Sex Differences in the Effect of Dietary Restriction on Life Span and Mortality Rates in Female and Male Drosophila Melanogaster
ABSTRACT Dietary restriction (DR) has been shown to increase life span in taxonomically diverse animal species. In this study we tested for sex differences in the response of life span to graded severity of DR in Drosophila melanogaster. In both sexes, life span peaked at an intermediate food concentration and declined on either side. However, the magnitude of the response and the food concentration that minimized adult mortality differed significantly between the sexes. Female life span peaked at a food concentration 60% of the standard laboratory diet compared to a concentration of 40% for males. Moreover, female flies subject to DR lived up to 60% longer than did starved or fully fed females, whereas males subjected to DR lived only up to 30% longer. Analysis of age-specific mortality rates showed that DR extended life span by decreasing baseline mortality rates in both sexes, and to a greater extent in females. The differences in the response to DR in female and male Drosophila may be due to previously documented sex differences in sensitivity of life span to insulin/insulin-like growth factor-1 signalling or in nutrient/energy demand and allocation/utilization.
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- "Although individuals of both sexes should respond to nutrient limitation in ways that maximize their lifetime fitness (Collins 1980), males and females have distinct nutritional requirements based on their divergent reproductive roles. To date, only a few studies have examined sex-specific responses to early food limitation (but see Karlsson et al. 1997; Clarebrough et al. 2000; Hunt et al. 2004; Gwynne 2004; Boggs and Freeman 2005; Magwere et al. 2004; Maklakov et al. 2008; Stillwell and Davidowitz 2010). Such sex-specific responses may be especially marked in organisms whose mating systems include nuptial gifts. "
ABSTRACT: Animals with complex life cycles respond to early food limitation by altering the way resources are allocated in the adult stage. Response to food limitation should differ between males and females, especially in organisms whose mating systems include nutritional nuptial gifts. In these organisms, males are predicted to keep their allocation to reproduction (sperm and nuptial gift production) constant, while females are predicted to sacrifice allocation to reproduction (egg production) since they can compensate by acquiring nuptial gifts when mating. In this study, we investigated how dietary nitrogen limitation during the larval stage affects sex-specific resource allocation in Pieris rapae butterflies. Also, we tested whether nutrient-limited females increased nuptial gift acqui-sition as a way to compensate for low allocation to reproduction. We found that as predicted females, but not males, sacrifice allocation to reproduction when larval dietary nitrogen is limited. However, females were unable to compensate for this low reproductive allocation by increasing their mating rate to acquire additional gifts. Females reared on low nitrogen diets also reduced wing coloration, a potential signal of female fecundity status. We suggest that female mating frequency is constrained by male mate choice based on females' wing coloration. This study provides new insights into how larval dietary nitro-gen, a key nutritional resource for all herbivores, alters male and female allocation to reproduction as well as to ornamentation.Evolutionary Ecology 11/2013; 27(6). DOI:10.1007/s10682-013-9647-x · 2.37 Impact Factor
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- "The qualitative and quantitative composition of available food has a significant impact on life history traits (Tu & Tatar, 2003; Magwere et al., 2004; Rion & Kawecki, 2007; Lee et al., 2008), including the trade-off between reproduction and longevity. Under a high-quality diet, longevity is likely to be shortened due to the allocation of resources to reproductive activity (Jacob & Evans, 2000; Hunt et al., 2004), whereas under a poor diet, organisms switch to a physiological state geared towards survival at the expense of reproduction (Halliday, 1989; Boggs & Ross, 1993; Zera & Harshman, 2001; Kirkwood, 2002). "
ABSTRACT: A tenet of life history evolution is that allocation of limited resources results in trade-offs, such as that between reproduction and lifespan. Reproduction and lifespan are also influenced proximately by differences in the availability of specific nutrients. What is unknown is how the evolution of the ability to use a nutritionally novel diet is reflected in this fundamental trade-off. Does the evolution of the ability to use a nutritionally novel food maintain the trade-off in reproduction and longevity, or do the proximate effects of nutrition alter the adapted trade-off? We tested this by measuring trade-offs in male milkweed bugs, Oncopeltus fasciatus, fed either an adapted diet of sunflower or the ancestral diet of milkweed. Sunflower-fed males lived longer but invested less in reproduction, both in mating and fertility. Milkweed-fed males invested in both mating and fertility at the expense of survival. The evolution of an expanded diet was not constrained by the existing trade-off, but instead was accompanied by a different trade-off between reproduction and longevity. We suggest that this occurs because diets differ in promoting germ line development or longevity.Journal of Evolutionary Biology 02/2012; 25(5):873-80. DOI:10.1111/j.1420-9101.2012.02476.x · 3.48 Impact Factor
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- "The latter was the greatest prolongation of the adult phase in any treatment. Drosophila females also benefit more from dietary restriction (via DD) than males (Magwere et al. 2004; Bross et al. 2005). Males showed a 1.33-fold increase in adult duration on DR24, but a reduction on DR36 (83% of DRC). "
ABSTRACT: Studying aging is constrained using vertebrates by their longevity, size, ethical restrictions, and expense. The key insect model, Drosophila melanogaster, is holometabolous. Larvae feed on yeast in moist media and adults sponge food. Most aging studies are restricted to adults. Another key model, the nematode Caenorhabditis elegans, feeds on bacteria in moist media. For either invertebrate refreshing test materials, preventing degradation and obtaining accurate dosing are difficult even with synthetic media. The cricket Acheta domesticus has a short lifespan (∼120 days at 30°C) and is omnivorous. Age-matched cohorts are easily obtained from eggs. The life cycle is hemimetabolous and nymphs eat the same foods as adults. Growth is easily monitored, gender can be differentiated before maturity, and maturation is indicated by wings and mature genitalia. Crickets can be reared in large numbers at low cost. Test materials can be mixed into food and ingestion rates or mass budgets easily assessed. Here, we validate the cricket as a model of aging by testing two fundamental methods of restricting food intake: time-restricted access to food and dietary dilution. Growth, maturation, survivorship, and longevity varied with treatments and genders. Intermittent feeding (which is ineffective in flies) significantly extended longevity of crickets. Dietary dilution also extended longevity via remarkable prolongation of the juvenile period.Age 12/2010; 33(4):509-22. DOI:10.1007/s11357-010-9195-z · 3.45 Impact Factor