scholarly journals Pre-dispersal conditions and presence of opposite sex modulate density dependence and sex bias of dispersal

2017 ◽  
Author(s):  
Abhishek Mishra ◽  
Sudipta Tung ◽  
V.R. Shree Sruti ◽  
Mohammed Aamir Sadiq ◽  
Sahana Srivathsa ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Divergence ◽  
Population Level ◽  
Sex Bias ◽  
Adult Density ◽  
Evolutionary Rescue ◽  
Laboratory Populations ◽  
Opposite Sex ◽  
Evolutionary Consequences ◽  
Density Dependent Dispersal

ABSTRACTDensity-dependent dispersal (DDD) has been demonstrated in many species and has several ecological and evolutionary consequences. Yet we know little about how robust DDD is to the various conditions experienced by individuals. In this study, we use three independent experiments on laboratory populations of Drosophila melanogaster to examine the effects of pre-dispersal adult density, sex of the dispersers and presence of mates on the robustness of DDD patterns. We show that DDD can be greatly affected by both pre-dispersal density and interaction between the sexes. Moreover, the direction of sex-biased dispersal can reverse completely due to an interaction between the pre-dispersal and dispersal densities. We also show that interaction between the sexes can lead to negative DDD at the population level, even if, by themselves, neither sex exhibits DDD. Finally, we discuss potential implications of our results for processes like evolutionary rescue from extinctions and genetic divergence of populations.

scholarly journals The physical environment mediates male harm and its effect on selection in females

2017 ◽  
Vol 284 (1858) ◽  
pp. 20170424 ◽  
Author(s):  
Li Yun ◽  
Patrick J. Chen ◽  
Amardeep Singh ◽  
Aneil F. Agrawal ◽  
Howard D. Rundle
Keyword(s):  
Drosophila Melanogaster ◽  
Sexual Selection ◽  
Physical Environment ◽  
Selective Advantage ◽  
Laboratory Studies ◽  
Male Choice ◽  
Female Fitness ◽  
High Quality ◽  
Evolutionary Consequences ◽  
Natural And Sexual Selection

Recent experiments indicate that male preferential harassment of high-quality females reduces the variance in female fitness, thereby weakening natural selection through females and hampering adaptation and purging. We propose that this phenomenon, which results from a combination of male choice and male-induced harm, should be mediated by the physical environment in which intersexual interactions occur. Using Drosophila melanogaster , we examined intersexual interactions in small and simple (standard fly vials) versus slightly more realistic (small cages with spatial structure) environments. We show that in these more realistic environments, sexual interactions are less frequent, are no longer biased towards high-quality females, and that overall male harm is reduced. Next, we examine the selective advantage of high- over low-quality females while manipulating the opportunity for male choice. Male choice weakens the viability advantage of high-quality females in the simple environment, consistent with previous work, but strengthens selection on females in the more realistic environment. Laboratory studies in simple environments have strongly shaped our understanding of sexual conflict but may provide biased insight. Our results suggest that the physical environment plays a key role in the evolutionary consequences of sexual interactions and ultimately the alignment of natural and sexual selection.

scholarly journals Intergenerational paternal effect of adult density in Drosophila melanogaster

2018 ◽  
Author(s):  
Purbasha Dasgupta ◽  
Saubhik Sarkar ◽  
Akankshya A. Das ◽  
Tanya Verma ◽  
Bodhisatta Nandy
Keyword(s):  
Drosophila Melanogaster ◽  
Treatment Effect ◽  
Egg Size ◽  
Competitive Ability ◽  
Differential Mortality ◽  
Adult Density ◽  
Significant Treatment Effect ◽  
Male Fitness ◽  
Fitness Components ◽  
Significant Treatment

AbstractNotwithstanding recent evidences, paternal environment is thought to be a potential but unlikely source of fitness variation that can affect trait evolution. Here we studied intergenerational effects of males’ exposure to varying adult density in Drosophila melanogaster laboratory populations.We held sires at normal (N), medium (M) and high (H) adult densities for two days before allowing them to mate with virgin females. This treatment did not introduce selection through differential mortality. Further, we randomly paired males and females and allowed a single round of mating between the sires and the dams. We then collected eggs from the dams and measured the egg size. Finally, we investigated the effect of the paternal treatment on juvenile and adult (male) fitness components.We found a significant treatment effect on juvenile competitive ability where the progeny sired by the H-males had higher competitive ability. Since we did not find the treatment to affect egg size, this effect is unlikely to be mediated through variation in female provisioning.Male fitness components were also found to have a significant treatment effect: M-sons had lower dry weight at eclosion, higher mating latency and lower competitive mating success.While being the first study to show both adaptive and non-adaptive effect of the paternal density in Drosophila, our results highlight the importance of considering paternal environment as important source of fitness variation.

Pre-dispersal context and presence of opposite sex modulate density dependence and sex bias of dispersal

Oikos ◽  
2018 ◽  
Vol 127 (11) ◽  
pp. 1596-1604 ◽  
Author(s):  
Abhishek Mishra ◽  
Sudipta Tung ◽  
V. R. Shree Sruti ◽  
Mohammed Aamir Sadiq ◽  
Sahana Srivathsa ◽  
...  
Keyword(s):  
Density Dependence ◽  
Sex Bias ◽  
Opposite Sex

scholarly journals Evolution of reduced pre-adult viability and larval growth rate in laboratory populations of Drosophila melanogaster selected for shorter development time

2000 ◽  
Vol 76 (3) ◽  
pp. 249-259 ◽  
Author(s):  
N. G. PRASAD ◽  
MALLIKARJUN SHAKARAD ◽  
VISHAL M. GOHIL ◽  
V. SHEEBA ◽  
M. RAJAMANI ◽  
...  
Keyword(s):  
Growth Rate ◽  
Drosophila Melanogaster ◽  
Development Time ◽  
Larval Growth ◽  
Dry Weight ◽  
Relative Reduction ◽  
Larval Growth Rate ◽  
Laboratory Populations ◽  
The Difference ◽  
Faster Development

Four large (n > 1000) populations of Drosophila melanogaster, derived from control populations maintained on a 3 week discrete generation cycle, were subjected to selection for fast development and early reproduction. Egg to eclosion survivorship and development time and dry weight at eclosion were monitored every 10 generations. Over 70 generations of selection, development time in the selected populations decreased by approximately 36 h relative to controls, a 20% decline. The difference in male and female development time was also reduced in the selected populations. Flies from the selected populations were increasingly lighter at eclosion than controls, with the reduction in dry weight at eclosion over 70 generations of selection being approximately 45% in males and 39% in females. Larval growth rate (dry weight at eclosion/development time) was also reduced in the selected lines over 70 generations, relative to controls, by approximately 32% in males and 24% in females. However, part of this relative reduction was due to an increase in growth rate of the controls populations, presumably an expression of adaptation to conditions in our laboratory. After 50 generations of selection had elapsed, a considerable and increasing pre- adult viability cost to faster development became apparent, with viability in the selected populations being about 22% less than that of controls at generation 70 of selection.

Interspecific competition between Drosophila melanogaster and D. simulans: Effects of adult

1977 ◽  
Vol 25 (4) ◽  
pp. 699 ◽  
Author(s):  
JJ Moth
Keyword(s):  
Drosophila Melanogaster ◽  
Least Squares ◽  
Interspecific Competition ◽  
Adult Density ◽  
Species Frequency ◽  
Tissue Content ◽  
Strain Frequency ◽  
Percentage Data

The hatchability of eggs laid by D. simulans st and D. melanogaster Or-R-C in consecutive 12-hour periods was measured for the first seven days post eclosion in a replicated experiment where adult density at six levels, species frequency at two levels, and 32P tissue content at two levels were varied factorially. A similar experiment was done for D. simulans st and D. melanogaster yw. In both experiments, all unhatched eggs were classified as either dead or infertile. Least-squares analyses of variance on arcsine-transformed percentage data indicated that the three strains produced significantly different proportions of hatched, dead, and infertile eggs. Increased adult density significantly decreased the proportion of hatched eggs (and increased the proportion of dead eggs) for D. simulans st and D. melanogaster Or-R-C, but not for D. melanogaster yw. Effects of strain frequency were not significant for D. simulans st or D. melanogaster Or-R-C, but for D. melanogaster yw higher hatchability and lower proportions of infertile eggs were obtained in pure populations. Hatchability varied between periods; changes in hatchability being random (but significant) for D. melanogaster yw, and consistent (but not significant) for D. simulans st (a decrease in hatchability with time) and D. melanogaster Or-R-C (an increase with time). The competing strain of D. melanogaster did not influence the proportions of hatched, dead or infertile eggs from D. simulans st.

scholarly journals Phenotypic coupling of sleep and starvation resistance evolves in D. melanogaster

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Didem P. Sarikaya ◽  
Julie Cridland ◽  
Adam Tarakji ◽  
Hayley Sheehy ◽  
Sophia Davis ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Population Level ◽  
Adaptive Mechanism ◽  
Starvation Resistance ◽  
Plastic Response ◽  
Metabolic Phenotypes ◽  
Percent Change ◽  
Carbohydrate Levels ◽  
Complex Relationships ◽  
Function Of Sleep

Abstract Background One hypothesis for the function of sleep is that it serves as a mechanism to conserve energy. Recent studies have suggested that increased sleep can be an adaptive mechanism to improve survival under food deprivation in Drosophila melanogaster. To test the generality of this hypothesis, we compared sleep and its plastic response to starvation in a temperate and tropical population of Drosophila melanogaster. Results We found that flies from the temperate population were more starvation resistant, and hypothesized that they would engage in behaviors that are considered to conserve energy, including increased sleep and reduced movement. Surprisingly, temperate flies slept less and moved more when they were awake compared to tropical flies, both under fed and starved conditions, therefore sleep did not correlate with population-level differences in starvation resistance. In contrast, total sleep and percent change in sleep when starved were strongly positively correlated with starvation resistance within the tropical population, but not within the temperate population. Thus, we observe unexpectedly complex relationships between starvation and sleep that vary both within and across populations. These observations falsify the simple hypothesis of a straightforward relationship between sleep and energy conservation. We also tested the hypothesis that starvation is correlated with metabolic phenotypes by investigating stored lipid and carbohydrate levels, and found that stored metabolites partially contributed towards variation starvation resistance. Conclusions Our findings demonstrate that the function of sleep under starvation can rapidly evolve on short timescales and raise new questions about the physiological correlates of sleep and the extent to which variation in sleep is shaped by natural selection.

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