scholarly journals Community composition and species richness of parasitoids infesting Yponomeuta species in the Netherlands

2004 ◽  
Vol 73 (4) ◽  
pp. 255-261 ◽  
Author(s):  
Daniel F.R. Cleary
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
The Netherlands ◽  
Community Composition ◽  
Host Species ◽  
Community Similarity ◽  
Parasitoid Species ◽  
Temporal And Spatial Variation ◽  
Significant Difference ◽  
Temporal And Spatial

Parasitoid assemblages infesting Yponomeuta species in the Netherlands were investigated. Parasitoid species richness and community composition were related to host species, habitat, temporal and spatial variation. Both community structure and species richness did not differ among habitats. There was no significant difference in species richness between years (1994 and 1995) but there was a significant difference in community composition. Community composition and species richness both differed among host species, although this latter result was solely due to the host species Y. evonymellus. There was no significant relationship between community similarity and distance. These results indicate that the parasitoids of the moth genus Yponomeuta in the Netherlands appear to form a spatially stable, but temporally variable community. Most of the variation in community structure was, however, related to the host species. The marked difference in parasitoid species richness and community composition of Y. evonymellus when compared to the other species warrants further study.

scholarly journals Do syntopic host species harbour similar symbiotic communities? The case ofChaetopterusspp. (Annelida: Chaetopteridae)

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e2930 ◽  
Author(s):  
Temir A. Britayev ◽  
Elena Mekhova ◽  
Yury Deart ◽  
Daniel Martin
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Host Species ◽  
Interspecific Interactions ◽  
Single Species ◽  
Intraspecific Interactions ◽  
Mean Intensity ◽  
Species Dominance ◽  
High Species Richness ◽  
Symbiotic Community

To assess whether closely related host species harbour similar symbiotic communities, we studied two polychaetes,Chaetopterussp. (n = 11) andChaetopteruscf.appendiculatus(n = 83) living in soft sediments of Nhatrang Bay (South China Sea, Vietnam). The former harboured the porcellanid crabsPolyonyxcf.heokandPolyonyxsp., the pinnotherid crabTetriassp. and the tergipedid nudibranchPhestillasp. The latter harboured the polynoid polychaeteOphthalmonoe pettiboneae, the carapid fishOnuxodon fowleriand the porcellanid crabEulenaios cometes, all of which, exceptO. fowleri, seemed to be specialized symbionts. The species richness and mean intensity of the symbionts were higher inChaetopterussp. than inC.cf.appendiculatus(1.8 and 1.02 species and 3.0 and 1.05 individuals per host respectively). We suggest that the lower density ofChaetopterussp. may explain the higher number of associated symbionts observed, as well as the 100% prevalence (69.5% inC.cf.appenciculatus). MostChaetopterussp. harboured two symbiotic species, which was extremely rare inC.cf.appendiculatus, suggesting lower interspecific interactions in the former. The crab and nudibranch symbionts ofChaetopterussp. often shared a host and lived in pairs, thus partitioning resources. This led to the species coexisting in the tubes ofChaetopterussp., establishing a tightly packed community, indicating high species richness and mean intensity, together with a low species dominance. In contrast, the aggressive, strictly territorial species associated withC.cf.appendiculatusestablished a symbiotic community strongly dominated by single species and, thus, low species richness and mean intensity. Therefore, we suggest that interspecific interactions are determining species richness, intensity and dominance, while intraspecific interactions are influencing only intensity and abundance. It is possible that species composition may have influenced the differences in community structure observed. We hypothesize that both host species could originally be allopatric. The evolutionary specialization of the symbiotic communities would occur in separated geographical areas, while the posterior disappearance of the existing geographical barriers would lead to the overlapped distribution.

scholarly journals Responses of community structure and diversity to nitrogen deposition and rainfall addition in contrasting steppes are ecosystem-dependent and dwarfed by year-to-year community dynamics

2019 ◽  
Vol 124 (3) ◽  
pp. 461-469 ◽  
Author(s):  
Xuejun Yang ◽  
Zhenying Huang ◽  
Ming Dong ◽  
Xuehua Ye ◽  
Guofang Liu ◽  
...  
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Global Change ◽  
Nitrogen Deposition ◽  
Community Composition ◽  
Community Dynamics ◽  
Environmental Variability ◽  
The Other ◽  
Desert Steppe ◽  
Typical Steppe

Abstract Background and Aims Long-term studies to disentangle the multiple, simultaneous effects of global change on community dynamics are a high research priority to forecast future distribution of diversity. Seldom are such multiple effects of global change studied across different ecosystems. Methods Here we manipulated nitrogen deposition and rainfall at levels realistic for future environmental scenarios in three contrasting steppe types in Mongolia and followed community dynamics for 7 years. Key Results Redundancy analyses showed that community composition varied significantly among years. Rainfall and nitrogen manipulations did have some significant effects, but these effects were dependent on the type of response and varied between ecosystems. Community compositions of desert and meadow steppes, but not that of typical steppe, responded significantly to rainfall addition. Only community composition of meadow steppe responded significantly to nitrogen deposition. Species richness in desert steppe responded significantly to rainfall addition, but the other two steppes did not. Typical steppe showed significant negative response of species richness to nitrogen deposition, but the other two steppes did not. There were significant interactions between year and nitrogen deposition in desert steppe and between year and rainfall addition in typical steppe, suggesting that the effect of the treatments depends on the particular year considered. Conclusions Our multi-year experiment thus suggests that responses of community structure and diversity to global change drivers are ecosystem-dependent and that their responses to experimental treatments are dwarfed by the year-to-year community dynamics. Therefore, our results point to the importance of taking annual environmental variability into account for understanding and predicting the specific responses of different ecosystems to multiple global change drivers.

HYMENOPTERA OF THE WAGNER NATURAL AREA, A BOREAL SPRING FEN IN CENTRAL ALBERTA

1994 ◽  
Vol 126 (S169) ◽  
pp. 181-220 ◽  
Author(s):  
Albert T. Finnamore
Keyword(s):  
Species Richness ◽  
Host Species ◽  
Habitat Structure ◽  
Natural Area ◽  
Parasitoid Species ◽  
Boreal Spring ◽  
Arthropod Fauna ◽  
Pan Traps ◽  
Malaise Traps ◽  
Spring Fen

AbstractThe Wagner Natural Area, located 8 km west of Edmonton, Alberta (53°34′N 113°47′W), contains a boreal spring fen estimated to be 4700 years old. The site was selected in 1985 for a survey of its arthropod fauna. A transect of the site from marl pools through fen, edge effect, and treed swamp was sampled for arthropods using pan and Malaise traps. Specialized microhabitats outside the transect were identified and sampled using pan traps. The Wagner fen samples contain 2181 species of arthropods contributing to a total known biota of 2905 species in the peatland. Of those, 1410 are Hymenoptera. Although seven other peatland studies are known, the inability of systematists to name most species prevents direct comparisons among peatlands. Data obtained from the Hymenoptera collections at Wagner demonstrate a progression in species richness as one approaches the forest–fen edge from either fen or forest. A large proportion [30% (382 species)] of Hymenoptera species, termed the aerial component, is active both in the forest–fen edge and in the fen. The aerial component is a highly mobile, at least locally transient, but often uncollected component of peatland ecosystems. Presence of the aerial component is probably associated with habitat structure. Those peatlands possessing more complex vegetation architecture have greater proportions of aerial species. About 80% of Hymenoptera at Wagner are parasitoids, most of which attack larva of holometabolous hosts. Based on the host groups sought by parasitoids and the ratio of parasitoid species per host species, the fen is estimated to contain about 6000 species of arthropods.

scholarly journals Multi-Sensor Observations of Submesoscale Eddies in Coastal Regions

2020 ◽  
Vol 12 (4) ◽  
pp. 711
Author(s):  
Gang Li ◽  
Yijun He ◽  
Guoqiang Liu ◽  
Yingjun Zhang ◽  
Chuanmin Hu ◽  
...  
Keyword(s):  
High Frequency ◽  
Color Index ◽  
Ocean Color ◽  
Coastal Region ◽  
Surface Currents ◽  
Temporal And Spatial Variation ◽  
Significant Difference ◽  
Eddy Structures ◽  
Temporal And Spatial ◽  
Submesoscale Processes

The temporal and spatial variation in submesoscale eddies in the coastal region of Lianyungang (China) is studied over a period of nearly two years with high-resolution (0.03°, about 3 km) observations of surface currents derived from high-frequency coastal radars (HFRs). The centers and boundaries of submesoscale eddies are identified based on a vector geometry (VG) method. A color index (CI) representing MODIS ocean color patterns with a resolution of 500 m is used to compute CI gradient parameters, from which submesoscale features are extracted using a modified eddy-extraction approach. The results show that surface currents derived from HFRs and the CI-derived gradient parameters have the ability to capture submesoscale processes (SPs). The typical radius of an eddy in this region is 2–4 km. Although no significant difference in eddy properties is observed between the HFR-derived current fields and CI-derived gradient parameters, the CI-derived gradient parameters show more detailed eddy structures due to a higher resolution. In general, the HFR-derived current fields capture the eddy form, evolution and dissipation. Meanwhile, the CI-derived gradient parameters show more SPs and fill a gap left by the HFR-derived currents. This study shows that the HFR and CI products have the ability to detect SPs in the ocean and contribute to SP analyses.

scholarly journals Bacteria associated with jellyfish during bloom and post-bloom periods

2018 ◽  
Author(s):  
Maja Kos Kramar ◽  
Tinkara Tinta ◽  
Davor Lučić ◽  
Alenka Malej ◽  
Valentina Turk
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Community Composition ◽  
Bacterial Community Structure ◽  
Bacterial Community Composition ◽  
Body Part ◽  
Body Parts ◽  
Population Peak ◽  
Significant Difference ◽  
Jellyfish Population

AbstractThis study is the first to investigate bacterial community associated with live medusaAurelia sp. in the Gulf of Trieste (northern Adriatic Sea) using both culture independent and culture-based methods. We have analysed bacterial community composition of different body parts of medusa: exumbrella surface, oral arms (‘outer’ body parts) and of gastric cavity (‘inner’ body part) and investigated possible differences in medusa associated bacterial community structure at the time of jellyfish population peak and during senescent phase at the end of bloom, when jellyfish start to decay. Based on 16S rRNA clone libraries and denaturing gradient gel electrophoresis (DGGE) analysis, we demonstrated significant difference between bacterial community associated withAureliaand the ambient seawater bacterial assemblage. Comparing bacterial community composition between differentAureliamedusa body parts, communities differed significantly, especially the one within the gastral cavity. The pronounced difference is dominance ofBetaproteobacteria(Burkholderia, CupriavidusandAchromobacter) in gastral cavity of medusa andAlpha- (Phaeobacter, Ruegeria) andGamma-proteobacteria(Stenotrophomonas, Alteromonas, PseudoalteromonasandVibrio) on ‘outer’ body parts. This suggests that body-part specific bacterial association might have an important functional roles for the host. The results of bacterial isolates showed the dominance ofGammaproeteobacteria, especiallyVibrioandPseudoalteromonasin all body parts. Finally, comparison of medusa associated bacterial community structure, at the time of jellyfish population peak and during senescent phase at the end of bloom showed increased abundance ofGammaproteobacteria, especiallyVibrio. Our results suggest members ofVibriogroup are possible commensal opportunistic visitors, later becoming consumer of moribund jellyfish biomass and that the structure of jellyfish bacterial community might be affected by anthropogenic pollution in the marine environment.

scholarly journals Sponge-Associated Amphipod Communities as Bioindicators for Pollution

2021 ◽  
Author(s):  
◽  
Ronja Hauke
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Sex Ratios ◽  
Diversity Indices ◽  
Life Cycle Stage ◽  
Sponge Species ◽  
Pollution Level ◽  
Sponge Tissue ◽  
Pollution Levels ◽  
Significant Difference

<p>Pollution negatively impacts organisms across all marine ecosystems. Coastal areas are particularly vulnerable to pollution due to their proximity to human settlements. Amphipods are commonly used as bioindicators to monitor pollution burdens, due to their high sensitivities and their ubiquity. Pollution can reduce amphipod abundance, species richness, evenness and diversity. Community structure, proportionality of adults to juveniles and sex ratios may also be affected. Sponges often harbour high densities of amphipods, offering food, refuge and nurseries to their symbionts. Sponge-associated amphipods differ in their level of specialization on their host. This study provides first insights into the usefulness of sponge-associated amphipod communities as bioindicators. For this, it hypothesized that amphipod densities, species diversity, community structure, sex ratio and age proportionality will differ according to pollution levels.  To test this, sponges were collected from three sites with varying degrees of pollution in Wellington Harbour. The sponges were weighed, and their volume was measured. They were dissected and their amphipods were identified to species level, counted, measured (length) and their sex and life cycle stage (adult or juvenile) were recorded. From this data, amphipod densities, species richness, evenness and Shannon-Wiener diversity indices were calculated and compared among pollution levels. Community structure was also compared between sites and sponge species. Pollution level significantly affected species richness, evenness, diversity and community structure. The highest values for species richness, evenness and diversity were found in sponges from the least polluted. The lowest levels of these factors were found in sponges from the most polluted site. Sponges from the intermediate site generally harboured moderate richness, evenness and diversity compared to the other sites. Community composition was significantly affected by pollution, although effect sizes differed between sponge species. Higher pollution levels seemed to favour dominance of species that are better adapted to living in sponges. Generalists seemed to thrive in low to intermediate pollution levels. The majority of sex ratios measured had a female bias, which appeared to increase with increasing pollution although the difference was not statistically significant. The proportion of adults also showed a non-significant increase with pollution level. There was no significant difference in amphipod abundance per litre of sponge tissue between pollution levels, possibly because pollution levels may have been too low to cause a reduction in amphipod density. These results show that sponge-associated amphipod communities are useful as bioindicators, as amphipod diversity, richness and evenness were significantly reduced by pollution and the sponge association allows for these community-scale comparisons to be made within an easily measurable framework. Species evenness in particular provided an accurate indication of different pollution levels.</p>

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