Objects no longer used, forgotten practices, places from another time, extinction of species, mythical spaces and outdated styles: what has disappeared around us? The Disappearance series travels to the heart of erasures of which we have had little or no knowledge over time. First missing: the nine-spotted ladybug.
The story of the nine-spotted ladybug is a sad one. Once one of the most abundant lady beetle species in Canada, it is now essentially (but not officially) extinct. “I’ve never seen it, and I don’t think I’ll ever see it,” laments André-Philippe Drapeau Picard, an entomologist at the Montreal Insectarium.
The nine-spotted ladybug (Coccinella novemnotata) swarmed in Quebec before the 1970s. This small beetle (4.7 to 7.0 millimeters) was typically found in open areas, such as fields and wastelands. It could be recognized by its bright orange elytra, adorned with nine black dots – although the number of dots could sometimes differ.
Entomologist Nicolas Bédard of Natural Resources Canada has also never seen a nine-spotted ladybug. “When I come across a ladybug, I check if it belongs to this species. I want to be able to raise a flag if I ever come across a specimen. »
In Quebec, the last reported sighting of the nine-spotted ladybug dates back to the 2010s, near Mont Saint-Hilaire, in Montérégie. The previous recorded sighting occurred three decades earlier, in the 1980s, said Drapeau Picard.
About a decade ago, officers from the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) searched for the nine-spotted lady beetle across the country. They visited 230 sites and spent 262 hours digging. They only found four specimens: three in Medicine Hat, Alberta, and one in Osoyoos, British Columbia.
In 2016, COSEWIC concluded that the nine-spotted lady beetle was “endangered”. Last February, this status was finally enshrined in Canada’s Species at Risk Act. In Quebec, the nine-spotted lady beetle is one of four insect species considered “threatened”, alongside the rusty-spotted bumblebee and two butterflies (the salt marsh copper and the Maritime ringlet).
Exotic competitors
The precise causes of the decline of the nine-spotted lady beetle remain poorly understood to this day. Several phenomena probably contribute to its downfall, but specialists find it difficult to assess the relative importance of each of these.
Let us first note the proliferation of non-native ladybugs, such as the seven-spotted ladybug and the Asian ladybug, which works against C. novemnotata. These competitors can hog available prey, prey on native lady beetles, and introduce new pathogens to North America.
Then, modern pesticides used by farmers very effectively combat the presence of aphids in the fields. However, even if the nine-spotted ladybug does not hesitate to swallow anything that falls under its mandible, it was particularly fond of aphids. His pantry was therefore emptied.
When I come across a ladybug, I check if it belongs to this species [coccinelle à neuf points]. I want to be able to raise a flag if I ever come across a specimen.
Mr. Bédard, a beetle specialist, is convinced that the proliferation of exotic ladybugs has played a crucial role in the decline of the nine-spotted one. “It’s absolutely crazy how many Asian and seven-spotted ladybugs there are, even back in the forest! These foreign species — apparently perfectly adapted to Quebec — create new pressures on ecosystems and can trigger a “domino effect,” he explains.
Reintroduction efforts
How to kick the nine-spotted ladybug? South of the border, entomologists at Cornell University in New York State have been trying for some years to reintroduce this insect to the northeastern United States. As part of the Lost Ladybug Rescue Project, they are breeding specimens in captivity from individuals found on Long Island in 2011.
The team then appeals to citizens to release these specimens into the wild. Specifically, it sells nine-spot ladybird larvae to amateur entomologists. These arrive by post. Installed in a garden or vegetable patch, the larvae become insects, eat unwanted aphids, and – it is hoped – set out to conquer the territory.
The commercial side of the Lost Ladybug Rescue project is running into trouble, however, environmentalist Rebecca Smyth, an affiliate manager at Cornell University, said in an email exchange with The duty.
“We lack production capacity, delivery costs are exorbitant, our “product” is very expensive, etc. We would still like to involve interested participants in the reintroduction effort, but we will need grants to support the projects and get more people involved,” says Ms.me Smith.
Intrinsic value
The nine-spotted lady beetle certainly represents one of the most tragic disappearances from the insect landscape of North America. The exotic species that have replaced it may be occupying its ecological niche, but the seriousness of this loss should not be minimized, underlines Mr. Drapeau Picard.
“Each species has intrinsic value and is worth protecting for that reason,” he says. At the moment, it is clear that there are more and more species at risk. For insects, the three main factors are always the same: climate change, the large-scale use of pesticides and the loss of habitats”, the latter factor possibly stemming from the spread of exotic species.
From tropical jungles to boreal forests, certain insect populations have shown a decline in recent decades. This decline — which we observe in particular in Quebec — worries scientists. It is urgent to curb this degradation of our “entomological heritage”, implores André-Philippe Drapeau Picard.