BiosafeTrain

Yet another grain of sand

"All I am doing is making a contribution, adding a grain of sand to the Mountain of Science and I would like to offer many grains of sand; I'd like to make as much contribution as possible", answers Dennis with a shy smile, when I asked him what he felt his contribution was to biosafety.

At five feet eleven inches the bashful Dennis admits that there is no lone scientist who can come up with a solution to a subject as huge as genetically modified organisms. "It takes quite a number to get it," he adds.

Dennis Ndolo Obonyo 34, formerly a research officer, won a scholarship from the BiosafeTrain Project to do his PhD in Entomology at the School of Biological Sciences at the University of Nairobi. "I recently resigned from my job so as to give more attention to my studies," he says.

Side effects of GM maize on parasitoids

Dennis's project is on environmental impact assessment of genetically manipulated (GM) maize in Kenya. He studies the tri-trophic interactions between parasitoids, lepidopteran stem borers and the maize plant "I am trying to look at the effect that GM maize has on non-target organisms, as GM maize is designed to target the stem borers. These pests have natural enemies that contribute to controlling the stem borer population. These natural enemies are the "non-targets", he explains. "The study I'm doing aims to find out the impact of Bt maize [maize containing a gene from the insect pathogenic bacterium Bacillus thuringiensis] on the natural enemies of the stem borers. When we are talking about the natural enemies of the stem borers we group them into two; we have parasitoids - organisms that usually lay eggs inside the host (which are the stem borers) and in the process kill it. Parasitoids are usually smaller than their host. Predators - these are usually larger than their prey - feed on the stem borers. I'm not working with predators but with parasitoids"

What does tri-trophic interactions mean? I ask. At this point he tears a paper off his notepad, borrows my pen and draws a little pyramid. The organisms on the lower level are food for the upper one. Soon I understand: "tri" means third, "trophic" means feeding. - "So, I'm researching the effects at the third feeding level. Maize is the first level, followed by the stem borer. The natural enemies of the stem borers are on the third level." He continues: "I am looking at the life history parameters of natural enemies against Bt maize and normal, non-Bt maize. Among the life history parameters, we are looking at characters that indicate host suitability and general quality of the natural enemy: progeny numbers, sex ratios, development time, and parasitoid abnormalities."

Side effects of GM maize on the stem borer pests

Dennis is yet to make a conclusion on his research. "I need to carry out a few more experiments to make reasonable conclusions", he ponders. But apart from trying to find out the effect of Bt maize on the non-target natural enemies, he also found it necessary to find the effect on the development of stem borers, and their oviposition preference (meaning the choices the stem borers make on whether to lay eggs in Bt or non-Bt maize). He is also trying to determine whether hosts feeding on Bt maize affect the parasitoid choices for hosts. "From this experiment it looks like the parasitoids have a preference for larvae reared on non-Bt plants. "This is an interesting result but I am working on more experiments so as to make my results as conclusive as possible," he says with a furrowed look and takes note on his writing pad, as if to put a reminder on some of his work. He looks up and points out "I am yet to analyse the oviposition preference, as I have to subject them to statistical analysis then I may make solid conclusions."

Like most research, his has also come with its set of challenges. Dennis laments that finding the effect of Bt maize on the development of stem borers is a bit problematic. "The main problem is that Bt maize kills stem borers, making it difficult to determine its effect on development." However, Dennis has found a solution to this teething problem. "I'm exposing the larvae to Bt maize for shorter intervals."

KARI facilities

He is currently doing his research at the Kenya Agricultural Research Institute (KARI), Nairobi. "KARI has all the facilities to do my research including a appropriate glasshouse facilities. GM crops have to be studied in confinement, in my case a "biosafety level 2" greenhouse".

A possible thumbs up for GM in Kenya?

GM maize is still under trials in Kenya. South Africa is the only African country where it has been commercialized. Dennis' views on GMOs are quite positive. "GMOs could contribute greatly in alleviating food shortages in Africa. He acknowledges that a lot of studies are needed to address the concerns that people have on the safety of GM crops.

Dennis is married and has a five-year-old son. When asked how he sees the future of GM in the country, he shrugs: "The future of GM in Kenya is clear. Research into GM technology has been received positively and has got support from the government. I guess the future is GM unless studies show otherwise."

Dennis intends to go on with his career as a research scientist in entomology. "Or a career that would link entomology and GM technology. That would be great for me" he says. "I really wanted to do a GM-related topic for my masters. I love both topics so I won't mind working on both in the future."

By Joy Owango, February 2007.