Sunday, October 23, 2016

Garden Pest Control, Goldenrod Style

Frustratingly, we are often gone during the time when the goldenrods are in full bloom.  I say "frustratingly" because I am fascinated by pollinators and by the interaction between plants and the insects that use them...and goldenrods are among the most highly utilized flowers in my gardens.  Only asters seem to attract more insects.

We only have 2 species of goldenrod in our yard so far.  One species, wreath goldenrod (Solidago caesia), I planted.  The second species, whose identity is more problematic, came in on its own.  When I looked at the USDA Plant Profiles site, there are 12 goldenrods said to be native to Okaloosa County, Florida.  I can eliminate two of those species based on growth habit, but I am still left with at least 10 possible species that might be "my" goldenrod.  That said, I'm not sure how important it is to know the exact identity as, to my knowledge, all goldenrods are spectacular pollinator plants.

Like most years, we were gone for 10 days during peak goldenrod bloom time this year, but I was able to get a few photos the day we left and, again, a day or two after we got back.  I don't have all the insects identified, but I thought I'd share some of the photos with you anyway.

As I listed the species I'd photographed nectaring on or otherwise using our goldenrods, I realized that goldenrods are marvelous predator attractants.  There were at least 6 different wasp species nectaring, most of whom feed their young on moth or other caterpillars.  (Note:  I am paranoid about wasps, but have never been bothered by a wasp feeding on a flower.  Generally only social wasps and bees are aggressive, and then only in defending their nests.)  There were other insect predators, too.

There were at least 4 different mason or potter wasps, all of whom feed their young on caterpillars:

Among these cute little solitary wasps, some (the mason wasps) utilize existing small holes to pack with paralyzed caterpillars and lay an egg upon, before closing up the opening with mud.  The holes in our bricks around the windows, where a prior owner had to board up the windows in preparation for a hurricane, are popular nesting spots for mason wasps.  Others of these wasps build free standing pots of mud which are filled with paralyzed caterpillars before an egg is laid and the pot is sealed.  Those are, not surprisingly, known as potter wasps.

Shown below, northern paper wasps can be very colorful.  This IS a social species and they build a classic "wasp nest" made of regurgitated wood fibers (paper).  Typical of social wasp species, paper wasps do defend their nest - but the individual wasps pay no attention to people when they are away from the nest, feeding on nectar.  Like the species above, this species hunts caterpillars but they hunt other insects, too, to feed their larvae.  They chew up their prey and feed their young on the protein rich regurgitated mix that results.

Thread-waisted wasps are odd looking creatures, but again they are great predators.  While the adult feeds on nectar at flowers, they feed their young on moth caterpillars.  Good protein for growing bodies!

Breaking the long line of caterpillar predators, there were also five-banded tiphiid wasps.  Tiphiid wasps lay each egg on a white grub in the soil (yes, THOSE white grubs).  When the egg hatches, the wasp larva burrows into the grub and slowly eats it from the inside, saving the most important organs for last, so that the grub remains alive and "fresh" until the bitter end.

Two other predatory insects that I found and photographed on the goldenrod were a pair of ladybugs (whose photo was so bad that I'm going to save my photographic reputation and not share it) and a milkweed assassin bug. 

Assassin bugs are indiscriminate predators and feed on many different kinds of insects.  I have to wonder how this brightly colored insect can get close enough to any other insect to capture it and eat it, but obviously they do.

There were common green bottle flies nectaring on the goldenrod, too.  These are one of the insect species whose larvae feed on carrion - and those larvae are also used by forensic scientists to date the age of corpses.  Obviously, the adults feed on flower nectar.

When you think of pollinators, you think of bees, right?  So far I haven't actually shared photos of any bees that were visiting the goldenrod, but there were, indeed, several different species of native bees that I saw.

In fact, bees were the most obvious insects feeding on the goldenrod blooms - at least in part because some of them were the biggest insects.  What is the first thing you notice in the photo above?  The two big eastern carpenter bees, of course.

Zooming in a little bit closer, you can see the righthand one in decent focus.  The left one, the one that is flying, is unfortunately out of focus, but I think you can still see the "bare" abdomen that is indicative of carpenter bees.  That big shiny black abdomen is the quickest and easiest way to separate carpenter bees from similarly sized and shaped bumblebees, whose abdomens are covered with hair.

There was one big black bee that also had a shiny abdomen.  I'd never seen one quite like it before, so I submitted the photos to BugGuide, where I was told it was also a carpenter bee....

.... a female southern carpenter bee (Xylocopa micans).  The males of this species have yellow or orangish hair on their thorax, similar to the eastern carpenter bee above, but they often seem to have green eyes... or at least that's what it seems like, looking at the images on BugGuide.

There was a male green metallic bee (Agapostemon splendens), a species I've seen on other flowers in the yard before.

There were also a couple of bees that I haven't identified yet.

I may need to ask for help from BugGuide to identify these, too.

If we'd been home during the peak goldenrod bloom time, I'm sure that I'd have more insect photos to share with you.  There were, for example, several butterflies that I'd see nectaring on the goldenrod, but they were always gone by the time I got outside with my camera.

All in all, though, I'm pretty happy with the 15 different species I observed using the goldenrods in our yard.  These pollinators will also be pollinating other flowers in the area...and over half of these species will also be controlling leaf-eating insect species in the yard as they raise their families.  That's pest control I LOVE to see happening!


Corner Gardener Sue said...

It's fun to see kinds of insects we have in common, and which may be a bit different. I am not great at identification, though, so am not always aware of which we both have. I have seen the ones with the black abdomens here before.

For some reason, goldenrod does not seem like a plant that would be native to Florida to me, maybe because it is not "tropical" looking. Not all of your native plants are, though, I'm figuring out from your other posts.

I am sad that most of the plants here in SE Nebraska are pretty much finished blooming. In some ways, I am ready for winter to just get here, so spring can be back soon.

Gaia Gardener: said...

Hi, Sue,

Actually, we are not tropical here; maybe considered sub-tropical? Our date of first average freeze is Nov. 15 and our date of last average freeze is March 15. On the other hand, it's rare for a freeze to last more than a couple hours....

Here along the northern edge of the Gulf Coast, we only have a couple "palm" species, but lots and lots of evergreen plants. That's the biggest difference, aside from the number of trees, of course. Ironically, many of the prairie grasses are native down here, although they aren't found in the large numbers here that they are in the middle of the country.

We are just really beginning our gardening season here. It's been too blasted hot and humid to get out and do much for the last 6 months or so. Most of the native plants will be going dormant in some form or another, but they can still be planted or transplanted now, which allows their roots to get well established before next summer's heat begins.

Enjoy the quiet time of winter - it's a good time to relax a bit and concentrate on some non-gardening activities! As you dream about next summer's garden, of course.

Gardener on Sherlock Street said...

I'm looking at some more golden rod for my garden. It really does attract all types of pollinators. Your photos are just as great as ever. Thank you for sharing them.

Gaia Gardener: said...

Thanks so much, GonSS! I would highly recommend goldenrod, but do be careful which variety you get. Canada goldenrod is too aggressive for most yards, for example. Alternatively, just be ready to pull out sections when it gets too enthusiastic.

The wreath goldenrod (Solidago caesia) has been a perfect angel so far. I had elm-leafed goldenrod (S. ulmifolia) in Kansas, which I loved. One year it seeded heavily when we had an abnormally wet August; otherwise it never moved around at all. Both of those 2 species like shadier spots. Stiff or rigid goldenrod doesn't run, and neither did Wichita Mountains goldenrod - both of which like the sun and did well in my Kansas garden.

Corner Gardener Sue said...

I wonder what all ideas I have about Florida are off base. I didn't realize you had freezes there, since it is so far south. I think I'd enjoy it there. I hope by the time spring gets here, our house will have much less clutter.

Gaia Gardener: said...

Good luck with the decluttering, Sue. That's been on my "to-do" list for years now and I've made some progress, but not as much as I'd like to make.

As with all places, Florida has its good points and its bad points. Winter is pretty nice, actually. Summer gets a bit long.....