It is important to be able to differentiate between the invasive harlequin ladybird and native species of ladybirds. This is according to Annerie Senekal, an assistant curator at Stellenbosch University (SU) Botanical Garden.
Many people don’t know that South Africa has native species of ladybirds, said Senekal.
Annerie Senekal, an assistant curator at Stellenbosch University (SU) Botanical Garden, recently raised the importance of being able to identify an invasive species of ladybird, the harlequin ladybird. According to an Instagram post by SU Botanical Garden on 8 August, “the harlequin poses a problem by outcompeting our native species”. PHOTO: Nadia Swart
A distinctive trait that can be used to identify the invasive species of harlequin ladybird is the black ‘W’ marking on its head, said Minette Karsten, entomology researcher at SU.
“Our local ladybirds come in all kinds of colours: black, red, yellow, spotted, and striped,” reads an Instagram post by SU Botanical Garden on 8 August.
“You might’ve noticed more ladybirds and aphids in the garden lately, since it is a normal time of year for their numbers to boom,” reads the post.
History of the harlequin
The harlequin ladybird was first introduced from East Asia as a biological control agent for aphids and scale insects, according to Kobus Bothma, multidisciplinary professional agronomist.
An agronomist is a scientist who studies the use of land, soil management, and crop production, according to the Cambridge dictionary.
The harlequin ladybird has been spotted across the entirety of the Stellenbosch University (SU) Botanical Garden, according to Annerie Senekal, an assistant curator at SU Botanical Garden. The black ‘M’ (or ‘W’) on the harlequin ladybird’s head is a distinct trait of the insect, said Minette Karsten, entomology researcher at SU. INFOGRAPHIC: Nadia Swart
The earliest known record of the harlequin ladybird in South Africa was in 2001, said Karsten.
“Harlequin ladybirds (Harmonia axyridis) have been spotted in [the SU Botanical Garden] for several years,” said Senekal, in correspondence with SMF News. “Their larvae are usually seen in early spring, followed by the adults a few weeks later.”
‘An invasive beetle’
Harlequin ladybirds “can outcompete local ladybird species”, said Senekal.
In some cases, the harlequin ladybird can reduce biodiversity in the ecosystem, said Bothma, who added that the insect also has a negative impact on the wine grape growing industry.
“It does have an impact on the ecosystem, as it is an invasive beetle competing with local species of ladybirds for food source[s] and habitat,” said Bothma, in correspondence with SMF News.
“The general public mostly considers them a nuisance pest,” said Karsten. “They tend to gather in people’s homes during winter and some individuals are allergic to them.”
“Harlequin ladybirds have been spotted in [Stellenbosch University (SU) Botanical Garden] for several years,” said Annerie Senekal, an assistant curator at SU Botanical Garden. The larvae typically appear in early spring, with the adults emerging a few weeks afterward, she said. PHOTO: Nadia Swart
Farmers or gardeners who come across harlequin ladybirds should use environmentally friendly or biological pesticides to promote the activity of natural predators, said Bothma.
He also said that pest control chemicals should only be applied when the damage could lead to economic loss.