Host Specificity Range Research Articles

First description of nymphal stages of Hoplopleura edentula (Anoplura: Hoplopleuridae) and a global checklist of the Hoplopleura associated with Clethrionomys

Abstract We present the first record of the characteristics of the three nymphal stages of Hoplopleura edentula, one of the common Eurasian species of the genus Hoplopleura. Lastly, a list of all species of Hoplopleura parasitizing the host genus Clethrionomys is provided. The descriptions of sucking louse species usually lack the features of the nymphal stages. In addition, it is impossible to determine whether the host is the main one or an accidental when there is a co-occurance of two or more lice species, unless we observe nymphs of the same species. As a result, data on the host cycle, the range of host specificity and other aspects of parasite-host system functioning, the possibility of transfer between hosts, and the possibility of transmission of pathogens, are incomplete. This study examines 114 specimens of the bank vole Clethrionomys glareolus, in which 38 Hoplopleura edentula were found.

Host and ecology both play a role in shaping distribution of digenean parasites of New Zealand whelks (Gastropoda: Buccinidae: Cominella).

Digenean parasites infecting four Cominella whelk species (C. glandiformis, C. adspersa, C. maculosa and C. virgata), which inhabit New Zealand's intertidal zone, were analysed using molecular techniques. Mitochondrial 16S and cytochrome oxidase 1 (COI) and nuclear rDNA ITS1 sequences were used to infer phylogenetic relationships amongst digenea. Host species were parasitized by a diverse range of digenea (Platyhelminthes, Trematoda), representing seven families: Echinostomatidae, Opecoelidae, Microphallidae, Strigeidae and three, as yet, undetermined families A, B and C. Each parasite family infected between one and three host whelk species, and infection levels were typically low (average infection rates ranged from 1·4 to 3·6%). Host specificity ranged from highly species-specific amongst the echinostomes, which were only ever observed infecting C. glandiformis, to the more generalist opecoelids and strigeids, which were capable of infecting three out of four of the Cominella species analysed. Digeneans displayed a highly variable geographic range; for example, echinostomes had a large geographic range stretching the length of New Zealand, from Northland to Otago, whereas Family B parasites were restricted to fairly small areas of the North Island. Our results add to a growing body of research identifying wide ranges in both host specificity and geographic range amongst intertidal, multi-host parasite systems.

An integrated approach to biology

Zoology, being a basic bioscience, is essential for a better understanding of applied biological disciplines. A sound background in zoology can often be the key to success in modern day cutting-edge biological research. Students of zoology have many more interesting questions to ask now than ever before. Precisely when did humans take to clothing? How is losing body hair actually correlated to body louse speciation? What is so unique about a schistosome that enables it to parasitize two very different host species, to have a free living stage and show a broad range of host specificity in one life cycle? Genomics has already helped us to get the molecular expression profiles of many organisms. But to understand how all the information obtained at the molecular level fits into the scheme of things, we need a sound foundation in zoology. It is all the more fun studying zoology now with so many interesting questions to ask and ideas to explore.

Germination, Host Preference, and Phenolic Content of Witchweed (Striga hermonthica) Seed Populations

Phenolic content, germination percentage, and host preference were compared among 11 seed populations of witchweed (Striga hermonthica(Del.) Benth. # STRHE). Significant differences in germination percentage occurred among the seed populations after preconditioning by their exposure to different durations of warm-moist conditions. Greatest percentage of seed germinated after 8 days of preconditioning. Preconditioning for more than 16 days reduced percentage germination. The host specificity range of witchweed seed populations that parasitized pearl millet [Pennisetum americanum(L.) K. Schum] was broader than were those seed populations that attacked sorghum [Sorghum bicolor(L.) Moench.]. Results of thin-layer chromatography indicated large variations in phenolic content among the witchweed seed populations.