Wednesday, May 27, 2009

Dragonflies in a garden pond.


Picture of above dragonfly naiad from uky.edu/Ag/CritterFiles



While a garden pond at least 20 ft in diameter may be the best possible size to encourage dragonflies to breed in a garden habitat, I'm betting a smaller urban watering hole will work for at least a few visits.
Last year dragonflies were seen in our garden and we don't really have what could be called a pond. Just a tub sunken into the ground, partially filled with gravel to sculpt various depths,and refilled with the hose. A couple of larger rocks added for perching or climbing out the sides. More a bird bath than a pond really. Birds love to bath there and even the squirrels will drink from the edge. We keep two sides free of plant life in case a bat decides to swoop through for a sip.

Interesting creatures swim about in water after a few days. Beetle larvae that look ferocious,mosquito larvae that remind of tadpoles and dragonfly naiads are a part of pond life.

more pond bugs
Mosquitoes numbers seem about the same as usual at least until the city sprays, which will probably also take out the dragonfly larvae. But we will see.


NWF garden for wildlife dragonflies...


Read these excerpts ...
You don't necessarily need a large pond to attract dragonflies. "I've got friends whose 'pond' is a wooden half barrel," says Biggs, "and fork-tailed damselflies still come and breed in it. One of my grad students reared damselflies in plastic wading pools." Whatever the size, place your pond where it will be protected from wind and will get midday sun.
The ideal dragonfly pond should vary in depth, shallow at the edges and at least two feet deep in the center. "Deep water offers nymphs a refuge from raccoons and other predators," says Craig Tufts, chief naturalist for NWF, who helped oversee the construction of the pond that is the centerpiece of the natural garden in front of NWF's headquarters in Reston, Virginia. "Varied depths are also important to accommodate a variety of water plants." It's not that the nymphs or adults eat the plants. Dragonflies are voracious carnivores. Rather, underwater plants provide important habitat for the nymphs, which need places to rest, hunt for food and hide from predatory fish. And emergent vegetation-sedges, rushes and other plants that stick up above the water's surface-provides perching places for adults.
Such vegetation is also critical for dragonflies because the nymphs crawl up it when they emerge, making the transformation from water dweller to their free-flying adult form. And though dragonflies don't rely on specific host plants to nourish their young the way butterflies do, some species do use water plants as nurseries. They insert their eggs into the soft stems. What you plant around the pond is almost as important as what you plant in it. Don't mow the border-let the grasses and rushes grow. "Make sure you have some shrubs within a few feet of the water," says May. "That will provide more perching sites."


Although experts say that about 15 percent of North America's 307 dragonfly species are in danger of extinction, the dragonflies at greatest risk for extinction are the stream dwellers, species that won't be attracted to your backyard pond. "You can help protect their habitats by supporting laws and practices that reduce water pollution and protect riparian areas," says Tufts. "You'll be helping a lot of other creatures in the process."

news.bbc.co.uk earth news

Mosquito Control
Swallows, bats, and dragonflies are three animals that love to eat adult mosquitoes.
Putting up bat and bird houses can thus help keep mosquito numbers down.
Some insect larvae also eat mosquitoes including dragonflies, phantom gnats, and more. Promoting a wide array of insect life helps to prevent an outbreak of any one species.
Dragonfly larvae are big eaters of mosquito larvae. Adult dragonflies are also called mosquito hawks.
mosquitoes have some beneficial qualities mainly as food sources for fish and aquatic insects as larvae and for dragonflies, other insects, and bats as adults.


Each spring, the Chamber of Commerce in Wells, Maine, situated near thousands of acres of salt marshes, starts taking orders for dragonfly nymphs – or larvae – from town residents. The developing dragonflies cost about $30 per 50, and people order thousands of them.
The nymphs are released into local freshwater ponds. There, they feed on mosquito larvae, and after developing into adulthood, begin to hunt adult mosquitoes.
While there have been no studies proving the dragonflies are effective, locals swear they have seen major reductions in the mosquito populations, and other nearby towns have adopted the same method.

Sagebug how to dragonflies

Most dragonflies are particular about the ponds they’ll inhabit. They require shelter, sunlight, unpolluted water, emergent plants and hunting areas.


Many people report success in attracting dragonflies by adapting plastic wading pools and wooden half-barrels.

Whatever the size of your pond, be sure to locate it where it is protected from wind and will receive midday sun
Dragonflies are strict carnivores, so neither the nymphs or adults need water plants for food, but underwater plants are a critical requirement for dragonflies. Underwater plants provide dragonfly nymphs with places to rest, places to hunt for food, and places and hide from predatory fish. Water plants that stick up above the water’s surface provide excellent perching places for adults.
Excessive plant growth, especially of free-floating plants, may be a problem. Periodically skim off excess growth of floating plants. Monthly, prune dying plant material. Clean out some of the decaying plant material that has accumulated in the bottom of the pond in the spring. Remember that a natural pond is not a swimming pool and too much cleaning can do more harm than good.
If you want breeding populations of dragonflies in your pond, do not add fish. They will prey on the nymphs and eggs.

pondhawk ips odonata
The female inserts each egg individually into some suitable vegetation, from dead wood to reeds,
sometimes above the waterline, sometimes below.
In cases where the eggs are laid above the waterline, several situations may occur. Sometimes the eggs are laid over water, and the newly emerged larva drops in. Sometimes, the vegetation dies and falls into the water, or becomes submerged after the rains
If you are interested in allowing these creatures some space in your pond, observe where egg laying is occurring and make some allowance for this when you perform any maintenance.

After the egg has hatched, the larva (also called a nymph or naiad) is a cryptically colored, free living, aquatic predator.

Larvae prey mainly on other aquatic insects, such as mosquito larvae or even other odonate larvae. Larger larvae may prey on fish fry. In turn, dragonflies are preyed on by a number of species, including fish and frogs. They may serve as hosts for certain aquatic mites and avian parasites. Many species live among the aquatic vegetation.

As with all insects, the larvae undergo a series of molts as they grow and develop.
While some species have relatively short larval development times (1-2 months from the egg hatching to emergence), most spend at least a year and some much longer (5 years or more in places where the climate is arduous) as aquatic larvae. Most will spend at least one winter in your pond and have to suffer through any maintenance activities you perform. Some may not survive activities such as cleaning the "mulm" from your pond.



The globe skimmers, genus Pantala frequently lay eggs in very small ponds, even fountains.

15 Comments:

Blogger Barbara E said...

Gloria,
Thanks for all of the great info and the links. I do not have a water feature, other than a small terracotta plate that has water dripping into it and another small bird bath that I fill and clean regularly. Have wanted more - your info gives me much to think about.
Barbara

28/5/09 10:04 PM  
Blogger firefly said...

Me too. We have lots of dragonflies each year, but I'd like to see more of them and fewer mosquitoes. My next project is getting a pond-like thing (whiskey barrel? fountain pool? I don't know yet) into the yard.

(Just wanted to point out that Wells is in Maine with an "e". I went looking for the source site as I suspect the spelling error sprang from there, but couldn't find it.)

1/6/09 4:28 PM  
Blogger Gloria said...

Thanks Firefly, sometimes spellcheck doesn't catch errors like that and I didn't notice.

Barbara& firefly, A small pond isn't hard to maintain. I was looking at plants this weekend. A few tall rushes and a green and red veined broadleaf that I have lost the name of. A dwarf cat tail was very cute. Have to think about this a bit. Only a couple of plants will fit.

2/6/09 1:23 PM  
Blogger Cheryl said...

Fantastic post...so much information.

'until the city sprays'scared me a bit. We do not have that here. I find it worrying that it will take out so many other insects while getting rid of the mosi's.

I suppose we all think differently about things, and that is how it should be.

5/6/09 3:32 PM  
Blogger EAL said...

Great info! I hope to see some dragonflies around the pond this summer.

7/6/09 11:05 PM  
Blogger Marshlady said...

I love your blog! I'll be by often to gather more info for my backyard habitat. I wish we here in Florida would sell or give away dragonflies and damselflies for mosquito control. Unfortunately our city still sprays a few times a year. It really doesn't work, and it kills all the good pollinators!

Anyway, I don't mean to ramble on, just thank you!

22/6/09 5:18 PM  
Blogger garden girl said...

Very informative post! Thanks for the info Gloria!

26/6/09 3:15 PM  
Blogger s.meile said...

Check out our Pollinators at http://www.kiffen.ch/pollinator-c-177_237_239.html

5/7/09 5:21 AM  
Blogger Allvira said...

For controlling another types of insects, pests you may get it here from Crop protection techniques.
Thanks

6/7/09 6:01 AM  
Anonymous Anonymous said...

Hi, great blog. Although fairly small, my pond has an abundance of dragonfly larvae every year, and it is at about this time that i find their empty skins attached to the reeds in my pond. Earlier however I found floating in the water what i thought was an empty skin but what actually tuned out to be a dead larvae. It was fully intact and there were no signs it had been attacked. Do you have any idea why this larvae might have died?

Thanks!

13/7/09 2:30 PM  
Blogger Rosemarie said...

Wow, now that's something I've never seen before.

17/7/09 11:08 AM  
Blogger DaGenester said...

Thanks for this info. I was looking in my pond today, and I saw about 5 or so crazy lookin' things swiming around. Did a little research, found they were Dragonfly Larvae/Nymphs. I have a small pond, incorporated into a waterfall. I have not put plants in it yet, but there are a number of minnows and snails. I will be adding plants very soon - especially because of this article. Thanks very much.
PS - I am out in Tucson, AZ, where it is 105 outside right now. :) Yes, we even have Dragonflies here.

5/8/09 2:36 PM  
Blogger Scott said...

Haven't seen a post since May...hope you haven't left us forever.........

19/12/09 12:26 PM  
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14/1/10 2:02 AM  
Anonymous Anonymous said...

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17/1/10 11:04 PM  

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