In
the fight for survival, invasive harlequin ladybirds are decimating
their competitors. New research reveals their success may be thanks to a
biological weapon - a parasite which kills native ladybird species but
is harmless to the harlequin.
Originally imported from central
Asia to control aphids in greenhouses, the harlequin ladybird (Harmonia
axyridis) has since spread across Europe. New research
reveals it carries single-celled fungal parasites known as
microsporidia its whole life. Somehow the ladybird keeps them in an
inactive state in its haemolymph (the arthropod equivalent to blood),
but when they find their way into native ladybirds - for example, by
eating harlequin larvae or eggs - they become active and kill their new
host.
“I have worked on insect immunity for 20 years, and I
had never seen a haemolymph sample that was full of microsporidians that
do not harm the carrier,” says Andreas Vilcinskas
(Justus-Liebig-University, Giessen, Germany and involved in the study).
As well as having an edge in attack, the harlequin's no slouch in
defence. Its immune system is extremely powerful and allows it to fight
off pathogens more easily than native species can. One element of its
immune system, a compound called harmonine, has even been suggested a
possible target for drug development.
According to the German
team behind the research, the harlequin is on a course for conquering
the world. As well as the factors discussed above, it can also live in a
wide range of zones (and they've started appearing in South America and
South Africa). "I don't see any which way to stop them now - it's too
late in my opinion," said Dr Heiko Vogel (Max Planck Institute for
Chemical Ecology, Germany, and co-author).
Photo: Harlequin ladybird (right) and native species the seven-spot ladybird (left). Credit to J. C. Carton/Photoshot.
http://www.nature.com/news/
http://www.bbc.co.uk/news/
In
the fight for survival, invasive harlequin ladybirds are decimating
their competitors. New research reveals their success may be thanks to a
biological weapon - a parasite which kills native ladybird species but
is harmless to the harlequin.
Originally imported from central Asia to control aphids in greenhouses, the harlequin ladybird (Harmonia axyridis) has since spread across Europe. New research reveals it carries single-celled fungal parasites known as microsporidia its whole life. Somehow the ladybird keeps them in an inactive state in its haemolymph (the arthropod equivalent to blood), but when they find their way into native ladybirds - for example, by eating harlequin larvae or eggs - they become active and kill their new host.
“I have worked on insect immunity for 20 years, and I had never seen a haemolymph sample that was full of microsporidians that do not harm the carrier,” says Andreas Vilcinskas (Justus-Liebig-University, Giessen, Germany and involved in the study).
As well as having an edge in attack, the harlequin's no slouch in defence. Its immune system is extremely powerful and allows it to fight off pathogens more easily than native species can. One element of its immune system, a compound called harmonine, has even been suggested a possible target for drug development.
According to the German team behind the research, the harlequin is on a course for conquering the world. As well as the factors discussed above, it can also live in a wide range of zones (and they've started appearing in South America and South Africa). "I don't see any which way to stop them now - it's too late in my opinion," said Dr Heiko Vogel (Max Planck Institute for Chemical Ecology, Germany, and co-author).
Photo: Harlequin ladybird (right) and native species the seven-spot ladybird (left). Credit to J. C. Carton/Photoshot.
http://www.nature.com/news/
http://www.bbc.co.uk/news/
Originally imported from central Asia to control aphids in greenhouses, the harlequin ladybird (Harmonia axyridis) has since spread across Europe. New research reveals it carries single-celled fungal parasites known as microsporidia its whole life. Somehow the ladybird keeps them in an inactive state in its haemolymph (the arthropod equivalent to blood), but when they find their way into native ladybirds - for example, by eating harlequin larvae or eggs - they become active and kill their new host.
“I have worked on insect immunity for 20 years, and I had never seen a haemolymph sample that was full of microsporidians that do not harm the carrier,” says Andreas Vilcinskas (Justus-Liebig-University, Giessen, Germany and involved in the study).
As well as having an edge in attack, the harlequin's no slouch in defence. Its immune system is extremely powerful and allows it to fight off pathogens more easily than native species can. One element of its immune system, a compound called harmonine, has even been suggested a possible target for drug development.
According to the German team behind the research, the harlequin is on a course for conquering the world. As well as the factors discussed above, it can also live in a wide range of zones (and they've started appearing in South America and South Africa). "I don't see any which way to stop them now - it's too late in my opinion," said Dr Heiko Vogel (Max Planck Institute for Chemical Ecology, Germany, and co-author).
Photo: Harlequin ladybird (right) and native species the seven-spot ladybird (left). Credit to J. C. Carton/Photoshot.
http://www.nature.com/news/
http://www.bbc.co.uk/news/
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