Friday, 11 October 2013

Biosciences Seminar Speaker - 14 October 2013

Biosciences Seminar Series - Michaelmas 2013
14 October 2013 - 1pm - Zoology Museum (Wallace 129)


Chasing the High-fliers: 

Recent Insights from Radar Studies of Insect Migration

Dr. Jason Chapman

(Rothamsted Research, UK)

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How would you go about detecting and tracking little insects, such as moths, flying high up in the air at 100m height or more? Or millions of birds or bats? It turns out it is not as hopeless as it sounds, as all these organisms can be detected by radars!  Actually, the aerosphere supports an enourmous abundance of life forms and the field of aeroecology now crucially relies on the use of dedicated radar systems, such as entomological radars

Our next seminar speaker, Dr Jason Chapman, from the Insect Migration & Spatial Ecology group at Rothamsted Research (UK), is a well-known world expert in this field. He will present us a fascinating talk about how he and his group have used radar technologies to understand what determines the flight and migration behaviour of little moths.

Billions of insects migrate between winter and summer ranges to take advantage of seasonally-available breeding resources. To cover the distances required (100s km), many insects rely on wind assistance, and routinely ascend 100s m above the ground to migrate in fast-moving airstreams. Given that wind speeds are typically three to five times faster that the insects’ airspeeds, it was not clear what influence high-flying migrants could exert on their migration direction or whether substantial ‘return’ migrations to lower-latitude winter-breeding areas were possible. 

Photo provided by Jason Chapman

To answer these questions, I have studied the flight behavior and migration patterns of the Silver Y Autographa gamma and other moths with specialized entomological radars. 

Photo provided by Jason Chapman

Radar observations demonstrate that an ability to select favorably-directed airstreams (i.e. northwards in spring and southwards in autumn) is widespread among high-flying migrant Lepidoptera, and thus migrants gain considerable wind assistance for their seasonal migrations. Furthermore, moths preferentially fly at the altitude of the fastest winds, and partially compensate for wind drift away from their seasonally-preferred migration directions. 

Trajectory simulations show that these flight behaviors result in significant increases in mean nightly migration distance, and a high degree of success in reaching the next breeding region, while population monitoring indicates that high-latitude summer-breeding results in a fourfold population increase. Comparison of moth migration parameters with those of nocturnal passerine migrants demonstrates that the moths’ highly efficient strategies result in them achieving the same travel speeds and directions as birds capable of flying three times faster. 

The migration strategies employed by the study species explain how small, short-lived and relatively slow-flying organisms are able to cover great distances in seasonally-beneficial directions, and demonstrate that migration is highly adaptive.

Relevant Publications:
Chapman JW et al (2012). Seasonal migration to high latitudes results in major reproductive benefits in an insect. PNAS 109: 14924-14929.

Chilson PB, Bridge E, Frick WF, Chapman JW and Kelly JF (2012). Radar aeroecology: exploring the movements of aerial fauna through radio-wave remote sensing. Biology Letters 8: 698-701.

Alerstam T & Chapman JW et al (2011). Convergent patterns of long-distance nocturnal migration in noctuid moths and passerine birds. Proceedings of the Royal Society B 278: 3074-3080.

Chapman JW, Drake VA and Reynolds DR (2011a). Recent insights from radar studies of insect flight. Annual Review of Entomology 56: 337-356.

Chapman JW, Nesbit RL, Burgin LE, Reynolds DR, Smith AD, Middleton DR and Hill JK (2010). Flight orientation behaviors promote optimal migration trajectories in high-flying insects. Science 327: 682-685.

Everyone is welcome to attend - please do come along and again note the change of day for this week: Monday!

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