Team:Poitiers/Human Practices
Human practices
Students
At the beginning of our iGEM season, we conducted brainstorming sessions that allowed the selection of our project : the fight against the Asian hornet.
Why did we approach them?
We wanted to know if the Asian hornet issue was known by other people than beekeepers and Asian hornet specialists. We also wanted to know if our project was relevant and would interest a large public.
What did we learn?
Thanks to a survey that was mainly filled by students, we estimated that our project seemed to be relevant because it tackles a current issue in France, which a large public is aware of.
Our informative survey
Answers of the survey:
Beekeepers and Asian hornet specialists
The choice of our project seems relevant, so we seek to enrich our knowledge on the subject. We interacted with many beekeepers from all over the country, as well as with two Asian hornet specialists (Claire Villemant and Eric Darrouzet) and one social insects specialist (Freddie Jeanne Richard).
Why did we approach them?
Since we were inexperienced in bee and Asian hornet biology and behaviour, we approached beekeepers, social insects and Asian hornet specialists to get some first hand information about the biology and the behaviour of these insects.
What did we learn?
We learned that European bees (Apis mellifera) are used to the European hornet hunting technique, which consists in entering the hives and capturing bees. To fight against this predator, bees mass together at the entrance of their hive when they detect the presence of hornet, so that it can’t enter. But the Asian hornet hunting technique is totally different from its European cousin. Indeed, Asian hornet usually stay in stationary flight, back to the hives, waiting for bees workers returning to their hive to capture and kill them.
So they don’t try to enter the hives. Thus bees stay massed together in front of, or inside their hive, and don’t dare to go out. They finally die starving in winter because of the lack of food. That is why such a huge amount of bees die each year.
We also learned that there are 2 major fighting methods existing: finding and destroying nests, or trapping the hornet itself. According to Asian hornet specialists, finding and destroying nests would theoretically be the most efficient way to fight against the Asian hornet, but in reality it is currently impossible to do it efficiently. Indeed, Asian hornets do their nests high up in trees and are hidden behind leaves, making them hard to detect. And even if nests are spotted, they are still hard to destroy.
Then there is the trapping method left. We learned that this method is a major concern of biologists because none of the existing trapping methods is specific to the Asian hornet. A huge amount of trapped insects is pollinating species, which are important for the environment (wasps, bees, bumblebees…). There is a urgent need to design traps which could be selective and specific of the Asian hornet.
Thus, we decided to focus on the trapping method, and try to design a prototype trap which would be selective for the Asian hornet, and with a bait specific to it, which could be produced by synthetic biology.
For the bait, we found 3 possible molecules of interest which could have an attractive effect on the Asian hornet after a scientific literature monitoring. The interest of these molecules to fight against the Asian hornet was confirmed by Eric Darrouzet, an Asian hornet specialist. Thus we began our work to find a way to produce these molecules by synthetic biology.
Hornet trap users
Simultaneously, we contacted hornet trap users, and Jean-Pierre Thomain, the designer of the « Red Trap », a famous trap in France, which is known to have a 85% selectivity towards Asian hornets.
Why did we approach them?
We wanted to understand how the design of a trap could influence its selectivity.
What did we learn?
We learned that we could enhance the selectivity of our trap by calibrating the size of the entrance on the width of an Asian hornet worker, so that bigger insects like the European hornet, can’t be trapped.
Plus, by adding holes calibrated on bees’ size on the surfaces of the trap, we could allow smaller insects to escape from the trap.
We then came up with a first prototype design.
This trap was designed to be safe to use for each user and selective for the Asian hornet. The bait is placed on the tray which can be pulled-up with four strings so that it can come up to the plexiglas trap door. The users can then safely remove the previous bait and place a new-one, without risking to let any hornet escape.
When empty, the plexiglas plate can be removed by sliding after removing the safety lock.
The hornets enter this trap by the grid cones, which size is calibrated on the size of an Asian hornet worker, and are trapped in the first chamber. If smaller insects than the Asian hornet are trapped, they can still exit by the little holes on the sides of the trap, which size are calibrated on the size of bees workers.
The hornets then end up dying by starving or because of the heat, and fall on the first removable plate, locked by a safety pin. This plate can slide to let the dead insects fall into the second chamber, which was designed in case living insects enter the second chamber.
After a certain time, the second removable plate, also locked by a safety pin, can slide to let the dead insects fall in the drawer, which can be removed to throw away the dead insects.
So the users can safely get rid of the dead insects in the trap, without risking to let any hornet escape or being in contact with them.
Engineers
In order to design and engineer the trap imagined by our team, we contacted engineers. To enhance the selectivity of the trap, we also wanted to design a sprayer system which would trigger when an Asian hornet approaches.
Why did we approach them?
We wanted engineers’ help to study the possibility of designing such a trigger.
What did we learn?
The engineers told us that there would be two possibilities of trigger:
First, a visual trigger, which would visually detect the Asian hornet thanks to a camera,
Second, a sound trigger, which would detect the Asian hornet, thanks to its sound signature with a micro.
For the engineers, the visual trigger seemed too difficult to design and to expensive, but the sound trigger would be possible to make. But the price of such a trigger would be expensive. Finally, after a study on their part, no data was available on the acoustic signature of the Asian hornet. The design of a sound detector was therefore impossible.
The creation of a bank of sound signals would have lengthened the duration of the project and postpone the contribution of a solution to the problem. So we decided to focus on the bait.
Beekeepers
To make sure that such an intricate trap would be relevant, we needed the opinion of the very first concerned by our solution, and that is mainly beekeepers.
Why did we approach them?
We wanted beekeepers to answer a survey about our project to develop a way to produce specific molecules for the Asian hornet, and a trap which could be used with these molecules.
What did we learn?
Beekeepers would mainly be ready to pay for a cheap trap.
Indeed, on 37 beekeepers who answered our survey, more than ¾ of them are ready to pay for a trap which would cost between 10 and 30€.
However, they still would mainly be interested in an effective and specific solution against the Asian hornet.
Our survey for Beekeepers
Answers of this survey:
These results and our discussion with the engineers made us reconsider the need to design our own trap for the project.
It would be better to focus on the molecules’ production, which then could be used in any kind of traps, already making them specific to the Asian hornet.
After the survey, we bought chemically synthesized standards of these molecules to be sure of their attractiveness. We then organized several tests of these molecules on the field, thanks to beekeepers partners, to know the real effect of these molecules on the Asian hornets, so that it would really be interesting to produce them biologically afterwards.
Beekeepers volunteers then received a detailed protocol with a random molecules among the three molecules of interests (4-oxo-octanoic acid, 4-oxo-decanoic acid and 2-nonanone). The effects of these molecules are usually tested from july to november for one of our molecules, and from october to november for the two molecules remaining. But with the exceptional weather conditions of this summer, these periods have been delayed by two months. So, we do not have received the results of the field assays yet.
Field tests with the molecules in a trap
