RESUMEN
Wild and managed bees are well documented as effective pollinators of global crops of economic importance. However, the contributions by pollinators other than bees have been little explored despite their potential to contribute to crop production and stability in the face of environmental change. Non-bee pollinators include flies, beetles, moths, butterflies, wasps, ants, birds, and bats, among others. Here we focus on non-bee insects and synthesize 39 field studies from five continents that directly measured the crop pollination services provided by non-bees, honey bees, and other bees to compare the relative contributions of these taxa. Non-bees performed 25-50% of the total number of flower visits. Although non-bees were less effective pollinators than bees per flower visit, they made more visits; thus these two factors compensated for each other, resulting in pollination services rendered by non-bees that were similar to those provided by bees. In the subset of studies that measured fruit set, fruit set increased with non-bee insect visits independently of bee visitation rates, indicating that non-bee insects provide a unique benefit that is not provided by bees. We also show that non-bee insects are not as reliant as bees on the presence of remnant natural or seminatural habitat in the surrounding landscape. These results strongly suggest that non-bee insect pollinators play a significant role in global crop production and respond differently than bees to landscape structure, probably making their crop pollination services more robust to changes in land use. Non-bee insects provide a valuable service and provide potential insurance against bee population declines.
Asunto(s)
Productos Agrícolas/crecimiento & desarrollo , Insectos/fisiología , Polinización , Animales , Hormigas/fisiología , Abejas/fisiología , Ecosistema , Flores/crecimiento & desarrollo , Frutas/crecimiento & desarrollo , Avispas/fisiologíaRESUMEN
AIM: Campylobacteriosis is highly characterised by a strongly seasonal rate of incidence. Age is also known to be a risk factor for sporadic campylobacteriosis, but little has been done to quantify age-related rates of campylobacteriosis. This study investigates age-related incidence across countries and up to 12 years of data, as well as differences in seasonality within age groups. METHODS: Graphical and statistical analysis of officially collected campylobacteriosis reports from three countries available from official websites. RESULTS: For Australia, New Zealand and Canada, rates of campylobacteriosis show marked peaks at <4 years and 20-29 year age bands. These peaks indicate that stable age-related factors impact on campylobacteriosis epidemiology in all three countries. Seasonality is expressed differently across these age bands, and in years of extremes of incidence. CONCLUSION: Campylobacteriosis is highly seasonal, but overlying this is a stable age-related pattern of incidence, with two peaks approximately 20 years apart. Highest seasonal differences occur with ages between the two peaks.
Asunto(s)
Infecciones por Campylobacter/epidemiología , Estaciones del Año , Adolescente , Adulto , Distribución por Edad , Anciano , Australia/epidemiología , Canadá/epidemiología , Niño , Preescolar , Humanos , Incidencia , Lactante , Recién Nacido , Persona de Mediana Edad , Nueva Zelanda/epidemiología , Adulto JovenRESUMEN
AIMS: New Zealand has a very high rate of seasonal, sporadic campylobacteriosis compared to other OECD countries. Can the seasonality of New Zealand cases fit with an explanation of food-borne transmission (especially by chicken meat), and where does the fly-transmission hypothesis fit? METHODS: Analysis of seasonal campylobacteriosis reports at the District Health Board level compared to regional ambient temperatures, and chicken consumption data. Literature review particularly of food-associated disease risks and transmission routes. RESULTS: Campylobacteriosis rates in New Zealand show a national annual increase at a rate similar to chicken consumption. A drastic reduction in chicken consumption was associated with significantly reduced campylobacteriosis cases in two European countries, further strengthening the link between disease risk and chicken consumption. However, serotype analysis of the Campylobacter isolates is ambiguous regarding chicken meat itself as the major source of infection. The seasonal colonisation pattern in live chickens follows the seasonal increase in human cases. Flies are a plausible vector, associated with increasing overwintered fly foraging activity, rather than a summer increase in fly numbers. CONCLUSION: The typically sporadic rather than outbreak nature of campylobacteriosis, the disjoint between seasonal patterns of human and chicken infection, the seasonal pattern itself, and inconclusive serotype evidence indicates against chicken meat itself as the major source of infection. However, chicken consumption is a significant risk factor.