Search results for "specialist species"

A finely tuned strategy adopted by an egg parasitoid to exploit chemical traces from host adults.

2009

SUMMARY Scelionid egg parasitoids can obtain reliable information on the presence of host eggs by discriminating host gender on the basis of chemical footprints of their co-evolved hosts, with a strong preference for the footprint left by host females. Based on the concept of dietary specialization and infochemical use in natural enemies, it could be predicted that host gender discrimination in specialist species belonging to the genus Trissolcus is further tuned to specific cues from distinctive chemical traces left by host females as a consequence of copulation and/or oviposition. To test this hypothesis we used the system Murgantia histrionica – Trissolcus brochymenae. Our results showed…

DIET QUALITY AFFECTS WARNING COLORATION INDIRECTLY: EXCRETION COSTS IN A GENERALIST HERBIVORE

2009

Aposematic herbivores are under selection pressure from their host plants and predators. Although many aposematic herbivores exploit plant toxins in their own secondary defense, dealing with these harmful compounds might underlay costs. We studied whether the allocation of energy to detoxification and/or sequestration of host plant defense chemicals trades off with warning signal expression. We used a generalist aposematic herbivore Parasemia plantaginis (Arctiidae), whose adults and larvae show extensive phenotypic and genetic variation in coloration. We reared larvae from selection lines for small and large larval warning signals on Plantago lanceolata with either low or high concentratio…

The long history of rich fens supports persistence of plant and snail habitat specialists

2021

Increasing evidence for the effects of Holocene history on modern biotic communities suggests that current explanations of community patterns and conservation strategies require revisiting. Here we focused on Central European rich fens that are at high risk among mire habitats because of their relatively low environmental stability, and hence sensitivity to successional shifts. At each of 57 study sites, inventory of specialist species of bryophytes, vascular plants and land snails, measurements of local environmental conditions, area, and radiocarbon dating were conducted. We used Moran’s I spatial autocorrelation, multiple linear regression models, MDS, db-RDA, and null models to identify…

Parasite communities in the red mullet, Mullus barbatus L., respond to small-scale variation in the levels of polychlorinated biphenyls in the Wester…

2012

We examined parasite populations and communities in the Mediterranean sentinel fish species, Mullus barbatus, sampled at a small-scale PCB gradient at the shelf sediments off Catalonian coasts of the Western Mediterranean. A recurrent feature at both the population and community level was the differentiation of the samples along the increasing PCB levels simultaneously registered in the sediments. Both directly transmitted ectoparasites and endoparasites with complex life-cycles transmitted via food chains exhibited a decrease in abundance with the increase in PCB levels. Parasite numerical responses translated into significant differences in infracommunity structure with decreasing predict…

The structure of parasite component communities in brackish water fishes of the northeastern Baltic Sea

2001

We used nestedness analysis to seek non-random patterns in the structure of component communities of metazoan parasites collected from 31 sympatric fish species from the northeastern Bothnian Bay, the most oligohaline area of the Baltic Sea. Only 8 marine parasite species were found among the 63 species recorded, although some marine fish species reproduce in the bay and others occasionally visit the area. Marine parasite species can utilize both freshwater and marine fish species as intermediate or final hosts, and marine fish can harbour freshwater parasite species. This exchange of parasite species between marine and freshwater fish has probably resulted from ecological factors acting ov…

Correction to: “Generalist” Journals between Dissemination of Economics and Regime Propaganda

2020

Helminth communities of owls (strigiformes) indicate strong biological and ecological differences from birds of prey (accipitriformes and falconiform…

2012

We compared the helminth communities of 5 owl species from Calabria (Italy) and evaluated the effect of phylogenetic and ecological factors on community structure. Two host taxonomic scales were considered, i.e., owl species, and owls vs. birds of prey. The latter scale was dealt with by comparing the data here obtained with that of birds of prey from the same locality and with those published previously on owls and birds of prey from Galicia (Spain). A total of 19 helminth taxa were found in owls from Calabria. Statistical comparison showed only marginal differences between scops owls (Otus scops) and little owls (Athene noctua) and tawny owls (Strix aluco). It would indicate that all owl …

Rapid evolutionary adaptation to elevated salt concentrations in pathogenic freshwater bacteria Serratia marcescens.

2014

Rapid evolutionary adaptions to new and previously detrimental environmental conditions can increase the risk of invasion by novel pathogens. We tested this hypothesis with a 133-day-long evolutionary experiment studying the evolution of the pathogenic Serratia marcescens bacterium at salinity niche boundary and in fluctuating conditions. We found that S. marcescens evolved at harsh (80 g/L) and extreme (100 g/L) salt conditions had clearly improved salt tolerance than those evolved in the other three treatments (ancestral conditions, nonsaline conditions, and fluctuating salt conditions). Evolutionary theories suggest that fastest evolutionary changes could be observed in intermediate sele…

Food selection of a generalist herbivore exposed to native and alien seaweeds

2018

Understanding which factors influence the invasion of alien seaweed has become a central concern in ecology. Increasing evidence suggests that the feeding preferences of native herbivores influence the success of alien seaweeds in the new community. We investigated food selection of a generalist native grazer Paracentrotus lividus, in the presence of two alien seaweeds (Caulerpa cylindracea and Caulerpa taxifolia var. distichophylla) and two native seaweeds (Dictyopteris membranacea and Cystoseira compressa). Sea urchins were fed with six experimental food items: C. cylindracea, C. taxifolia var. distichophylla, a mixture of C. cylindracea and C. taxifolia var. distichophylla, D. membranace…

Life-history trade-offs in a generalist digenean from cetaceans: the role of host specificity and environmental factors

2015

Background Adults and larvae of generalist parasites are exposed to diverse hosts and local environmental conditions throughout their life cycles, thus local adaptation is expected to occur through phenotypic plasticity and/or natural selection. We investigated how the combined effect of cryptic host specificity and local selective pressures could shape reproductive traits of a putative generalist parasite in the oceanic realm. Methods The LSU rDNA, ITS2 and the mt-COI of individuals of the digenean Pholeter gastrophilus (Kossack, 1910) Odhner, 1914 (Heterophyidae Leiper, 1909) from oceanic striped dolphins, Stenella coeruleoalba Meyen, and coastal bottlenose dolphins, Tursiops truncatus Mo…