Friday 5: Starting an Insect Garden

I adore gardens and plants!  That doesn’t mean that I’m a competent gardener because that’s not the case at all.  Still, every now and again I will very successfully grow something, just enough that I’m not completely discouraged and really enjoy mucking about in the dirt planting and harvesting.  I’ve been especially taken by the native plant garden at work.  It’s a demonstration garden and I want to implement several new ideas I’ve learned from my coworkers and the garden they’ve built in my yard.  I finally have a yard that’s big enough to plant both a good-sized vegetable garden (this always comes before flowers for me!) and several ornamental flowering plants and I’ve been happily plotting and planning so I’m ready to go in the spring.  I’ve got my native plants picked out already, based mostly on their height and their (wait for it…) attractiveness to insects.  I want to have the same pretty bees, butterflies, flies, and beetles visiting my yard that I see at work!  Here are the plants I’ve chosen to start with.

Tickseed, Coreopsis major

tickseed lowers with butterfly

Tickseed, Coreopsis major, with sleepy orange butterfly nectaring

This is a very common native plant at work as it’s found out in the prairie and it is planted in both the roof garden and the native plant demonstration garden.  It’s a beautiful yellow color and doesn’t get very tall.  Plus, butterflies and other nectar feeders, like the sleepy orange butterfly you see in the image, love it!  I got some of these from work when our garden volunteers thinned the plants for the fall, so they’re already in the ground next to my house.  They’ll bloom in May or so and remain in flower for a few months if all goes well.  Exciting!

Cardinal Flower, Lobelia cardinalis

cardinal flower

Cardinal Flower, Lobelia cardinalis

I got some of these plants from work too and I love them!  Mine were recently planted, so I won’t get flowers until late next summer, but the plants are a gorgeous, vibrant green that are quite pretty even without flowers.  These are, as you might imagine from the color and shape, hummingbird flowers and I’m excited by the possibility of their bringing ruby-throated hummingbirds into my yard.  They’re also attractive to several bee species.  They require moist soils, but I happen to have the perfect place right in my backyard!  The drain from my air conditioner releases a small stream of water into a low point in my yard, so I planted my cardinal flowers there.  I suspect they’ll have a fighting chance of surviving as I won’t have to remember to water them and my new flowers will be a nice little side effect of cooling my house in the summer.

Buttonbush, Cephalanthus occidentalis

buttonbush flower with butterfly

Buttonbush, Cephalanthus occidentalis, with a zabulon skipper

I was shocked to see how many different species came to the flowers of this shrub last summer!  Butterflies, bees, flies, beetles…  Seems that if there was a pollinator out and about, it would eventually find its way to the buttonbush.  It’s a beautiful tall plant with fantastic flowers, so I’m hoping I can find a good place in my yard to grow one.  It does well in moist soils, so I might plant one near my cardinal flowers.

Frost Aster, Symphyotrichum pilosum

Frost aster

Frost aster, Symphyotrichum pilosum

Frost asters are often considered weeds and they can become weedy.  However, if you don’t let them spread all over everywhere they are lovely fall-blooming plants!  Plus, fall insects LOVE these.  Frost asters are all over the prairie at work and when they bloomed there were so many they looked like snow!  I saw dozens of different pollinator species lurking among the flowers and you could hear hundreds and hundreds of bees and flies happily buzzing away out there.  The migrating monarchs loved them too!  I don’t see any real downside to planting some of these in my yard, so long as I keep and eye on them and start pulling up the recruits.  They’re nice little bushy plants, the flowers are adorable, and I can get them from work for free.  What’s not to love?

Common Milkweed, Asclepias syriaca

common milkweed with bumblebee

Common Milkweed, Asclepias syriaca, with an unidentified bumblebee

This is far and away the least handsome of the plants I’ve chosen, but after spending a summer looking for monarch larvae for the Monarch Larva Monitoring Project, I’m very excited about the idea of having some of these in my yard.  I’ve already collected seeds, so I just need to choose a place in my backyard to grow them in the spring.  These will go in the backyard for sure, so the neighbors can’t see them.  The plants are nice enough while they’re green and lush and the flowers are rather pretty, but then all the leaves fall off and leave the ugly pods out in the open.  Then the pod and the stem both turn brown and crispy and stay that way for a very long time.  They really are ugly plants and I can only imagine the nasty notes we’d get from our homeowners association if I planted these in front of the house.  But, there’s nothing stopping me from planting some in the backyard!   Calling all monarchs: I’ll have dinner waiting for you in a few months!

There are a few other plants I’m considering as well, including aromatic aster (gorgeous purple flowers in the fall) and purple coneflower, that are insect magnets in North Carolina.  I think there just might be enough water to grow some pitcher plants in that wet area of the yard too!  It’s really exciting to think of all the possibilities and learn about all these unfamiliar plants, so I hope I can get a great garden going come spring.  If I do, expect a lot of photos of my bugs!

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Unless otherwise stated, all text, images, and video are copyright © C. L. Goforth

Friday 5: Verdant Eaters of Insects

Green Swamp

Longleaf pine forest in the Green Swamp

Earlier this week, I got to go on a trip to some of North Carolina’s awesome wild areas with a bunch of other people from the museum where I work.  We ended the day at Lake Waccamaw, a fascinating bay lake in the southeastern part of the state.  The water was bizarrely warm but oh so clear, so I enjoyed my swim in it quite a bit.  The highlight of the trip for me, though, was getting to see the carnivorous plants in the Green Swamp.  One of my favorite memories as a kid was the venus fly trap my mom bought my sister and me, how we fed it flies and were fascinated by how it consumed its prey.  I never knew then that they were native to North Carolina, nor that North Carolina is one of the best places in the world to see carnivorous plants.  Now I’ve had a chance to see the carnivorous plants I grew up reading about in the wild!  Today I’m going to share the five carnivorous plant species I saw at the Green Swamp because who doesn’t love a good carnivorous plant?

Venus Fly Trap

Venus fly trap

Venus fly trap

There is something so alien about this plant!  It certainly looks strange with all the spiky bits coming off the leaves, but this plant is quite mysterious too.  It sort of remembers things, and no one really knows why.  The exact mechanism behind the trap that snaps shut on helpless prey remains uncertain.  This plant knows the difference between a living organism and a non-living organism too.  It’s just weird and oddly sentient for a plant.  But how beautiful!  And it was absolutely amazing to see them scattered all across the ground underfoot.  I was so happy I nearly cried.

Yellow Pitcher Plant

Yellow pitcher plant

Yellow pitcher plant

Pitcher plants are super cool plants too!  This plant doesn’t snap shut on its prey like the venus fly traps do, but they have an effective alternative system: downward pointed hairs guide the insect victims into the digestive soup at the bottom of the trumpet-shaped leaves where they are slowly digested.  If you pull an old, dead leaf off a plant and cut it open, you can sometimes see the exoskeletons of consumed bugs!  Another beautiful plant, and, as an added bonus, many of these had green lynx spiders sitting on the “lid” of the plant too.

Purple Pitcher Plant

Purple pitcher plant

Purple pitcher plant

Purple pitcher plants are closely related to the yellow pitcher plants and were found within a few feet of their yellow brethren in the Green Swamp.  These plants are very different though!  Unlike the yellows that use digestive juices to digest their prey, the purple pitcher plants depend on a variety of invertebrates, including a mosquito and a midge larvae, to break down the insects that fall into the puddle of rainwater that accumulates at the bases of the leaves for them.  How awesome is that?!

Bladderwort

Bladderwort

Bladderwort

Bladderworts are fantastic aquatic plants!  They store little bubbles of air in special chambers armed with triggers.  When a small insect, other invertebrate, or even a small fish swims by and bumps the trigger, the door to the chamber snaps open and water floods in, dragging the prey animal inside.  Then the plant secretes digestive chemicals and consumes the prey.  It’s hard to imagine that such an adorable little flower is attached to such a violent plant!

Sundew

Sundew

Sundew

Until about 6 months ago, I had never even heard of a sundew.  Then I saw a picture of one on a blog somewhere and fell instantly in love.  I knew I HAD to see one!  And I did!  These tiny plants are capable of catching things much larger than they are, including strong flying insects such as damselflies.  They lure prey in with tasty globs of sweet mucus that line their leaves, but the globs are very sticky and trap insects that come too close.  Once the insect dies, usually from exhaustion or asphyxiation, the plant secretes digestive chemicals and absorb the nutrients through the leaves.  They’re adorable, yet surprisingly deadly.

Aren’t carnivorous plants fun?  I just love them!  And now that I know I can go see them any time I want without even leaving my state, I suspect I’ll find my way back to the swamp many times to see them again and again.  Nothing beats going out into the wild and seeing these things growing out there!  I was battling the last dregs of a cold and I found it very nearly unbearably warm the day we went, but I came away from the swamp happier than I’ve been for a long time.  Funny what nature can do for a person’s emotional state!

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Unless otherwise stated, all text, images, and video are copyright © C. L. Goforth

Insects and Plants Use the Same Strategy for Breathing Underwater

Exposing the air store

A giant water bug, Abedus heberti, breathing using a physical gill

You all know that I have a soft spot in my heart for all things related to aquatic  insect respiration.  I’ve written several blog posts about the topic in the past.  I was thus very excited to come across a new paper a month ago, a commentary on physical gills in aquatic invertebrates and plants by Ole Pedersen and Timothy Colmer.  It was the first time I’d ever considered the possibility that plants might have hit upon the same means of underwater respiration as insects.  Mind blown!  So, I’d like to share the paper with you all too, just in case any of you find it as fascinating as I do.  (One can dream, right?)

Freshwater insects, spiders, and plants all have one thing in common: they are adapted for life on land and depend on respiratory systems that were intended for use in air.  Oxygen is much less abundant in water than in air and moves very slowly through water, so any organism built for living on land that wants to move to an aquatic habitat has to adapt to the available oxygen of their new watery home.  Insects have evolved a variety of means of compensating for the relatively low oxygen levels in water, many of which I highlighted in another blog post.  These include snorkels (such as those on giant water bugs and water scorpions), scuba tank style air stores (also in the giant water bugs, among other true bugs and many aquatic beetles), physical gills (many true bugs and diving bell spiders), plastrons (in a very limited number of aquatic insects), and gills (damselflies, mayflies, hellgrammites, etc).  According to Pedersen and Colmer, nearly all of these animals must return to the surface at some time to refresh their air supply because the respiratory needs of the animal is greater than the ability of the respiratory surface to supply oxygen.

However, gas films such as physical gills and plastrons significantly increase the length of time an organism can remain submerged.  These air films are so important that Pedersen and Colmer suggest that many insects that live in riparian areas or around ponds have body surfaces capable of trapping air films too.  These may prevent drowning if a terrestrial riparian insect becomes submerged, either accidentally or by choice.  Air films are clearly important to a variety of aquatic and riparian insects and spiders.

cattails and algae

Cattails and algae help clean the water

But they’re also important to plants!  The authors discuss how many wetland plants have surfaces that repel water and create gas films around the surface of submerged leaves.  These gas films work the same way they do in insects – absorbing oxygen from the water and improving the respiration of the organism in water.  Plants don’t have the necessary structures to create permanent plastrons, but a plant that is submerged (during flooding, for example) can often survive two weeks or more completely submerged thanks to a little film of air that surrounds it.

The authors did a short study comparing the oxygen uptake by both an insect (a true bug in the genus Aphelocheirus, one of the plastron-bearing insects that only very rarely goes to the surface) and a plant (reed canary grass, Phalaris).  They found that gas films strongly improved the ability of both the insect and the plant to take up oxygen from the water and that the gas films worked in both high and low dissolved oxygen concentrations.  The authors also removed the gas films and discovered that the oxygen uptake strongly decreased.  In the end, they concluded that gas films increase the area through which organisms can absorb oxygen from the water, greatly enhancing their ability to survive underwater and the time they could remain submerged.

Sweetwater

Sweetwater Wetlands

The authors further suggest that gas films might aid in plant photosynthesis.  Plants require carbon dioxide to photosynthesize and normally it enters the plants through pores in the leaves called stomata.  In water, however, stomata are thought to close, so carbon dioxide must travel directly through the leaf’s surface, a long and slow process.  Plants with gas films have an advantage: they can both absorb carbon dioxide more readily through the gas film than without it and they likely keep their stomata open, allowing carbon dioxide to easily flow into the leaves and allow photosynthesis to take place.

shallow treatment

A giant water bug going to the surface to get more oxygen

Pedersen and Colmer concluded with a few comments about water quality and gas film respiration.  They posit that these sorts of systems only work in relatively clean water, that in polluted waters the oxygen levels are too low to support submerged plants and animals with simple gas films.  In dirty water, insects with snorkel or scuba tank like respiratory systems stand a better chance of getting the oxygen they need because they don’t depend on oxygen in the water and go to the surface for oxygen instead.

What I really like about this paper is the connection it draws between the plants and arthropods, how two very different groups of organisms have hit upon the same solution to functioning underwater.  Clearly this system wouldn’t work for all wetland organisms as animals with lungs don’t passively absorb oxygen the way plants and arthropods do, but gas films seem to work well for things that have more passive respiratory systems, regardless of the type of organism. I think that’s pretty darned cool!  Plants and arthropods are wildly different organisms and it’s simply amazing to consider that they’ve developed similar solutions to deal with living in and around water.  Yet one more example of how fantastic the natural world is!

Literature Cited:

Pedersen O, & Colmer TD (2012). Physical gills prevent drowning of many wetland insects, spiders and plants. The Journal of experimental biology, 215 (5), 705-9 PMID: 22323192

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Unless otherwise stated, all text, images, and video are copyright © C. L. Goforth