Altitudinal variation for senescence in Melanoplus grasshoppers

Tatar, Marc; Gray, Dennis W.; Carey, James R.

doi:10.1007/s004420050246

Cited by 72 publications

(78 citation statements)

References 45 publications

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“…The first involves comparisons between two or more field-collected biotypes such as between guppy biotypes collected from streams that differ in predation levels (Reznick et al ., 1996(Reznick et al ., , 2001, between grasshopper biotypes collected from regions of the Sierra Nevada that differ in altitude (Tatar et al ., 1997), and between rotifer species collected from the wild that differ in preferred habitats (Kirk, 1997). The second type of comparison is between biotypes that differ in degrees of laboratory selection such as between laboratory-adapted and wild-type lines of Drosophila melanogaster (Sgro & Partridge, 2000;Linnen et al ., 2001) or between laboratory vs. wild-derived mice (Miller et al ., 2000(Miller et al ., , 2002.…”

Section: Introductionmentioning

confidence: 99%

Age structure changes and extraordinary lifespan in wild medfly populations

et al. 2008

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SummaryThe main purpose of this study was to test the hypotheses that major changes in age structure occur in wild populations of the Mediterranean fruit fly (medfly) and that a substantial fraction of individuals survive to middle age and beyond (> 3-4 weeks). We thus brought reference life tables and deconvolution models to bear on medfly mortality data gathered from a 3-year study of field-captured individuals that were monitored in the laboratory. The average timeto-death of captured females differed between sampling dates by 23.9, 22.7, and 37.0 days in the 2003, 2004, and 2005 field seasons, respectively. These shifts in average times-to-death provided evidence of changes in population age structure. Estimates indicated that middle-aged medflies (> 30 days) were common in the population. A surprise in the study was the extraordinary longevity observed in field-captured medflies. For example, 19 captured females but no reference females survived in the laboratory for 140 days or more, and 6 captured but no reference males survived in the laboratory for 170 days or more. This paper advances the study of aging in the wild by introducing a new method for estimating age structure in insect populations, demonstrating that major changes in age structure occur in field populations of insects, showing that middle-aged individuals are common in the wild, and revealing the extraordinary lifespans of wild-caught individuals due to their early life experience in the field.

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Section: Introductionmentioning

confidence: 99%

Age structure changes and extraordinary lifespan in wild medfly populations

et al. 2008

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“…However, ascertaining the relative contributions of the nonmutually exclusive genetic mechanisms will not illuminate whether the general theory adequately explains the wide diversity of senescence patterns found in nature. Relatively little work has examined the ecological context of senescence evolution (Reznick 1993;Tatar et al 1997;Dudycha 2000).…”

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NATURAL GENETIC VARIATION OF LIFE SPAN, REPRODUCTION, AND JUVENILE GROWTH IN DAPHNIA

Dudycha

Tessier

1999

Evolution

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Abstract.-The evolutionary theory of senescence predicts that high extrinsic mortality in natural populations should select for accelerated reproductive investment and shortened life span. Here, we test the theory with natural populations of the Daphnia pulex-pulicaria species complex, a group of freshwater zooplankton that spans an environmental gradient of habitat permanence. We document substantial genetic variation in demographic life-history traits among parent and hybrid populations of this complex. Populations from temporary ponds have shorter life spans, earlier and faster increases of intrinsic mortality risk, and earlier and steeper declines in fecundity than populations from permanent lakes. We also examine the age-specific contribution to fitness, measured by reproductive value, and to expected lifetime reproduction; these traits decline faster in populations from temporary ponds. Despite having more rapid senescence, pond Daphnia exhibit faster juvenile growth and higher early fitness, measured as population growth rate (r). Among populations within this species complex we observed negative genetic correlations between r and indices of life-history timing, suggesting trade-offs between early-and late-life performance. Our results cannot be explained by a trade-off between survival and fecundity or by nonevolutionary theories of senescence. Instead, our data are consistent with the evolutionary theory of senescence because the genetic variation in life histories we observed is roughly congruent with the temporal scale of environmental change in the field.

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“…Studies concerned with aging in the wild have traditionally focused on either survival estimates using mark-recapture techniques (Caughley 1977;Austad 1993;Krebs 1999) or relatively rough life table differences between cohorts that were subjected to different selection pressures in the field (Reznick et al 2004;Tatar et al 1997). The applicability of these tools for demographic analysis is limited, as age-distribution information is not provided, in contrast to residual demography.…”

Section: Discussion and Concluding Remarksmentioning

confidence: 99%

Survival and aging in the wild via residual demography

Müller

Wang

Yu³

et al. 2007

Theoretical Population Biology

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SummaryInformation about the age distribution and survival of wild populations is of much interest in ecology and biodemography, but is hard to obtain. Established schemes such as capture-recapture often are not feasible. In the proposed residual demography paradigm, individuals are randomly sampled from the wild population at unknown ages and the resulting captive cohort is reared out in the laboratory until death. Under some basic assumptions one obtains a demographic convolution equation that involves the unknown age distribution of the wild population, the observed survival function of the captive cohort, and the observed survival function of a reference cohort that is independently raised in the laboratory from birth. We adopt a statistical penalized least squares method for the deconvolution of this equation, aiming at extracting the age distribution of the wild population under suitable constraints. Under stationarity of the population, the age density is proportional to the survival function of the wild population and can thus be inferred. Several extensions are discussed. Residual demography is demonstrated for data on fruit flies Bactrocera oleae.

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Altitudinal variation for senescence in Melanoplus grasshoppers

Cited by 72 publications

References 45 publications

Age structure changes and extraordinary lifespan in wild medfly populations

Age structure changes and extraordinary lifespan in wild medfly populations

NATURAL GENETIC VARIATION OF LIFE SPAN, REPRODUCTION, AND JUVENILE GROWTH IN DAPHNIA

Survival and aging in the wild via residual demography

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