Nursery pollination by a moth in Silene latifolia: the role of odours in eliciting antennal and behavioural responses

Abstract

Summary• Since the 1970s it has been known that the nursery pollinator Hadena bicruris is attracted to the flowers of its most important host plant, Silene latifolia , by their scent. Here we identified important compounds for attraction of this noctuid moth.• Gas chromatographic and electroantennographic methods were used to detect compounds eliciting signals in the antennae of the moth. Electrophysiologically active compounds were tested in wind-tunnel bioassays to foraging naïve moths, and the attractivity of these compounds was compared with that to the natural scent of whole S. latifolia flowers.• The antennae of moths detected substances of several classes. Phenylacetaldehyde elicited the strongest signals in the antennae, but lilac aldehydes were the most attractive compounds in wind-tunnel bioassays and attracted 90% of the moths tested, as did the scent of single flowers.• Our results show that the most common and abundant floral scent compounds in S. latifolia , lilac aldehydes, attracted most of the moths tested, indicating a specific adaptation of H. bicruris to its host plant.

Three floral volatiles contribute to differential pollinator attraction in monkeyflowers (Mimulus)

“…In Silene latifolia, for example, the pollinating moth Hadena bicruris responds most strongly to lilac aldehydes (Dötterl et al, 2006), despite the presence of more than 40 volatiles in the total bouquet (Jürgens et al, 2002); these lilac aldehydes alone were able to replicate the behavioral effects of the full floral bouquet where other bouquet components were not. In work with S. latifolia and the closely related S. dioica, manipulating the emission of one key volatile, phenylacetaldehyde, had significant effects on pollen transfer; when the two species had similar levels of phenylacetaldehyde, interspecific transmission of pollen increased (Waelti et al, 2008).…”

Veratrole Biosynthesis in White Campion

“…The majority of variation in odor between the bouquets of the flowers from the two continents is attributed to veratrole emission, which is frequently absent in the scent bouquet of North American white campion . Although veratrole is a potent attractant to H. bicruris (Dötterl et al, 2006), this specialist pollinator did not accompany white campion to North America (Wolfe, 2002). In this population, the flower visitors are typically generalist insect pollinators (Young, 2002); thus, selection pressure on veratrole synthesis is presumably absent, contrary to European white campion, whose reproductive success apparently depends on the emission of this floral volatile (Dötterl et al, 2006).…”

“…Among the volatiles emitted by the male and female flowers of white campion is veratrole (1,2-dimethoxybenzene). Veratrole is one of only seven compounds emitted by white campion that elicit strong behavioral responses in H. bicruris (Dötterl et al, 2006). Following pollination, the emission of veratrole drastically decreases while the emission of other behaviorally active compounds remains unchanged (Muhlemann et al, 2006).…”

CYP76C1 (Cytochrome P450)-Mediated Linalool Metabolism and the Formation of Volatile and Soluble Linalool Oxides in Arabidopsis Flowers: A Strategy for Defense against Floral Antagonists

“…Bioassays with pure compounds further confirmed that preference for mutant flowers resulted from an attraction to linalool and from the lack of defensive volatiles and stored products (linalool oxides). It has been shown that lilac compounds are important in a specialized nursery pollination system for recognition by the noctuid moth nursery pollinator of white campion (Silene latifolia) (Dötterl et al, 2006b(Dötterl et al, , 2007. Moreover, lilac aldehydes from Asimitellaria were shown to induce the nectaring behavior of long-tongued fungus gnats but are repellent for short-tongued fungus gnats in olfactometer tests (Okamoto et al, 2015).…”