evidence of the occurrence of a possible salivary metalloproteinase was described in an insect of the same genus ( Bell et al., 2005). The results described in this paper suggest that a salivary collagenase (a metalloproteinase) injected into prey disrupts its tissues resulting in some cell clusters still seen inside in the midgut of predator and that protein digestion is accomplished mainly in its middle and posterior midgut and carbohydrate digestion mostly in anterior midgut. Adult males of P.