Search results for "Parasitism"
showing 10 items of 200 documents
Climate change impact on extrinsic and intrinsic competition between egg parasitoids
2012
Climate changing is a real phenomenon and the last decade was the warmest decade ever. The impact of climate change on animal communities is complex, affecting species interactions in all trophic levels, in different ways and in different bio-geographic zones. Here we will discuss about the possible effects of climate changes in shaping the competition between egg parasitoid species to consume the same hosts. Egg parasitoids are important biological control agents due to their ability to kill the pest before the crop-feeding stages emerge. Competitive effects can be divided in “extrinsic competition”, the indirect interactions between adult females searching for hosts, and “intrinsic compet…
New records of the genus Orobanche L. (Orobanchaceae) to the Tunisian flora with lectotypification of the name O. rapum-genistae Thuill.
2023
Based on several field surveys and on the study of original material, we have identified three new species of Orobanche L. s.s. (Orobanchaceae) new to the flora of Tunisia. Orobanche alba Willd., O. calendulae Pomel, and O. gracilis Sm. are reported as new for the country, and the occurrence of O. rapum-genistae Thuill. is confirmed. The lectotypification of O. rapum-genistae is here proposed with a specimen housed in Genève (G). The geographical distribution of the four taxa in Tunisia is given, and details of habitats and hosts are provided. Altogether, the genus Orobanche in Tunisia now includes 18 species; a dichotomous key is proposed to facilitate the identification of these taxa.
Avian brood parasitism in the new and old worlds
The parasitoid species complex associated with sexual and parthenogenetic Naryciinae (Lepidoptera: Psychidae): Integrating ecological and molecular a…
2011
This study describes the parasitoid species complex associated with seven closely related species of sexual (Siederia rupi- collella, S. listerella, Dahlica lazuri, D. charlottae and D. lichenella) and parthenogenetic (Dahlica fennicella and D. triquetrella) Naryciinae (Lepidoptera: Psychidae) in Central Finland. A thorough ecological analysis of all the species of parasitoids recorded was combined with analyses of molecular data. Mitochondrial and nuclear DNA data were obtained from all the species in order to (1) detect cryptic species associated with host specialization, (2) assign undescribed males to females, and (3) verify the morphological identification of closely related species. A…
Effect of the host plant on the immunity of a phytophagous insect : influence of grape variety on the ability of the European grapevine moth to defen…
2013
In tritrophic interactions involving phytophagous insects, host plants and natural enemies, trophic levels are highly dependent on each other. Host plant may strongly affect directly phytophagous insect and indirectly natural enemies growing on these phytophagous insects. When a natural enemy attacks a phytophagous insect, the host immune system constitutes the last chance for the host to survive to an infection. A great variation of insect immune system is generally found in populations for susceptibility to pathogens, suggesting that variable selection pressures may have shaped and driven adaptation of immune traits. This project aims to determine the influence of both host plant and natu…
Biological invasion and parasitism: invaders do not suffer from physiological alterations of the acanthocephalan Pomphorhynchus laevis.
2009
SUMMARYBiological invasions expose parasites to new invasive hosts in addition to their local hosts. However, local parasites are often less successful in infecting and exploiting their new hosts. This may have major consequences for the competitive ability of hosts, and finally on the fate of the parasite-host community. In Burgundy (Eastern France), the acanthocephalan parasite,Pomphorhynchus laevis, infects 2 amphipod species living in sympatry: the nativeGammarus pulexand the invasiveGammarus roeseli. WhileP. laevisaffects the behaviour and the immunity ofG. pulex,G. roeseliseems unaffected by the infection. In this study, we examined in detail the ability of the parasite to affect the …
Low parasitism rates in parthenogenetic bagworm moths do not support the parasitoid hypothesis for sex
2012
The parasite hypothesis for sex is one of the many theories that have been suggested to solve the mystery of the widespread occurrence of sex despite its high short-term costs. It suggests that sexual lineages have an evolutionary advantage over parthenogens because they can frequently generate new genotypes that are temporarily less prone to coevolving parasites. In this study, we looked for further supporting evidence for the parasite hypothesis of sex in an attempt to understand the coexistence of sexual and parthenogenetic bagworm moths (Naryciinae). The bagworm moths and their parasitoids form one of the few natural host-parasite systems where sexual and parthenogenetic hosts are appar…
Two new records of Alloxysta (Hymenoptera: Cynipoidea: Figitidae: Charipinae) from Colombia
2016
The Charipinae from Colombia has been recently studied. Nine Charipinae species are known to be present in this country: Alloxysta arcuata (Kieffer, 1902), Alloxysta castanea (Hartig, 1841), Alloxysta consobrina (Zetterstedt, 1838), Alloxysta hansoni Pujade-Villar, 2011, Alloxysta obscurata (Hartig, 1840), Alloxysta medinae Ferrer-Suay & Pujade-Villar, 2012, Alloxysta pilipennis (Hartig, 1840), Alloxysta torresi Ferrer-Suay & Pujade-Villar, 2012 and Phaenoglyphis villosa (Hartig, 1841). Here more Charipinae material has been studied from collections made with Malaise traps by the Humboldt Institute in several places of Colombia. In this study, two species are recorded for the first …
Connection between temperature, larval production, virulence and geographical distribution of Rhipidocotyle parasites infecting the duck mussel, Anod…
2015
In this thesis, two bucephalid trematode parasites Rhipidocotyle campanula and R. fennica, which use the same first (Anodonta anatina) and second intermediate (Rutilus rutilus) host were studied. The aim was to investigate the effect of temperature on one of the key processes in the transmission of these parasites: 1) the emergence of cercarial larvae from A. anatina over short (1 h) and 2) long (throughout the annual cercarial shedding period, from May to October) time periods as well, as on 3) mussel survival and 4) the seasonal timing of cercarial release. In addition, the aim was to study how the cercarial shedding traits are linked to the 5) geographical occurrence and abundance of the…
Relationship between the endangered freshwater pearl mussel Margaritifera margaritifera, its salmonid host and co-infectants
2018
The relationship between the freshwater pearl mussel (hereafter FPM), Margaritifera margaritifera, and its salmonid host — pivotal for the conservation of this endangered bivalve — is characterized by a long parasitic stage (up to 11 months) and excessive host specificity. This thesis focuses on this relationship by experimentally studying the effect of FPM infection on the growth and resistance of salmonid fish and how the infection influences vulnerability of the host to other parasites and diseases, as well as how exposure of the host to other parasites affects vulnerability to FPM. Infection with FPM results in (i) reduced growth of the host, brown trout, during the parasitic period. Gl…