Search results for "herbivore"
showing 10 items of 126 documents
Belowground responses by AM fungi and animal trophic groups to repeated defoliation in an experimental grassland community
2005
Abstract We tested a hypothesis that the effects of defoliation on plants and soil organisms vary with the number of successive defoliations. We established a 23-week greenhouse experiment using replicated grassland microcosms that were composed of three plant species, Trifolium repens , Plantago lanceolata and Phleum pratense , growing together in grassland soil with a diverse soil community. The experiment consisted of two treatment factors-defoliation and harvest time-in a fully factorial design. The defoliation treatment had two levels, i.e. no trimming and trimming of plants every 2 weeks, and the harvest time five levels, i.e. harvests after 1–3, 5 and 7 trimmings. Shoot production (t…
Helminth communities of two lizard populations (Lacertidae) from Canary Islands (Spain): Host diet-parasite relationships
2005
Abstract A parasitological survey has been carried out to determine the relationships between host diet and parasite fauna. Diet, and infracommunities and component communities of two subspecies of lacertid lizards, Gallotia galloti galloti (Oudart, 1839) and G. g. palmae (Boettger et Müller, 1914) from Tenerife and La Palma islands (Canary Islands, Spain), have been analysed. High values of parasite infection parameters were found in both subspecies, which were only infected by nematodes of the family Pharyngodonidae. Plant matter was mainly consumed by both lizard subspecies and relevant amounts of mineral matter were also found in both hosts. Diet of these lacertid lizards was correlate…
Daurian pikas ( Ochotona daurica ) and grassland condition in eastern Mongolia
2003
Pikas ( Ochotona spp.) are burrowing herbivorous mammals believed to play a keystone role in determining the biodiversity of steppe ecosystems. Impacts of domestic livestock grazing on the distribution and abundance of the Daurian pika Ochotona daurica were investigated in eastern Mongolia where the species is widespread and abundant. Effects of pikas on plant species richness and vegetation coverage were examined at different distances from burrow systems. Daurian pikas were nearly absent from severely grazed study sites, and incidence of the species increased with decreasing grazing intensity. The number of occupied burrow systems and usage of burrows was higher in sites with lower grazin…
Microbial symbionts of parasitoids
2020
Parasitoids depend on other insects for the development of their offspring. Their eggs are laid in or on a host insect that is consumed during juvenile development. Parasitoids harbor a diversity of microbial symbionts including viruses, bacteria, and fungi. In contrast to symbionts of herbivorous and hematophagous insects, parasitoid symbionts do not provide nutrients. Instead, they are involved in parasitoid reproduction, suppression of host immune responses, and manipulation of the behavior of herbivorous hosts. Moreover, recent research has shown that parasitoid symbionts such as polydnaviruses may also influence plant-mediated interactions among members of plant-associated communities…
Can herbivore-induced volatiles protect plants by increasing the herbivores’ susceptibility to natural pathogens?
2018
In response to insect herbivory, plants mobilize various defenses. Defense responses include the release of herbivore-induced plant volatiles (HIPVs) that can serve as signals to alert undamaged tissues and to attract natural enemies of the herbivores. Some HIPVs can have a direct negative impact on herbivore survival, but it is not well understood by what mechanisms. Here, we tested the hypothesis that exposure to HIPVs renders insects more susceptible to natural pathogens. Exposure of the caterpillars of the noctuid Spodoptera exigua to indole and linalool, but not exposure to (Z)-3-hexenyl acetate, increased the susceptibility to Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV). …
Immunological priming in the wood tiger moth (Parasemia plantaginis)
2014
Hyönteisiin lukeutuu monia merkittäviä tuholaisia, taudinvälittäjiä ja hyödyllisiä lajeja, minkä takia hyönteisten taudit, taudinaiheuttajat ja immuunipuolustus ovat ekologisesta, ekonomisesta ja lääketieteellisestä näkökulmasta tärkeitä tutkimuskohteita. Viimeaikaiset tutkimukset paljastavat hyönteisten ja muiden selkärangattomien immuunijärjestelmien pystyvän erikoistumaan ja luomaan pitkäkestoista immuniteettia. Jälkimmäinen ilmiö tunnetaan tieteellisissä artikkeleissa nimellä ”immunological priming”, jonka voisi kääntää suomeksi esimerkiksi ”immuunipohjustukseksi”. Immuunipohjustus on muistinkaltaista vastustuskykyä, joka auttaa elimistöä puolustautumaan tehokkaammin toistuvia tartuntoj…
Imprints of latitude, host taxon, and decay stage on fungus-associated arthropod communities
2022
Interactions among fungi and insects involve hundreds of thousands of species. While insect communities on plants have formed some of the classic model systems in ecology, fungus-based communities and the forces structuring them remain poorly studied by comparison. We characterize the arthropod communities associated with fruiting bodies of eight mycorrhizal basidiomycete fungus species from three different orders along a 1200-km latitudinal gradient in northern Europe. We hypothesized that, matching the pattern seen for most insect taxa on plants, we would observe a general decrease in fungal-associated species with latitude. Against this backdrop, we expected local communities to be struc…
Fungal-Mediated Multitrophic Interactions : Do Grass Endophytes in Diet Protect Voles from Predators?
2009
Plant-associated micro-organisms such as mycotoxin-producing endophytes commonly have direct negative effects on herbivores. These effects may be carried over to natural enemies of the herbivores, but this has been rarely explored. We examined how feeding on Neotyphodium endophyte infected (E+) and endophyte free (E−) meadow ryegrass (Scherodonus pratensis) affects body mass, population size and mobility of sibling voles (Microtus levis), and whether the diet mediates the vulnerability of voles to least weasel (Mustela nivalis nivalis) predation. Because least weasels are known to be olfactory hunters, we also examined whether they are able to distinguish olfactory cues of voles fed on E+ a…
Relationship between diet and helminths in Gallotia caesaris (Sauria: Lacertidae)
2004
Diet and helminth fauna were analysed in Gallotia caesaris, a small lacertid lizard endemic to El Hierro (Canary Islands, Spain) in order to study the evolutionary and functional relationships between the two traits. This species is omnivorous but consumed a high proportion (82.13%) of plant matter including not only seeds but also leaves and other vegetative parts. Helminth fauna included many helminth species typical of herbivorous reptiles. Both herbivory and helminth presence were higher than expected for a lizard of its size. Comparison with other lacertids suggests that both traits result from an adaptation to insular conditions but that some "evolutionary time" to develop them is nee…
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…