Oily substances from gastral intersegmental glands of the antPachycondyla tridenta (Ponerinae): Lack of pheromone function in tandem running and antibiotic effects but further evidence for lubricative function

Protein Components of the Arthrodial Membrane Gland in a Neotropical Harvestman (Arachnida, Opiliones)

The content of arthrodial membrane glands in arthropods has seldom been studied. Here, we have analyzed the proteins of the arthrodial membrane gland of the trochanter-coxa articulation of the fourth pair of legs in the harvestman Mischonyx cuspidatus via reverse-phase high-performance liquid chromatography (RP-HPLC), polyacrylamide gel electrophoresis (PAGE), and nanoscale liquid chromatography coupled to mass spectrometry (nLC-MS/MS) analysis. Most of the fractions studied are hydrophobic, being proteins with molecular weights of ∼28, 62, and ∼198 kDa. These proteins seem to be homologous to proteins involved in product secretion, cytoskeleton, protein binding, cellular metabolism, and antimicrobial action among others. Lubricant function is also possible based on the literature. We were able to identify 147 proteins in the inner region, 91 proteins from the outer dorsal region, and 36 proteins from the outer ventral region. Some proteins are present only in one of these regions and some are shared by one or more regions. Our work provides, to the best of our knowledge, the first proteome characterization of the content of an arthrodial membrane gland in arachnids. Dataset Identifier: ftp://massive.ucsd.edu/MSV000087195/.

Insects use lubricants to minimize friction and wear in leg joints

A protein-based lubricating substance is discovered in the femoro-tibial joint of the darkling beetle Zophobas morio (Insecta). The substance extrudes to the contacting areas within the joint and appears in a form of filiform flows and short cylindrical fragments. The extruded lubricating substance effectively reduces the coefficient of sliding friction to the value of 0.13 in the tribosystem glass/lubricant/glass. This value is significantly lower than 0.35 in the control tribosystem glass/glass and comparable to the value of 0.14 for the tribosystem glass/dry PTFE (polytetrafluoroethylene or Teflon). The study shows for the first time that the friction-reducing mechanism found in Z. morio femoro-tibial joints is based on the lubricant spreading over the contacting surfaces rolling or moving at low loads and deforming at higher loads, preventing direct contact of joint counterparts. Besides Z. morio, the lubricant has been found in the leg joints of the Argentinian wood roach Blaptica dubia.

Diversity and morphology of abdominal glands in workers of the ant genus Myopias (Formicidae, Ponerinae)

Histological examination of serial sections through the abdomen of workers of three species of Myopias ants revealed the presence of several exocrine glands. These include the common venom and Dufour glands as well as the pygidial gland, but also more specific sternal glands and glands associated with the sting base and the gonostyli. Two of these glands have not been reported previously among ants: one is the paired oblong plate gland, that occurs next to the oblong plate and may have a pheromonal function. The other novel gland is the paired sting shaft gland, that occurs at the dorsal side in the proximal region of the sting shaft. A remarkable characteristic of these Myopias ants is that all glands of class-3 show ducts with gradually widening internal diameter. Myopias emeryi shows a clearly more simple variety of abdominal glands than Myopias maligna and M. sp.1.