The genetic effects of competition in seaweed flies

Leggett, M.; Wilcockson, Ray; Day, Thomas H.; Phillips, David S.; Arthur, Wallace

doi:10.1111/j.1095-8312.1996.tb01692.x

Cited by 14 publications

(4 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3 ). The nonlinear influence of larval density on female fecundity is a novel finding and indicates potential facilitation between larvae during development, as has been reported in other insect species (e.g., Leggett et al 1996 ; Fletcher 2009 ; Ronnas et al 2010 ).…”

Section: Discussionsupporting

confidence: 60%

Sex‐specific effects of developmental environment on reproductive trait expression in Drosophila melanogaster

Edward

Chapman

2012

Ecology and Evolution

View full text Add to dashboard Cite

Variation in the expression of reproductive traits provides the raw material upon which sexual selection can act. It is therefore important to understand how key factors such as environmental variation influence the expression of reproductive traits, as these will have a fundamental effect on the evolution of mating systems. It is also important to consider the effects of environmental variation upon reproductive traits in both sexes and to make comparisons with the environment to which the organism is adapted. In this study, we addressed these issues in a systematic study of the effect of a key environmental factor, variation in larval density, on reproductive trait expression in male and female Drosophila melanogaster. To do this, we compared reproductive trait expression when flies were reared under controlled conditions at eight different larval densities that covered a 20-fold range. Then, to place these results in a relevant context, we compared the results to those from flies sourced directly from stock cages. Many reproductive traits were surprisingly insensitive to variation in larval density. A notable exception was nonlinear variation in female fecundity. In contrast, we found much bigger differences in comparisons with flies from stock cages—including differences in body size, latency to mate, copulation duration, fecundity, and male share of paternity in a competitive environment. For a number of traits, even densities of 1000 larvae per vial (125 larvae per mL of food) did not phenocopy stock cage individuals. This study reveals novel patterns of sex-specific sensitivity to environmental variation that will influence the strength of sexual selection. It also illustrates the importance of comparisons with the environment to which individuals are adapted.

show abstract

Section: Discussionsupporting

confidence: 60%

Sex‐specific effects of developmental environment on reproductive trait expression in Drosophila melanogaster

Edward

Chapman

2012

Ecology and Evolution

View full text Add to dashboard Cite

show abstract

“…The reason for this assertion is that the effects of female choice on offspring fitness are principally a consequence of heterosis. Controlled laboratory experiments on egg-to-adult viability have consistently revealed strong heterosis (Butlin et al 1984;Leggett et al 1996), and heterosis is a feature of virtually all natural populations of seaweed flies (Butlin et al 1982 a;Day et al 1983;Butlin & Day 1989). The magnitude of the heterosis partly determines the strength of indirect sexual selection in each population, but it does not alter the direction of the selection; aa females consistently produce unfit offspring if they mate assortatively, whereas (3(3 females produce fitter offspring by mating disassortatively.…”

Section: Discussionmentioning

confidence: 99%

Sexual selection in natural populations of seaweed flies: variation in the offspring fitness of females carrying different inversion karyotypes

Gilburn

Crean

Day

1996

Proc. R. Soc. Lond. B

View full text Add to dashboard Cite

The effect of indirect sexual selection on offspring fitness with respect to a large chromosomal inversion system was estimated in nine widely separated populations of the seaweed fly, Coelopafrigida. The pattern of female rejection was determined for each population and estimates were made of the relative fitnesses of the inversion karyotypes. Two sets of progeny frequencies were calculated: the first on the basis of the observed pattern of mating, and the second on the hypothetical basis that all females had accepted the male available: in other words, random mating. The relative fitnesses of the offspring produced by these two mating regimes were compared. In seven of the populations the exercise of choice resulted in a modest change in progeny fitness. The change depended on the karyotype of the female: (3(3 females produced fitter offspring in all populations, eta's usually produced less fit offspring, and there was little effec progeny of oe(3's. An association was also found between a physical factor, tidal range, and the offspring fitness of ctct females, but no association exists for a(3 or (3$ females. It is suggested that the relevant genes have been subject to different evolutionary forces on the two forms of the inversion.

show abstract

“…No environmental variables were measured at the time of sampling; however, because the mean size of etc/. males is strongly correlated with larval density under laboratory conditions (Leggett et al 1996), it was used as a measure of competition and general stress experienced by larvae. A strong association exists between CVA and the mean size of act males (regression coefficient, /?…”

Section: (б) Genetic Variation In Adult Size In Natural Popu Lation Smentioning

confidence: 99%

“…Relation between CVA's (for male size) and the mean size of oca males in samples from different geographical regions. The mean size of aa males is negatively associated with larval density (Leggett et al 1996). CVAs refer to the genetic variation attributable to the a/?…”

Section: (б) Genetic Variation In Adult Size In Natural Popu Lation Smentioning

confidence: 99%

Sexual selection in seaweed flies: genetic variation in male size and its reliability as an indicator in natural populations

Day

Crean

Gilburn

et al. 1996

Proc. R. Soc. Lond. B

View full text Add to dashboard Cite

Characters that are evolving in response to indirect sexual selection operating through the production either of attractive sons (the Fisher process) or of progeny with high viability (good genes), are expected to exhibit high levels of additive genetic variation. In seaweed flies ( frigida) male size is subject to both direct and indirect sexual selection, whereas female size has probably evolved in response to direct selection alone. Coefficients of additive genetic variance (CVfs) in adult size were shown to be larger in males than females. Virtually all the genetic variation is attributable to the otp chromosomal inversion which is known to be associated with larval survival. Sexual selection appears to have led to differential expression of relevant loci in the two sexes, and in the focussing of this variation into a single region of the genome. Samples from 25 natural populations provided estimates of CVfs in male size. Although the CVA values suggest male size is, on average, a reliable indicator of offspring fitness, both spatial and temporal differences in CVA's were observed. We suggest that indirect sexual selection is a very inconstant force of evolution.

show abstract

The genetic effects of competition in seaweed flies

Cited by 14 publications

References 25 publications

Sex‐specific effects of developmental environment on reproductive trait expression in Drosophila melanogaster

Sex‐specific effects of developmental environment on reproductive trait expression in Drosophila melanogaster

Sexual selection in natural populations of seaweed flies: variation in the offspring fitness of females carrying different inversion karyotypes

Sexual selection in seaweed flies: genetic variation in male size and its reliability as an indicator in natural populations

Contact Info

Product

Resources

About