Plant Bugs Miridae

The sex pheromone of Trigonotylus caelestialium represents an interesting case because the three components of the blend (hexyl hexanoate, ( )-2-hex-enyl hexanoate, and octyl butyrate, -10 5 1) are produced by both sexes, along with a number of similar compounds [127]. The female must be able to manipulate the blend ratio that she releases in order to be able to attract males with a subset of compounds that are otherwise shared by both males and females. In field trials, dose also appeared to be important, with doses in the low microgram range remaining attractive to males for several days [127]. 

A preliminary report has identified pheromone blends for two tropical species, Distantiella theobroma and Suhlbergella singularis [146]. Females of both species produce hexyl (R)-3-hydroxybutyrate and its ( )-2-butenoate ester (-1 2). In initial field trials, male S. singularis were attracted to the blend. Further work is in progress to conclusively identify and optimize blends for each species [146]. 

Electroantennogram studies have also proven fruitless in the search for Lygus bug pheromones. Antennae from males and females respond to numerous compounds in extracts from both sexes, and although some sex-specific differences have been noted in the magnitudes of antennal responses, no obvious pheromone candidates have emerged [147,148]. Even with abundant evidence that females use a volatile sex attractant, Lygus spp. pheromones have resisted all attempts at identification for more than 30 years. 

---