scholarly journals Time-since-invasion increases native mesoherbivore feeding rates on the invasive alga, Sargassum muticum (Yendo) Fensholt

2017 ◽  
Vol 98 (8) ◽  
pp. 1935-1944 ◽  
Author(s):  
Martyn Kurr ◽  
Andrew J. Davies
Keyword(s):  
Invasive Plants ◽  
Enemy Release Hypothesis ◽  
Sargassum Muticum ◽  
Enemy Release ◽  
Feeding Rates ◽  
Herbivore Species ◽  
Feeding Trials ◽  
Negative Impacts ◽  
Abundance And Diversity ◽  
Invasive Alga

Invasive algae can have substantial negative impacts in their invaded ranges. One widely cited mechanism that attempts to explain how invasive plants and algae are often able to spread quickly, and even become dominant in their invaded ranges, is the Enemy Release Hypothesis. This study assessed the feeding behaviours of two species of gastropod herbivore from populations exposed to the invasive alga Sargassum muticum for different lengths of time. Feeding trials, consisting of both choice and no-choice, showed that the herbivores from older stands (35–40 years established) of S. muticum were more likely to feed upon it than those taken from younger (10–19 years established) stands. These findings provide evidence in support of the ERH, by showing that herbivores consumed less S. muticum if they were not experienced with it. These findings are in accordance with the results of other feeding-trials with S. muticum, but in contrast to research that utilizes observations of herbivore abundance and diversity to assess top-down pressure. The former tend to validate the ERH, and the latter typically reject it. The potential causes of this disparity are discussed, as are the importance of palatability, herbivore species and time-since-invasion when considering research into the ERH. This study takes an important, yet neglected, approach to the study of invasive ecology.

scholarly journals On the Health Benefits vs. Risks of Seaweeds and Their Constituents: The Curious Case of the Polymer Paradigm

Marine Drugs ◽  
2021 ◽  
Vol 19 (3) ◽  
pp. 164
Author(s):  
João Cotas ◽  
Diana Pacheco ◽  
Glacio Souza Araujo ◽  
Ana Valado ◽  
Alan T. Critchley ◽  
...  
Keyword(s):  
Brown Seaweed ◽  
Dry Weight ◽  
Sargassum Muticum ◽  
Human Nutrition ◽  
Health Impacts ◽  
Gracilaria Gracilis ◽  
Red Seaweeds ◽  
Positive Effects ◽  
Negative Impacts ◽  
Biomedical Potential

To exploit the nutraceutical and biomedical potential of selected seaweed-derived polymers in an economically viable way, it is necessary to analyze and understand their quality and yield fluctuations throughout the seasons. In this study, the seasonal polysaccharide yield and respective quality were evaluated in three selected seaweeds, namely the agarophyte Gracilaria gracilis, the carrageenophyte Calliblepharis jubata (both red seaweeds) and the alginophyte Sargassum muticum (brown seaweed). It was found that the agar synthesis of G. gracilis did not significantly differ with the seasons (27.04% seaweed dry weight (DW)). In contrast, the carrageenan content in C. jubata varied seasonally, being synthesized in higher concentrations during the summer (18.73% DW). Meanwhile, the alginate synthesis of S. muticum exhibited a higher concentration (36.88% DW) during the winter. Therefore, there is a need to assess the threshold at which seaweed-derived polymers may have positive effects or negative impacts on human nutrition. Furthermore, this study highlights the three polymers, along with their known thresholds, at which they can have positive and/or negative health impacts. Such knowledge is key to recognizing the paradigm governing their successful deployment and related beneficial applications in humans.

Testing the enemy release hypothesis: trematode parasites in the non-indigenous Manila clam Ruditapes philippinarum

Hydrobiologia ◽  
2009 ◽  
Vol 630 (1) ◽  
pp. 139-148 ◽  
Author(s):  
C. Dang ◽  
X. de Montaudouin ◽  
J. Bald ◽  
F. Jude ◽  
N. Raymond ◽  
...  
Keyword(s):  
Ruditapes Philippinarum ◽  
Enemy Release Hypothesis ◽  
Manila Clam ◽  
Enemy Release ◽  
Trematode Parasites

scholarly journals Testing the enemy release hypothesis in a native insect species with an expanding range

PeerJ ◽  
2015 ◽  
Vol 3 ◽  
pp. e1415 ◽  
Author(s):  
Julia J. Mlynarek
Keyword(s):  
Related Species ◽  
Enemy Release Hypothesis ◽  
Enemy Release ◽  
Infection Prevalence ◽  
Water Mite ◽  
Closely Related Species ◽  
Study Region ◽  
Ecological Release ◽  
Non Invasive ◽  
Enallagma Boreale

The enemy release hypothesis (ERH) predicts that the spread of (invasive) species will be facilitated by release from their enemies as they occupy new areas. However, the ERH is rarely tested on native (non-invasive, long established) species with expanding or shifting ranges. I tested the ERH for a native damselfly (Enallagma clausum) whose range has recently expanded in western Canada, with respect to its water mite and gregarine parasites. Parasitism levels (prevalence and intensity) were also compared betweenE. clausumand a closely related species,Enallagma boreale, which has long been established in the study region and whose range is not shifting. A total of 1,150 damselflies were collected at three ‘old’ sites forE. clausumin Saskatchewan, and three ‘new’ sites in Alberta. A little more than a quarter of the damselflies collected were parasitized with, on average, 18 water mite individuals, and 20% were parasitized by, on average, 10 gregarine individuals. I assessed whether the differences between levels of infection (prevalence and intensity) were due to site type or host species. The ERH was not supported:Enallagma clausumhas higher or the same levels of parasitism in new sites than old sites. However,E. borealeseems to be benefitting from the recent range expansion of a native, closely related species through ecological release from its parasites because the parasites may be choosing to infest the novel, potentially naïve, host instead of the well-established host.

Impacts of the invasive alga Sargassum muticum on ecosystem functioning and food web structure

2013 ◽  
Vol 15 (11) ◽  
pp. 2563-2576 ◽  
Author(s):  
Tânia Salvaterra ◽  
Dannielle S. Green ◽  
Tasman P. Crowe ◽  
Eoin J. O’Gorman
Keyword(s):  
Food Web ◽  
Ecosystem Functioning ◽  
Sargassum Muticum ◽  
Food Web Structure ◽  
Web Structure ◽  
Invasive Alga

scholarly journals Enemy release mitigates inbreeding depression in native and invasive Silene latifolia populations: experimental insight into the role of inbreeding × environment interactions in invasion success

2018 ◽  
Author(s):  
Karin Schrieber ◽  
Sabrina Wolf ◽  
Catherina Wypior ◽  
Diana Höhlig ◽  
Stephen R. Keller ◽  
...  
Keyword(s):  
Genetic Differentiation ◽  
Inbreeding Depression ◽  
Invasive Plants ◽  
Natural Enemies ◽  
Invasion Success ◽  
Interactive Effects ◽  
Plant Performance ◽  
Silene Latifolia ◽  
Enemy Release ◽  
Fruit Number

AbstractInbreeding and enemy infestation are common in plants and can synergistically reduce their performance. This inbreeding × environment (I×E) interaction may be of particular importance for the success of plant invasions if introduced populations experience a release from attack by natural enemies relative to their native conspecifics. Using native and invasive plant populations, we investigate whether inbreeding affects infestation damage, whether inbreeding depression in performance is mitigated by enemy release and whether genetic differentiation among native and invasive plants modifies these I×E interactions. We used the plant invader Silene latifolia and its natural enemies as a study system. We performed two generations of experimental out- and inbreeding within eight native (European) and eight invasive (North American) S. latifolia populations under controlled conditions using field-collected seeds. Subsequently, we exposed the offspring to an enemy exclusion and inclusion treatment in a common garden in the species’ native range to assess the interactive effects of population origin (range), breeding treatment and enemy treatment on infestation damage as well as plant performance. Inbreeding increased flower and leaf infestation damage in plants from both ranges, but had opposing effects on fruit damage in native versus invasive plants. Both inbreeding and enemy infestation had negative effects on plant performance, whereby inbreeding depression in fruit number was higher in enemy inclusions than exclusions in plants from both ranges. Moreover, the magnitude of inbreeding depression in fruit number was lower in invasive than native populations. Our results support that inbreeding increases enemy susceptibility of S. latifolia, which magnifies inbreeding depression in the presence of enemies. Enemy release in the invaded habitat may thus increase the persistence of inbred founder populations and thereby contribute to successful invasion. Moreover, our findings emphasize that genetic differentiation among native and invasive plants can shape the magnitude and even the direction of inbreeding effects.

scholarly journals No improved resistance against generalist herbivores found for invasive genotypes: a case study of Senecio vulgaris (Asteraceae) and a generalist snail (Achatina fulica)

2016 ◽  
Author(s):  
Viet Thang Nguyen ◽  
Noel Ndihokubwayo ◽  
Dandan Cheng
Keyword(s):  
Invasive Plants ◽  
Natural Enemies ◽  
Land Snails ◽  
Enemy Release ◽  
Achatina Fulica ◽  
Senecio Vulgaris ◽  
Generalist Herbivores ◽  
Introduced Range ◽  
The Difference

Invasive plants escape from some natural enemies as predictions of Enemy Release Hypothesis (ERH). However, in fact they still have to face the pressure of generalist herbivores in introduced ranges resulting in the maintenance or enhancing of resistance ability to generalist herbivores. In this study, we carried out a general feeding bioassay in a laboratory with leaves of Senecio vulgaris to test the difference in resistance between ranges. White jade land snails (WJLD, Achatina fulica) were fed with the leaves of Pakchoi (Brassica chinensis), Lettuce (Lactuca sativa), native and invasive plants of S. vulgaris. The feeding experiment with S. vulgaris leaves was carried out in two waves. We found that both native and invasive S. vulgaris plant were resistant again to WJLD compared to Pakchoi and Lettuce. However, there were no significant differences between native and invasive plants of S. vulgaris in relation to the resistance against WJLD. The results prove the maintenance of chemical defense against generalist herbivores in invasive plants in introduced range. The success of S. vulgaris to invader China could not be explained by releasing from natural enemies but possessing of defense ability against herbivores before it introduced to China.

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