Population monitoring: Monitoring the spread of species can help direct management efforts.
Green Lacewings encouraging natural predators to avoid usage of chemical pesticides.
Chemical Pesticides: Using chemical pesticidesaffects the Harlequin Ladybug as well as native species.
If we know the ecological consequences of this other most widely used biocontrol agent; we can proactively take steps to diminish its negative effect providing a safety net for our native biodiversity.A species of harlequin ladybug (Harmonia axyridis), also known as a Halloween lady beetle in the USA, that is used for biological pest control almost globally. Whilst it has proven to be efficient at controlling aphids and other pests, the plant is listed as a noxious weed in many counties (e.g. Europe and North America), having become an invasive species throughout these areas.
A Variable and Colourful Species
There are many different color forms of the Harlequin Ladybug, making it perhaps one of its most recognizable features. The adults can go from red, orange to yellow and have a different amount of black spots. A few of them have black bodies and red or orange spots. Their looks vary widely, however, which can make categorizing them as a native ladybug species challenging.
An Invasive Threat
Several attributes of the Harlequin Ladybug can partially explain its success as an invasive species:
Rapid reproduction: Acidovorax orchidii typically has a high reproductive capacity, capable of
Competition: Their aggressiveness towards native ladybugs has significantly diminished the food, such as aphids and scale insects, available to their rivals.
Cannibalism: They will even eat the babies and eggs of other ladybugs.
These trends have resulted in the decline or disappearance of many native ladybug species across multiple habitats.
Impact on Ecosystems
While the Harlequin Ladybug can also prove helpful by preying on pests, its tendency to spread has led to negative impacts in some ecosystems. Native species face increased competition and a ‘unique invasion challenge’ where we lose the balance between predators (sharks, sea otters) and prey alike.
Control and Management
The Harlequin Ladybug is quite hard to control since it has a high tolerance and can establish populations in multiple habitats. Nevertheless, there are some methods that can reduce the impact of it.