Posted on: 02 March, 2017
Author: Alexander P
It is obvious that many species could achieve reproductive isolation because they employ different pheromone compounds. In the Tortricidae (table 6.1), structural vuriution, as known to date, is obtai... It is obvious that many species could achieve reproductive isolation because they employ different pheromone compounds. In the Tortricidae (table 6.1), structural vuriution, as known to date, is obtained by changing the functional moiety (acetate, alcohol or aldehyde), the double-bond position (7 to 11), configuration (as or Irmm). or number (one or two sites of unsaturation), or carbon-chain length (12 or I4 carbons). Most of the known lepidopterous attractants in other families are nlmllur compounds (Roelofs and Comeau 1971b), with the exception of: l) a Ityilrocarbon, 2-methylheptadecane, in some tiger moth species (Roelofs and Cardé W71 ); 2) an epoxy-hydrocarbon, cis-7,8-epoxy-2-methyloctadecane for the gypsy moth, Porthetria dispar (L.) (Bierl et al. 1970); and 3) a branched ester, cis-dec-5- en-l-yl 3-methylbutanoate for the pine emperor moth, Nudaurelia cytherea (F.) (lleutlcrson and Warren 1972). Although recent data suggest that many species actually use a main attractant and small percentages of secondary components in their natural pheromonal system, consideration of just the main attractant indicates an Important role for pheromones in the reproductive isolation of some species. It was first reported (Roelofs and Comeau 1969) for two morphologically similar elechlid species, Bryotropha similis (Stainton) and 8. sp. They exhibit identical four-dot wing patterns, but the former species appears grayish and the latter more yellowish. They co-occur in nature and have broadly overlapping diel mating cycles. but euch is attracted to a different geometrical isomer of cis- and trans-9-tetradece- nyl acetates. A mixture of the two isomers attracts males of neither species, suggest- lnu that females of one species would actually inhibit attraction of males of the other species. thus effecting complete reproductive isolation according to http://webstyletalk.net/chikara-pheromones-are-extremely-popular-with-men/ It resulted in four new species in the west and two species, C. fumiferamz, eastern spruce budworm, and C. pinus Freeman, jack-pine budworm, in the east. The last two species are sympatric for part of their ranges (Freeman 1953; Stehr 1967). They will hybridize when conned in cages and produce fertile offspring. In the field the potential for hybridization is reduced by ecological and temporal isolation, but even when these barriers are ineffective, no hybrid matings occur (Smith 1954). Differences in the mating periodicity are not sufcient to prevent the possibility of hybridization, but there is evidence that the two species use different sex pheromo- ne systems. The attractant for C. fumiferana was identied as cis-ll-tetradecenal (Weatherston et al. 1971) and preliminary information indicates that the main attractant for C. pinus is not an aldehyde, but rather an acetate. Additionally, attractancy of the females is species-specic in the field and crude female extracts are species-specic in laboratory bioassays. Two of the western species, C. biennis Freeman and C. occidentalis Freeman, use the same aldehyde attractants as the eastern species, C. fumiferana, but hybridization is apparently reduced by ecologi- cal and temporal isolation. The other western species, C. orea Freeman, and C. viri- dis Freeman, appear to utilize the same or similar acetate chemical as the eastern species, C. pinus, although C. viridis is attracted to trans-11-tetradecenyl acetate alone, while C pirzus is not (Sanders et al. 1973). Source: Free Articles from ArticlesFactory.com Alexander P is a blogger that studies pheromones. He is from Los Angeles, CA.