(3S,6E)-nerolidol-mediated rendezvous of Cyclocephala paraguayensis beetles in bottle gourd flowers

Abstract

Cyclocephalini beetles of the genus Cyclocephala (Coleoptera: Melolonthidae: Dynastinae) use flowers of some plants as food, shelter, and mating sites. However, little is known about floral scent chemistry involved in this interaction. Here we show that a sesquiterpene alcohol mediates attraction of Cyclocephala paraguayensis Arrow, on bottle gourd flowers, Lagenaria siceraria (Cucurbitaceae). Both males and females started to aggregate on the flowers at twilight; after that, mating began and remained for the entire night. GC-FID/EAD analysis of the L. siceraria floral scent collected in the field revealed that only the major constituent of the airborne volatiles elicited electroantennographic responses on male and female antennae of C. paraguayensis. This compound was identified as (3S,6E)-nerolidol, which was tested in two field trapping trials in Brazil. In the first bioassay, traps baited with nerolidol (mix of isomers) captured significantly more adult C. paraguayensis than control traps. In the second field trial, catches in traps baited with a mixture of isomers or enantiopure nerolidol were significantly higher than captures in control traps, but the treatments did not differ significantly. Analysis from the gut content of adult C. paraguayensis showed the presence of pollen, suggesting that they also use bottle gourd flowers for their nourishment. Taken together, these results suggest that (3S,6E)-nerolidol plays an essential role in the reproductive behavior of C. paraguayensis by eliciting aggregation, mating, and feeding.

Chemistry, biosynthesis and biology of floral volatiles: roles in pollination and other functions

“…Finally, some recent studies focused only on florivorous beetles and identified the floral attractants. The (3 S )-isomer of ( E )-nerolidol ( 113 ) mediated the attraction of florivorous Cyclocephala paraguayensis beetles to bottle gourd ( Lagenaria siceraria , Cucurbitaceae) flowers, 240 and 2-isopropyl-3-methoxypyrazine ( 143 ) and 2-isobutyl-3-methoxypyrazine ( 159 ), major compounds of Acrocomia and Attalea palms, attracted Cyclocephala amazona and C. distincta florivores. 241 Aulacophora foveicollis (Coleoptera: Chrysomelidae), a beetle pest that feeds on flowers and leaves of two Curcurbitaceae species (Gâc, Momordica cochinchinensis ; creeping cucumber, Solena amplexicaulis ), was attracted by a blend of linalool oxide (furanoid) ( 145 ), 1-octanol ( 160 ), and nonanal ( 126 ).…”

“…331 The plants mainly release (E)-carvone epoxides, though some also release smaller amounts of the (Z)-isomers (summarized by Brandt et al 364 ). For each diastereomer two enantiomers are possible, summing up to a total of four stereoisomers of carvone epoxide (239)(240)(241)(242). All ve orchid species recently studied for the presence of the stereoisomers of carvone epoxide released only the (−)-(E)-isomer (239).…”

Biosynthesis and the Transcriptional Regulation of Terpenoids in Tea Plants (Camellia sinensis)

“…The genes responsible for the biosynthesis of other essential terpene substances, such as nerolidol, α-farnesene, and β-ocimene, have also been studied in tea plants [ 46 , 48 , 60 ]. Nerolidol, a sesquiterpenoid alcohol, is the most effective allelopathic compound showing effective applications in agricultural practices [ 161 , 162 , 163 , 164 ]. In terms of health-promoting properties and floral scents, nerolidol is also known for its pharmaceutical and medicinal values [ 165 , 166 , 167 ].…”

Egg development and viability in three species of Cyclocephala (Coleoptera: Scarabaeidae: Dynastinae)

“…Additionally, C. celata are among the main pollinators of soursop orchards in northeastern Brazil (Parizotto and Grossi, 2019). Adult C. paraguayensis , on the other hand, are florivores associated with numerous plant hosts in the Amaryllidaceae, Annonaceae, Apocynaceae, Cactaceae, Calophyllaceae, and Solanaceae (Moore and Jameson, 2013; Favaris et al ., 2020; ACD Maia, pers. comm.).…”