Remating effects on the genetic structure of female life histories in populations of Drosophila mojavensis

Abstract

A quantitative genetic analysis of nine adult fitness components was performed in two populations of cactophilic Drosophila mojavensis under natural conditions of fermenting cactus and ethanol vapour. Female progeny from 18 sires and 36 dams were treated to a range of six exposure periods to males to assess effects of remating frequency on female fitness. Lifetime fecundity increased with increasing male exposure, but longevity showed an intermediate optimum with temporary exposure to males of 2-4 days. Narrow-sense heritabilities were significant for egg production traits while broad-sense heritabilities were significant for longevity-related traits. Positive genetic correlations between components of fitness were expressed among functionally related traits, e.g. longevity was positively correlated with lifetime fecundity, the number of clutches laid, clutch size, and the number of eggs laid per day. Negative genetic correlations were detected between early and late life fecundity suggesting genetic tradeoffs among components of adult fitness.Keywords: cactus, Drosophila, genetic correlation, heritability, life history, remating. IntroductionThe degree of parental investment in their genetic progeny is thought to result from a balance between future reproductive success and the immediate costs of parental care through investment of resources in current offspring. This classical tradeoff envisioned by Trivers (1972) has been perceived as a driving force in the evolution of plant and animal mating systems, particularly where sexual selection is involved (Parker, 1979). In many insect species, paternal contributions are essential elements of courtship behaviour and serve as nuptial gifts prior to copulation (Zeh & Smith, 1985). These paternal contributions include the provision of food captured or glandular secretions provided by males (Thornhill & Alcock, 1983). These contributions are presumably adaptive because they increase male mating success and may influence the fitness of his progeny. If females can choose males on the basis of their ability to provide, and such behaviour increases female fitness, sexual selection should reinforce natural selection and males that provide larger contributions will be favoured.The paternal contribution of substances other than *Correspondence 515 sperm used by females after copulation is well documented in 10 orders of insects (Thornhill & Alcock, 1983;Boggs, 1990). Within the Drosophilidae, paternal investment may involve courtship feeding (Steele, 1986a, b), where males present a nuptial gift of regurgitated food to the female as part of courtship behaviour or the direct contribution of ejaculate compounds that females assimilate into somatic and reproductive tissues (Chen & Buhier, 1970;Baumann, 1974;Markow & Ankney, 1984; Scott, 1986;Bownes & Partridge, 1987;Markow et al., 1990). Many compounds are present in the ejaculate of Drosophila males that can influence female receptivity to remating (Mane et a!., 1983; Scott, 1986), increase oviposition rates (Chen, 1984), and ...

Bateman's principles and human sex roles

“…For example, female Drosophila mojavensis that are mated with four males have a shorter lifespan and lower lifetime RS than females that are mated with two males [62]. Courtship has been shown to reduce lifespan in male insects (e.g.…”

Premating isolation is determined by larval rearing substrates in cactophilic Drosophila mojavensis. X. Age‐specific dynamics of adult epicuticular hydrocarbon expression in response to different host plants

“…Few data exist for wild adults in natural conditions, but laboratory studies of cactus‐reared flies suggest > 90% of adults die by 30 days (Ganter et al. ; Etges and Heed ; Jaureguy and Etges ). Natural populations of Opuntia ‐breeding D. mercatorum and D. hydei exhibited daily survival rates of 0.81–0.97, but there was considerable year‐to‐year variation in mortality in Hawaiian populations (Johnston and Templeton ).…”

“…Adults were sampled for CHC extraction on the day of eclosion, that is, day zero, and thereafter at 3, 6, 10, 14, 18, 24, and 28 days of age. Few adults survive past 4 weeks under these conditions (Etges and Heed ; Jaureguy and Etges ). Other flies raised in these experimental conditions were used to assess transcriptome variation across the life cycle.…”

Genetics of Incipient Speciation in Drosophila Mojavensis. Iii. Life-History Divergence in Allopatry and Reproductive Isolation

“…First, genetic differences in life‐history traits between Baja California and mainland Mexico populations of D. mojavensis were inferred to have resulted from host plant adaptation that enabled colonization of the mainland where organ pipe cactus is common, but agria is absent, except in the small coastal area including Punta Onah, Sonora (Heed 1978, 1981; Ruiz et al 1990; Etges et al 1999). Life‐history traits including egg‐to‐adult DEVT and VIAB, adult thorax size, age at first reproduction, longevity, ovariole number, clutch size, and lifetime fecundity vary significantly between Baja California and mainland populations of D. mojavensis , and often in cactus‐specific ways, that is, expressed as region or population × cactus interactions (Etges and Klassen 1989; Etges 1990; Etges and Heed 1992). Further, Etges (1990) reported positive associations between latitude and DEVT, as well as adult thorax size, for three mainland and four Baja populations, but these correlations were not always expressed in both rearing environments.…”