Fields of gold

Prairie parkland landscapes are at their peak golden color now. The fall landscape is transforming daily, and with the nice fall weather lately, it’s a glorious time to be out walking around. I’ve given up trying to find the migrating birds at this points and am just enjoying the golden colors everywhere.

The prairie at Tamarack park in White Bear Lake looks golden with stems drying Big Blue Stem and Indian grass, as well as a healthy crop of Showy Goldenrod. Leaves of a few of the maples and ashes have begun to change color also.

There is a similar scene in the restored prairie at Reservoir Woods in St. Paul where the low vegetation is a solid mass of several species of Goldenrod, with a few purple and blue asters and the stems of Indian Grass mixed in.

Bright yellow plumes of Showy Goldenrod rise above the rest of the vegetation in this landscape. And the flowers are a major attraction for honeybees and bumblebees by the dozens.

I don’t think I’ve seen this many honeybees in a native landscape for quite some time. Goldenrod and Asters are the late blooming plants in the fall that bees depend on to stock their larders with pollen over the winter.

Stiff Goldenrod with its erect, rigid stems and fat, almost succulent looking leaves is also in full flower not, but is not nearly as attractive to the bees as the Showy Goldenrod.

Stiff Goldenrod flowers seem larger and more attractive to my eyes, but not to the bees.

Canada Goldenrod has already bloomed and is putting out seeds that the migrating sparrows and finches will appreciate.

Earlier in the fall the American Goldfinches began harvesting the seedheads of the Meadow Blazingstar and led their newly fledged offspring over to the seedheads of the Canada Goldenrod.

What new things will I see on tomorrow’s walk?

Blooms in the backyard

In the Minnesota backyard, some of the summer blooms are in their full glory, particularly the purple coneflower. Butterflies and bees are drawn to these flowers…

A Great Spangled Fritillary stopped by…

And examined each of the disk flowers in the flower head intensively.

I caught the approach of one of the honeybees buzzing the coneflowers.

And was able to zero in on the bee when it landed.

Even the Goldfinches were checking on the flower heads, I suppose to see if they had made any seed yet. But these flowers have just opened up in the last few days.

Flowers of the desert

Although we have been a little early in some places and a little late in others, we still have seen some of the spring wildflower show as we travel.

One of the most exotic flowers we saw were on this claret cup cactus, actually an endangered species found only at the intersection of Arizona, New Mexico, and Mexico — which is exactly where we were when we saw it. The plant puts out brilliant scarlet flowers on cylindrical stems that mound together into a cactus clump.

The color of the flowers suggests it might be pollinated by hummingbirds, although the shape of the flower is wrong. However, the “flower” is actually the outer sepals and petals combined, and the nectar reward for the hummingbird pollinators is in the central chamber surrounded by hundreds of thready stamens.

Cylindrical flowers of the Ocotillo are the more typical hummingbird floral type, but a number of other birds enjoy these flowers for their nectar, as well as the insects they attract.

Why bother probing into the flower for nectar when you can just rip the flower off the stem and eat the whole thing, as this male Pyrrhuloxia is doing?

Looking for insects on unopened Ocotillo buds? A male Gila Woodpecker might enjoy both a nectar and an insect reward from these flowers.

A female Rufous Hummingbird foraged on a bunch of Penstemon flowers in the early morning at Cave Creek ranch in Portal Arizona.

A Clear-wing Moth and Pygmy Blue butterfly foraged on the bush lupine right outside our room at Cave Creek ranch in Portal Arizona. This plant had so many flowers and apparently so much nectar, it was constantly moving with the all the butterflies and bees swarming on it.

The Southern California deserts didn’t receive enough rain this year to produce much of a wildflower show, but the Desert Agave still bloomed here, along with many Ocotillo plants, giving this desert in Anza Borrego State Park some color. The Agave plants only send up one flower spike in their lifetime, as tall as the plant’s energy resources will allow, to attract bats to pollinate them.

Fall reminiscence

After four days of the white stuff raining down on us, I need a shot of color from the brilliant hues of this past Fall season.  

Late in the summer and early fall, the dominant color in the prairie garden changes to yellow as several species of Goldenrod bloom. The yellow blooms and rust-brown grasses of this prairie are accented by the flowers of several aster species in shades of blue to purple.

Here is a feast of nectar and pollen for bees, and the flowers blooming this late in the summer and fall have their undivided attention.

Five-foot tall Maximillion sunflowers are just one of many sunflower species that bloom in the fall.

A New England Aster blooming along the sidewalk to my front door was a magnet for bumblebees, honeybees, and at least two species of syrphid (hover) flies.

One way to ensure seed set in a plant is to capture as many pollinators as possible, and this seems to be the strategy influencing the flowering times of Goldenrod and Aster species. By blooming so late in the summer and early fall, they are pretty much the only pollen and nectar sources around.

And to ensure that bees do visit their copious numbers of flowers, the plants need to advertise themselves with the colors that are most attractive to bee eyes — yellow-green and blue-purple. Bees also key in on light that is a combination of yellow and ultra-violet, something humans can’t detect, but probably marks landing platforms or serves as nectar guides on flowers.

Summer’s brilliant colors fade in the fall as the landscape transforms. It will be another 8-10 months before I can enjoy scenes like this again.

a most particular flower

Walking around Tamarack Nature Center in White Bear Lake, MN the other day, I saw some unusual plants in wetter patches of the prairie.

This is the white form of Bottle Gentian – the more typical flower color is lilac to deep purple color.

Although the flowers look like buds that aren’t yet open, this is the typical mature flower presentation with its petals closed up tight.

The petals are tightly closed at their tips.

You have to wonder how or whether such a flower can get pollinated.  But it turns out that this plant is very particular about which pollinators it allows to perform the pollination service.  In this case, it requires large-bodied bumblebees that are strong enough to separate the tips of the petals so they can crawl into the flower to pick up the pollen and nectar within.

The bumblebee is about as big as the flower, and uses its front legs to separate the flower tips and push its head into the flower, with the body following.  Photos from naturallycuriouswithmaryholland.wordpress.com .

As the bumblebee enters the flower, it pushes its thorax against the flower’s reproductive parts, rubbing pollen onto the exposed stigma, pollinating it.  By vibrating its wings and body inside the flower, the bee causes that flower’s anthers to release pollen onto the surface of the bee, which it combs off into pollen sacs later.  The nectar is located at the base of the flower, so again, it requires a large bee with a long tongue to reach the nectar source.

In the video below, you can see how hard the bee works to get into the flower and hear the buzzing while the bee is completely encased by the flower. (Video by NaturalistDave Nature Video)

Typically, the bumblebee will visit just one flower of the group at the tip of the plant, moving to the next plant after exiting a particular flower. This ensures the cross-pollination which is required for seed set. When pollinators are excluded from these flowers, only 4% of the flowers were able to produce seed, but when pollinators were allowed, 96% of the flowers produced seed.

Why would bumblebees go to all this work to get into such a tightly closed flower, when there are so many other flowers with nectar and pollen to harvest in the prairie?  Or are there?

Bottle Gentian times its flowering for periods when there are fewer bumblebee pollinated flowers available.  Bee Balm (center) has finished flowering on this prairie and goldenrod has not yet bloomed, so the rich nectar and pollen resources in Bottle Gentian represent a good alternative.

it’s not always a perfect fit

While waiting for the hummingbirds to show up to have their photos taken last week, I got plenty of time to watch some insect pollinators in action.  Some plants are obviously not fussy about what or how many pollinators they attract, so they put out a vast array of flowers — like a buffet table.

Black-eyed Susans and Purple Coneflower put their pollen and nectar up for grabs on the tiny disc flowers at the center of the flower. All comers are welcome to partake here — in this case, a Tiger Swallowtail was dipping its long proboscis carefully into each of the tiny openings of the disc flowers.

But some plants are fussier about which pollinator they cater to and which they can physically exclude.  It was amusing to watch several different bee species work the plants with tubular flowers, especially the ones with deep necks, like Salvia and Bee Balm.

A slender honeybee fits just perfectly into the deep corolla of a Salvia plant, as it crawls down to the base where the nectar is located.  Bumblebees would not fit here.

Both honeybees (above) and common eastern bumblebees (in this photo) “flock” to the Hyssop plants in great numbers.  But you notice that the while honeybee’s head fills the flower opening, the bumblebee’s head is too big, and it must rely on a long tongue to reach the nectar at the base.

Sometimes smaller is better, as far as pollination of the flower is concerned, because the smaller honeybee does a better job of contacting the flower’s reproductive parts and transferring pollen from one flower to the next.

Lobelia flowers were a perfect fit for the smaller worker bumblebees, but that didn’t keep larger-bodied bumblebees from trying to get its nectar.

Look what happens when this medium-sized bumblebee tries to get into the Lobelia flower.

This bumblebee is too big to fit into the flower opening, while another, smaller worker bumblebee, (below) crawls right in.  And notice how nicely that smaller bee contacts the protruding (white) stigma (the female reproductive part) of the flower as it enters and exits.  No doubt this bee will transfer pollen effectively.

This bee was able to work itself all the way into the flower, so that just the back legs were dangling outside.

Meanwhile, tiny little forget-me-not flowers, with their miniscule central opening, require the services of small bees with slender tongues to reach the chamber with the nectar.  Sweat bees are just the right size, and I found two different species hovering and probing the flowers.

That’s a pretty tiny opening to access this flower for its nectar supply.

Green sweat bees are common in the garden — I hadn’t noticed the black variety before today.  The green one looks well dusted with pollen.  Both species have sleek, almost hairless abdomens, unlike bumblebees and honeybees, but have lots of short hairs on their heads and abdomens, great places to collect pollen as they search flowers for nectar.

it’s all about the buzz

You’ve seen how busy bees gather pollen from some flowers — for example, they systematically crawl over the surface of Coneflowers and Black-eyed Susans, the tops of which are dotted with little ray flowers sticking their pollen up for grabs as the bee comes by.  Many different kinds of pollinators might walk around picking up pollen from these plants, so there is lots of competition for the pollen. But there is no guarantee that they will deposit any pollen on a nearby neighbor — they might just fly off to a completely different group of flowers instead.

A Common eastern bumblebee and a smaller green sweat bee competed for the pollen on some New England Aster flowers.

Other flowers present a nectar reward to the bee if it will kindly crawl into the tubular flower, brush against the anthers to receive pollen and then kindly deposit that pollen in another of the same type of flower they subsequently visit.  But who knows which flowers the bee might visit next — it might not be the same species at all.

A honeybee can crawl down the floral tube of the bee balm flowers to get at the nectar at the base, but the bee is not big enough to brush against the anthers (yellow-brown structures sticking out of the flower in the photo) to get a dusting of pollen.  Hummingbirds are a better fit for these flowers, and transfer the pollen from plant to plant very effectively.

Still other plants produce flowers that protect their pollen for just the right pollinator, one that specializes in picking up pollen from particular a species, and reliably deposits some of that pollen on a neighbor of the same species for some healthy cross fertilization.

Common eastern bumblebees are the chief pollinators of Spiderwort flowers in the spring.  The pollen in these flowers is encased (not free) in the anther, which opens from a pore at one end.

By locking the pollen up in a capsule, it is protected from just any random pollinator walking over the flower.  Shaking the flower might dislodge some of the pollen, but most pollinators can’t manage that.  Instead, bumblebees and some solitary bees grasp the anther capsule with their legs, or even mouthparts, and vibrate their wings at a very high (and audible) frequency — and pollen comes flowing out the pore at the end of the capsule, dusting the bee.  This technique is referred to as “buzz pollination”.

The video below illustrates the bumblebee action nicely:

“much of the food we eat owes its existence to the buzz of the bumblebee”

Bring on the bees

It’s prime time for summer flowers, and the bumblebees and honeybees are making the rounds carrying pollen from one flower to another and sipping nectar as their reward.

Tubular flowers of red bee balm (Monarda) are perfect for a slender honeybee or the long tongue of butterflies and hummingbirds. The nectar is deep down at the base of the flower, so it’s an effort for a small bee to get there.

Lead plant flowers open sequentially on a long raceme (flower stalk) exposing their yellow orange anthers to wandering bumblebee that collect and store pollen in sacs on their hind legs.

Milkweed flowers have special requirements of their pollinators — they need to stick their legs down slits in the female (pistil) parts of the flowers and drag out the pollen sacs (pollinia) on their hind legs. The slender leg of a honeybee is the perfect vehicle for this operation.  When they wander onto the next flower, the pollinia will get transferred as the bee’s leg drops into the appropriate slot.  To read more about how this is done, click on this link.

Bees love the pollen of the Cup Plant, a tall composite (daisy) with an abundance of bright yellow flowers.  Later in the summer, the Goldfinches will appreciate the fruits (well, seeds) of these pollinating efforts.  

In the fall, Goldfinches dissect the Cup Plant flowers, pulling the seeds right out of the flower head. Fortunately, there is a great abundance of flower heads to work on, and there are plenty of seeds left for the plant to fill up by backyard garden with its progeny.

A fly that is really a bee

If you’re always looking up to find the birds in the trees, you might miss something interesting on the ground by your feet.  And indeed, I almost stepped on this huge 2- inch long Elm Sawfly that really isn’t a fly at all.

You can see two pairs of wings on this sawfly, which means it is a member of the bee and wasp order of insects, not a fly.  The long orange, club-like antennae are also characteristic of bees, not flies.

One might wonder why a bee would be called a fly — and there isn’t any logical explanation except that the female uses her ovipositor (at the end of the abdomen) like a saw to open cavities in an elm leaf in which she lays about a dozen eggs.  Then she moves onto other leaves and does the same thing, until she has deposited about 150 eggs.  Whitish larvae hatch out and like all sawflies, immediately begin consuming the vegetation, growing about two inches in a month of eating, until they return to the soil to pupate over the winter.  An infestation of sawflies on a young tree may defoliate it so much that the tree becomes stunted, or even dies.

With those wicked-looking, piercing mandibles below its eyes, you might think this insect is carnivorous, but it actually feeds on nectar and pollen and occasionally the tender bark of young twigs.  But females don’t live long enough to do much damage to the plants; once they have deposited their eggs, they die.

This was a very sluggish individual that might have just emerged, since they usually appear at the end of May and early June.

These insects are probably not very numerous in this part of Minnesota since Dutch Elm disease has wiped out so many of their potential host plants.  In addition, both the eggs and the larvae may be parasitized by small wasps and never make it to the pupal stage.  If they reach the pupal stage in the soil, they may be preyed upon by shrews and deer mice, so seeing one just sitting on the trail might be a rare event.

Exploring Maplewood state park

We made a brief trip up north over the July 4 holiday to lovely Maplewood state park, about a 3-hour drive northwest of the Twin Cities.  Lakes, trails, great campsites, rental canoes and kayaks available, swimming beach, wildlife, and more.  What a beautiful place, and it must be even more so in the fall, when the maple-basswood forest has turned gold and red.

The view of upper and lower Lake Lida from Hallaway Hill must be spectacular in the fall.  Driving the man-made causeway west takes you out of the park.

The sumac was in full bloom, and honeybees were busy pollinating. In the fall, red plumes of sumac seeds will light up this hillside.

At the top of Hallaway Hill, we happened to be standing at the intersection of the territories of three Yellow Warbler males. If one male got too close to another male’s boundary, a brief aerial scuffle between them ensued. One of the resident males checked us out.

A pair of Trumpeter Swans fed on submerged vegetation on one of the lakes in the park.