Life-cycle variation ofMyzus persicae(Sulz.) (Hom., Aphididae) in different parts of the world, in relation to genotype and environment

Abstract

Life-cycle variation, involving alternative methods of overwintering (holocycly and anholocycly), is found in many important pest aphids, and may have considerable ecological, genetic and economic significance. The occurrence of life-cycle variation in Myzus persicae (Sulz.) in different parts of the world is reviewed. The holocycle of M. persicae, with sexual reproduction and overwintering of eggs on Prunus, occurs in the temperate regions of every continent, and although anholocycly is widespread in warm climates there are indications that the potential for sexual reproduction may be retained throughout the whole range of the species. The environmental factors involved in the determination of sexual morphs are considered. Photoperiodism provides the timing mechanism for sexual morph production, and the photoperiodic response is probably tuned to different regional conditions and buffered against other environmental variables within certain limits. The only other environmental factor clearly implicated in sexual morph production is temperature, and an attempt is made to correlate the global pattern of life-cycle variation in M. persicae with temperature differences between regions, by dividing the world into six zones delimited by selected isotherms. The overall pattern of life-cycle variation can be explained largely on the basis of climatic differences between zones, and the effects of these differences on gene and genotype frequencies within the species. Clones of androcyclic character seem to be widespread and, although genetically isolated anholocyclic biotypes undoubtedly exist, androcyclic clones could be the principal source of parthenogenetic overwinterers in all parts of the world where life-cycle differences exist within populations.

Microsatellite variation in cyclically parthenogenetic populations of Myzus persicae in south-eastern Australia

“…This, in large part, is attributable to the fact that most of our collections were made from peach trees in spring, and were offspring of the founding females that emerged from sexually-produced eggs. Studies of M. persicae populations in Western Australia, where M. persicae is believed to over-winter exclusively by parthenogenesis on secondary host plants (Blackman, 1974), may find a pattern similar to that described for M. persicae in Scotland (Fenton et al, 1998) and S. avenae in eastern France (Haack et al, 2000).…”

“…Heredity (2002) 88, 258-266. DOI: 10.1038/sj/hdy/6800037 of all of these (Blackman, 1974). Additionally there is genetic variability in developmental regulation of reproductive mode within and among populations (Moran, 1992).…”

Categories of Resistance to Greenbug (Homoptera: Aphididae) Biotype I in <B> <I>Aegilops tauschii</I> </B> Germplasm

“…In the lab, GPA exhibits an anholocylic life cycle under typical Arabidopsis growth conditions. However, in many GPA lineages, sexual reproduction can be induced in the laboratory by maintaining colonies at cool temperatures under short-day conditions (Blackman, 1974).…”

Spatial and temporal genetic variability in French populations of the peach–potato aphid, Myzus persicae

“…In optimal conditions, a parthenogenetic generation (from birth to the mature adult) is accomplished within 8-10 days; thus more than 20 asexual generations can precede the sexual phase in cyclically parthenogenetic aphids. In temperate regions, like France, both reproductive modes can coexist in sympatry (Blackman, 1974). Blackman (1974) proposed that the geographical distribution of reproductive modes results from a selective pressure: the climate.…”