There are many
animals, insects, and mites that feed on plants. From learning about
herbivorous insects, I thought mites also feed by sticking their stylet, needle
like mouthparts, into the leaves and sucking up the nutrients. I was surprised
to find out from reading, Herbivore
Exploits Chink in Armor of Host, that some mites and insects actual feed
through the stomata opening on the leaves. It had never occurred to me that
this feeding behavior could happen.
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| http://www.sciencephoto.com/media/374168/view |
This unique feeding behavior had been observed in certain insects, but never mites. Research was being done on Raoiella indica, also known as the red palm mite to discover why the mite was able to produce such large and dense populations on a single palm plant. To find the answer to this question, researchers used low-temperature scanning electron microscopy to examine the mites feeding on their host. It was found that R.indica, at all active stages, were inserting their stylet between the guard cells of the stomata opening. The mites were able “to actively bypass the mechanical defenses by exploiting a series of structural weakness in the architecture of their host.”
The affect of the R.indica feeding from the stomata of the plant is still unknown. If the mites do cause damage to the guard cells during feeding it will affect the plant. Stomata regulate the exchange of gases and water in and out of the plant. Once the guard cells are damaged the plant is no longer able to control the opening and closing of the stomata. This results in a loss of regulation and also leaves the internal plant tissue open to attack from the outside world. Some examples of harmful sources that can enter the plant include pathogens and fungi. To understand how this feeding behavior is affecting the plant more research needs to be completed. The research could show the advantages and disadvantages to this type of feeding compared to other herbivore feeding behaviors.
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| http://www.reportapest.org/pestlist/raoind.htm |
Link to Article: http://www.ars.usda.gov/SP2UserFiles/person/333/Herbivore%20Exploits%20Chink%20in%20Armor%20of%20Host.pdf
Another article for more information on the mite:
http://www.bioone.org/doi/full/10.1653/024.092.0212
Is there more research being done on this now, or was this just a one-time finding?
ReplyDeleteNo, this wasn't just a one time finding. The red palm mite along with other members in the family Raoiella have been observed feeding in the same way. I just did a quick search to see if I could find any more articles. I did find an article about Raoiella and their host range. Within this article it stated that they feed on their hosts with the same feeding behavior that was mentioned above, but it doesn't go into detail about how the behavior affects the host plant. So I don't know if research is being done at this moment in time about the feeding behavior specifically .
ReplyDeleteWow that's really interesting, I've never heard of this before. Is the mite host specific or does if feed on other palms as well? I also wonder how this behaviour fits in evolutionarily. Is this a relatively new behaviour or is it one that was common in the past and has been lost by the majority of phytophagous insects.
ReplyDeleteThe mite actually feeds on several different palm species. It has been found on around 32 different species of palm and also on banana plants in the Caribbean. Your next question is very interesting, I don't know if this is a relatively new behavior within the mites. I want to say it would be though because it seems to be a more effective way of feeding. It allows the mite to bypass the plants defenses.
DeleteThat is really interesting. I too hadn't though about insects feeding that way but now that i think about it its surprising more dont. P.S. might want to put the scientific names in italics :p
ReplyDeleteThanks for the heads up!
DeleteHuh. This really is a "why didn't insects think of that before" type concept. If I was given a grant to do research topic, I would be interested in finding a way to measure the fore exerted by the closed guard cells on the stylet of the mite. Is it that easy to bypass? Thanks for blowing my mind!
ReplyDeleteI know it blew my mind as well. Regards to your question, from what i read it seems as if the mite feeds when they are open. I am unsure if the mite actual feeds at times the stomata is closed. If the mite did feed when it was closed that would bring up the question, like you said, how easy is it? Only more research will be able to determine the force that is exerted by the closed guard cell vs. the force of the mites stylet.
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