Ahh chooo! Pine Pollen and Climate Change

 

pine_malecones2 copy

The bane of many a Southerner’s existence is springtime pollen. All that yellow dust swirling on the breeze and coating your car, that’s pine tree sperm.

The male cones of a Loblolly Pine (Pinus taeda) look like a bunch of tiny bananas growing from twig tips. If you’re thinking, “wait, that’s not a cone,” the woody cone we use to hot glue decorative wreaths or smear with peanut butter for DIY bird feeders is the female cone. Its spirals of woody shingles (or bracts) protect the tree’s eggs and, after fertilization, the developing pine embryos inside.

Male cones are much smaller and shorter lived. They release pollen for a couple of weeks each spring. And it’s a LOT of pollen: 3-5 pounds per tree. Why so much? Pines transfer pollen from male to female cones by wind. It’s not a very efficient system. More pollen increases the chance of fertilization.

With Climate Change, pollen’s gonna get worse. Ladeau and Clark (2006) found that pines growing in an elevated CO2 environment produce more pollen cones, and more pollen, at younger ages.

p.s. If you ever wondered what a pine pollen grain looks like, it’s a microscopic Mickey Mouse logo!

Ladeau SL, Clark JS. 2006. Pollen production by Pinus taeda growing in elevated atmospheric CO2. Functional Ecology. 20(3) 541-547.

Signs of Spring: Robins and Lawn Mowers

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Two robins (Turdus migratorius) hopped through the yard this week – spring is on its way. The sound of lawn mowers now drift through the air, confirming the avian prediction. Shockingly, these two very distinct signs of warming weather are actually related, according to a backyard research study conducted in 1979.

L.A. Eiserer conducted a series of scientific (well, somewhat) studies examining the impacts of lawn mowing on robin-hunting behaviors. Robins spend more time foraging when grass is short, especially just after it has been mowed.

So is it the mowing or the height of the grass that impacts robin behavior? Eiserer mowed his lawn to two different heights, 2.5 and 4.5 inches. (I wonder if his neighbors complained.) The robins spent 10x as much time in the shorter patch. Apparently, the birds eat different foods when exposed to different heights of grasses. In short grass, robins go for worms; in longer grass, they pluck small insects off the blades. The short-grassed hunting grounds may just be more efficient for finding a heartier meal.

But that doesn’t discount the act of mowing. Observations over the same time of day show the birds prefer hunting in a freshly mowed yard rather than the day after. No difference in grass height, but perhaps the act of mowing disturbs invertebrates, allowing for a more successful hunt.

Overall, I miss the days when a researcher could sit on a suburban porch and time how long a couple of robins spend looking for food. As I struggle to teach my students how to think like scientists, reading a study like this makes me long for the good old days.

 

Eiserer, L.A. 1980. Effects of Grass Length and Mowing on Foraging Behavior of the American Robin. The Auk. 97(3) 576-580.

Happy Darwin Day!!!

barnacle

Barnacles. Not that appealing, right? Charles Darwin probably would have agreed… until he ran into a small problem. He found a new species of barnacle on his trip around the world and couldn’t place it into a taxonomic category. So, Darwin ended up examining, dissecting and analyzing every known species of barnacle, re-ordering the entire crustacean sub-class to figure out where his little guy fit.

It took 8 years… of barnacles… and microscopes. Turns out that Darwin’s newly discovered species (which he politely called “Mr. Arthrobalanus”) was the smallest barnacle in the world. With close and careful observation, Darwin also realized that some species of barnacle, thought to consist only of females, actually housed minuscule males inside small compartments of the feminine form. However, the most influential aspect of such this detailed study was the realization that immense variation occurs within and among species (variation being a key component in natural selection). Those barnacles changed not just biology, but our understanding of the world.

February 12, 2016 is Darwin’s 207th Birthday. Enjoy some cake (and maybe even send some love to Mr. Arthrobalanus)!

 

Interested in learning more about Darwin? I recommend three books: The Autobiography of Charles DarwinThe Voyage of the Beagle, and Origins: Selected Letters of Charles Darwin (although all of Darwin’s letters can be found online at the Darwin Correspondence Project).

Snowbird Shape-shifters

snowbirds850_JML

Those small slate-and-white sparrows hopping across the frozen ground are true snowbirds. They spend summer in Canada and move south to the U.S. during the winter. Some, like their human counterparts, even migrate to Florida.

In the late 1800s, R.W. Shufeldt wrote of two birds called “snowbirds.” One medium-sized bird, the Snow Bunting, became known as the “snowflake.” The smaller bird, the Dark-eyed Junco, was unequivocally called the “snowbird.” Shufeldt expressed his displeasure at the bird’s new moniker “junco” – he tried to determine, unsuccessfully, the etymology of the word (it means “reeds or rushes”) since the Dark-eyed Junco does not live among reeds or rushes.

Shufeldt’s article also referenced Alexander Wilson’s description of Junco folklore. New Englanders told Wilson that Dark-eyed Juncos change their plumage to become the Chipping Sparrows of summer. Before you laugh (or after you’re through), many birds significantly alter their plumage during the breeding season… although the Dark-eyed Junco does not. These two birds are both sparrows, trill similar songs, and feed on the ground.

While Dark-eyed Juncos do not morph into Chipping Sparrows, they have their own form of transmutation. Those round balls of bird aren’t fat, they’re fluffy. Feathers trap air, an excellent insulator. The birds puff up their feathers, a downy winter coat, keeping them toasty warm.

p.s. Red and the Peanut wrote a great post about the name “snowbird.” I recommend it!

Is Your Favorite Animal a WUG?

AnimDiversity_RNG

Think of your favorite animal. Is it warm and fuzzy? Or fine and feathered?

Many people think of “animals” as mammals, birds, or reptiles. Occasionally a fish, crustacean, or insect will creep in there. But, let’s face it, our view of animals is limited.

Children reflect this discrepancy when asked to draw a picture of a habitat. For instance, Snaddon et al. (2008) found that children drew ~75% mammals, birds, and reptiles in their portrayals of a rainforest. In reality, rainforest animals are 90% insects.

The rainforest isn’t unique. Most animals are insects (beetles, to be specific). It makes the Victorian hobby of beetle-collecting seem a little more understandable now.

And the Nematodes! Nematodes (roundworms) make up a surprisingly high percentage of animal species. Scoop up a trowel-full of soil from your yard, and you’re likely to have thousands upon thousands of nematodes in there.

If we can get children to understand that ecosystems, like rainforests, contain more animals than just vertebrates (and plants too!), the consequences include a better understanding of ecosystem functions and conservation issues.

So introduce yourself and your children to insects and worms (sometimes called “wugs” – worms and bugs). Attend insect-related events at a museum, make insect-face masks for play, visit natural environments, sow insect-promoting native plants (and keep careful track of all the worms in the ground), or tend an insect or worm as a pet for a couple days.

Maybe your new favorite animal won’t have fur or feathers.

 

Snaddon JL, Turner EC, Foster WA (2008) Children’s Perceptions of Rainforest Biodiversity: Which Animals Have the Lion’s Share of Environmental Awareness? PLoS ONE 3(7): e2579. doi:10.1371/journal.pone.0002579

G’night, Groundhog

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It may seem like an odd time for a post about groundhogs (Marmota monax) – a couple months early, right? But I think now is an even better time. Groundhogs (a.k.a. woodchucks or whistle-pigs) are considered one of the few true hibernators of winter.

What about bears? This is where we get into an issue of degrees (pun totally intended). Bears lower their metabolism and body temperature, and by doing so, conserve energy in winter when food supplies dwindle. Normally, bear body temperature is ~98.6⁰ F (37⁰ C), just like humans. In torpor (like a mild hibernation), their body temperatures drop to 86⁰ F (30⁰ C).

The groundhog, in comparison, can lower its body temperature from 99⁰F to 37⁰ F (5⁰ C)! That’s hibernation! It allows the rodent to decrease its energy use to 1% of normal.

Think of torpor and hibernation like changing the temperature settings in your house. In torpor, you drop the settings a couple of degrees while you’re at work. Hibernation is like shutting temps way down, just enough to keep the pipes from freezing, while you head to Florida for a month-long vacation.

Some scientists study how the groundhog accomplishes this marvelous feat. Figuring out those specifics could impact healthcare and space travel for humans.

p.s. Some animals hibernate in the summer, but this is called aestivation (est-eh-VAY-shun).

p.p.s. This watercolor is now available on RedNewtGallery’s Etsy site. (yay!)

Where Art & Biology go to Shop

etsy

Thanks to everyone who’s encouraged me to set up a shop for the illustrations found on this blog and on A-wing and A-way – it’s now OPEN!

Welcome to RedNewtGallery on Etsy!

p.s. If you see any artwork on either blog you’d like posted in the Shop, just comment below and I’ll add it ASAP. For instance, the illustration from my most popular blog post (Penis Bones) is not currently on the site. Hope you can see why! Haha!

Of Leaves & Worms

leavesEvery autumn, vibrant leaves float down from the tree tops to stitch a patchwork quilt resting on the forest floor.

Over time, leaves are broken down by fungi, bacteria and other detrivores (organisms that eat dead stuff) like earthworms. The superpower of the earthworm (Lumbricus terrestris) is its ability to compost vegetation and return vital nutrients to the soil.

Charles Darwin was fascinated by earthworms, conducting wonderful experiments to determine how much soil they moved and whether worms preferred to collect leaves from the broad end or pointed end. Worms pull leaves into their burrows (narrow end first) to plug the opening and protect themselves from ‘early birds’.

In much of North America, earthworms were killed off in the last ice age (~10,000 years ago). The worms you see now in Michigan, Maine and Minnesota are all invaders. Sounds great, right? More nutrients in the soil? Unfortunately, the northern hardwood forest ecosystem is adapted to a thicker leaf litter layer and slower release of nutrients. So now, the introduction of the earthworm changes which seeds can germinate (and which trees will continue to survive), nutrient run-off, and which animals live in the new, de-littered forest. (1)

If you’re interested in appreciating the awesome recycling power of the worm, check out a delightful little book by Amy Stewart – “The Earth Moved: On the Remarkable Achievements of Earthworms”.

Want to read more specifics about leaf-earthworm experiments? Natural History Magazine has an entertaining write-up.

  1. Hale CM et al. 2008. Exotic earthworm effects on hardword forest floor, nutrient availability and native plants a mesochosm study. Oecologia. 155:509-518.

A World Without Bunnies

rabbitsI hate to break it to you, but there’s really no such thing as a bunny.

Among rabbit-like animals, we have “rabbits”, “hares”, and “pikas” (by the way, NONE of these animals are rodents – rabbits and rodents diverged fifty million years ago).

Rabbits are generally smaller than hares – slightly shorter ears too. The big difference, though, occurs at birth. Rabbit young are born after a much shorter pregnancy (30 days rather than 42 days) and the babies are less developed. Just-born rabbits (“kittens”) haven’t grown any hair yet, whereas the hare babies (“leverets”) are furry.

Rabbits also enjoy a cozier household than hares. Rabbits live in underground burrows, called warrens (check out this concrete cast of a rabbit warren).  Only the Cottontail Rabbit (Sylvilagus floridanus) stays above ground like hares.

If you’re wondering how those poor Cottontails deal with cold winter weather, see this neat Urban Wildlife study by the Lincoln Park Zoo.  And while we’re on the subject of urban rabbits, read how city-rabbits are trading their sprawling suburban homes for compact city flat.

Wildflower Stories: Milkweed, Monarchs and Monsanto

ATwildflowers_milkweedlMonarch butterfly populations have declined an estimated 90% over the past 20 years. [1] What’s going on?! The answer involves genetic engineering, protozoans and herbicide.

Milkweed (Asclepias syriaca), a member of the Dogbane family of plants, is closely associated with Monarch butterflies. Monarch caterpillars feed on milkweed and assimilate the plant’s chemical defenses, providing the Monarchs protection over the rest of their lives.

Milkweed grows in disturbed soils, like those used in agriculture. The plant is often found between rows of corn or soybeans. However, genetic modification of corn and soybean allows herbicides (such as Monsanto’s RoundUp) to be more efficient at killing other plants, like milkweed. Fewer milkweeds, fewer Monarchs.

milkweed_flowers
So good-hearted people came to the rescue, planting Milkweed in their yards in an effort to help the butterflies. Unfortunately, many people planted the wrong species of Milkweed. Here in the U.S., native Milkweed dies back each year. This dieback limits the population of a Monarch parasite called OE (Ophryocystis electroscirrha). [2] However, the species of Milkweed people planted is evergreen, so the parasites keep proliferating and Monarchs get so sick they don’t survive their migration to Mexico and back.

If you’d like to find the right Milkweed for your neck of the woods, here’s a handy tool from Xerces.

  1. http://news.nationalgeographic.com/news/2014/10/141010-monarch-butterfly-migration-threatened-plan/
  2. http://monarchparasites.uga.edu/whatisOE/