Stylopsal: The First Identified Female-produced Sex Pheromone of Strepsiptera

Abstract

A female-produced sex pheromone of Stylops muelleri was identified as an unusually branched saturated aldehyde (9R)-3,5-syn-3,5,9-trimethyldodecanal. We named it stylopsal. Its structure was established by using mass spectrometry, infrared spectroscopy, and organic synthesis of candidate compounds. The synthetic standard of (9R)-3,5-syn-3,5,9-trimethyldodecanal gave identical chromatographic and mass spectrometric data as the natural pheromone and also was active in electroantennographic and behavioral assays. The female fat body lipids contained the corresponding fatty acid, indicating a possible link between lipid metabolism and the pheromone biosynthesis.

We do not select, nor are we choosy: reproductive biology of Strepsiptera (Insecta)

“…There is emerging evidence to suggest that receptive female Strepsiptera attract the short-lived males by means of a long-range sex pheromone (Cva cka et al, 2012;Tolasch et al, 2012). Males sense airborne and contact pheromones of a prospective mate through chemoreceptors on their antennae and maxillary palps, and through sensory hairs on their tarsi and aedeagi.…”

“…It elicits strong responses from male antennae in electrophysiological recordings and is strongly attractive to males in behavioural bioassays (Tolasch et al, 2012). Males approach and walk on pheromone impregnated filter paper with their aede-agus in an upright position (Cva cka et al, 2012;Tolasch et al, 2012). Female S. melittae continue to release pheromones until they mate, upon which they immediately and drastically decrease pheromone emission (Tolasch et al, 2012).…”

Total Synthesis, Stereochemical Assignment, and Field‐Testing of the Sex Pheromone of the Strepsipteran Xenos peckii

“…Comparison of spectral data derived from these materials to those of the natural pheromone, along with results from a field trapping experiment, unambiguously demonstrate that (3 R ,5 S ,9 R ,7 E ,11 E )‐3,5,9,11‐tetramethyl‐7,11‐tridecadienal is the X. peckii sex pheromone. The pheromone differs both in its unsaturation and termination of the polyketide chain from the recently reported ( R , R , R )‐3,5,9‐trimethyldodecanal ( 2 ) pheromone of the bee parasitoids S. mellittae and S. muelleri . Despite these differences, the two strepsipteran pheromones still bear an astounding resemblance not only in their molecular structure and functional group but also in their stereochemistry, suggesting similar pathways for their biosyntheses.…”

“…She emits a long‐range, male‐attractant sex pheromone, which we recently identified as (7 E ,11 E )‐3,5,9,11‐tetramethyl‐7,11‐tridecadienal ( 1 ) (Figure ) . While this structurally unusual pheromone resembles that of the bee parasitoids S. mellittae and S. muelleri (Strepsiptera: Stylopidae) [(3 R ,5 R ,9 R )‐trimethyldodecanal ( 2 )], these two aldehydes (i.e., 1 and 2 ) are the only pheromones known in the entire order Strepsiptera.…”

The unusual eyes of Xenos peckii (Strepsiptera: Xenidae) have green- and UV­-sensitive photoreceptors

“…Males pupate without exiting their hosts, and only later eclose, becoming airborne immediately. Mature, unmated females emit a sex pheromone (Cva cka et al, 2012;Tolasch et al, 2012), which attracts adult males ( Fig. 1A) through olfaction, while females also protrude their cephalothorax out of the wasp, potentially providing an additional visual signal.…”