Posted on: 02 March, 2017
Author: Alexander P
Exclusive mating cycles also appear to function in maintaining separation of two closely related lymantriids, the gypsy moth (Porthetria dispar) and the nun moth (Lymantria morzacha (L.)), both of wh... Exclusive mating cycles also appear to function in maintaining separation of two closely related lymantriids, the gypsy moth (Porthetria dispar) and the nun moth (Lymantria morzacha (L.)), both of which co-occur widely from Europe to Japan. The gypsy moth sex attractant pheromone is cis-7,8-epoxy-2-methyloctade- cane (Bierl et al. 1970) and the nun moth has recently been shown to be lured to this chemical (Schonherr 1972). In Europe the nun moth’s mating periodicity occurs from about 6 p.m. until 1 a.m. (Ambros 1940), while the gypsy moth’s cycle is apparently diurnal (Jacentovsky 1932, 1934). The gypsy moth was introduced into North America in New England in 1868 or 1869 and various investigations there on its mating periodicity showed this interval to be 9 a.m. to 3 or 4 p.m. in 1896 (Forbush and Ferna1d),9 a.m. to 6 p.m. in 1932 (Collins and Potts) and 9 a.m. to 8 pm." in 1974 (Cardé et al.). Thus, in North America the gypsy moth appears to have evolved a lengthened mating periodicity in response to lessened communication distance orientation behavior by males. It would be inefficient for males responding to low release rates to orient to fast pheromone-releasing females of another species, only to reach a critical concentration, which elicits searching behavior for a phantom female according to http://thongchaimedical.org/scientifically-proven-best-pheromones/ Pheromone rhythms Differing circadian mating rhythms can also be important for the partitioning of fully sympatric Lepidoptera that use the same chemical communication system. In most Lepidoptera, the female secretes pheromone (calls) and is receptive to mating only during a relatively brief period during the day or night. As might be expected, the periodicity of male response is roughly coincident with the rhythm of female attractiveness. Long before the first sex attractant structure was elucidated, the potential importance of mating periodicity as a reproductive isolating mechanism was recognized. In a now classic series of experiments with saturniids, Rau and Rau (1929) demonstrated that silkworm moths could possess vastly different mating rhythms: for example, Callosamia promethea (Drury), was noted toattract and mate from 3 p.m. to 7 p.m. compared to 9 p.m. to 5 a.m. for Samia Cynthia (Drury). Indeed it now appears that such variation in mating periodicity isolates certain sympatric saturniids. C. promethea, C. angulifera (Walker) and C. securifera (Maas- sen) are all sympatric in South Carolina, where recent studies by Dominick and Edwards (Ferguson 1971-2) have shown that C. securifera commenced calling about 10 a.m. while males ceased ying between 3 and 4 p.m. At about this time, females of the second diurnal species, C. promethea, initiated calling and male response, which continued until sunset. Finally, C angulifera has an entirely noc- turnal cycle, reported to occur between dusk and midnight (Collins and Weast 1961; Ferguson 1971-2). At least two of the species, C. promethea and angulifera, are known to cross-attract (Collins and Weast 1961). The synthetic mixtures found by eld tests to be the best attractants for some species may not always be the natural pheromone mixture, but they must generally hear close resemblance to it. In the case of Platynota idaeusalis (Walker), the tufted npple bud moth, eld tests showed that males were attracted to trans-11-tetr|d- ccen-l-ol (tll-14 2 OH) (Roelofs and Comeau 1971b), but the addition of the corresponding acetate, tll-14 : Ac, greatly increased attractancy (Comeau 1971). Later, analysis of female gland extracts proved that both compounds are indeed produced by the females (Hill et al. 1974). * Source: Free Articles from ArticlesFactory.com Alexander P is a blogger from Los Angeles that studies pheromones.