S-isorobinal as the female sex pheromone from an alarm pheromone emitting mite, Rhizoglyphus setosus

Abstract

The female sex pheromone of Rhizoglyphus setosus Manson (Astigmata: Acaridae) was identified as S-isorobinal (4S-4-isopropenyl-3-oxo-1-cyclohexene-1-carboxyaldehyde), which stimulated males sexually and enhanced the frequency of the male's tapping and mounting behavior. Although the female hexane extract indicated no sign of sex pheromone activity against tested males, possibly due to the presence of the alarm pheromone neryl formate, an SiO2 column fraction containing isorobinal elicited sex pheromone activity at a dose of one female equivalent. The stereochemistry of natural isorobinal was identified as S by an HPLC using a chiral column. Both S- and R-isorobinals exhibited maximum activity at the same dose of 1 and 10 ng with a convex dose-response relationship. Amounts of S-isorobinal were determined to be 11.7 +/- 1.0 ng per female and 6.4 +/- 1.3 ng per male by GLC. This is the second example of two pheromones (the alarm pheromone neryl formate, and the sex pheromone S-isorobinal) demonstrated to be components of the same opisthonotal gland secretion.

Synthesis of (+)-(S)-isorobinal together with its antipod, a cyclic monoterpene functioning as the sex pheromone of Rhizoglyphus setosus and its distribution among Astigmata

“…"oki", 2) without any biological activity, and was then re-identified as the sex pheromone of R. setosus, together with its S stereochemistry. 4) In this study, the stereochemistry of 1 present in each corresponding extract of two species, the unidentified Rhizoglyohus sp. "oki" and Rhizoglyohus sp.…”

“…3) (S)-Isomer of 1 has been demonstrated as the female sex pheromone of the related mite, Rhizoglyphus setosus (Acari: Acaridae), 4) using both enantiomers of 1 prepared by a group from Tohoku University 5) and also by us. Herein we report the syntheses of both enantiomers to determine the stereochemistry and the natural distribution of 1 among Astigmata.…”

Chemical Ecology of Astigmatid Mites LXXIII. Neral as an Alarm Pheromone of the Acarid Mite, Oulenzia sp. (Astigmata: Winterschmidtiidae)

“…Active components of these pheromones are secreted from a pair of opisthonotal glands present in each species (Kuwahara et al, 1979 and1980;Mizoguchi et al, 2003). Chemical structures of the pheromones so far known are classified into three groups; 1) monoterpenes, 2) aromatics and 3) hydrocarbons (Kuwahara, 1999).…”

“…Other than alarm pheromones, sex and aggregation pheromones are also present as the same gland components of Astigmata (Kuwahara et al, 1980;Mizoguchi et al, 2003), and it is reasonable to understand that each species can handle a kind of pheromone function within the three. Recently, it has been realized that a species of mites can manipulate at least two kinds of pheromones (Kuwahara, 2001), such as found in Rhizoglyphus robini where a combination of the alarm and sex pheromones (neryl formate and α-acaridial, respectively) present in the same gland is manipulated to show each own function (Mizoguchi et al, 2003), and as found in Schwiebea elongata where neral functions not only as an alarm pheromone at a high dose but also as an attractant at a low dose, possibly an aggregation pheromone (Nishimura et al, 2002).…”

“…Recently, it has been realized that a species of mites can manipulate at least two kinds of pheromones (Kuwahara, 2001), such as found in Rhizoglyphus robini where a combination of the alarm and sex pheromones (neryl formate and α-acaridial, respectively) present in the same gland is manipulated to show each own function (Mizoguchi et al, 2003), and as found in Schwiebea elongata where neral functions not only as an alarm pheromone at a high dose but also as an attractant at a low dose, possibly an aggregation pheromone (Nishimura et al, 2002). Therefore, a new identification of the alarm phero mone from an unidentified mite Oulenzia sp.…”