A physics student from Stellenbosch University, Alem Gebru, will represent South Africa at the Falling Walls Lab – an international platform where “young bright minds” get only three minutes to present their ideas to a select jury of scientists and business men.
The Falling Walls Lab is part of the Falling Walls Conference which every year takes place in Berlin, Germany. The Falling Walls initiative was started 20 years after the fall of the Berlin wall and aims to foster discussion on research and innovation and promotes the latest scientific findings among a broad audience.
Alem recently competed against 21 entries in the South African leg of the competition which took place in Johannesburg.
“I have always wanted to do research that will be relevant to society and especially Africa,” the Ethiopian-born student says. He came to Stellenbosch University (SU) on a TRECCAfrica fellowship after obtaining an MSc in physics at Lund University in Sweden.
As part of his doctoral research in the Department of Physics at SU, Alem developed a technique to remotely classify insects based on the frequency of their wing beats and iridescence features. The instrument, using laser radar and sunlight, can also determine their sex and the direction of flight.
Insects are the largest and most diverse animal group on earth. Yet it remains exceedingly difficult to study their movements and interactions in their natural habitat.
The new method promises a radical transformation of the way entomologists collect data about large numbers of insects and their interactions. It is especially relevant in the study of pests like mosquitoes, or the wellbeing of important pollinators like bees.
Alem says his technique involves the use of both a laser radar system and natural sunlight: “If one wants to use light to detect something, you need to choose a specific light source with a smaller wavelength than the size of the thing you want to detect, which, in our case, are insects. We implement an optical technique called Light Detection and Ranging (LIDAR). That is because LIDAR has a wavelength which is much smaller than the tiniest insect.”
The instrument can also switch to using sunlight. Alem explains: “The moment an insect flies into the telescope’s field of view, the scattered light is reflected back onto the telescope and goes to the beam splitter where the light is broken into both visible and infrared light.”
Figure above: Example of a chasing event likely due to predation. The red arrows indicate body size and the blue and green arrows indicate wing oscilliation of the small and big insect, respectively. Image courtesy of Alem Gebru and the Journal of Applied Remote Sensing, Vol. 9, 2014.
Prof. Erich Rohwer, head of the Department of Physics at SU and his supervisor, says more efficient and accurate insect-monitoring techniques could give us a detailed understanding of insect activity and help to get a better picture of the environment.
Alem’s co-supervisor is Dr Mikkel Brydegaard from Lund University in Sweden where he specialises in laser radar and optical remote sensing of insects. He is also involved with the development of realistic instrumentation and optical sciences in Africa and South America.
According to Dr Brydegaard modern electro-optic methods now allow for the assessment of the abundance and fluxes of pests like mosquitoes and beneficial insects like bees on a landscape scale.
“The method has the potential to significantly increase our understanding of, and ability to quantify and manage, the ecological environment,” he says.
In conjunction with his supervisors and other scientists, Alem has already co-published two articles in international peer-reviewed journals and presented his work at two international conferences.
Alem will present his work with 100 finalists in Berlin on 8 November 2015.
