Does enemy release matter for invasive plants? evidence from a comparison of insect herbivore damage among invasive, non-invasive and native congeners

2007 ◽  
Vol 9 (7) ◽  
pp. 773-781 ◽  
Author(s):  
Hong Liu ◽  
Peter Stiling ◽  
Robert W. Pemberton
Keyword(s):  
Invasive Plants ◽  
Enemy Release ◽  
Insect Herbivore ◽  
Herbivore Damage ◽  
Non Invasive

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.

scholarly journals Plant and insect herbivore community variation across the Paleocene–Eocene boundary in the Hanna Basin, southeastern Wyoming

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7798
Author(s):  
Lauren E. Azevedo Schmidt ◽  
Regan E. Dunn ◽  
Jason Mercer ◽  
Marieke Dechesne ◽  
Ellen D. Currano
Keyword(s):  
Community Composition ◽  
Plant Communities ◽  
Plant Diversity ◽  
High Water ◽  
Insect Herbivore ◽  
Herbivore Damage ◽  
Late Paleocene ◽  
Hanna Basin ◽  
Laramide Basins ◽  
Herbivore Communities

Ecosystem function and stability are highly affected by internal and external stressors. Utilizing paleobotanical data gives insight into the evolutionary processes an ecosystem undergoes across long periods of time, allowing for a more complete understanding of how plant and insect herbivore communities are affected by ecosystem imbalance. To study how plant and insect herbivore communities change during times of disturbance, we quantified community turnover across the Paleocene­–Eocene boundary in the Hanna Basin, southeastern Wyoming. This particular location is unlike other nearby Laramide basins because it has an abundance of late Paleocene and Eocene coal and carbonaceous shales and paucity of well-developed paleosols, suggesting perpetually high water availability. We sampled approximately 800 semi-intact dicot leaves from five stratigraphic levels, one of which occurs late in the Paleocene–Eocene thermal maximum (PETM). Field collections were supplemented with specimens at the Denver Museum of Nature & Science. Fossil leaves were classified into morphospecies and herbivore damage was documented for each leaf. We tested for changes in plant and insect herbivore damage diversity using rarefaction and community composition using non-metric multidimensional scaling ordinations. We also documented changes in depositional environment at each stratigraphic level to better contextualize the environment of the basin. Plant diversity was highest during the mid-late Paleocene and decreased into the Eocene, whereas damage diversity was highest at the sites with low plant diversity. Plant communities significantly changed during the late PETM and do not return to pre-PETM composition. Insect herbivore communities also changed during the PETM, but, unlike plant communities, rebound to their pre-PETM structure. These results suggest that insect herbivore communities responded more strongly to plant community composition than to the diversity of species present.

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 Novel chemistry of invasive exotic plants

2006 ◽  
Vol 2 (2) ◽  
pp. 189-193 ◽  
Author(s):  
Naomi Cappuccino ◽  
J.Thor Arnason
Keyword(s):  
North America ◽  
Invasive Plants ◽  
Secondary Compounds ◽  
Exotic Plants ◽  
Exotic Plant ◽  
Exotic Plant Species ◽  
Non Invasive ◽  
The Many ◽  
Invasive Exotic ◽  
New Habitats

Of the many exotic plants that have become naturalized in North America, only a small proportion are pests capable of invading and dominating intact natural communities. In the present study, we tested the hypothesis that the most invasive plants are phytochemically unique in their new habitats. A comparison of exotic plant species that are highly invasive in North America with exotics that are widespread, but non-invasive revealed that the invasive plants were more likely to have potent secondary compounds that have not been reported from North American native plants. On average, the compounds found in the invasive plants were reported from fewer species, fewer genera and fewer families than those from non-invasive plants. Many of the unique phytochemicals from invasive plants have been reported to have multiple activities, including antiherbivore, antifungal, antimicrobial and allelopathic (phytotoxic) effects, which may provide the plants with several advantages in their new environments.

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