This cutworm moth (Family Noctuidae) is the fattest animal in the world. In just two summer months of feasting on flower nectar, the migratory moths balloon from 20% to 80% body fat (1). Storing this much energy has a price though – no romance. Migratory moths put reproduction on hold to save up energy for their journey.
Thanks to all that fat, cutworm moths are a major food item for grizzly bears in the summer (2).
It got me wondering: These moths delay reproduction so they can migrate, but putting on fat makes them more delicious. Why not just stay put and make some babies instead? Since their migration is basically east-west, major temperature/seasonal shifts don’t require the move*. Local plants (food) don’t require the move either **. Parasites might. Army cutworm moths are highly parasitized. Moths with parasites stay in the Rocky Mountains longer, growing larger and fatter. So the bears may do the whole population of moths a favor by culling those with parasites.
* Altitude is a factor in temperature and season. But if moths stayed near the mountains, they could stay put moving up and down in altitude without flying a few hundred miles to and from the plains.
** Larvae eat a wide range of leaves and stems. Adults suck up flower nectar. So a large number of larvae may reduce some food for the adults.
- Kevan, PG and DM Kendall. 1997. Liquid Assets for Fat Bankers: Summer Nectarivory by Migratory Moth in the Rocky Mountains, Colorado, U.S.A. Arctic and Alpine Research 29(4):478-482
- French, SP, MG French and RR Knight. 1992. Bears: Their Biology and Management. p 389.
Five years ago, this blog was born. In 2013, I wrote a grand total of two posts and received 21 visitors – not stellar for promoting conservation and an appreciation of biodiversity. But the number of posts and visitors have grown over the years… this site has now been viewed over 15,000 times! I can’t thank you enough.
Here’s a brief look back at the “top” posts:
- First post: “Carapace Cornucopia” (one of my favorite paintings)
- Most-viewed post: “Penis Bone – No Joke” … yes, that is the top-performing post. 🙂
- Month with highest number of views: September 2015 (2.5k) thanks to Scientific American blog, Symbiartic, and my students’ amazing work
- Thanks, Philippines! Visitors from the #2 country of origin like the folktale of the Firefly and the Apes.
- My favorite post: Springtime Symbiosis
- Most enjoyable science paper to read: Signs of Spring
- Cutest model (tie): Who’s in My House? and Purring Predators
- Smelliest model: Corpse Flower Opens – And Stinks
Thanks for visiting, and for all the encouragement and positive comments!
Take a walk in a winter forest and you can’t help but notice beech trees. Silky smooth bark and sand-colored dry leaves stick out like Christmas lights against a dull and gloomy background. While every other leaf drifted to the forest floor months ago, beech leaves hold tight like cat hair on a sweater.
It’s called marcescence – these leaves that just won’t drop – and it’s common in oak and beech (the trees are close relatives). But why keep the leaves? Are these trees just photosynthetic versions of hoarders?
One possible reason may be to protect that bud, the thin tapered structure often described as “cigar-shaped.” Inside the scaly covering are the beginnings of the new year’s growth. Hungry deer can ruin a tree’s plans for spring. But with beech trees, deer tend to get a mouthful of dry leaves whenever aiming for a yummy bud. (1)
What about attacks from smaller enemies? Insects seem to prefer infesting trees with leaves hanging on over winter. R. Karban decided to yank all the leaves off a few dozen small oaks and compare infestation levels of a tree-noshing wasp. (2) His numbers indicate that wasps prefer leaf-hoarding trees three-to-one compared to his denuded ones.
I believe Nature is constantly sending messages of wisdom if we’ll just listen. In this case, perhaps she’s saying “every action has an upside and downside, but with diversity, there’s always hope for a better future.”
- Svendsen, Claus R. 2001. Effects of marcescent leaves on winter browsing by large herbivores in northern temperate deciduous forests. Alces 37(2): 475-482.
- Karban, R. 2007. Deciduous leaf drop reduces insect herbivory. Oecologia. 153: 81-88.
Flowers need bees. A bee’s job is to move pollen from one bloom to another; plants pay for the bee’s service with sweet nectar. Cunningly, some bees have found a way to get a paycheck without the work.
Carpenter bees (Xylocopa sp.) exhibit a behavior called “nectar theft.” Rather than reaching the base of the flower through its opening (and getting a pollen dusting in the process), robber bees bite a hole in the base of the flower to slurp up nectar, bypassing the pollen-yielding anthers entirely.
We can’t necessarily blame them though, as it may be the plant’s own darn fault. Flowers with long tube-like bases are more likely to get robbed since the brawny carpenter bees can’t reach the nectar any other way (1). This relationship may even keep the flower tubes shorter over evolutionary time, since short flowers are more likely to be pollinated (and less likely to be robbed).
In order to deter break-ins, some flowers have evolved thicker flower walls, new toxins, or even special relationships with animal “special forces.” Some tropical flowers produce extra nectar in a special chamber for ants, who act like police in stopping the robber bees (2).
P.S. The bees I watched for this sketch were upstanding citizens – no thievery going on here!
P.S.S. It’s a girl! This bee’s got a black face. Males have a large patch of white on their faces. (http://www.uark.edu/ua/arthmuse/carpbee.html)
- Navarro L and R Mendel. 2009. Relationship between floral tube length and nectar robbing in Duranta erecta L. (Verbenaceae). Biological Journal of the Linnean Society. 96 (2) 392-398.
- Gerling D, HHW Velthuis, and A Hefetz. 1989. Bionomics of the Large Carpenter Bees of the Genus Xylocopa. Annual Review of Entomology. 34:163-190.
As Obi-Wan Kenobi explained, The Force is “an energy field created by all living things. It surrounds us and penetrates us; it binds the galaxy together.” These sage words constituted my first exposure to an ecological idea: Energy.
Jedi are no fools. Every drop of energy we use (and rely upon) comes from outer space. Solar energy reacts with carbon dioxide and water inside those wondrous Earthly chemists, plants, to build the most amazing molecule of all – sugar. Sugars combine to form building blocks of plant bodies and, when eaten by an animal, these components break apart to release energy. We use this energy to power our bodies.
Life forms even store energy by combining sugars into fats or oils. The oil saved up by an unfathomable number of plants, buried millions of years ago, power our machines today. We call these ancient plant oils “fossil fuels.” Breaking apart those molecules releases the energy (and carbon dioxide) made long, long ago.
In a sense, that energy does surround and penetrate us; it flows through us.
May the Fourth (be with you) is Star Wars Day. Enjoy it by appreciating the energy of all living things that bind us together.
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.
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 Darwin, The 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).