Variation in Population Sex Ratio and Mating Success of Asexual Lineages of \u3ci\u3eAlsophila pometaria\u3c/i\u3e (Lepidoptera: Geometridae)

Populations of Alsophila pometaria (Harris) are largely gynogenetic and composed of asexual females that must mate with a conspecific male to reproduce. Within this asexual contingent, there are a variety of electrophoretically defined multilocus genotypes. In this study we found that populations differ in sex ratio. We also found that there is an indication of differential mating success among asexual genotypes in a population of A. pometaria

Survivorship and Growth of Sexually and Asexually Derived Larvae of \u3ci\u3eAlsophila pometaria\u3c/i\u3e (Lepidoptera: Geometridae)

A substantial body of theory is devoted to understanding the relative advantages of sexual and asexual reproduction. It is generally understood that asexual forms potentially have a higher rate of reproduction because they save the cost of producing males. The micro-evolutionary consequences of sexual and asexual reproduction are less clear. Sexual reproduction generates abundant genotypic diversity which may be adaptively advantageous (Williams 1975; Maynard Smith 1978). Asexual reproduction may perpetuate combinations of genes that are co-adapted (Templeton 1979), heterotic (Suomalainen et al. 1976; White 1979), or specialized (Vrijenhoek 1979, 1984). Thus, it is possible that the fitness of a sexual population may be lower than an asexual, in part, because recombination tends to break up especially favorable genotypes (Williams 1975; Hebert 1978). If it is generally observed that asexual reproduction has an immediate adaptive as well as a reproductive advantage, then it is difficult to see how sexual reproduction can be maintained by short-term advantages (Williams 1975). A comparison of closely related sexual and asexual forms is a promising avenue of research to evaluate experimentally the consequences of both modes of reproduction (Maynard Smith 1978). In this study, geometrid moth larvae (Alsophila pometaria) derived from both kinds of reproduction were reared on different host plants. The goal was to assess larval viability and growth in an ecologically relevant context and thus partially characterize the fitness of sexual and asexual reproduction

Variation in Population Sex Ratio and Mating Success of Asexual Lineages of \u3ci\u3eAlsophila pometaria\u3c/i\u3e (Lepidoptera: Geometridae)

Populations of Alsophila pometaria (Harris) are largely gynogenetic and composed of asexual females that must mate with a conspecific male to reproduce. Within this asexual contingent, there are a variety of electrophoretically defined multilocus genotypes. In this study we found that populations differ in sex ratio. We also found that there is an indication of differential mating success among asexual genotypes in a population of A. pometaria

The Origin and Distribution of Clonal Diversity in \u3ci\u3eAlsophila pometaria\u3c/i\u3e (Lepidoptera: Geometridae)

A survey of spatial and temporal variation in the frequency of electrophoretically defined genotypes in the geometrid moth Alsophila pometaria revealed a high diversity of uncommon or rare asexual genotypes and clinal distributions of two of the more common clones. There was substantial year-to-year variation in genotype frequencies in seven of eleven sites. Progeny tests have revealed that sexual reproduction is uncommon in two populations and that new asexual genotypes arise from the sexual population. The recurrent origin of asexual genotypes is likely to account for the high genetic and ecological diversity of the asexual contingent of this species’ populations, in contrast to the lower genetic diversity in some obligately asexual species in which such recruitment does not occur

Male Effects on Fecundity in \u3ci\u3eDrosophila melanogaster\u3c/i\u3e

Effects of male Drosophila melanogaster on female fecundity and productivity were examined, considering both females held in containers with males and females exposed to male effects not involving contact. Females were more fecund when male effects were present, and the largest increase was recorded when vials were previously conditioned by males. This effect was probably due to the growth of transmitted microorganisms, which were observed on the laying surface, as further experiments with vials conditioned by virgin females showed a similar increase in fecundity. A male-specific effect was isolated by conditioning bottles containing only agar with males and virgin females. The observation of a male factor that stimulates oviposition without mating is novel and suggests complicated fertility interactions between the sexes

Oxidative Stress Resistance: A Robust Correlated Response to Selection in Extended Longevity Lines of \u3ci\u3eDrosophila melanogaster\u3c/i\u3e?

Stress resistance is associated with longevity in Drosophila melanogaster and other model organisms used for genetic research. The present study tests for oxidative stress resistance in one set of lines selected for late-life reproduction and extended longevity. Both females and males from the selected lines were appreciably more resistant to oxidative stress than were flies from the control lines. A relative increase in oxidative stress resistance is a correlated response to selection in this laboratory selection experiment. Increased oxidative stress resistance appears to be a relatively robust correlated response to laboratory selection for late-life reproduction and extended longevity

Superoxide Dismutase Activities in Long-Lived \u3ci\u3eDrosophila melanogaster\u3c/i\u3e Females: \u3ci\u3echico\u3c/i\u3e\u3csup\u3e1\u3c/sup\u3e Genotypes and Dietary Dilution

Superoxide dismutase (SOD) activities were determined for dietary dilution conditions that extend the life span of Drosophila melanogaster. The hypothesis motivating this research was that elevated SOD activity is associated with increased life span resulting from flies being held on a restricted diet. SOD activities were also measured for chico1 which is a mutation in the insulin receptor substrate protein gene associated with life span extension. This allowed us to confirm the results of (Clancy et al. 2001) and extend the results by measuring CuZn SOD and Mn SOD activities in addition to the previously determined overall SOD activity. If the same form of SOD activity (CuZn SOD or Mn SOD) was elevated on the dilute diet that extends life span and in the long lived chico1 homozygotes, then it would suggest that life span extension by dietary restriction and by insulin signaling muta-tions has a similar underlying mechanism. However, overall SOD activity, and CuZn SOD or Mn SOD activities did not differ among the diets tested. As observed previously (Clancy et al. 2001), overall SOD activity was elevated in chico1 homozygotes compared to the heterozygote or wild type. Results from the present study indicate that elevated CuZn SOD activity, not Mn SOD, is the basis for the relatively high level of SOD activity in the chico1 homozygotes

A dataset for assessing temporal changes in gene expression during the aging process of adult \u3ci\u3eDrosophila melanogaster\u3c/i\u3e

A Drosophila melanogaster genome-wide transcriptome dataset is available for studies on temporal patterns of gene expression. Gene expression was measured using two-dye color oligonucleotide arrays derived from Version 2 of the Drosophila Genomics Resource Center. A total of 15,158 oligonucleotide probes corresponded to a high proportion of the coding genes in the genome. The source of the flies was a highly genetically heterogeneous population maintained in an overlapping generation population regime. This regime was designed to maintain life history traits so that they were similar to those found in natural populations. Flies collected for the cohorts were obtained in a short period of time in a carefully controlled manner before virgin females and males were allowed to mate. Mated females were introduced into two large population cages in unusually high numbers (approximately 12,000 per cage) for a Drosophila laboratory longevity study. Samples were taken weekly from each cohort for 11 weeks; only a small proportion of surviving flies were present at the last two collection time points and thus they were exceptionally old compared to those collected in early-tomidlife samples. The data set is useful for studies of temporal patterns of gene expression as flies age. The very large size of each cohort, and relatively frequent incidence of temporal samples, allows for a fine-scale study of gene expression from young to very old flies

A dataset for assessing temporal changes in gene expression during the aging process of adult \u3ci\u3eDrosophila melanogaster\u3c/i\u3e

A Drosophila melanogaster genome-wide transcriptome dataset is available for studies on temporal patterns of gene expression. Gene expression was measured using two-dye color oligonucleotide arrays derived from Version 2 of the Drosophila Genomics Resource Center. A total of 15,158 oligonucleotide probes corresponded to a high proportion of the coding genes in the genome. The source of the flies was a highly genetically heterogeneous population maintained in an overlapping generation population regime. This regime was designed to maintain life history traits so that they were similar to those found in natural populations. Flies collected for the cohorts were obtained in a short period of time in a carefully controlled manner before virgin females and males were allowed to mate. Mated females were introduced into two large population cages in unusually high numbers (approximately 12,000 per cage) for a Drosophila laboratory longevity study. Samples were taken weekly from each cohort for 11 weeks; only a small proportion of surviving flies were present at the last two collection time points and thus they were exceptionally old compared to those collected in early-tomidlife samples. The data set is useful for studies of temporal patterns of gene expression as flies age. The very large size of each cohort, and relatively frequent incidence of temporal samples, allows for a fine-scale study of gene expression from young to very old flies

Environmental Effects on Remating in \u3ci\u3eDrosophila melanogaster\u3c/i\u3e

The effects of density and food on remating were investigated using Drosophila melanogaster. The frequency of remating was unaffected by density for some combinations of fly strains but was reduced at low relative densities for other combinations. Until females had used most of their stored sperm, remating was less likely when food was absent or contact with food was prevented. Food availability had little effect on the incidence of remating once stored sperm were depleted and had no effect on initial virgin mating frequency. This study indicates that environmental factors can have a substantial direct influence on the frequency of remating in populations of Drosophila melanogaster