43 research outputs found

    The gall midges (Diptera: Cecidomyiidae) of Acacia spp. (Mimosaceae) in Kenya

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    Twenty-eight new species of plant-feeding Cecidmnyiidae are described from galls taken on five species of Acacia in Kenya. The new species are placed in seven genera, four of them new. The new taxa, to be attributed to Gagne, are as follows, in bold face: in Acacidiplosis: ananas, cespitosa, conica, crispa, echinata, erupta, hamata, imbIicata, lamosa, lugosa, spinosa, undulata, and verticillata; in Aposchizomyia: acuta, brevis, crenata, longa, striata, and turnouri; Asphondylia napiformis; in Athidiplosis: bullata and walteri; in Contarinia. earolinae, hongoi, and plicata, Kimadiplosis divel sa, in Lupesia. niloticae and armata. The larvae, pupae, and the host-specific galls of these species generally offer the best characters for species discrimination. Galls of several additional species of gall midges from Acacia spp. in Kenya are described, but the gall makers are left unnamed for lack of suitable specimens. Collula acaciae (Kieffer 1912) is shown to be a junior homonym of Collula acaciae (Kieffer 1909) andis renamed kiefferi. Gail midges from acacias in Africa, India, and Australia are reviewed. Cecidomyia acaciaelongifoliae Skuse (1890) from Australia is newly combined in Dasineura. Two ofthe Bew species, Acacidiplodisspinosa and Aposehizomyia acula, inhibit flowering of Acacia nilotica and are potential biological control agents of their host in Australia

    Long-term spatiotemporal stability and dynamic changes in helminth infracommunities of spiny mice (Acomys dimidiatus) in St. Katherine’s Protectorate, Sinai, Egypt

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    The importance of parasites as a selective force in host evolution is a topic of current interest. However, short-term ecological studies of host-parasite systems, on which such studies are usually based, provide only snap-shots of what may be dynamic systems. We report here on four surveys, carried out over a period of 12 years, of helminths of spiny mice (Acomys dimidiatus), the numerically dominant rodents inhabiting the dry montane wadis in the Sinai Peninsula. With host age (age-dependent effects on prevalence and abundance were prominent) and sex (female bias in abundance in helminth diversity and in several taxa including Cestoda) taken into consideration, we focus on the relative importance of temporal and spatial effects on helminth infracommunities. We show that site of capture is the major determinant of prevalence and abundance of species (and higher taxa) contributing to helminth community structure, the only exceptions being Streptopharaus spp. and Dentostomella kuntzi. We provide evidence that most (notably the Spiruroidea, Protospirura muricola, Mastophorus muris and Gongylonema aegypti, but with exceptions among the Oxyuroidae e.g. Syphacia minuta), show elements of temporal-site stability, with rank order of measures among sites remaining similar over successive surveys and hence some elements of predictability in these systems

    A taxonomic revision of Cryptostegia R. Br. (Asclepiadaceae: Periplocoideae)

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    Use of CLIMEX modelling to identify prospective areas for exploration to find new biological control agents for prickly acacia

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    Selection of biocontrol agents that are adapted to the climates in areas of intended release demands a thorough analysis of the climates of the source and release sites. We present a case study that demonstrates how use of the CLIMEX software can improve decision making in relation to the identification of prospective areas for exploration for agents to control the woody weed, prickly acacia Acacia nilotica ssp. indica in the arid areas of north Queensland

    Field-based ecological studies to assess prospective biological control agents for invasive alien plants: an example from giant rat’s tail grass

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    Biological control (biocontrol) of invasive alien plants is a widely utilised weed management tool. Prospective biocontrol agents are typically assessed through host-specificity testing and pre-release efficacy studies performed in quarantine. However, rearing of the potential biocontrol agents and/or test plants is often difficult or impossible under quarantine conditions. Moreover, practitioners may attain laboratory-artefacts in quarantine, which may result in the potential agent being needlessly rejected. Field-based studies in the weed’s indigenous distribution could overcome these issues. Sporobolus pyramidalis and Sporobolus natalensis (giant rat’s tail grass; Poaceae) are indigenous in Africa but have become problematic invasive alien plants in Australia. A previous biocontrol programme was terminated because the candidate agent could not be reared and tested in quarantine. We performed field-based host-specificity and efficacy studies for prospective biocontrol agents in South Africa (indigenous distribution). Forty-seven non-target grass species were sampled during host-specificity assessments. Candidate agent efficacy was estimated based on damage to the target weeds, for each host-specific candidate individually and in combination with other host-specific candidates. Three species of endophagous wasps were deemed host-specific. Efficacy assessments identified an undescribed stem-boring wasp (Tetramesa sp.) species as the most damaging candidate. A second Tetramesa species was much less damaging alone but had a cumulative impact on the plant in combination with the more damaging Tetramesa species. Both Tetramesa species are recommended for importation into quarantine in Australia for confirmatory host-specificity testing with a significantly reduced test plant list. Synthesis and applications: Similar field-based assessments in the indigenous distribution of weeds targeted for biocontrol could be included in future programmes. Where rearing of potential agents and/or test plants is difficult or impossible under quarantine conditions, our field-based method provides an alternative. Where quarantine-based testing is feasible, this method ensures that only candidates that have passed an ecologically realistic host-specificity and potential efficacy screening are imported into quarantine. This may reduce the number of agents that are imported and the length of time each agent is kept in quarantine. This is advantageous because quarantine space is highly valuable and is usually a limiting factor in pre-release assessments of biocontrol agents
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