Search results for "productive"

A combination of dichogamy and herkogamy mediates reproductive success in the desert shrub Zygophyllum fabago

2020

Abstract Zygophyllum fabago is a species within the arid-adapted family Zygophyllaceae. The species is characterized by the co-occurrence of dichogamy and herkogamy. In order to understand the effect of these two complementary anti-selfing mechanisms in reproductive success, we conducted a detailed study of floral biology in Z. fabago. Our results indicated an incomplete separation of the female and male phases which is referred to as partial dichogamy. We found two floral morphs with distinct stigma position: the Central-morph (C-morph) and the Lateral-morph (L-morph). The stigma-stamen distance in the L-morph was significantly larger than in the C-morph in early, mid, and late male stages…

An experimental assessment of reproductive isolation and its consequences for seasonal hybridization dynamics

2018

Stabilizing selection on microsatellite allele length at arginine vasopressin 1a receptor and oxytocin receptor loci

2017

The loci arginine vasopressin receptor 1a ( avpr1a ) and oxytocin receptor ( oxtr ) have evolutionarily conserved roles in vertebrate social and sexual behaviour. Allelic variation at a microsatellite locus in the 5′ regulatory region of these genes is associated with fitness in the bank vole Myodes glareolus . Given the low frequency of long and short alleles at these microsatellite loci in wild bank voles, we used breeding trials to determine whether selection acts against long and short alleles. Female bank voles with intermediate length avpr1a alleles had the highest probability of breeding, while male voles whose avpr1a alleles were very different in length had reduced probability of …

Viability selection creates negative heterozygosity–fitness correlations in female Black Grouse Lyrurus tetrix

2017

There is widespread interest in the relationship between individual genetic diversity and fitness–related traits (heterozygosity–fitness correlations, HFC). Most studies found weak continuous increases of fitness with increasing heterozygosity while negative HFC have rarely been reported. Negative HFC are expected in cases of outbreeding depression and outbreeding is rare in natural populations; but negative HFC may also arise through viability selection acting on low heterozygosity individuals at an early stage producing a skew in the heterozygosity distribution leading to negative HFCs. We tested this idea using survival and clutch parameters (egg mass, egg volume, chick mass, clutch size…

Multiple mechanisms of cryptic female choice act on intraspecific male variation in Drosophila simulans

2016

Postcopulatory sexual selection can arise when females mate with multiple males and is usually mediated by an interaction between the sexes. Cryptic female choice (CFC) is one form of postcopulatory sexual selection that occurs when female morphology, physiology, or behavior generates a bias in fertilization success. However, its importance in nonrandom reproductive success is poorly resolved due to challenges distinguishing the roles of females and males in generating patterns of fertilization bias. Nevertheless, two CFC mechanisms have recently been documented and characterized in Drosophila simulans within the context of gametic isolation in competitive hybrid matings with Drosophila mau…

Reproductive inequalities in the acanthocephalan Corynosoma cetaceum: looking beyond 'crowding' effects.

2018

Background: At present, much research effort has been devoted to investigate overall (average) responses of parasite populations to specific factors, e.g., density-dependence in fecundity or mortality. However, studies on parasite populations usually pay little attention to individual variation (inequality) in reproductive success. A previous study on the acanthocephalan Corynosoma cetaceum in franciscana dolphins, Pontoporia blainvillei, revealed no overall intensity-dependent, or microhabitat effects, on mass and fecundity of worms. In this study, we investigated whether the same factors could influence mass inequalities for this species of acanthocephalan.Methods: A total of 10,138 speci…

Demographic history has shaped the strongly differentiated corkwing wrasse populations in Northern Europe

2019

Understanding the biological processes involved in genetic differentiation and divergence between populations within species is a pivotal aim in evolutionary biology. One particular phenomenon that requires clarification is the maintenance of genetic barriers despite the high potential for gene flow in the marine environment. Such patterns have been attributed to limited dispersal or local adaptation, and to a lesser extent to the demographic history of the species. The corkwing wrasse (Symphodus melops) is an example of a marine fish species where regions of particular strong divergence are observed. One such genetic break occurred at a surprisingly small spatial scale (FST ~0.1), over a s…

Experimental contact zones reveal causes and targets of sexual selection in hybridizing lizards

2016

Divergence in sexually selected traits in allopatry should affect the degree and direction of hybridization. However, few studies have established the causes and targets of sexual selection during secondary contact. Common wall lizards (Podarcis muralis) from north-central Italy have highly exaggerated male sexual traits compared to populations in Western Europe. Using experimental populations, we show that this creates asymmetries in male dominance, spatial habitat use and reproductive success upon secondary contact. Hybridization occurred almost exclusively between males of the Italian lineage and females of the Western European lineage. We provide evidence to suggest stronger ongoing sel…

Long-Distance Travellers: Phylogeography of a Generalist Parasite, Pholeter gastrophilus, from Cetaceans

2017

We studied the phylogeography and historical demography of the most generalist digenean from cetaceans, Pholeter gastrophilus, exploring the effects of isolation by distance, ecological barriers and hosts' dispersal ability on the population structure of this parasite. The ITS2 rDNA, and the mitochondrial COI and ND1 from 68 individual parasites were analysed. Worms were collected from seven oceanic and coastal cetacean species from the south western Atlantic (SWA), central eastern Atlantic, north eastern Atlantic (NEA), and Mediterranean Sea. Pholeter gastrophilus was considered a single lineage because reciprocal monophyly was not detected in the ML cladogram of all individuals, and seque…

Long-Term Prophylactic Antibiotic Treatment: Effects on Survival, Immunocompetence and Reproduction Success of Parasemia plantaginis (Lepidoptera: Er…

2016

Hundreds of insect species are nowadays reared under laboratory conditions. Rearing of insects always implicates the risk of diseases, among which microbial infections are the most frequent and difficult problems. Although there are effective prophylactic treatments, the side effects of applied antibiotics are not well understood. We examined the effect of prophylactic antibiotic treatment on the overwintering success of wood tiger moth (Parasemia plantaginis) larvae, and the postdiapause effect on their life-history traits. Four weeks before hibernation larvae were treated with a widely used antibiotic (fumagillin). We monitored moths' survival and life-history traits during the following …