Search results for "Host"
showing 10 items of 1982 documents
BLOOD PARASITES AND MALE FITNESS IN THE PIED FLYCATCHER
1993
In vertebrates the effect of parasites on host ecology has almost been ignored. Recently the view that well-adapted parasites do not harm their hosts has been challenged and there is growing evidence that parasites do have a present-day effect on a great variety of host fitness components. The pied flycatcher is a small migratory passcrine bird. Any decrease in condition caused by disease should affect its ability to cope with physical demands of migration. Here we examine whether blood parasites have any effect on male arrival time. Males infected with Trypanosoma arrived on average 2 days later than males with no Trypanosoma infection. Infected males also had shorted tails and tended to h…
Gastrointestinal Helminths of Loggerhead Turtles (Caretta caretta) from the Western Mediterranean: Constraints on Community Structure
1998
Richness and composition of gastrointestinal helminth communities of 54 loggerhead turtles, Caretta caretta, from the western Mediterranean were interpreted from patterns of helminth exchange at 2 host taxonomic scales: exchange between marine turtles and other marine hosts and exchange within turtles. We predicted exchange of the former to be unimportant ecologically and evolutionarily because of the host phylogenetic distance. The absence of records of successful exchange at this host taxonomic scale confirmed that host physiological barriers seem to prevent contemporary parasite transfer between marine turtles and other sympatric hosts. Marine turtles also seem to exhibit an evolutionary…
Interspecific extrinsic and intrinsic competitive interactions in egg parasitoids
2012
Interspecific competitive interactions can occur either between adult parasitoids searching/exploiting hosts (extrinsic competition) or between parasitoid larvae developing within the same host (intrinsic competition). Understanding how interspecific competition between parasitoids can affect pest suppression is important for improving biological pest control. The purpose of this work was to review both extrinsic and intrinsic competition between egg parasitoid species. These are organisms that are often candidates for biological control programs due to their ability to kill the pest before the crop feeding stage. We first reviewed the literature about interspecific competitive abilities of…
Globularia nudicaulis, a new host of Cucumber mosaic virus
2006
) is a perennial, foundnaturally on European mountains at altitudes between 900 and 2000 m.In June 2004, G. nudicaulis plants, with a yellow mosaic and/or variega-tion on malformed leaves, were noted among plant species cultivated in theBotanical Garden at Bologna University, Italy. No elongated virus-likeparticles were observed in affected-leaf extracts by transmission electronmicroscopy using a leaf dip method. By applying a protein A sandwichenzyme-linked immunosorbent assay (PAS-ELISA) technique ( Edwards Csystemic symptoms were observed in Nicotiana tabacum , N. benthamiana ,N. glutinosa, N. clevelandii and Capsicum annuum, and Cucumis sativusand C. melo. Reverse transcription-polymera…
New distributional data on <em>Haemogregarina stepanowi</em> (Apicomplexa) and <em>Placobdella costata</em> (Hirudinea) paras…
2021
The host-parasite system “Emys trinacris – Placobdella costata – Haemogregarina stepanowi” is known for Sicily, but scarce information is available to date about the distribution of the two parasites on the island. Therefore, an extensive sampling effort through visual census and collection and analysis of blood smears of the endemic Sicilian pond turtle E. trinacris was carried out in 46 water bodies scattered throughout mainland Sicily. Our findings revealed that the distribution of both parasites is limited to the Nebrodi area, where the infection of H. stepanowi has shown a high incidence on the local turtle populations. Our data suggest no correlation between the current distribution o…
The effect of host mycorrhizal status on host plant-parasitic plant interactions
2001
Two pot experiments were conducted to examine three-level interactions between host plants, mycorrhizal fungi and parasitic plants. In a greenhouse experiment, Poa annua plants were grown in the presence or absence of an AM fungus (either Glomus lamellosum V43a or G. mosseae BEG29) and in the presence or absence of a root hemiparasitic plant (Odontites vulgaris). In a laboratory experiment, mycorrhizal infection (Glomus claroideum BEG31) of Trifolium pratense host plants (mycorrhizal versus non-mycorrhizal) was combined with hemiparasite infection (Rhinanthus serotinus) of the host (parasitized versus non-parasitized). Infection with the two species of Glomus had no significant effect on th…
Arthropod-induced neoplastic formations on trees change photosynthetic pigment levels and oxidative enzyme activities
2005
Abstract In order to test the hypothesis that arthropod-induced neoplastic formations on trees affect biochemical characteristics of both the newly formed galls and host plant tissues, biochemical characteristics with a possible adaptive role were determined in nine gall-former–host tree combinations. Photosynthetic pigments, extractable protein content, and oxidative enzyme activities were determined in gall tissues, leaf tissues of galled leaves, and leaves on ungalled tree branches. Neoplastic tissues were characterized by a low content of photosynthetic pigments, decreased chlorophyll a/b ratio, lower extractable protein content, and decreased activities of peroxidase and polyphenol oxi…
Responses of Metaphycus sp. nr. flavus to semiochemicals released from a scale host, Coccus hesperidum
2004
Metaphycus sp. nr. flavus (Encyrtidae: Hymenoptera) is a parasitoid species collected from the Mediterranean region which lays its eggs in the immature stages of several economically important soft scale insects (Hemiptera: Coccidae), including brown soft scale, Coccus hesperidum L. (= host insect). Preliminary tests suggested that the parasitoid is most successful in producing offspring when it oviposits in the younger stages of brown soft scale. In Y-olfactometer bioassays measuring wasp choices and residence times, naïve parasitoids were significantly more attracted to yucca leaves infested with 26, 27, or 28 d-old scale than to uninfested leaves, whereas leaves with older (29-30 d-old) …
The ovipositing female of Ooencyrtus telenomicida relies on physiological mechanisms to mediate intrinsic competition with Trissolcus basalis
2012
Ongoing studies by our group showed that the outcome of the intrinsic competition between two solitary egg parasitoids, Trissolcus basalis (Wollaston) (Hymenoptera: Scelionidae) and Ooencyrtus telenomicida (Vassiliev) (Hymenoptera: Encyrtidae), is dominated by O. telenomicida. In this article we investigated the role played by the ovipositing O. telenomicida female in the suppression of a T. basalis competitor. Laboratory experiments were conducted by allowing an O. telenomicida female to puncture the eggs of Nezara viridula (L.) (Heteroptera: Pentatomidae) with her ovipositor (= no oviposition) or to parasitize them. The results show that O. telenomicida relies on some physiological mechan…
Coupures morphologiques et biochronologie chez les Kosmoceratinae de l'Est de la France (Callovien inférieur pp. à Callovien supérieur pp.)
1998
Abstract For the first time in eastern France, a detailed succession of the uppermost Lower Callovian to Lower Upper Callovian Kosmoceratinae is presented, according to the fossils collected in situ at Blye (Jura, France). It is compared with the abundant data from Champagne and Bourgogne. These ammonites may allow more accurate correlations between the subboreal and subtethysian biostratigraphical frameworks. They record numerous morphological changes, sometimes different from those generally accepted. They allow the precise recognition of the limits of the biostratigraphical units, and the definition of successive faunal units available in the lowermost Upper Callovian.