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.

Host-plant mediated effects of root herbivory on insect seed predators and their parasitoids

Abstract: The effects of root herbivory on a tephritid seed predator (Terellia ruficauda) and its parasitoids were investigated. Soil fauna were manipulated by insecticide treatment; host plant (Cirsium palustre) phenology and the oviposition behaviour of both tephritid and parasitoids (Pteromalus elevatus and Torymus chloromerus) recorded. Although insecticide-treated (and hence reduced root herbivory) plants had larger flowerheads, population abundances of both tephritids and parasitoids were greater on thistle plants subjected to root herbivory. Percentage parasitism was similar in both treatments. Root herbivory is thought to enhance the nutrient quality of plants and this may have resulted in the tephritid preferentially feeding on thistles whose roots had been attacked. Parasitoids on these plants were probably affected by a combination of increased plant attractivity (as for the tephritids), smaller flowerheads aiding ovipositor entry and more tephritid hosts being present. This is the first study to show that root herbivores, through plant-mediated interactions, can affect seed herbivores and also, albeit indirectly through the host, natural enemy trophic levels.

Exploring the chemical safety of fly larvae as a source of protein for animal feed

Abstract: There is an urgent need to increase the supply of sustainable protein for use in animal feed and the use of insect protein provides a potential alternative to protein crops and fishmeal. For example, fly larvae are highly compatible with use in animal feed containing much digestible protein with levels of key amino acids that are comparable with those found in high value alternatives such as soybean. However, the safety of protein from insects and subsequently the meat and fish from animals fed on such a diet requires further assessment. Here we present safety data from the larvae of the four fly species that have perhaps the greatest economic relevance in relation to their use as animal feed being: house fly (Musca domestica), blue bottle (Calliphora vomitoria), blow fly (Chrysomya spp.) and black soldier fly (Hermetia illucens). Diverse rearing methods were used to produce larvae fed on a range of waste substrates and in four geographically dispersed locations being; UK, China, Mali and Ghana. Chemical ...

Influence of agricultural management, sward structure and food resources on grassland field use, by birds in lowland England

Abstract: 1. Agricultural management of grassland in lowland Britain has changed fundamentally in the last 50 years, resulting in spatial and structural uniformity within the pastoral landscape. The full extent to which these changes may have reduced the suitability of grassland as foraging habitat for birds is unknown. This study investigated the mechanisms by which these changes have impacted on birds and their food supplies. 2. We quantified field use by birds in summer and winter in two grassland areas of lowland England (Devon and Buckinghamshire) over 3 years, relating bird occurrence to the management, sward structure and seed and invertebrate food resources of individual fields. Management intensity was defined in terms of annual nitrogen input. 3. There was no consistent effect of management intensity on total seed head production, although those of grasses generally increased with inputs while forbs were rare throughout. 4. Relationships between management intensity and abundance of soil and epigeal invertebrates were complex. Soil beetle larvae were consistently lower in abundance, and surface-active beetle larvae counts consistently higher, in intensively managed fields. Foliar invertebrates showed more consistent negatively relationships with management intensity. 5. Most bird species occurred at low densities. There were consistent relationships across regions and years between the occurrence of birds and measures of field management. In winter, there was a tendency towards higher occupancy of intensively managed fields by species feeding on soil invertebrates. In summer, there were few such relationships, although many species avoided fields with tall swards. 6. Use of fields by birds was generally not related to measures of seed or invertebrate food abundance. While granivorous species were perhaps too rare to detect a relationship, in insectivores the strong negative relationships (in summer) with sward height suggested that access to food may be the critical factor. 7. While it appears that intensification of grassland management has been deleterious to the summer food resources of insectivorous birds that use insects living within the grass sward, intensification may have been beneficial to several species in winter through the enhancement of soil invertebrates. 8. Synthesis and applications. We suggest that attempts to restore habitat quality for birds in grassland landscapes need to create a range of management intensities and sward structures at the field and farm scales. A greater understanding of methods to enhance prey accessibility, as well as abundance, for insectivorous birds is required.

Biological Flora of the British Isles: Ambrosia artemisiifolia.

Abstract: This account presents information on all aspects of the biology of Ambrosia artemisiifolia L. (Common ragweed) that are relevant to understanding its ecology. The main topics are presented within the standard framework of the Biological Flora of the British Isles: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characters, herbivores and disease, and history, conservation, impacts and management. Ambrosia artemisiifolia is a monoecious, wind-pollinated, annual herb native to North America whose height varies from 10 cm to 2.5 m, according to environmental conditions. It has erect, branched stems and pinnately lobed leaves. Spike-like racemes of male capitula composed of staminate (male) florets terminate the stems, while cyme-like clusters of pistillate (female) florets are arranged in groups in the axils of main and lateral stem leaves. Seeds require prolonged chilling to break dormancy. Following seedling emergence in spring, the rate of vegetative growth depends on temperature, but development occurs over a wide thermal range. In temperate European climates, male and female flowers are produced from summer to early autumn (July to October). Ambrosia artemisiifolia is sensitive to freezing. Late spring frosts kill seedlings and the first autumn frosts terminate the growing season. It has a preference for dry soils of intermediate to rich nutrient level. Ambrosia artemisiifolia was introduced into Europe with seed imports from North America in the 19th century. Since World War II, it has become widespread in temperate regions of Europe and is now abundant in open, disturbed habitats as a ruderal and agricultural weed. Recently, the North American ragweed leaf beetle (Ophraella communa) has been detected in southern Switzerland and northern Italy. This species appears to have the capacity to substantially reduce growth and seed production of A. artemisiifolia. In heavily infested regions of Europe, A. artemisiifolia causes substantial crop-yield losses and its copious, highly allergenic pollen creates considerable public health problems. There is a consensus among models that climate change will allow its northward and uphill spread in Europe.