Search results for "competition"

Life-history variation, environmental fluctuations and competition in ecologically similar species: modeling the case of rotifers

2015

Competition for resources can lead to species exclusion. However, this exclusion may be avoided if species show differential adaptation to physical environment. Empirical studies on competition are difficult when species are phylogenetically close and have complex life cycles. This is the case of B. plicatilis and B. manjavacas, two cryptic rotifer species differing in their salinity niches and in life-history traits related to sex and diapause. These differences have been suggested to promote the stable co-occurrence observed in natural populations of these species. However, in a previous empirical study, the outcome of competition between both species was always exclusion. Here, we theore…

Resource competition between sympatric sibling rotifer species

2001

Mechanisms underlying competitive interactions are important in understanding the structure of planktonic communities, particularly the coexistence of similar species. Here we present experimental results of exploitative competition among three sympatric sibling species of the Brachionus plicatilis complex for two differently-sized species of food microalgae. These three rotifer species are to be found in seasonal succession in brackish ponds on the Spanish Mediterranean coast; they can, however, co-occur for long periods. The functional and numerical responses of the three Brachionus species to both food microalgae, although similar, differed. Neither rotifer population growth nor grazing …

Interspecific and intraspecific interactions in the monogenean communities of fish: a question of study scale?

2007

SUMMARYMonogenean communities of fish have generally been considered non-interactive as negative interspecific interactions have rarely been reported. Most of the earlier studies on monogenean communities, however, have been conducted not only in systems with relatively low parasite abundances but, more importantly, at study scales where microhabitat-level interactions between the parasites are easily overlooked. We examined the communities of 3 abundant Dactylogyrus (Monogenea) species on the gills of crucian carp (Carassius carassius) by analysing the interactions at the scale of individual gill filaments, where interactions between the species, if any, should most likely take place. Cont…

Increasing growth temperature alters the within-host competition of viral strains and influences virus genetic variation

2020

AbstractThe emergence of viral diseases in plant crops hamper the sustainability of food production, and this may be boosted by global warming. Concurrently, mixed viral infections are becoming common in plants, of which epidemiology are unpredictable due to within-host virus-virus interactions. However, the extent in which the combined effect of variations in the abiotic components of the plant ecological niche (e.g., temperature) and the prevalence of mixed infections (i.e., within-host interactions among viruses) affect the evolutionary dynamics of viral populations is not well understood. Here, we explore the interplay between ecological and evolutionary factors during viral infections,…

Dinner with the roommates: trophic niche differentiation and competition in a mutualistic ant‐ant association

2020

1. The potential for competition is highest among species in close association. Despite net benefits for both parties, mutualisms can involve costs, including food competition. This might be true for the two neotropical ants Camponotus femoratus and Crematogaster levior, which share the same nest in a presumably mutualistic association (parabiosis). 2. While each nest involves one Crematogaster and one Camponotus partner, both taxa were recently found to comprise two cryptic species that show no partner preferences and seem ecologically similar. Since these cryptic species often occur in close sympatry, they might need to partition their niches to avoid competitive exclusion. 3. Here, we in…

Niche segregation of coexisting Arctic charr (Salvelinus alpinus) and brown trout (Salmo trutta) constrains food web coupling in subarctic lakes

2012

SUMMARY 1. Generalist fish species are recognised as important couplers of benthic and pelagic food-web compartments in lakes. However, interspecific niche segregation and individual specialisation may limit the potential for generalistic feeding behaviour. 2. We studied summer habitat use, stomach contents and stable isotopic compositions of the generalist feeder Arctic charr coexisting with its common resource competitor brown trout in five subarctic lakes in northern Norway to reveal population-level and individual-level niche plasticity. 3. Charr and trout showed partial niche segregation in all five lakes. Charr used all habitat types and a wide variety of invertebrate prey including z…

How picky can you be? Temporal variations in trophic niches of co-occurring suspension-feeding species

2014

Abstract Suspension-feeders largely dominate faunal communities on rocky shores and compete for food using different feeding strategies. We used stable isotopes to assess the individual specialization within common suspension-feeder populations and to evaluate both inter-specific and intra-specific differences in food source exploitation. Trophic niches were characterized by metrics calculated in a space formed by mixing model outputs. Honeycomb worms ( Sabellaria alveolata ), blue mussels ( Mytilus edulis ) and barnacles ( Chthamalus montagui ), as well as three organic matter sources (benthic microalgae, phytoplankton and green macroalgae) were surveyed over a year using stable isotopic c…

Population changes in Czech passerines are predicted by their life-history and ecological traits

2010

A species’ susceptibility to environmental change might be predicted by its ecological and life-history traits. However, the effects of such traits on long-term bird population trends have not yet been assessed using a comprehensive set of explanatory variables. Moreover, the extent to which phylogeny affects patterns in the interspecific variability of population changes is unclear. Our study focuses on the interspecific variability in long-term population trends and annual population fluctuations of 68 passerine species in the Czech Republic, assessing the effects of eight life-history and five ecological traits. Ordination of life-history traits of 68 species revealed a life-history grad…

Temporal and dietary niche is context‐dependent in tropical ants

2020

The expression of virulence during double infections by different parasites with conflicting host exploitation and transmission strategies

2011

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 parasite may protect the host against the more-virulent competitor. We examine this conflict using the waterflea Daphnia magna and two of its sympatric parasites: the blood-infecting bacterium Pasteuria ramosa that transmits horizontally and the intracellular microsporidium Octosporea bayeri that can concurrently transmit horizontally and verticall…