Introducing West Africa’s largest insect collection

15 May 2020

Quick facts

IITA’s insect collection is based in Benin
It is the most extensive insect collection in West Africa
It has 366,000 insect species
Museum houses both pests and beneficial insects
Offers free insect identification services

How do you catch all these insects? How do you know where they are? Do you go into the bushes with a net and wave it in the air? There were so many questions that I kept asking as I stood perplexed. “Look around you,” Georg tells me with a look of amusement on his face. I look, nothing. “Lookup”, he directs my gaze. I look and spot what looks like a giant spider at whose sight I wince a little. Georg, amused, lets out a loud laugh, “look again”, he encourages me further. This time I let my eyes roam the entire room, which is about 40 by 40 ft; all over the walls are all kinds of enormous insects.

Introducing West Africa’s largest insect collection
Georg Georgen, an entomologist and head of IITA’s insect museum in Cotonou, Benin

By this time, I was almost screaming until my eyes rest on a colossal grasshopper and with a little more scrutiny, I realize they are plastic insects – decorations. Georg is laughing, clearly enjoying my scared reaction. “Insects are everywhere; you don’t see them because you are not looking for them. That is how it starts; we go out in the natural environment and look for them. First, we see the big ones, but as we look closely, we even see the tinier ones”. This is a scene from the International Institute of Tropical Agriculture (IITA)’s Biodiversity Centre based in Cotonou, Benin. It is West Africa’s biggest insect museum or “insect collection” as IITA’s entomologist and biocontrol specialist, Goergen Georg prefers to call it.

I am sure you have as many questions as I had. Insect museum? Why collect insects, how does one collect insects, who on earth collects insects? I put all these and more questions to Georg, a jolly man of German descent who grew up in Morocco playing with spiders and scorpions. No wonder he heads IITA’s insect collection. In a lightly air-conditioned room with blue cabinets lay 366,000 insect species. With a playful look and almost permanent smile, Georg, who laughs easily, eagerly shows me one insect collection after another. Some are quite pretty I must admit. The beetles have a vibrant sapphire green colour, and the house flies in the collection are not nasty pit latrine hopping creatures, they are a luxurious shimmery blue. Why collect insects, I ask as Georg pulls out another blue cabinet to reveal beautiful butterflies.In another drawer, I see spiders, and I let out a gasp. We need to stop looking at insects, so I insist on getting my question answered, why? “I’ll tell you, be patient”, Georg hushes as he pulls out yet more drawers. It’s evident he’s proud of the work he and his team are doing. “Some are pretty rare”, he adds as he pulls out another cabinet. Later, after he is done showing off his impressive collection, he answers my question, why collect insects?

Introducing West Africa’s largest insect collection
Some of the insects in the museum

Purpose of the collection

“We exist to offer a free identification service for any insect that is of concern to agriculture or health,” Georg says. “Over time, we have developed a reputation that we offer this service, and in return, we are often the first to be informed of new pests in West Africa. This was the case with the Fall armyworm (FAW). Once our partners proved that they were confronted with a new pest, they sent us samples for identification.” Georg and his team went ahead and identified the FAW as a new and invasive species on the African continent. Read about the fall armyworm and its discovery here.

History

CGIAR-IITA’s insect collection emerged from the first biocontrol success in Africa, which was targeted at the cassava mealybug. Scientists studied the cassava mealybug food web as well as its most efficient and effective natural enemy. However, in reviewing the mealybug’s natural enemies, the researchers were confronted with the lack of a facility to identify samples locally. “All samples were sent abroad for identification, which was characterized by long delays in both dispatch and response”. It is against that background and the regional need for  an arthropod diagnostic service that IITA decided to open its own identification center. What started as a small insect collection at IITA’s headquarters in Ibadan, Nigeria was later moved to Cotonou in Benin at the Institute’s biocontrol centre. From 1,000 specimens in Ibadan, the insect collection now boasts of 366,000 specimens and more than 6,000 identified species, making it the best insect collection in West Africa with both pests and beneficial insects.

This growth has come mostly from material kept from past projects, as Georg explains: “In the past, when a project would end, the identified materials would be discarded, which was a pity because they were valuable references. The insects are now preserved permanently so that future projects could benefit from them.” Permanent preservation is possible because of the suitable conditions in the museum, such as controlled access. One cannot have direct access to the collection; they must pass through two doors which limits unnecessary movement. The room is also permanently air-conditioned with back-up generators in case of electricity outage. The windows are not only small to avoid exposure to sunlight, but they are also never opened. Georg explains the rationale, “Insects decay mostly from fungi, attack from fellow insects and exposure to sunlight. If these conditions are minimized, then permanent preservation is possible.”

Introducing West Africa’s largest insect collection
Beetles in the insect collection

There are so many insects of the same species, i.e., several kinds of houseflies, butterflies, bees, or beetles, and there is a reason for this. “We collect everything we can get from different regions. It may seem like a waste to the untrained mind, but nothing is never in vain, as Georg explains. “When the opportunity availed itself, we collected aquatic beetles, and everyone wondered whether we had gone bonkers. Then, ten years later, it was discovered that aquatic beetles are involved in the transmission of the Buruli ulcer, a locally emerging infectious skin disease. Suddenly, everyone was interested in what type of aquatic insects we have in West Africa, and thankfully we had preserved some of them.” That is why, when Georg or anyone on his team, find themselves in a new environment, they collect a sample that is representative of the region’s insects—you never know when you will need them! “The idea is to store them and come back anytime by looking into the cabinets – i.e. the museum – because the past helps us to master current problems”. Also, one cannot know if a species is new to the continent or not without any reference. In the case of the Fall Armyworm, Georg says they would never have known that it was alien to Africa if they had not collected other moths to which it was compared.

 

So, there it is—the collection is essential to identifying and studying new invasive and beneficial insects as well as finding an effective biocontrol measure, i.e., natural enemies that can suppress an insect pest. Over the years, IITA has used natural enemies (beneficial insects) to control pests such as the cassava mealybug. Biocontrol of cassava mealybug delivered the highest return on investment in the history of the CGIAR. A Benefit:Cost ratio of 149:1, meaning every $1 invested in cassava mealybug biocontrol gave a return of $149. Other noteworthy biocontrol successes include controlling the water hyacinth on Lake Victoria, the world’s largest fresh water body, using weevils. . The water fern in Congo Brazzaville was also entirely controlled by introducing a specific weevil.

Find out more about the use of natural enemies in the control of pests, here and here.