Friday, May 30, 2014

The Butterflies and the Bees

Honeybees- there are plenty of these girls in my urban prairie
I've been struck by the depauperate native bee community in my vacant lot prairie, especially when compared with the countless butterflies I encounter on my walks.  At first I thought I simply got up too early for them. Native bees tend to fly mid-day, and I do most of my walking around dawn. However, after scoping out the lot at various points in the day, my species list of native bees did not greatly improve. I became concerned-- what do the bees know? Did someone salt the earth of this vacant lot? Is it a superfund site?

...Probably not. While it seems strange that there would be such a mismatch in bee and butterfly richness, in reality bees and butterflies have very different needs. It's true that both are invertebrate pollinators that feed on nectar. However, butterflies don't build nests, and bees don't have free-ranging larval stages dependant upon a few host plants.  I can't help but wonder if butterflies, being less limited by parental responsibilities in their travel (heck- think of the monarch migration!), range further and exploit more isolated stands.

That said, I have seen a ton of honeybees foraging in the dense blooms of the vacant-lot prairie.  There must be a hive nearby. Beekeeping is illegal inside Fort Worth city limits, so we either have a renegade beekeeper or a feral hive.  I'm hoping there's an outlaw apiarist in the community. I like the sound of it, and any feral honeybees around here are likely to be africanized.

The two species of native bee I've seen are one male Svastra spp. and one carpenter bee (Xylocopa virginiana). I wish I had pictures of the diverse butterflies to include in this post, but they are simply too quick for my camera (especially when they are fleeing my snap-happy puppy dog's pointy teeth). I did, however, manage to collect a specimen of the Svastra.

Svastra petulca (?) male, collected on Gaillardia pulchella
Clasping-leaf coneflower, Dracopis amplexicaulis
I have documented 25 species of blooming native wildflower in the vacant lot so far, plus 2 more in the surrounding neighborhood. See more pictures of this week's 3 additions to the vacant-lot wildflower list after the jump. 

Monday, May 26, 2014

A close call

            Sometimes we have close calls that we don't realize until much later. That's the wonderful thing about getting away scot-free-- there's no calamity requiring your attention. I had such an incident about three weeks ago.

Anything about this plant raising red flags ?
            As I mentioned in my first post, I am a recent transplant to Texas.  Texas is totally different from everywhere I've lived before.  The shallow soils over limestone, the southern plains flowers- even known plants can look different down here. Being of a naturalist bent, every new plant (more so every new wildflower) demands an immediate investigation.  It's my way of making myself at home in this new place. Earlier this May I was out walking the dog in the Fort Worth Nature Preserve, and I spotted a patch of prickly white flowers in an opening in the woods. I juggled the leash and my camera so I could document this unknown plant.

Niiice and close. Yep.
            I got close to zoom in on the succulent-looking flowers. I even sniffed them to see if they had a distinctive aroma. Somehow, in this examination I must have managed not to brush the leaves. The reason I say this is because the plants in question were Texas bull nettles- Cnidoscolus texanus.
            I had forgotten about this plant until yesterday, when I was touring another prairie and the land manager asked me if I knew what bull nettles were. I said I knew about nettles back east, and she pointed out some bull nettles and set me straight. Bull nettles sting much worse than Urtica dioica. Bull nettle, one of a few plants with the charming spanish common name of "mala mujer", can cause serious reactions in allergic individuals.  The prairie manager told me that the stings can burn like a hot iron for an hour. Other references referred to the pain as "fierce", "severe", and "not likely to be forgotten".
            Apparently some individuals of above average fortitude have managed to eat this plant. The seeds are edible, according to some sources, as are the roots. Supposedly they taste like potatoes. Part of me is amazed at my luck at avoiding an "unforgettable" encounter with this plant, the other part of me is embarrassed that I didn't think to crush and sniff the leaves- inexcusable for a botanist. I imagine I would've known without a doubt the plant's distinctive feature if I had done so. What price, knowledge.

Thursday, May 22, 2014

Sample Size is Important

What is this flower?
            I spent well over two hours last night trying to get an ID on a new flower blooming in the vacant-lot prairie. It wasn't in my wildflower books, at least not that I could recognize, and I was really thrown by it's combination of features. It had a disc like a sunflower, but what should have been simple rays were notched twice. It looked like a cross between a sunflower and a gaillardia.
            I was stumped- sunflower's disc, gaillardia's rays. Blue-grey-green foliage with scattered spiney serrations along the leaf edges. What to do? Well, I sent up a distress flare to my botanically inclined contacts. What's weedy, has notched rays, a sunflower-like disc, and grows in Texas? I needed to know.  After consulting with my naturalist friends, we decided it was a weird-looking Texas blue weed (Helianthus ciliaris). Generally, when you can't quite convince yourself an ID is right, that's because it isn't.
A more typical Helianthus ciliaris, taken with my iPhone.
            Not in this case, however.  I visited the plant again the next morning (such was my desire to GET IT IDENTIFIED), and another bud had opened. No notches in the rays. Now I could rest easy, having found a second, fairly typical, specimen of blueweed. Individual idiosyncrasy is the risk you run when you only have a few specimens from which to make a judgment. I actually liked the extra decorative flourish from my unusual variant's notched petals, but they sure did throw me. When I dug a little deeper to find out more about this new plant, a descriptor that stuck out to me was "highly variable".  That phrase tipped me over into certainty of my ID.
            Despite its weediness, blueweed is actually native to the southwest.  In Texas, blueweed is more typical of the panhandle and trans-pecos region than it is of the metroplex. Livestock don't eat it, it reproduces by rhizome, and it prefers poor soils and disturbed areas. Another term associated with this new flower: noxious weed.  
            Blueweed is classified as a "noxious weed" in the states of Washington and Oregon. This plant can be aggressive. It's highly drought tolerant, and, like cattails and phragmites, it grows from rhizomes. This means that mechanical chopping of the roots can multiply your problem. Like a starfish, each fragment regenerates into a new plant. Biological control isn't an option either- blueweed is highly resistant to natural pests. Sunflower beetles leave them alone.
            It is intriguing to see this sunflower functioning as a small part of my urban prairie, while in other places it can be a real problem. Washington state's King County noxious weed page suggested that perhaps it is our native grasses down here that help reign in this weed. Competition from our diverse grassland may keep blueweed from becoming an aggressive pest in its home turf, but there is no such checking force in the Pacific Northwest. I suppose this plant could serve as a reminder: what seems innocuous at home isn't always universally so. We should be careful with what we plant.

In other news, I added three new species to my vacant-lot prairie plant list. These include the aforementioned Helianthus ciliaris, and also Cooperia drummondii, and Asclepias viridis.

Another picture of ratany- to me it looks like an orchid when the flowers are open
I've included more pictures and the updated plant list after the jump. 

Saturday, May 17, 2014

Census of the Weeds

prairie coneflower, Ratibida columnifera 
Without quite realizing it, I've been noting every species of native wildflower I encounter when I wander the vacant lot across the street from my house. I think it is partly due to my gatherer instincts. Every flower I mark is a possible seed-source later in the season.  The other half of this unwitting push is my naturalist's inclination to catalog the world around me.  If I can put a name and a couple of factoids to the flowers I see, then I feel more engaged by my urban prairie.

diamond flowers (Stenaria nigricans var. nigricans)

Once I recognized that I was keeping a mental tally, I decided to commit the list to paper. More than that, I have made it a goal to get pictures documenting every species of wildflower, May - ?, that I see in this little prairie.

I've also seen some great plants pushing through people's lawns in my neighborhood-- hill country rain lily, western spiderwort, and others. Funny enough, the more boarded up windows and "KEEP OUT!" signs, the better the hunting. Alas. Such is the beauty of native plants-- all they need is to be left alone. 'Well-maintained' landscapes are much less hospitable than run-down and neglected lots.

hill country rain lily, Cooperia pedunculata 
Hill country rain lily, as you might gather from the name, pop up in the spring after a good soaking rain. This is exactly what these lovely lilies did this May. I checked their species distribution on USDA plants, and we are about a hundred miles north of their documented distribution. Good for you, plant. If the future's going to be hotter, then bring on the lilies.  I wonder if my prairie's extremely shallow soils over crumbly limestone are encouraging the more southern and western (droughty?) plants I seem to find here. On the other hand, I have yet to spot a cactus in this lot. So there's that. I scattered some seeds in the vacant lot prairie, and I collected a few more to plant around my lawn. 

There is another closely related species with smaller flowers, C. drummondii, which tends to bloom in the fall (not spring) and ranges north of C. pedunculata.  I actually did see one lone C. drummondii blooming near an abandoned structure on the edge of my vacant-lot prairie. I'll have to come back tomorrow morning to get a picture. Like many delicate wildflowers, the blooms only last a few days.  Then the plant goes crypto for the rest of the year.
texas frog fruit (Phyla nodiflora)

With regards to the western spiderwort (Tradescantia occidentalis), whose flowers only last hours anyway, someone mowed the entire stand a few days after I first noted it blooming. Again, alas. I picked up a seed head with one last blooming flower to set on my table at home. If the seeds are viable, I'll sow them in my own yard. Perhaps if I set them in a designated plot, they'll be respected as intentional and spared the lawn-mower's blade in the future.

I have a half-baked ambition to plant a garden in my front yard seeded entirely from the vacant lot and other seeds gathered around my neighborhood. This is my opportunity to build the appreciation of these "weeds".

If you're interested, I've included more pictures of the species I've documented so far and a plant list after the jump.

More Bee-like Beetles

Look at those antennae!

Like so many things, when you learn a new species you start seeing it everywhere. Were they there all along? Or did I just notice them because they had a population explosion? My first thought is that the former seems more likely.  

I don't mind seeing bee-like flower beetles everywhere. They are neat little critters, with fuzzy, clumsy little bodies and delicate fan-like ("lamellate") antennae.  Lamellate antennae are typical of the scarab beetle family, of which there are more than 30,000 species.

"Hey baby, wassuuuppp"

Beetles and other bugs use their antennae for smell.  They were all over the cactus blossoms. Glancing into a flower, you'd see a couple bee-like flower scarabs tumbling and rooting around. Are they gregarious? Were they mating?  Or are they just that common?

After doing a little research, it looks like all of the above are accurate.  Some beetles are only active in their adult forms for a few weeks, so the clock is ticking with regards to mating and eating. All the adults emerge at once, so they go from absent to super-abundant.

After mating, the female will lay her eggs in rotting plant matter and then die.  The larvae will feed on decaying deciduous trees and graminoid roots for 3 or 4 years before emerging as adults, and re-starting the cycle.  Because these creatures spend most of their lifecycle out-of-sight underground, and then suddenly flushing for a few weeks in spring, they are both rare and ubiquitous, everywhere and scarce, depending on the season. It is amazing that, if I hadn't been looking when I was, I could go an entire 11 months without seeing one of these beetles.


Sunday, May 11, 2014

Bees on the Fly

Hymenoptera (ants, bees, wasps) are second only to beetles for insect diversity in North America.  Most people recognize honey bees and bumble bees, the two common social bee families, but that is only the beginning. In fact, most bees have neither hives nor queens. The majority of bees live solitary lives.  Instead of hives, they excavate nests in dirt or dead wood.  These self-sufficient little creatures have unique habits which, when combined with their big eyes and fuzzy bodies (the 'cute' factor), make them intriguing objects of study.

 Megachile spp. (brevis?) says: "What're you looking at?"

Their small size and high diversity can make them difficult to identify to species without magnification in a lab setting. However, I have convinced myself that I got at least two bees to genus on a prickly pear (Opuntia spp) blossom last Saturday.

When getting a rough ID of a bee on the fly, there are a number of traits to consider. Things like behavior (posture, vocalizations, choice of food), body shape, placement of fuzzy bands, placement of scopa (pollen collecting hairs), and coloration are all good characteristics to remember.

Megachile spp. and crab spider on Opuntia (prickly pear) blossom

Keeping this in mind, I decided that two of the bees I observed fussing over the cactus flowers were in the Diadasia and Megachile genus, respectively.  Megachilids (commonly referred to as 'leaf-cutter' bees for their habit of excising semicircular patches from leaves to furnish their nests) are easy to spot. They have relatively large bobble-heads for their size, make a high-pitched humming noise, and, most distinctively, collect pollen on their bellies instead of their legs. They forage with a 'bottoms-up' posture that looks a little goofy on the flower.

Megachile "bottoms up!" pose 

Diadasia can be a little more challenging. To the relatively untrained eye (i.e., mine), Diadasia resemble Melissodes. Both are medium-sized fuzzy bees with large scopa on their hind legs. The differences are in the details.  Diadasia are overall a bit fuzzier, and they have round foreheads (vertices) instead of a flattened vertex like the Melissodes bees. The final factor that hinted "Diadasia" was that this bee was observed on a cactus.

Confirmed as Diadasia australis on by Dr. John S. Ascher

Diadasia are one of the many bees referred to as 'cactus bees'.  All sorts of bees love cactus, but Diadasia species are often classified as 'oligoleges' (think oligo- few), that is, they specialize on a few sources of pollen. A number of Diadasia have a special affection for cactus flowers. While many Diadasia love cacti, they do feed on other flowers. Oligoleges tend to be more particular about the pollen they collect than the nectar they sip.  Another common name for Diadasia is "chimney bee". They build turrets around the entrance to their nests in the ground. I didn't find this little lady's nest, but if you see a tunnel with a turret, you'll know a Diadasia might be calling that nest home.

One last thing to know about the vast body of bees: despite the fact that you can see I totally got up in their faces, these native bees didn't so much as buzz me. Most bees rarely sting. This is doubly true for solitary bees without a hive to defend.

Monday, May 5, 2014

Say what you see

Identifying insects can be hard, but sometimes it can be as simple as playing the game "say what you see".  Can you guess the name of the munching (not munched-on) bug in the picture below?

A bee assassin eating a euminid wasp on prairie parsley.

It's called a 'bee-assassin' (Apiomerus crassipes), and it's feeding on a euminid wasp (Symmorphus? Euodynerus?) that landed on the wrong prairie parsley (Polytaenia nuttallii). 

Bee assassins lurk under flowers, waiting for passing bees and wasps. When a bee or wasp alights on the flower, they grab them with their sticky forelimbs. Then, like spiders, they inject their saliva and slurp out their victim's liquefied insides.  Another interesting note- bee assassins don't have naturally sticky legs. They gather the resins they use to catch their prey from plants.

Assassin bugs (Reduviidae family) are generally noted as beneficial insects in the garden.  They can have a voracious appetite for garden pests.  Bee assassins themselves, despite their relation to such handy bugs, don't tend to specifically serve a beneficial (from an anthropocentric perspective) role. However, they are opportunistic hunters. While they have fine-tuned their hunting style to capture pollen and nectar feeders, they'll snatch anything they can reach.

Both bee assassins and euminid wasps are considered 'beneficial insects', so whom should we root for in this case?  I think most people would root for the bee assassin- our collective aversion to wasps is outsized relative to their capacity for harm. Even though I find wasps fascinating and don't fear them, I still startle when I hear one buzz my ear.  This is an unfortunate reflex. Wasps are excellent garden defenders. Euminid wasps carefully provision each of their eggs with a pesty insect snack. They are known predators of caterpillars and grubs.

I observed another example of "say what you see" a few feet over in the same parsley patch. I caught a glimpse of this fuzzy, buzzing flier out of the corner of my eye and stepped over to get a look.

bee-like flower scarab (Trichiotinus piger)

I was hoping for a bumble, but this odd-looking beetle did not disappoint. Adult bee-like flower scarabs feed on pollen, while the young are ground-dwelling grubs that feed on the roots of graminoid plants. According to the Xerces Society's book "Attracting Native Pollinators", these beetles are important for magnolia pollination.  Magnolia flowers evolved before the time of bees and butterflies, so to this day they are primarily pollinated by beetles.

I'd love to know why bee-like flower scarabs are so fuzzy. Is it to mimic bees and avoid predation? Is it to collect pollen? For now, I'll have to live with the mystery.

Friday, May 2, 2014

Flowers in the Wasteland

Dakota Vervain?  

           Every native plant enthusiast worth their salt knows that roadsides and wastelands are fertile hunting grounds for wildflowers.  These forgotten places go neglected and uncultivated, and thus provide refuge to 'weeds'- the native plants that I adore. I have a hoarder's soul when it comes to wildflowers, so I can't help but note where I find these gems.
            I recently moved to Fort Worth, and I've been quickly getting acquainted with the local flora.  My rental near TCU has a 2-3 acre vacant lot across the street. Yesterday I explored this marginal land to meet some of the locals.  This small sanctuary houses blooming green antelope horn (Asclepias viridis), golden mane tickseed (Coreopsis basalis), dakota vervain, pussytoes, prairie ragwort (Packera plattensis), horse nettle, pink ladies (Oenothera speciosa), and Texas wintergrass, whose inflorescences loosely resemble needle and thread. The thriving milkweeds made me smile (as a monarch fan), and transported me to my botanical state of bliss. Drunken frat boys, hooting from their patio, brought me back to the urban core. Ah, city living. 
Green Antelope Horn/ Asclepias viridis asperula

            I moved to North Texas from Central Nebraska less than a week ago. Some things are the same, in that the native flora includes a mix of familiar and unfamiliar tallgrass prairie plants, while some things are quite different (see: drunken frat boys observing my botanizing).  The weather's hotter, but just as variable as Nebraska. 95 degree days have been followed by 40 degree nights. My garden is in a state of panic.
            I am so excited to have the opportunity to live in a state rich in natural beauty.  I've already visited a few local prairies, and I plan to use this blog to capture my thoughts on my explorations of the open lands near my new Texas home.  I may also pontificate on prairies further afield, should I chance to visit them. My particular focus on native bees and flowers inspired the title of this blog, "The Bee Pasture".  I invite anyone interested to follow my musings, which I hope to update weekly on this site.

One more note: as I am new to Texas, all of my plant IDs are tentative, to be confirmed/contradicted (please do!) by friends and conservationists who know better.

Wish me luck and adventure!


Texas Bluebonnet

Golden mane Tickseed Green Thread