Adaptive significance of changes in morph production during the transition from parthenogenetic to sexual reproduction in the aphid Rhopalosiphum padi (Homoptera: Aphididae)

Abstract

Many aphid species have life cycles which alternate between asexual reproduction during spring and summer and sexual reproduction in autumn. This paper describes the sequences of morphs produced by clones of Rhopalosiphum padi (Linnaeus) in response to a range of photoperiods and temperatures in the laboratory, and under semi-natural conditions at the time of year when the transition from parthenogenetic to sexual reproduction occurs. By using similarities in the order in which the various morphs were born, clones of R. padi were found to produce eight progeny sequence types. A clone of R. padi will produce these sequence types sequentially as it changes from parthenogenetic to fully sexual reproduction. The progeny sequence produced by clones under conditions corresponding to those of spring and summer consist of parthenogenetic females only. During late summer, production of parthenogenetic females is followed by males. Later in the year, a clone produces progeny sequences consisting of parthenogenetic females, gynoparae and males. The asexual phase of reproduction is terminated in late autumn when only gynoparae and males are born. A minority of clones terminate parthenogenetic reproduction by producing only gynoparae. The function of these changes in progeny sequence in maximizing the reproductive success of a clone of R. padi is discussed.

Transcriptomic profiling of the reproductive mode switch in the pea aphid in response to natural autumnal photoperiod

“…Fecundity was also similar and only the percentage of sexual morphs differed, with less sexual morphs produced in outdoor compared to laboratory conditions. Austin et al (1996) also observed that in field conditions, the date of sexual production (mainly for the males) for different genotypes of Rhopalosiphum padi was different compared to controlled conditions. Beside the essential role of photoperiod in triggering the switch of reproductive mode in aphids, these studies indicate that climatic features interact with the photoperiod to modify the proportion and time of release of sexual morphs in autumn (Lees, 1959).…”

Genetic architecture of sexual and asexual populations of the aphid Rhopalosiphum padi based on allozyme and microsatellite markers

“… Allochronic isolation . Heterozygote deficit could also result from a Wahlund effect within sexual populations due to differences in the timing of production of sexuals between aphid lineages (Austin et al . 1996).…”

Plant quality, progeny sequence, and the sex ratio of the sycamore aphid, Drepanosiphum platanoidis

“…In general, a parthenogenetic mother will first produce parthenogenetic and/or sexual females and later produce males (and, under some conditions, a series of parthenogenetic females continues until death): see e.g., Acyrthosiphon pisum (Lamb & Pointing, 1972, 1975MacKay et al, 1983;Erlykova, 2003), Acyrthosiphon svalbardicum (Strathdee et al, 1993), Aphis fabae (Tsitsipis & Mittler, 1977), Aphis gossypii (Takada, 1988), Cryptomyzus spp. (Guldemond & Tigges, 1992), Megoura viciae (Lees, 1959(Lees, , 1960, Myzus persicae (Blackman, 1972;Hales et al, 1989), Rhopalosiphum padi (Dixon & Glen, 1971;Austin et al, 1996), and Sitobion avenae (Watt, 1984;Hand & Wratten, 1985;Newton & Dixon, 1987).…”