Frida Ben-Ami

Frida Ben-Ami
Tel Aviv University | TAU · School of Zoology

PhD

About

61
Publications
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1,672
Citations

Publications

Publications (61)
Article
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Two important characteristics of metapopulations are extinction–(re)colonization dynamics and gene flow between subpopulations. These processes can cause strong shifts in genome-wide allele frequencies that are generally not observed in “classical” (large, stable, panmictic) populations. Subpopulations founded by one or a few individuals, the so-ca...
Preprint
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In freshwater communities, organisms interact in a variety of ways, including predation, competition and parasitism. Parasites are ubiquitous, playing an important role in shaping freshwater communities. Endoparasites live within internal organs of their host, while ectoparasites, also known as epibionts, are confined to the external part of the ho...
Article
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In nature, parasite species often coinfect the same host. Yet, it is not clear what drives the natural dynamics of coinfection prevalence. The prevalence of coinfections might be affected by interactions among coinfecting species, or simply derive from parasite diversity. Identifying the relative impact of these parameters is crucial for understand...
Article
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Artificial cover objects, made of various materials, have been used for decades for reptile and amphibian surveys, as well as in habitat restoration programs. Their low cost and maintenance demands make them a cost effective and efficient survey method. Since flipping covers does not require special skills, and covers can be uniform in size and mat...
Preprint
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Temporary ponds represent ecologically important habitats that support high species diversity and provide essential ecosystem services, particularly in certain countries surrounding the Mediterranean Sea, where natural lakes are scarce. Israel is located along the southeastern Mediterranean coast and features Mediterranean and arid climatic zones t...
Article
Parasites often coinfect host populations and, by interacting within hosts, might change the trajectory of multiparasite epidemics. However, host-parasite interactions often change with host age, raising the possibility that within-host interactions between parasites might also change, influencing the spread of disease. We measured how heterospecif...
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The competitive exclusion principle asserts that two species cannot stably coexist in the same habitat. However, the presence of a parasite can facilitate temporary coexistence between two host species occupying the same habitat. Studies of parasite-mediated interspecific competition typically use two host species that are both susceptible to a sin...
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Disease agents play an important role in the ecology and life history of wild and cultivated populations and communities. While most studies focus on the adaptation of parasites to their hosts, the adaptation of free-living parasite stages to their external (off-host) environment may tell us a lot about the factors that shape the distribution of pa...
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The dynamics of extinction and (re)colonization in habitat patches are characterizing features of dynamic metapopulations, causing them to evolve differently than large, stable populations. The propagule model, which assumes genetic bottlenecks during colonization, posits that newly founded subpopulations have low genetic diversity and are genetica...
Article
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Parasites impose different selection regimes on their hosts, which respond by increasing their resistance and/or tolerance. Parental challenge with parasites can enhance the immune response of their offspring, a phenomenon documented in invertebrates and termed transgenerational immune priming. We exposed two parental generations of the model organ...
Article
Speciation is a complex and continuous process that makes the delineation of species boundaries a challenging task in particular in species with little morphological differentiation, such as parasites. In this case, the use of genomic data is often necessary, such as for the intracellular Microsporidian parasites. Here we characterize the genome of...
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Parasite-mediated selection is thought to maintain host genetic diversity for resistance. We might thus expect to find a strong positive correlation between host genetic diversity and infection prevalence across natural populations. Here, we used computer simulations to examine host–parasite coevolution in 20 simi-isolated clonal populations across...
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Over the course of seasonal epidemics, populations of susceptible hosts may encounter a wide variety of parasites. Parasite phenology affects the order in which these species encounter their hosts, leading to sequential infections, with potentially strong effects on within-host growth and host population dynamics. Here, the cladoceran Daphnia magna...
Preprint
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Niche partitioning is the most studied factor structuring communities of competing species. In fragmented landscapes, however, a paradox can exist: different taxa may competitively dominate different types of habitat patches, resulting in a form of spatial niche partitioning, yet differences in long-term distributions among species can appear surpr...
Article
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Juveniles of diverse host taxa, including vertebrates, invertebrates and plants, are more susceptible to parasitic infections than adults, a phenomenon still poorly understood. To shed light on the mechanisms underlying this host age effect, we investigated its expression during different steps of the infection process of a bacterial parasite of th...
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Exposure to a pathogen primes many organisms to respond faster or more efficiently to subsequent exposures. Such priming can be non-specific or specific, and has been found to extend across generations. Disentangling and quantifying specific and non-specific effects is essential for understanding the genetic epidemiology of a system. By combining a...
Preprint
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Cyclical parthenogenesis is a widespread reproductive strategy in which organisms go through one or multiple rounds of clonal reproduction before sexual reproduction. In populations of the planktonic cladoceran Daphnia magna sexual reproduction is typically less common than parthenogenesis and therefore hardly studied. We studied the sexual process...
Article
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Climate change has the potential to shape the future of infectious diseases, both directly and indirectly. In aquatic systems, for example, elevated temperatures can modulate the infectivity of waterborne parasites and affect the immune response of zooplanktonic hosts. Moreover, lake warming causes shifts in the communities of primary producers tow...
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Background: Host genetic diversity can affect various aspects of host-parasite interactions, including individual-level effects on parasite infectivity, production of transmission stages and virulence, as well as population-level effects that reduce disease spread and prevalence, and buffer against widespread epidemics. However, a key aspect of th...
Article
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The increase in global production of carbon nanotubes (CNTs), as well as their use in polymer nanocomposites has raised concerns as to their possible effects on the marine environment that could ultimately affect human populations. Specifically, CNTs have already been tested in antifouling formulations for the prevention of biofouling, mainly to pr...
Article
In most species, variation in age among individuals is the strongest and most visible form of phenotypic variation. Individual-level age effects on disease traits, caused by differences in the age at exposure of the host or its parents, have been widely documented in invertebrates. They can influence diverse traits, such as host susceptibility, vir...
Article
In recent decades, the Dead Sea region has suffered greatly from anthropogenic activities that have resulted in a massive decrease of the Dead Sea water level. This decrease has allowed the penetration of fresh ground water into the underground layer, which dissolved the salt layer and created sinkholes. Presently there are over 5000 sinkholes spre...
Article
The microsporidian parasite Hamiltosporidium tvaerminnensis can infect Daphnia magna both horizontally (through environmental spores) and vertically (through parthenogenetic and sexually produced eggs). The spores of H. tvaerminnensis come in three distinguishable morphologies, which are thought to have different roles in the transmission of the pa...
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Background: The persistence of high genetic variability in natural populations garners considerable interest among ecologists and evolutionary biologists. One proposed hypothesis for the maintenance of high levels of genetic diversity relies on frequency-dependent selection imposed by parasites on host populations (Red Queen hypothesis). A complem...
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Parasite virulence is a leading theme in evolutionary biology. Modeling the course of virulence evolution holds the promise of providing practical insights into the management of infectious diseases and the implementation of vaccination strategies. A key element of virulence modeling is a tradeoff between parasite transmission rate and host lifespa...
Article
The infection process of many diseases can be divided into series of steps, each one required to successfully complete the parasite's life and transmission cycle. This approach often reveals that the complex phenomenon of infection is composed of a series of more simple mechanisms. Here we demonstrate that a population biology approach, which takes...
Article
Parasites can adversely affect host population densities, but predators can regulate disease by reducing the density of susceptible hosts and consuming parasites contained in infected hosts. Some parasites induce phenotypic modifications in their hosts that potentially lead to increased predation. We investigated the role of parasite-induced modifi...
Article
The Mediterranean coast of Israel can be divided into two distinct provinces (south to north): the Nilotic, which up to the construction of the Aswan Dam received most of its quartz-rich sediments from the Nile, and the Levantine, which receives most of its sediments from local, carbonate-rich sources. These differences in sediment composition shou...
Article
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In many host populations, one of the most striking differences among hosts is their age. While parasite prevalence differences in relation to host age are well known, little is known on how host age impacts ecological and evolutionary dynamics of diseases. Using two clones of the water flea Daphnia magna and two clones of its bacterial parasite Pas...
Article
1.Host age is one of the most striking differences among hosts within most populations, but there is very little data on how age-dependent effects impact ecological and evolutionary dynamics of both the host and the parasite. 2.Here we examined the influence of host age (juveniles, young and old adults) at parasite exposure on host susceptibility,...
Chapter
Studies of the evolution of virulence aim at understanding how and why certain parasite strains have evolved to cause morbidity and mortality to their hosts, while others have remained benign. In parasitism, according to definition, a parasite benefits at the expense of its host. These benefits are usually realized upon harming the host following i...
Article
Hybrids have often been labeled evolutionary dead-ends due to their lower fertility and viability. However, there is growing awareness that hybridization between different species may play a constructive role in animal evolution as a means to create variability. Thus, hybridization and introgression may contribute to adaptive evolution, for example...
Article
Amphibians stand at the forefront of the global biodiversity crisis. The causes of their decline are diverse and include a rise in amphibian malformations due to various factors, especially trematode infection. However, linking amphibian mortality and morbidity with trematode infection has proven to be challenging due to the complex life cycle of t...
Article
Trematodes are significant pathogens of high medical, veterinary, and environmental importance. They are hard to isolate from their intermediate hosts, and their early life stages are difficult to identify morphologically. Therefore, primers were developed for trematodes to create a species barcoding system and allow selective PCR amplification in...
Article
SUMMARY Many parasites survive harsh periods together with their hosts. Without the possibility of horizontal transmission during host diapause, parasite persistence depends entirely on host survival. We therefore hypothesize that a parasite should be avirulent during its host's diapausing stage. In contrast, the parasite may express higher virulen...
Article
One explanation for the widespread abundance of sexual reproduction is the advantage that genetically diverse sexual lineages have under strong pressure from virulent coevolving parasites. Such parasites are believed to track common asexual host genotypes, resulting in negative frequency-dependent selection that counterbalances the population growt...
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Background Multiple infections of the same host by different strains of the same microparasite species are believed to play a crucial role during the evolution of parasite virulence. We investigated the role of specificity, relative virulence and relative dose in determining the competitive outcome of multiple infections in the Daphnia magna-Pasteu...
Article
Assessing the mode of reproduction of microparasites remains a difficult task because direct evidence for sexual processes is often absent and the biological covariates of sex and asex are poorly known. Species with geographically divergent modes of reproduction offer the possibility to explore some of these covariates, for example, the influence o...
Article
Water fleas (Cladocera) constitute a major component in freshwater food webs, with important ecosystem-level consequences. Their abundance and richness are strongly influenced by their ecology and coevolution with numerous endoparasites. We investigated how parasitism shapes cladoceran community structure and diversity. We surveyed 204 freshwater p...
Article
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In many natural populations, hosts are found to be infected by more than one parasite species. When these parasites have different host exploitation strategies and transmission modes, a conflict among them may arise. Such a conflict may reduce the success of both parasites, but could work to the benefit of the host. For example, the less-virulent p...
Article
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Ecology Letters (2011) 14: 125–131 The degree of specificity in host–parasite interactions has important implications for ecology and evolution. Unfortunately, specificity can be difficult to determine when parasites cannot be cultured. In such cases, studies often use isolates of unknown genetic composition, which may lead to an underestimation of...
Article
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Infection processes consist of a sequence of steps, each critical for the interaction between host and parasite. Studies of host-parasite interactions rarely take into account the fact that different steps might be influenced by different factors and might, therefore, make different contributions to shaping coevolution. We designed a new method usi...
Chapter
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Landscape survey of Ramat Bet Shemesh region undertaken in the 1990's including data on botany, terrestrial mammals, birds, reptiles, molluscs, sheep, goat and cattle herd management, historical data on Palestinian landuse of the region
Article
Stress conditions have been found to change the susceptibility of hosts or their offspring to infection. The usual method of testing at just one parasite dose level does not allow conclusions on the distribution of susceptibility. To better understand the epidemiology and evolution of host-parasite systems, however, knowledge about the distribution...
Article
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Shotgun sequences of DNA extracts from whole organisms allow a comprehensive assessment of possible symbionts. The current project makes use of four shotgun datasets from three species of the planktonic freshwater crustaceans Daphnia: one dataset from clones of D. pulex and D. pulicaria and two datasets from one clone of D. magna. We analyzed these...
Article
Multiple infections of a host by different strains of the same microparasite are common in nature. Although numerous models have been developed in an attempt to predict the evolutionary effects of intrahost competition, tests of the assumptions of these models are rare and the outcome is diverse. In the present study we examined the outcome of mixe...
Article
The Red Queen hypothesis predicts that sexual reproduction should be favoured when the risk of infection by parasites is high. However, this prediction may also be achieved independently by means of the reproductive assurance and the density-dependent transmission hypotheses because higher densities increase the chances of fertilization (i.e. mates...
Article
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Epidemiological models generally assume that the number of susceptible individuals that become infected within a unit of time depends on the density of the hosts and the concentration of parasites (i.e. mass-action principle). However, empirical studies have found significant deviations from this assumption due to biotic and abiotic factors, such a...
Article
This conchometric study explores the taxonomy of both Modern and Plio-Pleistocene Thiaridae of Israel. Modern species include Melanoides tuberculata, today widespread in Africa and Asia and Tarebia granifera, recently introduced via aquarist trade. Fossil species include M. tuberculata, M. dadiana and M. jordanica. M. dadiana differs from M. tuberc...
Article
Geographic parthenogenesis describes the observation that parthenogenetic organisms tend to occupy environments different from those of their close, sexually reproducing relatives. These environments are often described as extreme or disturbed habitats. We examined whether patterns of geographical parthenogenesis persist over time, by conducting a...
Article
An invasive operculate gastropod, the freshwater snail Tarebia granifera, is reported for the first time from Israel. In a survey of 52 freshwater sites populations of T. granifera were discovered at four sites, in abundance at two of them, one of which included individuals infected with the trematode Philophthalmus sp. In both sites T. granifera o...
Article
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Some aquatic snails are able to use chemical cues (kairomones) to differentiate between predators that have fed on snails and predators that have eaten other prey. However, it is unknown if terrestrial snails are able to differentiate between snail-fed predators and predators that have not recently consumed snails. Here we document diet-based chemi...
Article
The discovery of Transversotrema patialense cercariae in an aquarium harboring tropical fish triggered the present study. The purpose was to estimate the potential range of infection of local freshwater and fishpond populations by T. patialense. Experimental infection of T. patialense differed among 3 species employed: 76.5% for Tilapia zillii, 37....
Article
In this conchometric study, the systematics and distribution of the freshwater gastropod Melanopsis in the Levant are described. Of the ten species found, three are widespread, two have narrow distributions and five are known only from their type locality. Five smooth-shelled species are recognized (buccinoidea, ammonis, dircaena, khabourensis and...
Article
The freshwater gastropod Melanoides tuberculata broods its young in a pouch located in the anterodorsal region of the head-foot. The wall of the brood pouch is composed of smooth muscle surrounded by connective tissue. The lumen of the brood pouch is incompletely partitioned by trabeculae, formed by extensions or folds in the chamber wall that are...
Article
The Red Queen hypothesis predicts that sex should be more common in populations heavily infested with parasites, than in those without. This hypothesis was investigated in the aquatic snail Melanoides tuberculata, in which both sexual and parthenogenetic individuals exist in natural populations, and some populations are heavily infested by trematod...
Article
Based on conchiometrics of 161 snails of the freshwater genus Melanopsis collected from six sites in the Coastal Plain of Israel, three species were identified: buccinoidea (Olivier), costata (Olivier) and saulcyi Bourguignat. Species previously described from this region (lampra Bourguignat, phoeneciaca Bourguignat, belusi Bourguignat and hebraica...
Article
The ultrastructural features of oogenesis are described in an ovoviviparous (Melanoides tuberculata) and an oviparous (Melanopsis buccinoidea), freshwater snail. Yolk formation in both species appears to be primarily autosynthetic. In M. tuberculata protein yolk, formed by the endoplasmic reticulum and Golgi bodies, appears first. As vitellogenesis...
Article
Some freshwater snail species are severe pests to human health or agriculture. We tested the hypothesis that the fish Mylopharyngodon piceus, the black carp, may serve as a biological control agent of two pest snails, Physella acuta (a bank-dwelling snail) and Melanoides tuberculata (a substratum-dwelling snail). Experiments were carried out in the...
Article
Ten species and subspecies of lands nails are described from southwestern Jordan. Two of the species (Helix sp. and Sphincterochila sp.) differ from those known from Israel, and may be new species. One species (Buliminusglabratus) and one subspecies (Buliminus labrosus jiftliki) are described from Jordan for the first time.

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