Bugs and Microbugs: bacteria and insects
Written by Dr. T. M. Wassenaar Tuesday, 23 December 2008 16:37
Bugs that live in bugs--you may never have thought about it but bacteria live in insects too. In many cases the micro-organisms are absolutely required for the insects to survive, since they provide nutrients and vitamins. In return the insects provide a protected environment in the form of specialized cells in their body where the bacteria can safely live. Read about this interesting symbiosis between bacteria and insects This is nothing new. Insects trapped in amber some 30 million years ago already had bacteria in their intestines. What is shocking to many microbiologists is that these bacteria were still alive, as is claimed by the group who isolated them.
Just like any other organism, insects can suffer from bacterial diseases
Here is a weird example of pathogenic bacteria: certain species kill male insects only, but leave the females undisturbed. Such behaviour has serious consequences on the insect population. It is now being investigated to see if these bacteria can be used to combat pest insects.
Biological warfare against insects using bacteria is all science and no fiction. Such biological control is common practice, for instance using Bacillus thuringiensis. These bacteria produce a natural insecticide produced by bacteria that kills many types of crop pest insects, but is harmless to humans.
- Read more about Bacillus thuringiensis toxin (Bt). Not all agree to this method Greenpeace about Bt.
- Why not make the plants produce Bt themselves? Biotechnology made it possible, but Genetically Modified Crops have their own problems.
- Bacteria can also be used for control of mosquitos, for instance for control of malaria, or other mosquito-borne diseases.
- More about biopesticides.
Fortunately for the insects, they are not completely helpless against bacterial disease: insects have an immune system too.
One of the weirdest discoveries is that bacteria can speed up evolution of insects. The culprit is Wolbachia: a bacterium that lives inside insects and that changes their mating patterns or even their sexes!
Let's turn the fight around: insects killing bacteria. This may be of importance when dealing with bacteria that have become resistant against antibiotics. Not a nice idea, but already known in the Middle-Ages: maggots can heal wounds.
Animals, insects, even plants can suffer from bacterial diseases. And in the latter case, insects can transmit the bacteria. Just like ticks can infect humans with a bacterial infection (for instance Lyme's disease, caused by Borrelia burgdorferi) , insects can transfer bacterial diseases from one plant to another. This spread has been modelled, with some unexpecting findings.
Plants, insects (in fact all animals) and bacteria are all part of an ecosystem that can easily be disturbed. Man-made ecosystems require high crops of desired plants, and little growth of weeds. Insects that eat crops instead of weeds are unwanted, and we do our best to change the balance to our favor. It is now recognized that bacteria should not be ignored. Bacteria may be crucial in weed biocontrol by insects.
Next time you notice an insect maybe you'll think of its bacteria too.
Last Updated on Monday, 07 November 2011 22:01