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Monday, October 20, 2014

Blowflies are Pollinators Too

Mating Lucilia flies. © Beatriz Moisset

A bright metallic green insect lands on one of the flowers in your garden. It has large red eyes. Aside from the interesting colors, it looks like a plump house fly. You can't decide whether you like it or not. Its scientific name is Lucilia, its common one is greenbottle blowfly. It is unusual for a scientific name to be prettier than the common name. You dislike the common name even more when you find out its meaning. According to the Free Dictionary a blowfly is "any of several flies of the family Calliphoridae that deposit their eggs in carcasses or carrion or in open sores and wounds." Carrion? Open sores? Definitely not pretty.


Lucilia on common milkweed. © Beatriz Moisset

So, it is agreed, Lucilia is an ugly fly despite its startling colors. But, does it have some redeeming features? Fortunately, it does. Its habits are put to full advantage in forensics. By examining the Lucilia's maggots found in a corpse it is possible to determine the time of death. Another use is in medicine. This may cause you some revulsion, but it isn't as bad as it seems. Open wounds that don't heal and begin to accumulate dead tissue can be cleaned up by blowfly larvae. Let me clarify that only maggots raised in perfectly sterile conditions are used for this purpose. The larvae feed only on the dead cells and leave the healthy tissue untouched. This method is superior to that of the most expert scalpel held by a surgeon.


© Beatriz Moisset

But this is a blog about pollinators, so let us get into this subject. Blowflies, Lucilia in particular, are good pollinators of certain flowers. You see them frequently visiting a variety of blooms in your garden. They are more efficient than bees in pollinating onions and cabbages. I wonder why they show such preference for plants so notorious for their strong odor. Perhaps there is a connection between these plants' fragrance and that of smelly dead things fowever I haven't found any references so far. Most pollinators don't fair well in greenhouses. Lucilia, on the other hand, is easy to raise and to maintain in these conditions, so this is the preferred pollinator of the mentioned plants.

Two Lucilia flies pollinating Allium. © Beatriz Moisset

In summary, blowflies aren't that bad at all. In fact, they are so beneficial that we may begin to see their beauty. Let us welcome them in our gardens.
Lucilia on mountain mint. © Beatriz Moisset


List of articles
Beginners Guide to Pollinators and Other Flower Visitors

See:
Onion pollination by blowflies


© Beatriz Moisset. 2014

5 comments:

  1. I always enjoy your posts, Beatriz. Well done.

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  2. do you know which particular Lucilia sp. is used commercially to pollinate onions and cabbages? didn't know any diptera was used for commercial pollination at all (i think gall midges are inadvertently relied on for cocao pollination in chocolate production)

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  3. As far as I know, some Calliphora and Lucilia flies have been used for pollination, but I couldn't find a mention of a species. http://onlinelibrary.wiley.com/doi/10.1111/j.1744-7348.1983.tb02789.x/abstract.
    However some unverified source mentions Lucilia sericata.
    Sorry I can't be more helpful.
    The case of the cacao-pollinating midges is really interesting. The world would be poorer without those little creatures.

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  4. I have a huge colony of these blowflies on my milkweed patch, 2-3 flies on every single leaf. It doesn't look like they are good for the plant, and I don't understand why they are living on milkweed if they are flesh eaters. Should I be appreciating them? They seem to really keep the Monarchs from being able to approach the milkweed, and monarchs not blowflies were the goal. Help :/

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    Replies
    1. You may be confused. Blowflies don't have colonies. Perhaps you are seeing some other metallic green insect. As for eating flesh, it is the larvae that feed on flesh. The adults don't have the mouth pieces to do that. All they do is sip nectar. If you see them on the leaves, perhaps they are eating the sweet secretions of aphids. Do you have any aphids on your milkweeds? No, these flies can't do any damage to the plant.

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