Wednesday, April 25, 2012

Avoiding the Ivy League

What do you see?
Do you see a house beautifully landscaped in elegant, green vines? When I look at this picture, I see an ecosystem under attack. I also see right through those lush branches through to the choked out and dead branches of other plants beneath. English ivy may be an attractive and popular landscaping plant, but choosing a native vine for your spring garden will benefit not only your yard and home, but the environment too.

English ivy, as the name suggests, is not native to the United States. It is thought to have been brought here by early European immigrants, who sought to use it in landscaping. With its fast, climbing growth habit and dense, attractive, evergreen foliage, it quickly creates a carpet of green on lawns and house walls. However, not being from this area, English ivy has no natural predators, that is to say, no herbivorous animals that eat it to control its spread. Today English ivy occurs in 26 states, growing not just in backyards but in natural areas as well.

So what's the problem with English ivy? After all, it does make houses look rather attractive, as you can see here. The problem is that carpet of green is so thick, that it shades out sunlight, killing any and all plants beneath. A plant that has no access to sun cannot photosynthesize to make its own food, and so cannot survive.

Trees, shrubs, even ground plants all fall victim to this invader from across the ocean. Not only that, but ivy growing on structures can do immense damage, as its roots find their way into cracks in wood, mortar, and brick. The roots can not only break these materials apart, but the deep shade the vines create retains moisture against wood, facilitating rot.

What should you do if you have English ivy in your yard? Get rid of it! As best as you can, get right down to the roots and pull up as much of the complete roots as you are able. For vines climbing up trees, pull as much growing up the trunk as you can, or for vines too thick to pull, remove a section of the vine about 2' in length on the trunk, severing the vine's nutrient supply to the upper reaches. It will take a while, but eventually the vine will die off. Then just keep on top of any new growth. I followed this same procedure when purging my yard of ivy two years ago, and haven't had problems since.

If you'd like to replace the English ivy with another vine, allow me to suggest a few replacements, which happen to be wildlife magnets. Those in the eastern United States can use coral honeysuckle (Lonicera sempervirens), a favorite of the ruby-throated hummingbird. 
Those living on the west coast can use a close relative, Western trumpet honeysuckle (Lonicera ciliosa). 

Live in the eastern or central US? Try Virginia creeper (Parthenocissus quinquefolia), which feeds birds with its berries and rewards you with a spectacular show of fall color.

While Virginia creeper can also do damage to structures, the threat is not nearly as severe as with English ivy.

And lastly, my favorite vine of the southeast, the passionflower, or maypop (Passiflora incarnata), the host plant of the Florida state butterfly, the zebra longwing.

It is important to note that there are also non native species of passionflower, so be sure you stick to the scientific name on this one.

English ivy may be popular as a landscaping plant, but give me one of these gorgeous natives any day! Your yard will be beautiful and healthy, you'll attract wildlife, and you'll protect our wild places, all by simply replacing one plant with another. Happy gardening!

Wednesday, April 18, 2012

Wanted: Single White Flower Seeking Pollinator

Spring is the time for flowers. When the warmer weather and longer days arrive, plants everywhere produce their beautiful blossoms in a botanical proclamation of "Hey baby, wanna make some seeds?" But in order to make those seeds, flowers must first be pollinated, which when you think about it is no easy task. Plants can't get up and walk around to distribute their pollen, so they have to rely on pollinators. (Oh and if you're thinking about the ents, yes, they can walk, but they lost their entwives, so that makes pollination a moot point.)

For the most part, pollinators aren't visiting flowers for the pollen itself, it's the nectar they want. And in the process of getting that sugary goodness, they get pollen dusted on their bodies. 
When that animal visits another flower, some of the pollen from the previous flower brushes off, and it picks up some more pollen, and the critter has become a pollinator without even knowing it. So, if a flower can attract an animal to its nectar, it will have a chance at passing on its pollen.

There are all sorts of animal pollinators that flowers recruit to help them spread their genes, from bees, butterflies, and beetles, to hummingbirds, bats, and ants (not ents). And what's so neat about the whole process is that the structure of flowers many times depends on the pollinators that are used to spread its pollen! Whether it's bright colors, scent, shape, or even arrangement, flowers do their best to entice a potential pollinator.

Bright colors are often utilized to attract both insect and bird pollinators. Flowers that are pollinated most often by hummingbirds are generally red, orange, or a similar warm color. (These flowers are not frequented by bees, as they cannot see the color red.)
Scarlet sage (Salvia coccinea); a favorite among gardeners for attracting hummingbirds

In addition to bright colors, plants that attempt to attract insects also rely on markings that are known as bee guides as a kind of runway for insects. These are a flower's way of saying "This way to the nectar!" They can come in the form of lines leading to the center of the flower...

...or as a contrasting color, as in the case of this crested iris.
These yellow bee guides go all the way to the center of the flower.

Bee guides can also be invisible to our eyes, appearing in the ultraviolet spectrum, which bees can see.
On the left is a cucumber flower as we see it. On the right is the same flower under a UV light (with the yellow artificially colored), revealing the secret message intended for the eyes of bees.

Mammals have a highly developed sense of smell compared to other animal groups, so flowers pollinated by bats, for example, tend to have a strong scent. 
Now don't take this to mean that because you have a garden full of sweet smelling flowers that you are going to be raided by bats. The flowers in our gardens have been artificially selected, bred, and cross-bred for their scents to attract another species: humans.

Besides color, there's another way you can tell that a flower is trying to win the attention of hummingbirds, and that is by looking at its shape. Hummingbirds have long, narrow beaks to reach deep inside flowers, and so flowers that hummingbirds visit tend to be tube-shaped. The salvia I featured earlier is an example, as well as another favorite of mine which I currently have in my garden, coral honeysuckle. It always makes we wonder though; which came first, the tube-shaped flower, or the long beak?

Take a look at these two flowers. Which do you think is more attractive to ants and other crawling insects? If you picked the goatsbeard on the right, you are thinking like an ant, my friend. Ants don't have the luxury of being able to fly from flower to flower like bees and butterflies, and so a plant that has many flowers clustered together is going to be an ant's preferred one-stop-shop for all of its nectar needs. When you see flowers like goatsbeard and goldenrod, take a moment to look at the incredible diversity of insects that these flowers attract. It's for this very reason that I have both of these plants in my garden.

The next time you are in your backyard, visiting a nature center, or walking through a park, take a look at the flowers and see if you can guess what kind of animal might pollinate it. Once you see some of the patterns, it's almost like learning another language; you acquire the ability to "translate" the message that the flowers are sending to their potential pollinators. And if you smell a few flowers along the way? You just might pollinate some flowers with your nose!

Wednesday, April 11, 2012

Fan Request: Mimicry in the Natural World

After last week's post on the difference between butterflies and moths (you can read it here if you missed it), fellow Geek Rob Waters made a request for me to write a post about mimicry, monarch and viceroy butterflies for example. First of all, yes, I do take requests! You can do so by commenting here or on my Facebook page. Second, what a great idea, Rob! Mimicry comes in many forms and has many functions in the natural world. But whether it's is used to stand out in a crowd or to blend in, there are some pretty spectacular examples of mimicry in the animal kingdom. 

The idea that inspired this week's post is the classic case of the viceroy butterfly mimicking the colors of the poisonous monarch butterfly. 
Take a look; first the monarch:

And now the viceroy:
Quite the resemblance, isn't it? It feels like you're back watching Sesame Street to try to figure out how to tell the two apart. But you can...I'll just wait while you look them over.

*hums Jeopardy theme*

Did you find it? It's those bars on the viceroy's lower wings that give it away. And for a bonus round, if you ever see a butterfly with two black spots on the lower wings, like these:
What you're looking at is a male monarch butterfly! The monarch picture I used earlier is of a female. See? No spots on her, spots on him. Now scroll up and down repeatedly while thinking "Near...Far...Near...Far" in Grover's voice in your head. 

Until recently, it was thought that the monarch-viceroy relationship was an example of batesian mimicry, in which a harmless species (in this case the viceroy) has evolved to mimic the appearance of a truly poisonous species (in this case the monarch). However new research has shown that the viceroy is indeed poisonous! This now makes it a case of mullerian mimicry, where two or more poisonous species have similar appearances through convergent evolution. In both batesian and mullerian mimicry, the desired outcome is the same: if a predator eats a black and orange butterfly which causes it gastric distress, as in the case of this blue jay...

Frame 1) "All right! A juicy butterfly for dinner!"
Frame 2) "Now that the wings are gone, down the hatch it goes."
Frame 3) "Dude, I don't feel so good..."
Frame 4) *Hyerk* is going to learn to avoid all insects that are black and orange. Some insects advertise the same warning truthfully, and some "cheat" and copy off of other insects. Kinda like that kid who wouldn't stop looking at your paper during a test in 7th grade geography. Yeah, you know who you are....

A true case of batesian mimicry lies in the coral and milk snake relationship. The coral snake belongs to the cobra family (Elapidae) and has coloration like this:
I have had the privilege of seeing one of these in the wild while living in Florida. They are truly beautiful little snakes.

While its harmless lookalike, the milk snake, looks like this:
Same colors, different pattern. As the saying goes, "red touches yellow, kill a fellow; red touches black, friend of Jack" or "red touches black, venom lack". The coral snake has yellow and red bands adjacent to each other, while in the milk snake (of which there are many species and slight hue variations), the red and black bands are adjacent.

In both the butterfly and snake examples, their mimicry is used to stand out to potential predators as their way of saying "Eat me and you'll regret it, pal!" But mimicry is also used to blend in, as a form of mind-blowing camouflage. And in my opinion, no where is this more spectacular than in the insect kingdom.
Giant leaf insect

The Indian leaf butterfly with its wings open...

...and with its wings closed.

A king swallowtail caterpillar looking as unappetizing as bird droppings

Cryptic stick-mimic caterpillar

Orchid mantis
(Yes, there really is an insect there)

There are so many more examples, but it's really hard to top the orchid mantis. (And if you Google "orchid mantis" you'll see even more mind-blowing photos like the one above) There are even examples of plant mimicry as well, including an orchid that mimics insects! Whether it's being used to blend in like a super ninja or to outwardly advertise (or imply) danger, animal mimicry accomplishes an important function through some pretty amazing forms. But you don't have to take my word for it, take hers:

Wednesday, April 4, 2012

Butterfly or Moth?

What were those that just fluttered by? These insects are a common sight, but are they butterflies or moths? Have no fear, your Nature Geek is here! This week you'll learn just how to tell the difference between a moth and a butterfly.

Nocturnal vs. Diurnal
First, there's when each is typically active. Moths are typically most active at night (nocturnal), while butterflies are typically most active during the day (diurnal). This also explains another difference between moths and butterflies: their coloration. Moths are usually less brightly colored than butterflies, which makes sense. If you live in a world of darkness, there's not much need for bright colors. There are some beautiful, colorful moths out there though, such as the imperial moth:
I told you!
Body type
Butterflies have slender, sleek bodies that don't have a lot of fuzz on them. 
A zebra longwing butterfly, Florida's state insect.

Moths, on the other hand, are stocky, fuzzy things. Not unlike some men I've known, actually.
This cecropia moth is one fuzzy fellow.

Butterfly antennae, like their bodies, are slender, plus they have little clubs or balls on the end.
I know what you're thinking: "Hey! He's fuzzy!" 
Remember, I said that butterflies don't have a lot of fuzz on them. Moths still reign fuzzy supreme.

And moth antennae, also like their bodies, are quite fluffy, resembling feathers or bunny ears. Male moths have even larger antennae, which they use to detect the pheromones of females.
Oh yeah, he's fluffy and he knows it.

Resting Position
Moths and butterflies generally hold their wings differently when they are resting, but of course there are always exceptions. With butterflies, it's wings up...
A monarch butterfly, probably the most recognized species of butterfly in North America.

...and with moths, it's wings out.
A luna moth making a daytime appearance.

Like I said, there are always exceptions. Butterflies often sun themselves when cold, which involves holding their wings out to catch as many heat-giving rays as possible.
I can certainly identify with this painted lady butterfly. There's nothing like some warm sun on a cool morning.

So! Now that you are armed with the geeky knowledge of how to tell moths and butterflies apart, let's take a look at those white fluttery things again:
Moths or butterflies? If you said butterflies, you're right! Those slender bodies and beady antennae were your clues, weren't they? These commonly seen butterflies are cabbage whites, and if you want to get really geeky, the two spots on each wing (the second spot on the right butterfly is barely visible beneath the hind wing) tell us that these are two females.

Hey, what do you call a butterfly's mom? A motherfly! Hua? Hua? Don't worry, I won't quit my day job.