Building a Garden Pond for Aquatic Insects, Part 2

pondChoosing a Pond Location and Installing the Container

As promised, today I’m going to talk about choosing a site and installing the water container for an aquatic insect garden pond.  I think this was the hardest part of the process for the pond I built because it involved the majority of the planning and manual labor.  Once you get through these parts and get the substrates in, you’re basically done!

My pond was installed at the Biopshere II, so the first step was getting the project itself and the location approved by a committee.  If you are a homeowner, you should check your city ordinances for any regulations and restrictions regarding water features in your yard.  For me, the requirements were that the pond had to be a) low maintenance, b) at least partially above ground to keep people from falling in, and c) covered with something that would prevent children from drowning if they fall in.  These restrictions actually made every step harder than it might have been otherwise, but you have to work within the guidelines you are given.  Many cities require fences around ponds larger than a certain size or other safety features.  Be sure you follow the guidelines for the area in which your pond will be installed, especially if it’s going to be a large pond!

The next step was designing the pond.  When designing my pond, I decided to keep it simple.  I wanted the pond to be fairly small so that it would be reasonable to install within the time I had available and wouldn’t require a huge amount of water to fill.  (I do live in a desert after all!)  I wanted about 2/3 of the area to be open so that people could look into the pond and try to find aquatic insects, but 1/3 needed to be plants to keep the water properly oxygenated, absorb nutrients produced by things that fall to the bottom of the pond, and provide habitat for insects.  I decided which structures I wanted to put into the pond to make it as attractive to as many different aquatic insects as possible (the subject of my next post).  I also decided to have the pond self-fill to keep the maintenance level down.  This is about as basic as a pond gets, which was perfect for my needs.  However, you can make ponds that are quite elaborate.  You can add waterfalls, streams, filters, and all kinds of other features to make your pond look nice.  Some pond enthusiasts build ponds for fish or specific types of aquatic plants (such as water lilies) or use their ponds to raise frogs.  I have a single purpose for my pond – attracting aquatic insects – so I designed the pond to be appropriate for my needs.  If you are more concerned about aesthetics, you should consider some of the more complicated designs so your pondwill look pretty AND attract bugs to your yard!

Next, I chose a spot for my pond.  After moving having my pond’s location moved a few times by the Biosphere staff, I was finally assigned a spot, this courtyard:

Orchard Courtyard at Biosphere II

Orchard courtyard at Biosphere II

This space is outside the western part of the orchard area of Biosphere 2, the orchard courtyard.  Within this space, I was allowed to choose my exact spot.  My colleague had chosen her spot first, so I chose the area across the courtyard.  When choosing my exact spot within this space, I considered the following things:

— How level the area was.
— How hard it would be to move the things in the location (rocks, dirt, plants, roots, etc) to install the container that would become the pond.
— How much sun the area would get.  This is important when you consider what kinds of plants to use in the pond and the kinds of insects you wish to attract.
— How many trees were likely to lose leaves that would fall into the pond.

Moving more things than you have to is never fun, so I chose a location that was mostly flat already and only needed to have one large rock removed to work.  The area would be in the full fun for several hours a day, but not the entire day, so I could use plants that required full sun or partial shade in the pond.  Leaves are the enemy of any low maintenance pond because they accumulate quickly and need to be removed periodically, so I was very thrilled to find a space that didn’t have any overhanging trees and was unlikely to get many leaves blowing into it.  I think my site is about perfect!  That’s it in the image below.

Site of pond

Site of pond, before installation

The next step for me was choosing the container for my pond.  There are several options to consider.  Perhaps the most aesthetically pleasing is an in-ground pond.  To make these, you dig a hole and line it with either a flexible pond liner (the cheaper option) or a pre-formed plastic shell (the easier option).  I had originally wanted to do this, but the above-ground requirement imposed by B2 made this impossible – you can’t hold water above ground level with an in-ground pond!  (Good thing it didn’t work out anyway because it was nearly impossible to dig in this area without heavy digging equipment like a backhoe.)  In the end, I chose to use a stock tank, the kind you find at feed stores to water livestock.  Stock tanks are nice because they’re lightweight, they’re reasonably priced, and they’re durable, so they’ll last a long time.  You can also buy above ground plastic containers, but they’re likely to be more expensive and can disintegrate faster, especially in very warm or very cold areas.  My pond was created from a 6 foot diameter, 2 foot deep aluminum tank:

Stock tank

Stock tank for use as the container for my pond

I moved the stock tank from the top of my car to the bed of a friend’s pick up truck and we drove it out to B2.  Once there, installing the stock tank was very easy.  The big rock was moved so the tank would exactly fit into the space.  Because we were putting in an above-ground pond, we simply moved some of the larger rocks, leveled out the site out with a pick axe and shovels , rolled the tank up the ramp to the courtyard, and plopped it into place.

The two of us didn’t have any trouble at all getting the tank into place (and my friend is a very tiny woman), so this is something that I think anyone could easily do in their yards.  If you’re digging a hole and using a liner, you might want a small crew of diggers to help you out – or rent a small bulldozer or tiller to get everything loosened up and pulled out more quickly.  I’m personally pleased with how easy it was to get the tank installed and I’m happy I wasn’t allowed to do an in-ground pond.  It would have been so much more work!  The tank perhaps doesn’t look as nice as an in-ground pond, but the aesthetic gains don’t seem worth the extra time and energy to me.  Besides, once my pond has some landscaping done and rocks are piled up around the outside of the tank, it’s going to blend in well and look great!

Next time I’m going to talk about selecting substrates – plants and other features – to attract a variety of aquatic insects.  Check back soon!


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Unless otherwise stated, all text, images, and video are copyright © 2010

Building a Garden Pond for Aquatic Insects, Part 1


My aquatic insect pond

As part of the fellowship I have from the Biosphere (the one that prompted me to start this blog), I designed a permanent educational display that will be available to visitors to the Biosphere.  Because I am an aquatic entomologist, I wanted to introduce people to aquatic insects, especially those that are found in the Sonoran Desert.  I think this is important because most of the people I’ve talked to in the area a) don’t think there’s any water in the state and b) certainly never considered the possibility that there might be insects in that non-existent water.  Yes, Tucson and the Biosphere are in a desert and yes, that means it’s dry, but there IS water – quite a lot of it in fact!  And that water, especially when clean and cool, is home to tons of insects.

I love to teach people about aquatic insects so that they are aware of the role these insects play in the aquatic habitats of my desert.  So, naturally, the subject of my educational display is aquatic insects.  Through experience, I’ve found that the best way to teach people about aquatic insects is to show them live insects.  Nothing draws attention to aquatics like a big dragonfly nymph squirting water out of its butt to move or a giant water bug devouring some helpless fish!  However, my display needed to be largely maintenance-free too and most aquatic insect displays are  anything but.  After brainstorming options for how I might balance maintenance requirements with a splashy educational experience, I decided to build a pond.  I used what I know about the habitat requirements of Sonoran Desert aquatic insects to design a pond that should attract a variety of aquatic insects so that they will find and colonize it themselves.  This way, Biosphere visitors will see live insects in a semi-natural habitat and the maintenance on the display should be minimal, fulfilling both of my goals for the project.

For the next few posts, I’m going to talk about my pond.  But first, a disclaimer!  I have never made a pond before.  I’ve read several books on the subject, so I had a good idea of what I was trying to do, but I’ve never actually made one.  Anyone who reads this series and wants to build their own insect pond (or simply a garden pond) should wait until I have a chance to make sure it’s being colonized by insects at the May Biosphere fellows meeting before following my example.  That said, I hope you find the idea intriguing and consider building your own pond for aquatic insects!

Next time I’ll cover choosing a site and container to hold the water, followed by a post on selecting substrates (the stuff on the bottom or sticking out of the pond that the insects use to hold onto or otherwise use to survive), including rocks and plants.  I’ll finish up the series by posting about the plumbing and electrical systems my pond required and suggest some ways to avoid turning a garden pond into a stagnant mosquito magnet.  Hope you enjoy the series!


Posts in this series:


Unless otherwise stated, all text, images, and video are copyright © 2010

Is that a giant mosquito??!!

It’s late spring in Tuscon and we’re about to transition into summer.  This means that a lot of insects have been making an appearance in the area recently.  In particular, we’ve been invaded by one type of insect that I get questions about all the time.  It’s one I can ID without even seeing it, based solely on the description of non-entomologists.  The question is always this:

“What is that big insect with the really long legs that looks like a giant mosquito?”

The follow up question is always this:

“Does it bite?”

In case an image isn’t jumping instantly to mind the way it does for me, this is the insect that people are asking about with this question:

crane fly top view

Crane fly, top view

crane fly side view

Crane fly, side view

This insect is a crane fly (Order: Diptera, Family: Tipulidae).  That means it is NOT a mosquito (Order: Diptera, Family: Culicidae)!  Crane flies are large, slender flies with long wings and very long legs.  In the Tucson area, they are often about 3/4 inches long and with legs over an inch long, but they can get even bigger in other locations in Arizona.  These are big flies!  They also have a V-shaped line on the thorax and large large compound eyes.

I’ll admit that they do look a lot like mosquitoes, but there are several key differences.  The size is a big consideration.  Crane flies are often really big flies while most mosquitoes are, at best, medium sized flies.  Even if you’re looking at one of the smaller crane flies, one that is in the mosquito size range, there are several key differences to look for.  The mouthparts are all wrong.  Look at this photo of the crane fly, zoomed in to focus on it’s mouthparts:

Crane fly mouthparts

Crane fly mouthparts

Notice how there’s no long, needle-like mouthpart?  Mosquitoes use their proboscis to pierce the skin of their victims to suck their blood.  Crane flies, on the other hand, eat nectar or don’t eat at all.  As a result, they have thicker, blunt mouthparts with all kinds of crazy looking doodads sticking off them or no mouthparts at all.  (In answer to question 2 above, no, they don’t bite!)  And if that isn’t enough to convince you they’re not mosquitoes, take a good look at the wings.  Crane flies have smooth, membranous wings with no scales while mosquitoes usually have scales along the wing veins.

Crane fly larvae have a special place in my heart because several species have aquatic larvae, though many species live in the soil.  They’re really pretty disgusting looking, but that just makes me more fascinated with them.  Take a look at the larva in the image below and see if you can figure out why they’ve earned the common name leatherback.

Crane fly larva

Crane fly larva

Crane fly larvae have distinct heads that are often nestled down into the thorax and are hard to see (case in point: the head is on the left side of this larva).  The back ends are particularly interesting.  They have a ring of fleshy projections, often looking like tentacles, that surround the pores they use to breathe, their spiracles.  These tentacles make these really huge, fleshy larvae look extra awesome!  Unfortunately, I have never figured out what the insects use those lobes for beyond their usefulness in species identification.

I wanted to finish by mentioning one other structure that is very visible on crane flies.  Like all flies, crane flies have only 2 wings.  But did you notice those little knobby things where the hind wings would be?  If not, take a look at a zoomed-in image of them here:

Crane fly halteres

Crane fly halteres. Notice also the v shape on the thorax!

Those structures are called halteres.  Halteres are the remnants of the hind pair of wings and have been modified into new structures.  They are thought to be very important during flight, acting like a gyroscope to tell the fly how it is oriented in the air.  Crane fly halteres are very large and often highly visible due to the way the flies hold their wings out at rest – they’re an excellent fly to  illustrate these structures.  The next time you see a fly, take a close look and see if you can find the halteres!  They may be very small, but almost all flies have them.  Those tiny little wing nubs are likely why flies are such amazing fliers and responsible for their mid-air acrobatics, so they’re very important structures.

Next up is a series of posts on building a pond to attract aquatic insects, so check back in to learn all about my experiences building my pond.  Perhaps you’ll even be inspired to build your own!


Unless otherwise stated, all text, images, and video are copyright © 2010

Earth Day at the Biosphere!

The Biopshere II

Biosphere II. The habitat is the white section in the middle while the big pyramid to the left is the rainforest.

I’ve recently been hard at work preparing an educational display at the Biosphere II as part of my B2 Science and Society fellowship.  A lot of my free time has gone toward that and I unfortunately haven’t had much time to blog.  My next few posts will be about the project I’ve been working on, but until then I wanted to plug the event at which it will makes its debut: The Biosphere II Earth Day 2010!  The event takes place this Saturday, April 17th at the Biosphere II north of Tucson.

If you happen to be in the Tucson area, this is going to be a great event that I encourage you to attend.  The event planners promise heaps of educational displays, live music, sky gazing, green jobs panel discussions, and special tours all day.  They’re letting kids 12 and under in free, so bring the whole family and save!  The B2 Earth Day is a great way to celebrate a greener lifestyle and planet while having fun at a unique research facility.

The Biosphere Science and Society fellows will all be debuting their new permanent educational displays at this event.  My display is an aquatic insect pond.  I will augment my new pond with a display of live insects and information on the kinds of features you can include in your own pond to attract aquatic insects to your yard.  Come find me in the courtyard outside the orchard area of the Biosphere from 10AM-4PM and learn about the fascinating world of aquatic insects!  And while you’re there, check out my colleague Alandra Kahl’s rainwater harvesting wetland across the courtyard.

For more information about the Earth Day event, please see the Biosphere II website’s Earth Day 2010 page.  There you can download the flier for the event and watch a brief video.  The Biosphere website also contains directions and maps and has information about ticket prices and tours.  Hope to see you there!


Unless otherwise stated, all text, images, and video are copyright © 2010