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Alternate Hosts (alternate + hosts)
Selected AbstractsEgg parasitoids of Australian Coreidae (Hemiptera)AUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 1 2001Ian D Naumann Abstract Ten microhymenopteran species are recorded as parasitoids of the eggs of coreid bugs in Australia: Chrysochalcissa olivacea Girault (Torymidae) from Amorbus biguttatus Stål and Pternistria bispina Stål; two species of Anastatus Motschulsky (Eupelmidae) from Mictis profana (F.), Amorbus alternatus Dallas, Amblypelta lutescens lutescens (Distant) and an unidentified coreid; Xenoencyrtus hemipterus (Girault) (Encyrtidae) from Amorbus obscuricornis (Westwood) and Gelonus tasmanicus (Le Guillou); Ooencyrtus caurus Huang and Noyes (Encyrtidae) from A. lutescens lutescens;Centrodora darwini (Girault) (Aphelinidae) from an unidentified coreid; and four species of Gryon Haliday (Scelionidae) from Aulacosternum nigrorubrum (Dallas), A. lutescens lutescens, Amorbus rubicundus Stål, Mictis caja Stål, M. profana and an unidentified coreid. Alternate hosts and biological control prospects are discussed. [source] Finnish Cronartium ribicola does not infect alternate hosts of Cronartium flaccidumFOREST PATHOLOGY, Issue 4 2006J. Kaitera Summary Susceptibility of the main alternate hosts of Cronartium flaccidum, Vincetoxicum spp. and Melampyrum spp., to C. ribicola was investigated by artificial inoculations on detached leaves in the laboratory and on whole plants in the greenhouse. Neither uredinia nor telia developed on the leaves of either Vincetoxicum hirundinaria, Vincetoxicum nigrum, Melampyrum sylvaticum, Melampyrum pratense, Melampyrum nemorosum, Melampyrum arvense, Melampyrum cristatum or Melampyrum polonicum following inoculation by the 26 aeciospore sources collected from Pinus strobus, Pinus monticola, Pinus flexilis and Pinus peuce in 2000,2003. The results suggest that Finnish C. ribicola does not infect the main alternate hosts of C. flaccidum. Cronartium ribicola and C. flaccidum can thus be identified reliably by inoculations on their main alternate hosts. Résumé La sensibilitéàCronartium ribicola des principaux hôtes alternants de C. flaccidum, au sein des genres Vincetoxicum et Melampyrum, a étéétudiée par inoculations artificielles sur feuilles détachées au laboratoire et sur plantes entières en serre. Aucune formation d'urédinie ou de télie n'a été observée sur feuilles de Vincetoxicum hirundinaria, V. nigrum, Melampyrum sylvaticum, M. pratense, M. nemorosum, M. arvense, M. cristatum ou M. polonicum après inoculation par 26 sources d'éciospores récoltées sur Pinus strobus, P. monticola, P. flexilis et P. peuce en 2000,2003. Les résultats suggèrent que C. ribicola ne peut infecter les principaux hôtes alternants de C. flaccidum en Finlande. Cronartium ribicola et C. flaccidum peuvent donc être identifiés de façon fiable par inoculations de leurs principaux hôtes alternants. Zusammenfassung Die Anfälligkeit der wichtigsten Dikaryontenwirte von Cronartium flaccidum, Vincetoxicum spp. und Melampyrum spp. auf C. ribicola wurden mit künstlichen Inokulationen auf abgetrennten Blättern im Labor und auf ganzen Pflanzen im Gewächshaus untersucht. Es entwickelten sich weder Uredo- noch Teleutosporenlager auf den Blättern von Vincetoxicum hirundinaria, V. nigrum, Melampyrum sylvaticum, M. pratense, M. nemorosum, M. arvense, M. cristatum oder M. polonicum nach einer Inokulation mit 26 Aecidiosporen-Herkünften, die 2000,2003 von Pinus strobus, P. monticola, P. flexilis und P. peuce gesammelt wurden. Aus diesen Ergebnissen lässt sich schliessen, dass finnische C. ribicola die hauptsächlichen Dikaryontenwirte von C. flaccidum nicht infizieren. Somit können C. ribicola und C. flaccidum durch Inokulation auf ihre Dikaryontenwirte bestimmt werden. [source] Telotroch formation, survival, and attachment in the epibiotic peritrich Zoothamnium intermedium (Ciliophora, Oligohymenophorea)INVERTEBRATE BIOLOGY, Issue 3 2008Laura R.P. Utz Abstract. Aspects of the life cycle of the peritrich ciliate Zoothamnium intermedium, an epibiont on calanoid copepods in the Chesapeake Bay, were investigated using host and epibiont cultures. Experiments were designed to characterize the formation, survival, and attachment of free-swimming stages (telotrochs) and to assess whether telotrochs preferentially attach to primary (Acartia tonsa and Eurytemora affinis) or alternate hosts from the zooplankton community (the rotifer Brachionus plicatilis, barnacle nauplii, polychaete larvae, and a harpacticoid copepod). The results showed that telotroch formation started 2 h after the death of the host, with >90% of the zooids leaving the host carapace within 7 h. Formation of telotrochs was triggered only by the death of the host, failing to occur when the host was injured or unable to swim. Telotrochs failed to attach to non-living substrates and survived for only 14 h in the absence of host organisms, suggesting that members of Z. intermedium are obligate epibionts. Attachment success decreased with telotroch age, indicating that colonization success in nature may strongly depend on the ability to find a suitable host in a short period of time. Individuals exhibited no preferences in colonizing juvenile or adult stages of A. tonsa or E. affinis. While telotrochs were able to colonize barnacle nauplii and the harpacticoid copepod in the absence of individuals of A. tonsa or E. affinis, they did not attach to the rotifers or polychaete larvae. Telotrochs preferentially colonized individuals of A. tonsa when in the presence of other non-calanoid host species. [source] Host-race formation: promoted by phenology, constrained by heritabilityJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 4 2009A. V. WHIPPLE Abstract Host-race formation is promoted by genetic trade-offs in the ability of herbivores to use alternate hosts, including trade-offs due to differential timing of host-plant availability. We examined the role of phenology in limiting host-plant use in the goldenrod gall fly (Eurosta solidaginis) by determining: (1) whether phenology limits alternate host use, leading to a trade-off that could cause divergent selection on Eurosta emergence time and (2) whether Eurosta has the genetic capacity to respond to such selection in the face of existing environmental variation. Experiments demonstrated that oviposition and gall induction on the alternate host, Solidago canadensis, were the highest on young plants, whereas the highest levels of gall induction on the normal host, Solidago gigantea, occurred on intermediate-age plants. These findings indicate a phenological trade-off for host-plant use that sets up the possibility of divergent selection on emergence time. Heritability, estimated by parent,offspring regression, indicated that host-race formation is impeded by the amount of genetic variation, relative to environmental, for emergence time. [source] Dynamics of experimental production of Thelohanellus hovorkai (Myxozoa: Myxosporea) in fish and oligochaete alternate hostsJOURNAL OF FISH DISEASES, Issue 10 2003Y S Liyanage Abstract The dynamics of development and production of Thelohanellus hovorkai (Myxozoa) were examined to investigate factors inducing haemorrhagic thelohanellosis in carp, Cyprinus carpio L. Fresh actinospores of T. hovorkai were harvested from the oligochaete alternate host, Branchiura sowerbyi, and used for infection experiments with myxosporean-free carp. Visualization of actinospores by fluorescent labelling revealed that sporoplasms penetrated the gill filaments of carp immersed in an actinospore suspension as early as 30 min post-exposure (PE). Plasmodia of T. hovorkai developed in the connective tissues of various organs and matured 3,5 weeks PE; dispersion of myxospores from degenerate plasmodia occurred 5,7 weeks PE. Challenges with a high dose of actinospores (4.5 × 106 spores per fish) resulted in the onset of disease, which was more easily achieved by the oral intubation of actinospores than by immersion in an actinospore suspension. Actinosporean-free B. sowerbyi were exposed to different densities of myxospores (104,106 spores per oligochaete) and subsequently reared at different temperatures (15, 20, 25 °C). At 20 and 25 °C, actinospore releases were first detected 40,43 days PE, with multiple peaks of release (max. 7 × 105 actinospores day,1) during the next 60 days. We concluded that the developmental cycle of T. hovorkai was completed within 3,5 months at 20,25 °C, and that the ingestion of large numbers of actinospores orally, possibly by feeding on infected oligochaetes, resulted in a disease condition in carp. [source] | ||||||||||