Search results for "Cultural"
showing 10 items of 12990 documents
Acclimation capacity and rate change through life in the zooplankton Daphnia
2020
When a change in the environment occurs, organisms can maintain an optimal phenotypic state via plastic, reversible changes to their phenotypes. These adjustments, when occurring within a generation, are described as the process of acclimation. While acclimation has been studied for more than half a century, global environmental change has stimulated renewed interest in quantifying variation in the rate and capacity with which this process occurs, particularly among ectothermic organisms. Yet, despite the likely ecological importance of acclimation capacity and rate, how these traits change throughout life among members of the same species is largely unstudied. Here we investigate these re…
DYNAMIC TRANSMISSION, HOST QUALITY, AND POPULATION STRUCTURE IN A MULTIHOST PARASITE OF BUMBLEBEES
2012
The evolutionary ecology of multihost parasites is predicted to depend upon patterns of host quality and the dynamics of transmission networks. Depending upon the differences in host quality and transmission asymmetries, as well as the balance between intra- and interspecific transmission, the evolution of specialist or generalist strategies is predicted. Using a trypanosome parasite of bumblebees, we ask how host quality and transmission networks relate to parasite population structure across host species, and thus the potential for the evolution of specialist strains adapted to different host species. Host species differed in quality, with parasite growth varying across host species. High…
PROTECTION FIRST THEN FACILITATION: A MANIPULATIVE PARASITE MODULATES THE VULNERABILITY TO PREDATION OF ITS INTERMEDIATE HOST ACCORDING TO ITS OWN DE…
2011
Many trophically transmitted parasites with complex life cycles manipulate their intermediate host behavior in ways facilitating their transmission to final host by predation. This facilitation generally results from lowering host's antipredatory defenses when the parasite is infective to the final host. However, a recent theoretical model predicts that an optimal parasitic strategy would be to protect the intermediate host from predation when noninfective, before switching to facilitation when the infective stage is reached. We tested this hypothesis in the fish acanthocephalan parasite Pomphorhynchus laevis using the amphipod Gammarus pulex as intermediate host. Gammarids parasitized by n…
Rapid Diversification of Sperm Precedence Traits and Processes Among Three Siblingdrosophilaspecies: Divergent Sperm Precedence Mechanisms
2013
Postcopulatory sexual selection is credited with driving rapid evolutionary diversification of reproductive traits and the formation of reproductive isolating barriers between species. This judgment, however, has largely been inferred rather than demonstrated due to general lack of knowledge about processes and traits underlying variation in competitive fertilization success. Here, we resolved processes determining sperm fate in twice-mated females, using transgenic Drosophila simulans and Drosophila mauritiana populations with fluorescently labeled sperm heads. Comparisons among these two species and Drosophila melanogaster revealed a shared motif in the mechanisms of sperm precedence, wit…
SEXUAL SELECTION WHEN FERTILIZATION IS NOT GUARANTEED
2005
Much of the theory of sexual selection assumes that females do not generally experience difficulties getting their eggs fertilized, yet sperm limitation is occasionally documented. How often does male limitation form a selection for female traits that improve their mating rate? The question is difficult to test, because if such traits evolve to be efficient, sperm limitation will no longer appear to be a problem to females. Here, we suggest that changes in choosiness between populations, and in particular between virgin and mated females, offer an efficient way to test this hypothesis. We model the "wallflower effect," that is, changes in female preferences due to time and mortality costs o…
Sex in space: population dynamic consequences
1999
Sex, so important in the reproduction of bigametic species, is nonetheless often ignored in explorations of the dynamics of populations. Using a growth model of dispersal-coupled populations we can keep track of fluctuations in numbers of females and males. The sexes may differ from each other in their ability to disperse and their sensitivity to population density. As a further complication, the breeding system is either monogamous or polygamous. We use the harmonic mean birth function to account for sex-ratio-dependent population growth in a Moran–Ricker population renewal process. Incorporating the spatial dimension stabilizes the dynamics of populations with monogamy as the breeding sys…
VARIATION BETWEEN POPULATIONS AND LOCAL ADAPTATION IN ACANTHOCEPHALAN-INDUCED PARASITE MANIPULATION
2010
Many trophically transmitted parasites manipulate their intermediate host phenotype, resulting in higher transmission to the final host. However, it is not known if manipulation is a fixed adaptation of the parasite or a dynamic process upon which selection still acts. In particular, local adaptation has never been tested in manipulating parasites. In this study, using experimental infections between six populations of the acanthocephalan parasite Pomphorhynchus laevis and its amphipod host Gammarus pulex, we investigated whether a manipulative parasite may be locally adapted to its host. We compared adaptation patterns for infectivity and manipulative ability. We first found a negative eff…
2018
Aposematic theory has historically predicted that predators should select for warning signals to converge on a single form, as a result of frequency-dependent learning. However, widespread variation in warning signals is observed across closely related species, populations and, most problematically for evolutionary biologists, among individuals in the same population. Recent research has yielded an increased awareness of this diversity, challenging the paradigm of signal monomorphy in aposematic animals. Here we provide a comprehensive synthesis of these disparate lines of investigation, identifying within them three broad classes of explanation for variation in aposematic warning signals: …
Morphological and molecular variability within the fig cultivar 'Dottato' in the Italian protected designation origin area "fichi di Cosenza"
2017
The morphological and molecular diversity among fig accessions of 'Dottato', found in the PDO "Fichi di Cosenza" area was studied by evaluating 24 morphological traits and by genotyping with 18 microsatellite markers. The microsatellite allelic profiles among the putative clones of 'Dottato' indicated a moderate genetic variability, discriminating unambiguously most of the accessions. Only two groups of identity were found. The average expected and observed heterozygosity were 0.43 and 0.62, respectively. The mean polymorphic information content (PIC) was 0.4, varying from 0.08 (LMFC26) to 0.067 (FCUP 38-6). The morphological clustering allowed the distinction of all genotypes. Some genotyp…