Search results for "GRI"

Batesian Mimicry and Signal Accuracy

1997

RICE, W. R. 1989. Analyzing tables of statistical tests. Evolution 43:223-225. RICE, W. R., AND E. E. HOSTERT. 1993. Laboratory experiments on speciation: what have we learned in 40 years? Evolution 47: 1637-1653. SAWADA, S. 1963. Studies on the local races of the Japanese newt, Triturus pyrrhogaster Boie. II. Sexual isolation mechanisms. J. Sci. Hiroshima Univ. Ser. B 21:167-180. SPIETH, H. T, AND J. M. RINGO. 1983. Mating behavior and sexual isolation in Drosophila. Pp 223-284 in M. Ashburner, L. M. Carson, and J. N. Thompson Jr, eds. The genetics and biology of Drosophila. Academic Press, New York. TEMPLETON, A. R. 1996. Experimental evidence for the genetictransilience model of speciati…

The “unguarded-X” and the genetic architecture of lifespan: Inbreeding results in a potentially maladaptive sex-specific reduction of female lifespan…

2018

Sex differences in ageing and lifespan are ubiquitous in nature. The "unguarded-X" hypothesis (UXh) suggests they may be partly due to the expression of recessive mutations in the hemizygous sex chromosomes of the heterogametic sex, which could help explain sex-specific ageing in a broad array of taxa. A prediction central to the UX hypothesis is that inbreeding will decrease the lifespan of the homogametic sex more than the heterogametic sex, because only in the former does inbreeding increase the expression of recessive deleterious mutations. In this study, we test this prediction by examining the effects of inbreeding on the lifespan and fitness of male and female Drosophila melanogaster…

THE GENETIC COMPOSITION OF PHILAENUS SPUMARIUS POPULATIONS IN ISLAND HABITATS VARIABLY AFFECTED BY VOLES

1974

POSTMATING ISOLATION ANALYSIS IN FOUNDER-FLUSH EXPERIMENTAL POPULATIONS OF DROSOPHILA PSEUDOOBSCURA.

1996

In this paper, we report a detailed analysis intended to detect postmating barriers in experimental populations of Drosophila pseudoobscura obtained through nine founderflush cycles. The number of offspring produced was determined in three consecutive generations of hybridization. It is found that the evolution of premating barriers, as shown by two of these populations, is not necessarily accompanied by the evolution of postmating ones. Under the founder-flush model of speciation proposed by Carson (1971), the first step in the speciation process is usually thought to be an incidental genetic change through founder effect affecting mating behavior so that sexual premating isolation evolves…

Gene flow from an adaptively divergent source causes rescue through genetic and demographic factors in two wild populations of Trinidadian guppies

2016

Genetic rescue, an increase in population growth owing to the infusion of new alleles, can aid the persistence of small populations, but its use as a management tool is limited by a lack of empirical data geared towards predicting effects of gene flow on local adaptation and demography. Experimental translocations provide an ideal opportunity to monitor the demographic consequences of gene flow. In this study we take advantage of two experimental introductions of Trinidadian guppies to test the effects of gene flow on downstream native populations. We individually marked guppies from the native populations to monitor population dynamics for 3 months before and 26 months after gene flow. We …

Soil microbiome of primeval forest ecosystems in Transkarpathia

2018

The aim of this study was to investigate the soil microbiome of primeval forest ecosystems, namely the structure of microbial communities,the number of major ecological-functional groups, functional parameters such as: soil toxicity, as well as enzymatic activity of the soil by the level of catalase and invertase. To analyze the successional processes in the soil microbiocenosis due to the influence of endogenous and exogenous factors. To estimate the integrity of microbial communities in different edaphotopes of primeval forest ecosystems. Methods. Microbiological studies of soil were carried out according to generally accepted methods in soil microbiology. Enzymatic activity of the soil: …

Frequency-Dependent Selection in a Mammalian RNA Virus

1997

RNA viruses have been used as experimental systems to test evolutionary hypotheses such as Muller's ratchet (Chao 1990; Duarte et al. 1992, 1993; Clarke et al. 1993), the Red Queen hypothesis (Clarke et al. 1994), the nature of the adaptive topography (Elena, 1995; Elena et al. 1996), and the dynamics of adaptive evolution (Elena 1995; Novella et al. 1995). Two hypotheses which have received attention in virus studies are the competitive exclusion principle and frequency-dependent selection. The competitive exclusion principle (Hardin 1960) states that two populations or species competing for the same limiting resource cannot stably coexist because one competitor will displace the other. An…

FOUNDER-FLUSH SPECIATION IN DROSOPHILA PSEUDOOBSCURA: A LARGE-SCALE EXPERIMENT.

1993

A founder-flush-crash model of speciation has been proposed that may particularly apply to island and other colonizations. Previous laboratory experiments testing the model have given inconsistent results. We have conducted a large experiment with Drosophila pseudoobscura designed to meet the essential postulates of the model and to separately test some of the postulates. Forty-five experimental and 12 control populations have been studied during seven successive founder-flush-crash cycles, or about 50 generations. Sexual isolation tests yield significantly positive assortative mating in a few tests between pairs of experimental populations. Populations with fewer founders (N = 1 or 3) yiel…

2019

Hosts are typically infected with multiple strains or genotypes of one or several parasite species. These infections can take place simultaneously, but also at different times, i.e. sequentially, when one of the parasites establishes first. Sequential parasite dynamics are common in nature, but also in intensive farming units such as aquaculture. However, knowledge of effects of previous exposures on virulence of current infections in intensive farming is very limited. This is critical as consecutive epidemics and infection history of a host could underlie failures in management practices and medical intervention of diseases. Here, we explored effects of timing of multiple infections on vir…

Sperm Quality Assessment in Honey Bee Drones

2020

The quality of honey bee drone semen is relevant in different contexts, ranging from colony productivity to pathology, toxicology and biodiversity preservation. Despite its importance, considerably less knowledge is available on this subject for the honey bee when compared to other domestic animal species. A proper assessment of sperm quality requires a multiple testing approach which discriminates between the different aspects of sperm integrity and functionality. Most studies on drone semen quality have only assessed a few parameters, such as sperm volume, sperm concentration and/or sperm plasma membrane integrity. Although more recent studies have focused on a broader variety of aspects …