CABI

About: CABI is a nonprofit organization based out in Wallingford, United Kingdom. It is known for research contribution in the topics: Population & Introduced species. The organization has 789 authors who have published 1759 publications receiving 73843 citations. The organization is also known as: Centre for Biosciences and Agriculture International.

Distribution of invasive alien Tithonia (Asteraceae) species in eastern and southern Africa and the socio-ecological impacts of T. diversifolia in Zambia

Abstract: Background: Many alien plant species, such as Tithonia diversifolia, T. rotundifolia and T. tubaeformis , have been introduced to areas outside of their natural distribution range to provide benefits, but have subsequently become invasive, threatening biodiversity and agricultural productivity. Objectives: The aim of this study was to determine the current distribution and dates of introduction of invasive Tithonia species in eastern and southern Africa and to document the effects of T. diversifolia on rural livelihoods in Zambia. Method: Roadside surveys, and other sources of information, were used to determine the distribution of invasive Tithonia species in eastern and southern Africa. Household interviews were conducted to gauge perceptions and understand the impacts of T. diversifolia on local livelihoods in Zambia’s Copperbelt province. Results: Tithonia diversifolia is widespread in Uganda, Kenya, Tanzania, South Africa, Malawi and parts of Zambia but less so in Zimbabwe. Tithonia rotundifolia was comparatively uncommon in eastern Africa but common in some southern African countries, while T. tubaeformis was invasive in Swaziland, South Africa, Zambia and possibly also Zimbabwe. According to the majority of respondents in Zambia, T. diversifolia has negative impacts on native vegetation, mobility or access, water availability, crop yields and animal health. Conclusion: Invasive Tithonia species are widespread and spreading throughout much of Africa. Livelihood and biodiversity costs have not been considered by those actively promoting the use and further dissemination of T. diversifolia . We therefore recommend that detailed cost–benefit studies should be undertaken to support informed decisions on the future management of these species.

Host‐associated genetic divergence and taxonomy in the Rhinusa pilosa Gyllenhal species complex: an integrative approach

Abstract: A combined taxonomic, morphological, molecular and biological study revealed that stem-galling weevils from the genus Rhinusa associated with toadflaxes from the genus Linaria (Plantaginaceae) are composed of three different species: Rhinusa pilosa, Rhinusa brondelii and Rhinusa rara sp.n. The authentic field host plants are respectively, Linaria vulgaris, Linaria purpurea and Linaria genistifolia/ Linaria dalmatica. These weevil species can be distinguished from each other by a few subtle morphological characteristics, mainly in the shape of the rostrum and of the integument. An analysis of the mitochondrial [cytochrome oxidase subunit II gene (COII) and 16S ribosomal RNA gene (16S)] and nuclear (elongation factor-1α, EF-1α) sequence data revealed high genetic divergence among these species. Uncorrected pairwise distances on mtCOII gene were 14.3% between R. pilosa and R. brondelii, 15.7% between R. pilosa and R. rara, while R. brondelii and R. rara were approximately 11% divergent from each other. Divergences obtained on 16S and nuclear EF-1α genes were congruent. However, substantial intraspecific mitochondrial divergence was recorded for all studied populations of R. pilosa s.s. showing two mtDNA lineages, with estimated COII and 16S divergences of 4% and 1.6%, respectively. Nuclear pseudogenes (Numts) and Wolbachia influence, although recorded within both lineages, were excluded as possible causatives of the mtDNA divergence, while EF-1α indicated absence of lineage sorting. Species from the R. pilosa complex are estimated to have diverged from each other approximately 7.2 million years ago (mya; late Miocene), while R. brondelii and R. rara diverged from each other about 4.7 mya (early Pliocene). This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:EEDD6248-01DB-4B4A-B79D-C5606393E3AA.

Review of the species of Trichomalus (Chalcidoidea: Pteromalidae) associated with Ceutorhynchus (Coleoptera: Curculionidae) host species of European origin

Abstract: -Six especes de Trichomalus Thomson ont ete elevees en tant que parasitoides de Ceutorhynchinae en Europe lors de periodes d'echantillonnage entre 2000 et 2004. Trichomalus rusticus (Walker) est traite comme espece valide et non plus comme synonyme de T. lucidus (Walker), et T lyttus (Walker) est transfere de sa synonymie avec T. lucidus et nouvellement place en tant que synonyme de T. rusticus. Une cle illustree est fournie afin de differencier les mâles et les femelles des six especes (T. bracteatus (Walker), T. campestris (Walker), T. gynetelus (Walker), T. lucidus, T. perfectus (Walker) et T. rusticus) a l'exception des mâles de T. bracteatus et T. gynetelus. Un lectotype femelle est decrit pour T. rusticus. Trichomalus campestris est trouve pour la premiere fois parasitant Ceutorhynchus cardariae Korotyaev. Les associations hote-parasitoides determinees lors des echantillonnages sont discutees, et en particulier ce que ces resultats impliquent pour l'introduction d'especes en Amerique du Nord en tant qu'auxiliaires de lutte biologique.