All Stories

Science News: Interesting Insects

Commonly used insecticides cause damage to bee brains

Could insecticides be harming the pollinators our crops depend on? In the past few decades, honeybee colonies across North America have been mysteriously vanishing at a rapid rate in a phenomenon known as Colony Collapse Disorder (CCD). Since CCD poses an immense risk to agriculture and the economy, researchers are under a lot of pressure to diagnose the problem. Recent studies show certain crop insecticides may contribute to CCD by damaging pollinator brains and causing sluggish, unproductive bee colonies.

Although neonicotinoid insecticides don’t kill bees, as they do with pest insects, researchers have found that the use of these pesticides reduce bee performance by blocking brain activity and slowing cell growth. Even at levels approved for agricultural use, the insecticides damage foraging ability, bee learning and colony growth.  The effects of common pesticides may not be enough to cause widespread death, but many other challenges for bees have emerged in recent years. Lowered diversity in pollen sources, the introduction of new viruses and the spread of parasites have also added to the collapse. To protect bee populations, beekeepers are encouraging members of the public to minimize pesticide use and plant pollinator-friendly flowers.

Parasitic fungus controls ant behaviour

Do zombies exist in real life? They could if you’re an ant. The parasitic fungus, Ophiocordyceps unilateralis, also known as zombie ant fungus, infects hosts and produces chemicals to control insect behaviour. But don’t worry, new findings show this infection will never result in hordes of mind-controlled humans.

Researchers discovered that the fungus produces a specific cocktail of chemicals tailored for the Camponotini ant group. When these ants are infected, they leave their foraging areas and descend to the canopy floor to reach the humid, warm conditions preferred by the fungus. The still-living ant anchors itself to the underside of a leaf with its mandibles until it finally dies, forming a prime launchpad from where the fungal spores can grow and spread.

While the zombie fungus is only able to kill other ant types, without controlling their behaviour, Camponotini ants and the fungus have co-evolved as both species developed. Unfortunately for these ants, the fungus has overcome every improvement in their defenses up to this point. Since the fungus has become so specialized, it poses little risk of spreading to humans or any other animal species.

Read more about the effects of insecticides on pollinators and how the zombie ant fungus infects hosts. You can also meet some interesting insects by visiting the bees, stick bugs and other critters in our Search: Sara Stern Gallery.