نتایج جستجو برای: hoverfly
تعداد نتایج: 170 فیلتر نتایج به سال:
Despite widespread concern about declines in pollination services, little is known about the patterns of change in most pollinator assemblages. By studying bee and hoverfly assemblages in Britain and the Netherlands, we found evidence of declines (pre-versus post-1980) in local bee diversity in both countries; however, divergent trends were observed in hoverflies. Depending on the assemblage an...
We tested the prediction that, if hoverflies are Batesian mimics, this may extend to behavioral mimicry such that their numerical abundance at each hour of the day (the daily activity pattern) is related to the numbers of their hymenopteran models. After accounting for site, season, microclimatic responses, and general hoverfly abundance at three sites in northwestern England, the residual numb...
To study insect decline, an important threat to biodiversity, long-term datasets are needed. Here we present a of hoverfly (Diptera: Syrphidae) abundance and diversity in Dutch forest, surrounded by other forests, analyse the variation numbers over four decades. Between 1982 2021, decreased 80%. Until 1990, showed strong decrease 10.9% per year, mainly nationally rare species with carnivorous l...
An updated checklist of the genus Eumerus Meigen, 1822 is presented from Pakistan along with two new country records, i.e., vestitus Bezzi, 1912 and sogdianus Stackelberg, 1952. native to Central Southern Europe, but recorded east Asia, Afrotropical region, recently also India. Both species are collected northern areas – extreme edge western Himalayas, where a significant diversity hoverflies h...
We propose a conceptual model for pollination and fertilization of tomato flowers in greenhouses crops by hoverflies, when the maximal number adult pollinators maintained is less than what needed an economically successful greenhouses. The consists two-stage process additional feeding hoverfly to maintain pollinator density at desired level. First, with stochastic model, we calculate flies nece...
A computational model of a stealth strategy inspired by the apparent mating tactics of male hoverflies is presented. The stealth strategy (motion camouflage) paradoxically allows a predator to approach a moving prey in such a way that it appears to be a stationary object. In the model, the predators are controlled by neural sensorimotor systems that base their decisions on realistic levels of i...
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