Male endogenous pheromonal component of Bactrocera carambolae (Diptera: Tephritidae) deterred gecko predation

Abstract

Geckos consumed immature Bactrocera carambolae males readily, but their consumption was reduced significantly when offered sexually mature males. They showed a similar aversion for sexually mature males previously fed with methyl eugenol. When male flies at different ages were offered to starved geckos, geckos' consumption showed an age-related anti-feeding effect, which was concomitant with the production trend of 6-oxo-1-nonanol, a major endogenous component synthesized in the male rectal gland. The production of 6-oxo-1-nonanol was also age-related and corresponded with sexual maturity as reported previously. Topical application of the authentic chemical of 6-oxo-1-nonanol onto the thorax of female fruit flies, at the amount normally detected in the rectal gland of a sexually mature male, had the same deterrent effect against geckos.

Temporal accumulation of phenylpropanoids in male fruit flies, Bactrocera dorsalis and B. carambolae (Diptera: Tephritidae) following methyl eugenol consumption

“…the average peak production of the major component, 6-oxo-1-nonanol, was 26.1 ± 12.5 µg/male; [Wee & Tan 2005a]) and at the same time, engaging in ME foraging activity. While CF is less potent than DMP in repellent/deterrent activity, B. carambolae also uses the endogenously synthesized pheromonal compound as allomone to deter vertebrate predation (Wee & Tan 2005b). From an evolutionary perspective, this study suggests that B. dorsalis is probably more advance than B. carambolae in the species speciation within the dorsalis complex pertaining to their co-adaptation/coevolutionary relationship with pharmacophagy of plant secondary metabolites.…”

3-Oxygenated α-ionone derivatives as potent male attractants for the solanaceous fruit fly, Bactrocera latifrons (Diptera: Tephritidae), and sequestered metabolites in the rectal gland

“…There seems to be a kind of reductive-oxidative enzymatic equilibration in these biotransformation processes (Nishida et al, 2009). Selective incorporation of these metabolites suggested their possible role as a male sex pheromone component and/or allomone to deter predators, similar to other cases of Bactrocera species that use phenylpropanoid volatiles to attract conspecific females as well as defense substances (Nishida and Fukami, 1990;Shelly and Dewire, 1994;Shelly and Villalobos, 1995;Tan and Nishida, 1998;Khoo et al, 2000;Wee and Tan, 2005;Wee et al, 2007). An artificial mixture of major rectal volatiles (N-3-methylbutyl acetamideϩ3-oxo-a-ionol (4)) induced some shortrange attraction in virgin females in lab cage tests (Nishida, unpublished), and further behavioral tests are in progress to clarify the possible role of these pharmacophagously acquired rectal metabolites in the mating and/or defense system of B. latifrons.…”

Recent Advancements in Studies on Chemosensory Mechanisms Underlying Detection of Semiochemicals in Dacini Fruit Flies of Economic Importance (Diptera: Tephritidae)

“…Although most components have not been functionally characterized, 1-nonanol analogs that accumulate in the rectal glands as major aliphatic components have shown semiochemical activities in some fruit flies. For example, 6-oxo-1-nonanol was detected in the male rectal glands of B. carambolae, a species closely related to B. dorsalis, together with a minor component, 1,6-nonanediol [138,139]. The amount of 6-oxo-1-nonanol increased concomitantly with sexual maturity and triggered a chemotactic behavior known as zigzag flight in conspecific females [140].…”

“…carambolae , a species closely related to B . dorsalis , together with a minor component, 1,6-nonanediol [ 138 , 139 ]. The amount of 6-oxo-1-nonanol increased concomitantly with sexual maturity and triggered a chemotactic behavior known as zigzag flight in conspecific females [ 140 ].…”