Fungus creates zombie beetles
A recent article in ‘New Scientist’ describes a fungus Eryniopsis lampyridarum that infects its insect host but doesn’t kill them straight away as the beetle would simply drop to the ground and rot. This is not only a waste of a beetle but also doesn’t help the fungus spread as this beetle isn’t just any beetle.
This beetle Chauliognathus pensylvanicus uses flowers to attract a mate, landing on them and displaying in order to get the greatest possible impact on passing beetles. There are enough fungal spores on the flowers to infect a few beetles but the supply is very limited and the fungus does not infect the plant – so more beetles landing on the flowers will not carry a spore away. To counter this the fungus has evolved to use a remarkable and cunning plan!
If a female lands on a flower to feed and becomes infected with the fungus it does not die straight away, instead the fungus forces the beetle to clamp its jaws on the flower. This holds the dead beetle on the flower while the fungus grows and uses the beetle body to produce many spores. Once achieved the fungus has a second trick – it opens the wings of the (female) beetle to imitate its mating display, whereupon males will land in order to mate and become covered in spores. The males then fly to other flowers and other plants infecting new flowers as they go, initiating the repeat of the deadly cycle.