The defensive secretion of Carabus lefebvrei Dejean 1826 pupa (Coleoptera, Carabidae): Gland ultrastructure and chemical identification

Abstract

This study documents the defensive function of flavored humor secreted by the abdominal glands of Carabus lefebvrei pupae. The morphology and the ultrastructure of these glands were described and the volatile compounds of glands secretion were identified by gas chromatography/mass spectrometry. The ultrastructure analysis shows an acinose complex formed by about 50 clusters. Each cluster has 20 glandular units and the unit-composed of one secretory and one canal cell lying along a duct-belongs to the class 3 cell type of Quennedey (1998). In the cytoplasm, the secretory cell contains abundant rough endoplasmatic reticula, glycogen granules, numerous mitochondria, and many well-developed Golgi complexes producing electron-dense secretory granules. Mitochondria are large, elongated, and often adjoining electronlucent vesicles. The kind and the origin of secretory granules varying in size and density were discussed. The chemical analysis of the gland secretion revealed the presence of a mixture of low molecular weight terpenes, ketones, aldehydes, alcohols, esters, and carboxylic acids. Monoterpenes, especially linalool, were the major products. We supposed that ketones, aldehydes, alcohols, esters, and carboxylic acids have a deterrent function against the predators and monoterpenes provide a prophylaxis function against pathogens.

Measurement of Body Condition in a Common Carabid Beetle,Poecilus cupreus: A comparison of Fresh Weight, Dry Weight, and Fat Content

“…In carabids, high energetic demands of pupation connected with production of defensive secretions against predators result in newly emerged adults with often completely exhausted energy reserves (Giglio et al 2009). Fresh weight and fat content generally increase in adult carabids in time, and this increase is especially apparent in the first few weeks after eclosion (Chaabane et al 1997).…”

Profiling and characterization of volatile secretions from the European stink bug Graphosoma lineatum (Heteroptera: Pentatomidae) by two-dimensional gas chromatography/time-of-flight mass spectrometry

“…This fiber was also chosen as the best for the collection of volatile mixtures of a similar type as those expected for G. lineatum [7][8][9][10], such as e.g. some plant volatiles [30,31], coleopteran insect secretions [32], and honey [16]. An extraction temperature of 25 • C was used, because this temperature is close to insect defense natural conditions.…”

Current knowledge on exocrine glands in carabid beetles: structure, function and chemical compounds

“…Ultrastructural analyses have shown that this exudate is secreted by an acinose abdominal complex of exocrine glandular units (Giglio et al 2009). The independent glandular unit consists of a single secretory cell, a duct and its associated cell and belongs to gland cell class 3 according to the classification of Quennedey (1998).…”