Altitudinal patterns for longevity, fecundity and senescence in Drosophila buzzatii

We tested for variation in longevity, senescence rate and early fecundity of Drosophila buzzatii along an elevational transect in Argentina, using laboratory-reared flies in laboratory tests performed to avoid extrinsic mortality. At 25 °C, females from lowland populations lived longer and had a lower demographic rate of senescence than females from highland populations. Minimal instead of maximal temperature at the sites of origin of population best predicted this cline. A very different pattern was found at higher test temperature. At 29.5 °C, longevity of males increased with altitude of origin of population. No clinal trend was apparent for longevity of females at 29.5 °C. There was evidence for a trade-off between early fecundity and longevity at non-stressful temperature (25 °C) along the altitudinal gradient. This trait association is consistent with evolutionary theories of aging. Population-by-temperature and sex-by-temperature interactions indicate that senescence patterns are expressed in environment specific ways.     

Altitudinal and environmental variation in lifespan in the Copper butterfly Lycaena tityrus

1.  Variation in longevity within and between natural populations is widespread, and understanding the relative importance of environmental and genetic factors as well as their interactions in mediating such variation is crucial in longevity research.
2.  In this study lifespan of adult copper butterflies was examined in relation to altitude, temperature (20 and 27 °C), sex and adult feeding.
3.  As expected, longevity increased with decreasing temperature, and sucrose-fed butterflies had longer lifespans compared to water-fed and finally non-fed individuals. The impact of feeding, especially of having access to water or not, was larger at the higher compared to the lower temperature.
4.  Regarding altitudinal patterns, increased lifespan in high-altitude populations was largely restricted to beneficial feeding conditions, while under carbohydrate deprivation low-altitude animals lived longer, suggesting that low-altitude butterflies do better under food stress.
5.  Differences in longevity between sexes were small at 20 °C, while females lived substantially longer than males at the higher temperature. Consequently, females may be less susceptible to high temperature stress than males. Further, males suffered more from food stress than females, suggesting that females are generally more stress resistant than males.
6.  Using a full factorial design, this study demonstrates that variation in longevity is caused by several factors, and additionally by substantial interactive effects. Consequently, patterns of variation in longevity are complex, and one needs to be cautious when neglecting this source of variation, by focussing on individual factors only.     

No extension of lifespan by ablation of germ line in Drosophila

Increased reproduction is frequently associated with a reduction in longevity in a variety of organisms. Traditional explanations of this 'cost of reproduction' suggest that trade-offs between reproduction and longevity should be obligate. However, it is possible to uncouple the two traits in model organisms. Recently, it has been suggested that reproduction and longevity are linked by molecular signals produced by specific reproductive tissues. For example, in Caenorhabditis elegans, lifespan is extended in worms that lack a proliferating germ line, but which possess somatic gonad tissue, suggesting that these tissues are the sources of signals that mediate lifespan. In this study, we tested for evidence of such gonadal signals in Drosophila melanogaster. We ablated the germ line using two maternal effect mutations: germ cell-less and tudor. Both mutations result in flies that lack a proliferating germ line but that possess a somatic gonad. In contrast to the findings from C. elegans, we found that germ line ablated females had reduced longevity relative to controls and that the removal of the germ line led to an over-proliferation of the somatic stem cells in the germarium. Our results contrast with the widely held view that it is downstream reproductive processes such as the production and/or laying of eggs that are costly to females. In males, germ line ablation caused either no difference, or a slight extension, in longevity relative to controls. Our results indicate that early acting, upstream reproductive enabling processes are likely to be important in determining reproductive costs. In addition, we suggest that the specific roles and putative patterns of molecular signalling in the germ line and somatic tissues are not conserved between flies and worms.     

Altitudinal life history variation in the dung flies Scathophaga stercoraria and Sepsis cynipsea

 Field phenologies of high- (ca. 1500 m) and low- (ca. 500 m) altitude populations of the two most common European species of dung flies, Scathophaga stercoraria and Sepsis cynipsea, differ quite markedly due to differences in climate. To differentiate genetic adaptation due to natural selection and phenotypic plasticity, I compared standard life history characters of pairs of high- and low-altitude populations from three disjunctive sites in Switzerland in a laboratory experiment. The F1 rearing environment did not affect any of the variables of the F2 generation with which all experiments were conducted; hence, there were no carry-over or maternal effects. In Sc. stercoraria, high-altitude individuals were smaller but laid larger eggs; the latter may be advantageous in the more extreme (i.e. more variable and less predictable) high-altitude climate. Higher rearing temperature strongly decreased development time, body size and the size difference between males and females (males are larger), produced female-biased sex ratios and led to suboptimal adult emergence rates. Several of these variables also varied among the three sites, producing some interactions complicating the patterns. In Se. cynipsea, high-altitude females were marginally smaller, less long-lived and laid fewer clutches. Higher rearing temperature strongly decreased development time and body size but tended to increase the size difference between males and females (males are smaller); it also increased clutch size but decreased physiological longevity. Again, interpretation is complicated by variation across sites and some significant interactions. Overall, genetic adaptation to high-altitude conditions appears weak, probably prevented by substantial gene flow, and may be swamped by the effects of other geographic variables among populations. In contrast, phenotypic plasticity is extensive. This may be due to selection of flexible, multi-purpose genotypes. The results suggest that differences in season length between high- and low-altitude locations alone do not explain well the patterns of variation in phenology and body size. Received: 21 March 1996 / Accepted: 1 September 1996     

Altitudinal differentiation in the diapause response of two species of dung flies

1. Seasonality is a prime selective factor promoting genetic differentiation of populations. Local adaptation in diapause response was investigated in the two geographically and altitudinally widespread dung flies Scathophaga stercoraria (Diptera: Scathophagidae) and Sepsis cynipsea (Diptera: Sepsidae).
2. Replicate sibships from three sites in Switzerland with low and high altitude dung fly populations were raised in a common laboratory environment simulating the natural decreasing photoperiod and temperature regimen before winter. From field phenologies, the critical photoperiod inducing diapause was predicted to be longer for high than for low altitude populations (12 vs. 10 h for Sc. stercoraria , and 12.25 vs. 11 h for Se. cynipsea ) if they are locally adapted.
3. Contrary to expectation and to Sc. stercoraria , which diapauses in the pupal stage, Se. cynipsea diapauses in the adult stage.
4. Low but significant levels of genetic differentiation in pre-winter adult emergence were evident between low and high altitude populations of both species, but they were far from the differences predicted. Scathophaga stercoraria also showed geographical differentiation independent of altitude.
5. Sepsis cynipsea females stopped reproducing at some point before winter, but altitude did not affect the timing of adult diapause. High altitude females and females that did not initiate reproduction before winter survived the simulated winter better.
6. Both species largely used temperature rather than photoperiod as a cue inducing winter diapause, an untypical case of phenotypic plasticity. The hypothesis that Sc. stercoraria , whose generation times are much longer than those of Se. cynipsea , responds to a greater extent to temperature rather than photoperiod only was rejected.     

Life expectancy,maximum longevity and lifetime reproductive success in female Thornicroft's giraffe in Zambia

Gestation and longevity scale with body mass across taxa, yet within size dimorphic taxa, males tend to have reduced lifespans compared with females. Testing life history models, and accounting for sex differences in longevity, requires obtaining accurate longitudinal data from wild populations. We provide the first report describing key life history parameters from a long‐term study of giraffes in Africa. We followed a population of Thornicroft's giraffe (Giraffa camelopardalis thornicrofti) in Zambia for over 40 years. Maximum longevity among females was approximately 28 years, with lifespan accounting for 81% of the variance in lifetime reproductive success. Average adult female life expectancy was no different than average adult male life expectancy. However, the breeding lifespan of males was about half that of females, while maximum lifespan of males was 75% that of females. Our findings support the suggestion that sex differences in maximum lifespan arise from stronger selection for lengthy lives in females than in males. Among females, longer lives are associated with greater reproductive output.     

Life history evolution in a globally invading tephritid: patterns of survival and reproduction in medflies from six world regions

Comparisons among populations from different localities represent an important tool in the study of evolution. Medflies have colonized many temperate and tropical areas all over the world during the last few centuries. In a common garden environment, we examined whether medfly populations obtained from six global regions [Africa (Kenya), Pacific (Hawaii), Central America (Guatemala), South America (Brazil), Extra-Mediterranean (Portugal) and Mediterranean (Greece)] have evolved different survival and reproductive schedules. Whereas females were either short-lived [life expectancy at eclosion (e₀) 48–58 days; Kenya, Hawaii and Guatemala] or long-lived (e₀ 72–76 days; Greece, Portugal and Brazil], males with one exception (Guatemala) were generally long-lived (e₀ 106–122 days). Although males universally outlived females in all populations, the longevity gender gap was highly variable (20–58 days). Lifetime fecundity rates were similar among populations. However, large differences were observed in their age-specific reproductive patterns. Short-lived populations mature at earlier ages and allocate more of their resources to reproduction early in life compared with long-lived ones. In all populations, females experienced a post-reproductive lifespan, with this segment being significantly longer in Kenyan flies. Therefore, it seems plausible that medfly populations, inhabiting ecologically diverse habitats, have evolved different life history strategies to cope with local environmental conditions.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 97 , 106–117.     

Altitudinal variation in age and body size in Yunnan pond frog (Pelophylax pleuraden)

Large-scale systematic patterns of body size are a basic concern of evolutionary biology. Identifying body size variation along altitudinal gradients may help us to understand the evolution of life history of animals. In this study, we investigated altitudinal variation in body size, age and growth rate in Chinese endemic frog, Pelophylax pleuraden. Data sampled from five populations covering an altitudinal span of 1413 to 1935 m in Sichuan province revealed that body size from five populations did not co-vary with altitudes, not following Bergmann's rule. Average adult SVL differed significantly among populations in males, but not in females. For both sexes, average adult age differed significantly among populations. Post-metamorphic growth rate did not co-vary with altitude, and females grew faster than males in all populations. When controlling the effect of age, body size did not differ among populations in both sexes, suggesting that age did not affect variation in body size among populations. For females, there may be other factors, such as the allocation of energy between growth and reproduction, that eliminated the effect of age on body size. To our minds, the major reason of body size variation among populations in male frogs may be related to individual longevity. Our findings also suggest that factors other than age and growth rate may contribute to size differences among populations.     

Body condition but not dietary restriction prolongs lifespan in a semelparous capital breeder

Effects of diet on longevity are complex because acquired resources are shared among growth, reproduction and somatic maintenance. We simplify these axes by examining how dietary restriction and competitive contexts affect longevity using semelparous males of the Australian redback spider (Latrodectus hasselti). Plastic development of L. hasselti males results in trade-offs of body condition against faster development if females are present, facilitating scramble competition. In the absence of females, males develop slowly as high body condition adults, and are better equipped for mate searching. Here we focus on effects of diet and competitive context on body condition and longevity. Although male survival depended on body condition and exercise, contrary to studies in a wide range of taxa, dietary restriction did not increase longevity. However, there was an interactive effect of diet and competitive context on lifespan, because high-diet males reared in the absence of females lived longer than males reared in the presence of females. Thus males near females pay a survival cost of developing rapidly. This shows that life-history trade-offs affected by competitive context can impose longevity costs independent of the direct energy expenditure of searching, courtship, competition or reproduction.     

Geographic parthenogenesis and the common tea‐tree stick insect of New Zealand

Worldwide, parthenogenetic reproduction has evolved many times in the stick insects (Phasmatidae). Many parthenogenetic stick insects show the distribution pattern known as geographic parthenogenesis, in that they occupy habitats that are at higher altitude or latitude compared with their sexual relatives. Although it is often assumed that, in the short term, parthenogenetic populations will have a reproductive advantage over sexual populations; this is not necessarily the case. We present data on the distribution and evolutionary relationships of sexual and asexual populations of the New Zealand stick insect, Clitarchus hookeri. Males are common in the northern half of the species’ range but rare or absent elsewhere, and we found that most C. hookeri from putative‐parthenogenetic populations share a common ancestor. Female stick insects from bisexual populations of Clitarchus hookeri are capable of parthenogenetic reproduction, but those insects from putative‐parthenogenetic populations produced few offspring via sexual reproduction when males were available. We found similar fertility (hatching success) in mated and virgin females. Mated females produce equal numbers of male and female offspring, with most hatching about 9–16 weeks after laying. In contrast, most eggs from unmated females took longer to hatch (21–23 weeks), and most offspring were female. It appears that all C. hookeri females are capable of parthenogenetic reproduction, and thus could benefit from the numerical advantage this yields. Nevertheless, our phylogeographic evidence shows that the majority of all‐female populations over a wide geographic area originate from a single loss of sexual reproduction.     

Effects of recruiting age on senescence, lifespan and lifetime reproductive success in a long-lived seabird

Theories of ageing predict that early reproduction should be associated with accelerated reproductive senescence and reduced longevity. Here, the influence of age of first reproduction on reproductive senescence and lifespan, and consequences for lifetime reproductive success (LRS), were examined using longitudinal reproductive records of male and female blue-footed boobies (Sula nebouxii) from two cohorts (1989 and 1991). The two sexes showed different relationships between age of first reproduction and rate of senescent decline: the earlier males recruited, the faster they experienced senescence in brood size and breeding success, whereas in females, recruiting age was unrelated to age-specific patterns of reproductive performance. Effects of recruiting age on lifespan, number of reproductive events and LRS were cohort- and/or sex-specific. Late-recruiting males of the 1989 cohort lived longer but performed as well over the lifetime as early recruits, suggesting the existence of a trade-off between early recruitment and long lifespan. In males of the 1991 cohort and females of both cohorts, recruiting age was apparently unrelated to lifespan, but early recruits reproduced more frequently and fledged more chicks over their lifetime than late recruits. Male boobies may be more likely than females to incur long-term costs of early reproduction, such as early reproductive senescence and diminished lifespan, because they probably invest more heavily than females. In the 1991 cohort, which faced the severe environmental challenge of an El Ni?o event in the first year of life, life-history trade-offs of males may have been masked by effects of individual quality.     

Longevity costs of same‐sex interactions: first evidence from a parasitic wasp

Costs of sexual interactions play a key role in life‐history evolution. Although the costs of reproduction have been investigated in both sexes of many insects, the costs of same‐sex interactions have been examined in few species. In parasitic wasps, very little has been reported about the longevity costs of heterosexual interactions, and nothing is known about longevity costs of same‐sex interactions. In this study, the effects of heterosexual and homosexual activities on longevity were evaluated in Psyttalia concolor (Hymenoptera: Braconidae), a synovigenic koinobiont larval‐pupal endoparasitoid of tephritid flies. When compared with individually housed virgin wasps, male longevity was strongly reduced both in males kept with females, and in males kept with other males. When females were kept with males, their longevity was reduced compared with the virgin females and females kept with other females. Overall, the costs of male–female interactions were considerable in both sexes of P. concolor, while same‐sex activities were found to be costly only among males, suggesting that they may have implications for the evolution of the P. concolor mating system.     

The effects of reproduction on courtship, fertility and longevity within and between alternative male mating tactics of the horned beetle, Onthophagus binodis

Life history theory provides a powerful tool to study an organism's biology within an evolutionary framework. The notion that males face a longevity cost of competing for and displaying to females lies at the core of sexual selection theory. Likewise, recent game theory models of the evolution of ejaculation strategies assume that males face a trade-off between expenditure on the ejaculate and expenditure on gaining additional matings. Males of the dung beetle Onthophagus binodis adopt alternative reproductive tactics in which major males fight for and help provision females, and minor males sneak copulations with females that are guarded by major males. Minor males are always subject to sperm competition, and consistent with theoretical expectation, minor males have a greater expenditure on their ejaculate than major males. We used this model system to seek evidence that mating comes at a cost for future fertility and/or male expenditure on courtship and attractiveness, and to establish whether these traits vary between alternative mating tactics. We monitored the lifespan of males exposed to females and nonmating populations, and sampled males throughout their lives to assess their fertility and courtship behaviour. We found a significant longevity cost of reproduction, but no fertility cost. On average, males from mating populations had a lower courtship rate than those from nonmating populations. This small effect, although statistically nonsignificant, was associated with significant increases in the time males required to achieve mating. Minor males had lower courtship rates than major males, and took longer to achieve mating. Although we did not measure ejaculate expenditure in this study, the correlation between lower courtship rate and longer mating speed of minor males documented here with their greater expenditure on the ejaculate found in previous studies, is consistent with game theory models of ejaculate expenditure which assume that males trade expenditure on gaining matings for expenditure on gaining fertilizations.     

Variation in performance of western flower thrips populations on susceptible and partially resistant cucumber

Biotypic variation is of major concern in breeding for host plant resistance to insects. The existence or development of aggressive biotypes can lead to a rapid break-down of host plant resistance. Therefore the study of biotypic variation should be included in breeding programs for resistance to insects. In the present study we measured the reproduction of randomly collected females of ten different populations of the insect herbivore Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) on one susceptible and two resistant cucumber (Cucumis sativus L.) accessions. Significant differences between thrips populations were observed on all three cucumber accessions. None of the populations had a significantly higher reproduction than the Dutch reference population NL1. For three populations, the Dutch population NL1, a population from New Zealand (NZ), and an Italian population (IT), partial life history parameters, such as reproduction rate, developmental time and survival were determined and the relative rate of increase r _r was calculated. On all three cucumber accessions the r _r-value of population NZ was lower than of populations NL1 and IT. It is concluded that there is biotypic variation in F. occidentalis with regard to performance on cucumber plants with different levels of resistance. Reproduction is a good criterion for differentiating biotypes of F. occidentalis on cucumber.     

Feeding and breeding aspects of Stomoxys calcitrans (Diptera: Muscidae) under laboratory conditions

Bionomic aspects of Stomoxys calcitrans (Linnaeus, 1758) (Diptera: Muscidae) were studied under laboratory conditions. For this reason, laboratory-rearing techniques were optimized at the National Veterinary School of Toulouse. The colony was maintained at 25 ± 2 °C, 50 ± 10% RH under a 12-hour light cycle and observed daily. The size of each adult cage is 30 x 30 x 30 cm and designed to house about 500-1,000 flies. The average cycle from egg to adult was 19.2 ± 1.7 days. The mean longevity of imagos was 9.3 ± 5.8 days and not significantly different between sexes. Stable flies were split into two groups; the first was fed with blood, honey and water, and the second was fed only with honey and water. The mean weight of a blood meal was 11.1 ± 3.8 mg with no significant differences between males and females. The mean longevity of non-blood fed flies was found to be significantly higher (10.4 ± 3.9 days) than those fed with blood. The maximum lifespan was shorter for non-blood fed males (17 days) and females (18 days) than for those fed with blood (females: 24 days, males: 23 days). Under these laboratory conditions, S. calcitrans rearing was successfully established. In the end, the number of expected generations of S. calcitrans and the net reproduction rate were estimated to be 11.8 generations/year and 16.2 living females per female respectively.     

Sexes suffer from suboptimal lifespan because of genetic conflict in a seed beetle

Males and females have different routes to successful reproduction, resulting in sex differences in lifespan and age-specific allocation of reproductive effort. The trade-off between current and future reproduction is often resolved differently by males and females, and both sexes can be constrained in their ability to reach their sex-specific optima owing to intralocus sexual conflict. Such genetic antagonism may have profound implications for evolution, but its role in ageing and lifespan remains unresolved. We provide direct experimental evidence that males live longer and females live shorter than necessary to maximize their relative fitness in Callosobruchus maculatus seed beetles. Using artificial selection in a genetically heterogeneous population, we created replicate long-life lines where males lived on average 27 per cent longer than in short-life lines. As predicted by theory, subsequent assays revealed that upward selection on male lifespan decreased relative male fitness but increased relative female fitness compared with downward selection. Thus, we demonstrate that lifespan-extending genes can help one sex while harming the other. Our results show that sexual antagonism constrains adaptive life-history evolution, support a novel way of maintaining genetic variation for lifespan and argue for better integration of sex effects into applied research programmes aimed at lifespan extension.     

Does habitat fragmentation affect temperature-related life-history traits? A laboratory test with a woodland butterfly

Habitat fragmentation may change local climatic conditions leading to altered selection regimes for life-history traits in small ectotherms, including several insects. We investigated temperature-related performance in terms of fitness among populations of the woodland butterfly Pararge aegeria (L.) originating from populations of a closed, continuous woodland landscape versus populations of an open, highly fragmented agricultural landscape in central Belgium. Female fecundity and longevity were evaluated in a temperature-gradient experiment. As predicted, females of woodland landscape origin reached higher maximum daily fecundity and lifetime number of eggs than did agricultural landscape females at low ambient temperatures, but this reversed at high ambient temperature. Egg weight decreased with temperature, and eggs of woodland butterflies were smaller. Contrary to what is generally assumed, remaining thorax mass was a better predictor of lifetime reproductive output than was abdomen mass. Since we used the F2 generation from wild-caught females reared under common garden conditions, the observed effects are likely to rely on intrinsic, heritable variation. Our results suggest that differential selection regimes associated with different landscapes intervene by intraspecific variation in the response of a butterfly to variation in ambient temperature, and may thus be helpful when making predictions of future impacts on how wild populations respond to environmental conditions under a global change scenario, with increasing temperatures and fragmented landscapes.     

Heterosis of Quantitative Trait Loci Affecting Lifespan in Drosophila melanogaster

Knowledge of genes responsible for aging and death is a prerequisite for determining the relative contributions of the different evolutionary factors responsible for the limited duration of life. Polymorphism of these genes probably accounts for the variation in lifespan. Previously, quantitative trait loci (QTLs) controlling this variation were mapped with the use of 98 recombinant inbred (RI) lines originating from two parental isogenicDrosophila melanogaster stocks. In each RI line, lifespan was measured for 25 males and 25 females, and alleles were established for 93 marker genes segregating between the parental lines. Significant correlation between marker segregation and lifespan was revealed for several chromosome regions. The lifespan genes had sex-specific effects and late age onset. In the present work, the effects of the QTLs were compared for homozygous and heterozygous flies. In Six out of the eight detected QTLs alleles that decreased lifespan were recessive. Heterosis was observed for a of QTL at 33E–38A. Thus, heterosis might contribute to maintaining variation in lifespan in natural populations.     

Determinants of age-dependent change in a secondary sexual character

Many secondary sexual characters vary in a systematic way with the age of individuals, with young and old individuals displaying at lower levels than individuals of intermediate age. Analyses quantifying the within-individual and among-individual components of phenotypic variation can help partition effects of phenotypic plasticity and selective mortality. We analysed phenotypic variation in the expression of a secondary sexual character, tail length, in male and female barn swallows Hirundo rustica from four European populations studied during 11-26 years, using linear mixed effect models to describe age-related expression. Tail length increased from yearlings to intermediate aged birds with a subsequent decrease at old age. In males, this age-related pattern was because of both within-subject and between-subject effects, with no difference among populations. Males having longer lifespan had shorter tails when young than those having shorter lifespan. Females showed similar patterns of age-related variation as males, with no difference among populations. The major difference between sexes was that the between-subject effects (i.e. disappearance effects or selection) were much more important for males compared to females for which lifetime variation in tail length was mainly because of a within-subject effect (i.e., a plastic response). These findings suggest that whereas males trade greater expression of the secondary sexual character at young age against longevity, that was not the case for females. This is consistent with tail length being more costly in males than in females, with the cost of long tails potentially being offset by elevated mating success, whereas that is not the case in females.     

四种不同来源的超氧化物歧化酶（SOD）对黑腹果蝇寿命、 繁殖力和抗逆能力的影响

【目的】 评价不同来源的超氧化物歧化酶（SOD）对果蝇延长寿命, 增强繁殖力和抗逆能力的功效。【方法】以黑腹果蝇Drosophila melanogaster为实验材料, 比较研究从家蝇Musca domestica中提取的SOD、 在毕赤酵母Pichia pastoris中重组表达的人hEC SOD、 在酿酒酵母Saccharomyces cerevisiae中重组表达的中国拟青霉Paecilomyces sinensis SOD (ps-SOD)以及商品SOD对果蝇寿命、 繁殖力和抗逆能力的影响。【结果】在饲料中添加4种SOD均能显著延长果蝇的平均寿命, 雌果蝇寿命延长8.09%~12.38%, 雄果蝇寿命延长12.01%~15.86%; F1代雌性子代数量增加25.94%~30.07%, 雄性增加21.75%~39.54%。果蝇的耐高温和抗紫外辐射能力与添加的SOD浓度有关。在饲料中添加较高剂量的SOD, 使热暴露雌性果蝇的寿命延长7.45%~9.88%, 雄性果蝇延长13.46%~15.12%; 受紫外线辐射的雌性果蝇的寿命延长13.47%~20.47%, 雄性果蝇延长16.49%~23.73%。【结论】综合评价认为, 4种SOD均能延长果蝇寿命, 增强其繁殖力和抗逆能力, 但这些功效在本研究供试的4种SOD间无显著差异, 为不同来源SOD的应用提供了重要数据。