Abstract Diplopods are terrestrial arthropods important for the dynamics of terrestrial ecosystems. One of the reasons for that can be their low predation rate due to their defensive secretion. Thus, Orthoporus fuscipes, a species belonging to this group and endemic to northeastern Brazil, was investigated as to its population structure and chemical constituents of defensive secretion. The population structure showed that females are larger and have greater mass than do males, along with negative allometric growth between males and females. The defensive secretion hexane extract was submitted to fractionation using SiO2 open-column chromatography and the gas chromatographic coupled to mass spectrometric analysis was applied in the fraction possibilities to identify major fatty acid methyl esthers, along with minor alkanes, alkenes and fatty acids derivatives and the known quinoids 2-methoxy-3-methylhydroquinone, 2-methoxy-3-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone and 2,3-dimethoxyhydroquinone. In addition, the cytochrome oxidase I sequence for the species was deposited for the first time. ecosystems Thus fuscipes Brazil SiO opencolumn open column esthers alkanes 2methoxy3methylhydroquinone, 2methoxy3methylhydroquinone methoxymethylhydroquinone 2 methoxy 3 methylhydroquinone, methylhydroquinone 2-methoxy-3-methylhydroquinone 2methoxy3methyl1,4benzoquinone, 2methoxy3methyl14benzoquinone methoxymethylbenzoquinone 1,4 benzoquinone, 1 4 benzoquinone 2-methoxy-3-methyl-1,4-benzoquinone 2,3dimethoxy1,4benzoquinone 23dimethoxy14benzoquinone dimethoxybenzoquinone 2,3 dimethoxy 2,3dimethoxyhydroquinone. 23dimethoxyhydroquinone dimethoxyhydroquinone dimethoxyhydroquinone. 2,3-dimethoxyhydroquinone addition time 2methoxy3methyl1 4benzoquinone 2methoxy3methyl1,4benzoquinone 14 1, 3dimethoxy1 23 2, 3dimethoxyhydroquinone 2,3dimethoxyhydroquinone methoxymethyl 2methoxy3methyl 3dimethoxy

Abstract Background: The composition of the venom from solitary wasps is poorly known, although these animals are considered sources of bioactive substances. Until the present moment, there is only one proteomic characterization of the venom of wasps of the family Pompilidae and this is the first proteomic characterization for the genus Pepsis. Methods: To elucidate the components of Pepsis decorata venom, the present work sought to identify proteins using four different experimental conditions, namely: (A) crude venom; (B) reduced and alkylated venom; (C) trypsin-digested reduced and alkylated venom, and; (D) chymotrypsin-digested reduced and alkylated venom. Furthermore, three different mass spectrometers were used (Ion Trap-Time of Flight, Quadrupole-Time of Flight, and Linear Triple Quadruple). Results: Proteomics analysis revealed the existence of different enzymes related to the insect’s physiology in the venom composition. Besides toxins, angiotensin-converting enzyme (ACE), hyaluronidase, and Kunitz-type inhibitors were also identified. Conclusion: The data showed that the venom of Pepsis decorata is mostly composed of proteins involved in the metabolism of arthropods, as occurs in parasitic wasps, although some classical toxins were recorded, and among them, for the first time, ACE was found in the venom of solitary wasps. This integrative approach expanded the range of compounds identified in protein analyses, proving to be efficient in the proteomic characterization of little-known species. It is our understanding that the current work will provide a solid base for future studies dealing with other Hymenoptera venoms. Background known substances moment Methods conditions namely A (A B (B C (C trypsindigested trypsin digested D (D chymotrypsindigested chymotrypsin Furthermore Ion TrapTime Trap Time Flight QuadrupoleTime Quadrupole Quadruple. Quadruple . Quadruple) Results insects insect s angiotensinconverting angiotensin converting ACE, , (ACE) hyaluronidase Kunitztype Kunitz type Conclusion arthropods recorded them time analyses littleknown little species venoms (ACE