Browsing by Subject "Host Range"

Now showing 1 - 2 of 2
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    Carp Edema Virus Host Range Study in Lake Swartout and Outbreaks in four other lakes
    (2021-03-02) Tolo, Isaiah; Phelps, Nicholas B. D.; tolo0007@umn.edu; Phelps, Nicholas; Minnesota Aquatic Invasive Species Research Center (MAISRC)
    Mass mortality events of common carp (Cyprinus carpio, carp) associated with carp edema virus (CEV) alone or in coinfections with koi herpesvirus (KHV), is an emerging issue. Despite recent outbreaks of CEV in wild carp populations, the host range of North American species has not been well studied. To that end, we intensively sampled carp (n = 106) and co-habiting native fish species (n = 5 species; n = 156 total fish) from a CEV-suspect mass-mortality event of carp in a small Minnesota lake (Lake Swartout). Additionally, fecal and regurgitant samples (n = 73 each) from double-crested cormorants (Phalacrocorax auritus, DCCO) were sampled to test the potential of DCCO to act as a vector for virus transmission. CEV was confirmed to be widespread in the Lake Swartout carp population during the outbreak with high viral loads and histological confirmation, suggesting that CEV was the cause of the mortality event. There were no detections of CEV in any native fish species; however, DCCO regurgitant and fecal samples were positive for CEV DNA. In addition, three CEV-positive and one CEV+KHV-positive mortality events were confirmed with no observed mortality or morbidity of non-carp species in other lakes. This study provides evidence that CEV infection and disease may be specific to carp during mortality events with mixed-species populations, identifies DCCO as a potential vector for CEV, and further expands the known range of CEV, as well as coinfections with KHV, in North America.
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    Potential host use by the Mediterranean Pine Engraver on Novel Tree Species.
    (2009-05) Walter, Abigail Jan
    Introduced species have the potential to cause great environmental damage, but many species introduced to an area will not have a large impact. It is critical that we develop the ability to predict which species will become damaging invaders, and manage ecosystems to minimize the probability that introduced species could establish. I present research results on the potential of the Mediterranean pine engraver, Orthotomicus erosus (Wollaston), to utilize North American tree species as hosts. I confirm that several North American conifers, species of pine and spruce, are suitable for the development of O. erosus. I then investigate the host acceptance behaviors of adults in contact with the outer bark. I show that differences among species occur during boring into the outer bark, and that beetles bore into both suitable and unsuitable tree species. The behavior of beetles before they are in contact with the bark was investigated with an olfactometer; odors from several conifer species do not affect the behavior of adult beetles. I also test the feeding response of beetles to extracts of bark and phloem chemicals. Several extracts contain feeding incitant or stimulant compounds, but the presence of these compounds in various tree species is different than adult bark boring behavior on those species. Finally, I used the data from my previous experiments and the phylogenetic distance among tree species in an attempt to predict the response of O. erosus to a second set of tree species from independent validation experiments. Phylogenetic distance from species with known beetle responses was not a good predictor of beetle response to novel plants. This body of work shows that O. erosus may accept a larger set of trees than are suitable for reproduction. Furthermore, adult host acceptance behavior is not determined solely by gustatory stimuli. Detailed knowledge about the stimuli governing host acceptance behavior is needed to predict the acceptability of new tree species to the beetle. The presence of acceptable but developmentaly unsuitable plants may determine whether species such as O. erosus are able to establish in a new environment.