An attractant is any chemical that attracts an organism, e.g. i) synthetic lures; ii) aggregation and sex

pheromones A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...

(intraspecific interactions); and iii)

synomone A semiochemical, from the Greek σημεῖον (''semeion''), meaning "signal", is a chemical substance or mixture released by an organism that affects the behaviors of other individuals. Semiochemical communication can be divided into two broa ...

(interspecific interactions)

Synomone

An interspecific

semiochemical A semiochemical, from the Greek σημεῖον (''semeion''), meaning "signal", is a chemical substance or mixture released by an organism that affects the behaviors of other individuals. Semiochemical communication can be divided into two broa ...

that is beneficial to both interacting organisms, the emitter and receiver, e.g. floral synomone of certain ''

Bulbophyllum ''Bulbophyllum'' is a genus of mostly epiphytic and lithophytic orchids in the family Orchidaceae. It is the largest genus in the orchid family and one of the largest genera of flowering plants with more than 2,000 species, exceeded in number onl ...

'' species (

Orchidaceae Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two largest families of flowering ...

) attracts fruit fly males (

Tephritidae The Tephritidae are one of two fly families referred to as fruit flies, the other family being the Drosophilidae. The family Tephritidae does not include the biological model organisms of the genus ''Drosophila'' (in the family Drosophilidae), w ...

Diptera Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced ...

) as

pollinator A pollinator is an animal that moves pollen from the male anther of a flower to the female stigma of a flower. This helps to bring about fertilization of the ovules in the flower by the male gametes from the pollen grains. Insects are the maj ...

s. In this true mutualistic inter-relationship, both organisms gain benefits in their respective sexual reproduction - i.e. orchid flowers are pollinated and the '' Dacini'' fruit fly males are rewarded with a

sex pheromone Sex pheromones are pheromones released by an organism to attract an individual of the same species, encourage them to mate with them, or perform some other function closely related with sexual reproduction. Sex pheromones specifically focus on ind ...

precursor or booster; and the floral synomones, also act as rewards to pollinators, are in the form of

phenylpropanoid The phenylpropanoids are a diverse family of organic compounds that are synthesized by plants from the amino acids phenylalanine and tyrosine. Their name is derived from the six-carbon, aromatic phenyl group and the three-carbon propene tail of ...

s (e.g.

methyl eugenol Methyl eugenol (allylveratrol) is a natural chemical compound classified as a phenylpropene, a type of phenylpropanoid. It is the methyl ether of eugenol and is important to insect behavior and pollination. It is found in various essential oils. ...

) and phenylbutanoids (e.g.

raspberry ketone Raspberry ketone is a natural phenolic compound that is the primary aroma compound of red raspberry, red raspberries. Occurrence Raspberry ketone occurs in a variety of fruits, including raspberries, cranberry, cranberries, and blackberry, blackb ...

zingerone Zingerone, also called vanillylacetone, is a major flavor component of ginger, providing the sweet flavor of cooked ginger. Zingerone is a crystalline solid that is sparingly soluble in water and soluble in ether. Zingerone is similar in chemica ...

and anisyl acetone/a combination of the three phenylbutanoids.

References

a) Tan, K.H., R. Nishida and Y.C. Toong (2002) ''Bulbophyllum cheiri''s floral synomone lures fruit flies to perform pollination. Journal of Chemical Ecology 28:1161-1172.
b) Nishida, R., K.H. Tan, S.L. Wee, A.K.W. Hee and Toong, Y. C. (2004) Phenylpropanoids in the fragrance of the fruit fly orchid, ''Bulbophyllum cheiri'', and their relationship to the pollinator, ''Bactrocera papayae''. Biochemical Systematics & Ecology. 32: 245-252.
c) Tan, K.H., L.T. Tan, and R. Nishida (2006) Floral phenylpropanoid cocktail and architecture of ''Bulbophyllum vinaceum'' orchid in attracting fruit flies for pollination. Journal of Chemical Ecology 32: 2429-2441. a) Tan, K.H. and R. Nishida (2005) Synomone or Kairomone? - ''Bulbophyllum apertum'' (Orchidaceae) flower releases raspberry ketone to attract ''Bactrocera'' fruit flies. Journal of Chemical Ecology. 31(3): 509-519.
b) Nakahira, M., H. Ono, S.L. Wee, K.H. Tan, and R. Nishida (2018) Floral synomone diversification of ''Bulbophyllum'' sibling species (Orchidaceae) in attracting fruit fly pollinators. Biochemical Systematics and Ecology, 81: 86-95. . . .
R. Ragus
ORCID
(2020) Don’t forget the flies: dipteran diversity and its consequences for floral ecology and evolution. Applied Entomology and Zoology. 55:1–7. . {{s2cid, 210169152. a) Tan, K.H. and R. Nishida (2000) Mutual reproductive benefits between a wild orchid, ''Bulbophyllum patens'', and ''Bactrocera'' fruit flies via a floral synomone. Journal of Chemical Ecology 26: 533-546.
b) Tan, K.H. and R. Nishida (2007) Zingerone in the floral synomone of ''Bulbophyllum baileyi'' (Orchidaceae) attracts ''Bactrocera'' fruit flies during pollination. Biochemical Systematics and Ecology 35: 334-341. a) Katte, T., Tan, K.H., Su, Z.H., Ono, H. and Nishida, R. (2020) Floral fragrances in two closely related fruit fly orchids, ''Bulbophyllum hortorum'' and ''B. macranthoides'' (Orchidaceae): Assortments of phenylbutanoids to attract tephritid fruit fly species. Applied Entomology and Zoology 55 (1), 55-64.
b) Nishida, R., Howcroft, N.H., Tan, K.H., Su, Z.H. and Ono, H. (2022) Floral synomone components of fruit fly-attracting orchids, ''Bulbophyllum sinapis'' and ''B. hahlianum'', in Papua New Guinea. Biochemical Systematics and Ecology, 105: (in press). https://doi.org/10.1016/j.bse.2022.104481 Chemical ecology Semiochemicals