Famed for keeping agricultural pests in check, harlequin ladybirds - or ladybugs as they are commonly referred to as in the U.S. - are spreading rapidly to places they don't belong and threatening other wildlife.
"The rapid spread of this species has inspired biologists to study the process of invasion on a global scale," said Helen Roy, lead author from the Centre for Ecology and Hydrology in the U.K.
Originally from Asia, these orange spotted beetles can now be found throughout the U.S., in parts of Canada and most of Europe. The harlequin ladybird, Harmonia axyridis, has also made its way to a few regions of South America, as well as parts of northern and southern Africa.
While ladybirds were first introduced to the U.S. in 1916 as a biological control agent against agricultural pests like aphids, a dramatic population growth of the beetles has raised concern among scientists.
For instance, only fours years after being introduced to European Russia in 2010, the harlequin ladybird spread across all of the Netherlands, expanding its range southward by 200 miles per year. The beetles' ability to thrive in many differing habitats and climatic conditions is believed to have contributed to their success.
However, in order to maintain an ecological balance, researchers are now working to identify natural enemies of the ladybird. One helpful species is the parasitic wasp Dinocampus coccinellae, which is found all over the world and uses most types of ladybird species as hosts.
Researchers have also turned to citizen scientists to help monitor how fast ladybirds are expanding their range. In fact, sightings of ladybird species in the U.K. can be reported on an online survey.
"The involvement of the public in monitoring this species in a number of countries around the world is inspiring and has provided data on scales that would be otherwise unachievable," Roy said.
While researchers still aren't sure what effects the beetle's growing presence is having on the ecosystem, the data collected from such initiatives has inspired new projects both within and among countries.
"The coupling of citizen science approaches with global collaborations among researchers will provide the scale of information required to address some of the complex ecological questions that remain unanswered," Roy added.
Their study was recently published in the journal Biological Invasions.
