Seibersdorf, Australia
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News Article | December 22, 2016
Site: www.eurekalert.org

As Britain voted for Brexit amid furious debate over migration, trillions of migrants were coming and going, unseen by all but the sharpest eyes. For the first time, scientists have measured the movements of high-flying insects in the skies over southern England - and found that about 3.5 trillion migrate over the region every year. This movement of 3,200 tons of biomass, captured by University of Exeter and Rothamsted Research using specialised radar techniques, is more than seven times the mass of the 30 million songbirds which depart the UK for Africa each autumn. It is also the equivalent of about 20,000 flying reindeer. Dr Jason Chapman, of the Centre for Ecology and Conservation at the University of Exeter's Penryn Campus in Cornwall, said: "Insect bodies are rich in nutrients and the importance of these movements is underappreciated. "If the densities observed over southern UK are extrapolated to the airspace above all continental landmasses, high-altitude insect migration represents the most important annual animal movement in ecosystems on land, comparable to the most significant oceanic migrations." Although the origin and destination of each insect was not recorded, evidence from previous research suggests many will have been travelling to and from the UK over the English Channel and North Sea. The scientists recorded movement above radar sites in southern England and found large seasonal differences, with mass migrations of insects generally going northwards in spring and southwards in autumn. Until now, radar studies have measured migrations of relatively few nocturnal species of agricultural pests, and no study previously examined the vast numbers of daytime migrants. The study found seasonal variations from year to year, but overall the net northward spring movements of larger insects were almost exactly cancelled out by net southward movements in autumn over the 10-year research period. Dr Gao Hu, a visiting scholar with Dr Chapman from Nanjing Agricultural University, China, led the analyses of the radar data. He said: "Many of the insects we studied provide important ecological services which are essential for maintaining healthy ecosystems, such as pollination, predation of crop pests and providing food for insectivorous birds and bats." Co-author Dr Ka S (Jason) Lim, of the Radar Entomology Unit of the AgroEcology Department at Rothamsted Research, said migratory insects can serve as indicators of global environmental condition. "Animal migration, especially in insects, is a very complex behaviour which takes millions of year to evolve and is very sensitive to climatic condition," he said. "Global climatic change could cause decline of many species, but equally other highly adaptable species thrive and become agricultural crop pests." The study focussed on insects flying more than 150 metres above the ground, using radar for larger insects (10mg and over) and netting samples for smaller ones. The paper, published in the journal Science, is entitled: "Mass seasonal bioflows of high-flying insect migrants".


Segura D.F.,Instituto Nacional de Tecnologia Agropecuaria | Segura D.F.,Entomology Unit | Segura D.F.,CONICET | Vera M.T.,CONICET | And 4 more authors.
Biological Journal of the Linnean Society | Year: 2011

Reproductive isolation among populations of Anastrepha fraterculus has been found acting at the pre- and post-zygotic levels. Differences in timing of sexual activity and male sexual pheromone composition among populations could partially account for prezygotic isolation. Hybrid males were found to produce a novel pheromone, which is a mix of parental pheromones. In the present study, we found that the hybrid females showed a significant preference to mate with hybrid males than with parental males. Male location during pheromone emission is associated with its reproductive success and, thus, differences in the location of males during courtship could also play a role in isolation. We found evidence that reproductive isolation is also related to the location of males during courtship. Hybrid male behaviour regarding location during pheromone release was found to be influenced by the maternal lineage. If these populations hybridized in the field, the hybrid females would tend to mate with hybrid males probably leading to the formation of a new entity within the A. fraterculus complex. This simple and fast process could be one reason explaining the high number of taxonomic entities within this complex. Further studies on other members of the fraterculus species group may reveal whether this can be considered as an example of homoploid hybrid speciation. © 2011 The Linnean Society of London.


Schlager S.,Leibniz Institute of Vegetable and Ornamental Crops | Schlager S.,Humboldt University of Berlin | Ulrichs C.,Humboldt University of Berlin | Srinivasan R.,Entomology Unit | And 4 more authors.
Gesunde Pflanzen | Year: 2012

The larvae of the legume pod borer, Maruca vitrata (Lepidoptera: Pyralidae), cause severe damage on economically important legume crops in the tropics. The female moth produces volatile components to attract males for mating. The so-called sex pheromones are species-specific multi-component blends and are used as lures in crop protection for pest monitoring. Their chemical identification and ratios is critical to design efficient lures. The following sex pheromone components for M. vitrata have been described: (E, E)-10,12-hexadecadienal (major compound), (E, E)-10,12-hexadecadienol and (E)-10-hexadecenal (minor components). The ratio of 100:5:5 of these components was the most attractive in trapping experiments in Benin, Africa. According to this ratio, a synthetic pheromone lure was developed for commercial use. But the commercially available blend was not attractive in field trapping experiments in other regions of sub-Saharan Africa and Southeast Asia. These findings lead to the conclusion that there is a possible polymorphism in the blend composition of the M. vitrata sex pheromone among populations from different geographical regions. In Taiwan, M. vitrata moths were never caught efficiently by the commercially available pheromone lures and traps. This paper reports trap and lure optimization experiments for effective trapping of Taiwanese M. vitrata moths in different leguminous crops. © 012 Springer-Verlag.


News Article | December 22, 2016
Site: phys.org

For the first time, scientists have measured the movements of high-flying insects in the skies over southern England - and found that about 3.5 trillion migrate over the region every year. This movement of 3,200 tons of biomass, captured by University of Exeter and Rothamsted Research using specialised radar techniques, is more than seven times the mass of the 30 million songbirds which depart the UK for Africa each autumn. It is also the equivalent of about 20,000 flying reindeer. Dr Jason Chapman, of the Centre for Ecology and Conservation at the University of Exeter's Penryn Campus in Cornwall, said: "Insect bodies are rich in nutrients and the importance of these movements is underappreciated. "If the densities observed over southern UK are extrapolated to the airspace above all continental landmasses, high-altitude insect migration represents the most important annual animal movement in ecosystems on land, comparable to the most significant oceanic migrations." Although the origin and destination of each insect was not recorded, evidence from previous research suggests many will have been travelling to and from the UK over the English Channel and North Sea. The scientists recorded movement above radar sites in southern England and found large seasonal differences, with mass migrations of insects generally going northwards in spring and southwards in autumn. Until now, radar studies have measured migrations of relatively few nocturnal species of agricultural pests, and no study previously examined the vast numbers of daytime migrants. The study found seasonal variations from year to year, but overall the net northward spring movements of larger insects were almost exactly cancelled out by net southward movements in autumn over the 10-year research period. Dr Gao Hu, a visiting scholar with Dr Chapman from Nanjing Agricultural University, China, led the analyses of the radar data. He said: "Many of the insects we studied provide important ecological services which are essential for maintaining healthy ecosystems, such as pollination, predation of crop pests and providing food for insectivorous birds and bats." Co-author Dr Ka S (Jason) Lim, of the Radar Entomology Unit of the AgroEcology Department at Rothamsted Research, said migratory insects can serve as indicators of global environmental condition. "Animal migration, especially in insects, is a very complex behaviour which takes millions of year to evolve and is very sensitive to climatic condition," he said. "Global climatic change could cause decline of many species, but equally other highly adaptable species thrive and become agricultural crop pests." The study focussed on insects flying more than 150 metres above the ground, using radar for larger insects (10mg and over) and netting samples for smaller ones. The paper, published in the journal Science, is entitled: "Mass seasonal bioflows of high-flying insect migrants". Explore further: Migrating insects fly in the fast lane

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