Analysis of Anal Secretions from Phlaeothripine Thrips

Abstract

The anal secretions of 16 phlaeothripine thrips species (Thysanoptera: Phlaeothripidae) were studied, including a reinvestigation of three species previously reported. A total of 37 components were detected, including hydrocarbons, acetates, terpenes, carboxylic acids, a quinone, an aromatic compound, and a pyranone compound. The secretions of all species were composed of some of these components, with Xylaplothrips inquilinus possessing as many as 11 components. Of these components, (Z)-9-octadecene, (Z)-9-nonadecene, nonadecadiene, octanoic acid, decanoic acid, geranial, neral, alpha-pinene, beta-pinene, caryophyllene, 2-hydroxy-6-methylbenzaldehyde, and two unidentified monoterpenes [UK-I (M+136) and UK-II (M+168)] were detected for the first time. The chemicals were species-specific; four Liothrips species and three Holothrips species could be distinguished from each other and their congeners by the GC profiles of the ether extracts of their anal secretions. The anal secretions of gall-inducing thrips commonly contained terpenes. of which citral (a mixture of geranial and neral) and beta-acaridial repelled ants or had antifungal activity. The findings suggest that these terpenes play a defensive role and prevent galls from fungal infestation. 3-Butanoyl-4-hydroxy-6-methyl-2H-pyran-2-one, found from three Holothrips spp., caused paralysis in ants. Chemical analysis of anal secretion components is a useful method for the classification of tubuliferan species that are difficult to distinguish on the basis of morphological characters.

Terminal double bonds in the alkenes and acetates of defensive secretion from the thrips Suocerathrips linguis Mound & Marullo, 1994 (Thysanoptera: Phlaeothripidae)

“…Unsaturated aliphatic hydrocarbons in anal secretions of Thysanoptera were described by Howard et al (1987) and Suzuki et al (2004), e.g. heptadecadiene in some Docessissophothripini.…”

“…A heptadecadiene is also the main compound in Holothrips yuasai Karny. A nonadecadiene in Thysanoptera was detected in Eugynothrips (Loepothrips) intorquens (Karny) by Suzuki et al (2004); however, it is not structurally identified. Alkanes and alkenes in insect secretions take on various functions, e.g.…”

“…Secretions of various species of the family Phlaeothripidae (Tubulifera) contain long-chain, solid acetates, which are dissolved in liquid long-chain alkanes, e.g. hexadecyl acetate with pentadecane (1:2) in Gynaikothrips ficorum Zimmerman (Suzuki et al 1989(Suzuki et al , 2004.…”

Use of Expanding Foam for Confining Thrips in Cages on Cowpea, Vigna unguiculata (L.) Walp, Flowers

“…Despite the thrips occasionally reaching high densities (>20 adults/ leaf), they may be protected from predators by defensive allomones as is known from other thrips species (Blum et al 1992;Suzuki et al 2004). These defenses are characteristically produced in thrips when disturbed and can be recognized by the raised abdomen tip that secretes a droplet of repellent liquid (Lewis 1973).…”

ALLELOCHEMICS: AN INTERACTION BETWEEN PHYTOPHAGЕS AND Pseudomonas syringae pv. tomato ON TOMATO Solanum lycopersicum PLANTS

“…In fact, 2-methylbutanoic acid and dodecane are components of the thrips pheromone and allomons [29,30]. Western flower thrips showed a significant electro-antennographic response to-humulen [31], and (E)-β-ocimene was determined as minor component with synergetic activity in composition of aggregated pheromone of this pest [32].…”