Friday 5: Keeping Water Bugs in the Lab

I work with giant water bug eggs and need to know the exact date they were laid, so I need to keep bugs in the lab.  This means I need to keep my bugs alive!  Giant water bugs can live well over a year, so you need to have space and time to care for them if you’re going to bother.  That said, giant water bugs are incredibly easy to care for!  Here’s what I do for the back brooders that I use for my research.

Step 1.  Collect bugs in the field.

Me collecting in Florida Canyon

Me collecting in Florida Canyon

I have several places I like to collect giant water bugs.  One sire is part of the University of Arizona, the field research station for the Santa Rita Experimental Range at Florida Canyon.  (That’s pronounced flor-EEEEE-dah, by the way.)  There’s a great little pool, pictured above, located just downstream of the parking area.  All I have to do is take my trusty soup strainer down and scoop bugs out.  Transporting bugs back to the lab is the most tricky part of caring for them in the lab.  They’re aquatic insects, but they rely on surface air and they drown more easily than you’d expect.  You have to be very careful about how much water they’re sloshing around in.  Water bugs are also rather cannibalistic, so it’s best to keep them separated.  I usually place 2-3 bugs in a plastic bag with some wet vegetation gathered from the stream, then fill the bag with air before I seal it.  Then I pack a whole bunch of bags into a cooler.  Seems to work pretty well as I rarely end up with dead bugs, even if I have to leave them in the bags for a day or two.

Step 2.  Introduce bugs to their new home.

Keeping the bugs separate is important, so I use a system my advisor developed:

water bug housing

Water bug condo!

Plastic Rubbermaind boxes make great containers for back brooders!  Inside the box pictured here are a couple of little plastic blocks (not visible) that hold a sheet of plastic pegboard off the bottom of the box.  Bugs are placed in individual plastic drinking cups.  There’s a 1/2 inch hole in the bottom of each cup and each contains a small rock or cement block to give the bugs something to hold onto.  I fill the box so that the water in the cups is about an inch deep.  I can keep 15 bugs in each box without having to worry about them eating each other, so I can keep quite a few bugs in minimal space.  It’s a great system.  Wish I could take credit for it, but it was in place before I arrived and it’s all my advisor’s doing.

Step 3.  Feed bugs.

Belostoma micantulum

Belostoma micantulum eating a mealworm.

Feeding the bugs is important.  They need to eat to live of course, but if they don’t get enough to eat, they don’t produce eggs and I can’t do my work.  Giant water bugs are also predators, so you’ve got to feed them animals.  So, I feed my bugs mealworms once a week.  Mealworms don’t move around much so the water bugs sometimes have a hard time recognizing them as food.  Using a pair of forceps, I dangle a mealworm in front of a water bug and shake it around a bit.  Usually the bugs will grab it right away and slowly eat it over several hours.

Step 4.  Change the water.

Changing the water eliminates any wastes the bugs produce.  Using the pegboard setup makes cleaning the containers is a breeze!  I just take the lid off, pull the sheet of pegboard out with all the cups sitting on top, and set it on the lid.  All the water drains out of the cups as you lift the pegboard.  Then I simply dump the water in the sink, refill with water that’s been sitting out for a few days to remove the chlorine, and put all the stuff/bugs back in!  You can easily clean 15 bugs in less than a minute.

Step 5.  Mate the bugs to get eggs!

giant water bugs mating

Giant water bugs mating (Abedus herberti)

Mating back brooders is incredibly simple.  I’ve talked about how they mate in a previous post, but I didn’t discuss how I set up their mating chambers.  It’s so easy!  All you need are a few plastic bowls with lids (drill some holes in the lids so the bugs can breathe!), one medium sized rock to go in each bowl, and enough dechlorinated water to fill the bowls about 2 inches.  Then you just place two well-fed bugs (a male and a female that have not been mated for at least three weeks) into the container, snap the lid on, and leave them overnight!  Most of the time you’ll come back the next morning to freshly laid eggs.  Sometimes you don’t and have to futz about a bit to get them to lay, especially during the winter, but most of the time you just get a male and a female together and let them go at it.

And that’s it!  Caring for water bugs.  Easy as pie.  Well, easier actually.  Pie can be rather tricky to make.

Posting might be a little light next week!  Got things to do and people to see that might interfere with blogging, but I’ll be back to my regular schedule soon.  Have a great weekend everyone!


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