Tuesday, July 31, 2012

Monster of the dill

What: Last night I spotted a black swallowtail caterpillar (Papilio polyxenes) on our dill. When I came back this morning it was still there, perched on the same delicate pedicel (fancy name for the stalk that connects a flower to the main stem of the plant) of the dill's umbel (fancy name for an inflorescence [fancy name for a cluster of flowers connected by a central stalk to the main stem of the plant] where the flower stalks are of equal length and extend from a central point).

Prolegs on left, 6 legs on right
Ecological notes: I read two things about these caterpillars. The first is that they can decimate a patch of dill when their populations erupt, and they often do, in near biblical proportions (exaggeration, but warranted for gardeners with an affection for dill; in the photo to the right you can see all the "missing" flowers at the tips of the pedicels from where the munchkin gnawed them off). Many of their would be control-mechanisms, like birds, are thwarted by what's called an osmeterium, a weird little forked appendage at the front of the thorax (just behind the head). When provoked the caterpillar will rear up dramatically on its prolegs extend the osmeterium and emit a most rank and foul odor. Well, I had to test this out myself. I didn't smell anything except freshly cut dill (you can see a bunch of flowerless stalks that the caterpillar had nipped off), but what a beautiful treat! Perhaps the vibrant orange signals as a warning before emitting the odor, much like a skunk stomps its feet, chatters its teeth, and does a handstand before finally spraying an approaching predator.

Where: My backyard

Etymology notes: The root "osme" comes from the Greek ὀσμή, or "to smell" and the suffix "-rium/-ria" indicates a place or building (e.g. atrium, cafeteria, solarium).

Saturday, July 28, 2012

The Weird World of Mollusks

What: I don't think I'll ever be able to fully empathize with a mollusk, well at least not with a bivalve. But I do find them terribly fascinating, which isn't a bad start. And like most things, the more I learn and observe them the more I appreciate their quiet existence. While walking the shoreline at Delta Park, I was caught by the odd swirling groves etched into the sand. I had been spending some time trying to figure out how different water currents would manifest in the topography of the underlying sand - in some patches there were long straight furrows like a recently plowed field, while others had overlapping u-shaped mounds consistent in size for a given patch (see end of video for what I mean). I couldn't help but be distracted by the seemingly chaotic lines that the clams had carved across the ripples.

Ecological notes: While walking barefoot through the shallows, we didn't have to worry much about zebra mussels at Delta Park because the substrate is largely sand. Mussels are a subset of clams (see etymology notes below) that have byssal threads that serve to anchor their shells to a solid substrate - no solid substrates, no mussels. Only in a few places, like where we found heaps of downed trees partly submerged in the water, did we find zebra mussels. We did however find an abundance of freshwater clams. I unburied one, then left it with my camera set to take a picture every minute and a half. The time lapse was shot over about an hour and a half. In the first few seconds you can see the animal expel a mess of waste, which appears to be attached by a string.

There behavior still largely mystifies me. With their large rubbery foot the clams slowly reposition themselves along the shoreline - perhaps following changes in wind direction, water depth, or some other factor. Some of their trails were long slow arcs, others overlapping and confused circles. The groves left behind in the wake of their movement created small eddies in which algae settles. Fresher trails appeared as gray fissures bordered with crusty plates of sand fragmented. I checked some of the same trails after about 12 hours and they looked largely in tact, so I'm guessing it takes some stronger currents to breakdown the trails (and that they move really really slowly).
Smaller bivalves burrowed in sediments. Water level is super low right now
Their trails in the sand (hard to see unless you click on image to see a larger version).

Algae settled in old tracks

Where: Delta Park in Colchester (mouth of the Winooski River).

Etymology notes: The term clam is a muddy one to say the least. A clam could be a bivalve (a mollusk with a pair of hinged, clasping shells) that burrows into sediment - as opposed to a mussel, like a zebra mussel, which attaches itself to a substrate like pilings, other bivalves, whales, or just about anything else with a solid surface.  Or a clam could be an umbrella term for all bivalve mollusks (a square is always a rectangle, but a rectangle is not always a square like a mussel is always a clam but a clam not always a mussel). When I called ECHO to ask about help identifying freshwater clams, I was corrected: "freshwater mussels," which further confused the matter since I was referring to bivalves that burrow in the sand. Maybe there's a vernacular understanding of "mussels" as any of those freshwater filter feeders.

Other notes: Not sure about the edibility of the mussels, but they seemed an enticing source of food. Mussels themselves are not toxic, but they are filter feeders so you're essentially eating whatever microscopic stuff is floating down the Winooski or hanging out along the edges of Lake Champlain). Plus I'm not sure what species they are. Vermont's Wildlife Action Plan says that of the 18 species of mussels in Vermont, 13 are listed as threatened, of special concern, endangered, or already extinct (a rate on par with national figures). I used a field guide from Connecticut to try and ID these guys, with little luck. There's another publication UVM has that I plan on checking out to try and narrow it down: Fichtel & Smith's The Freshwater mussels of Vermont. Plus, depending on who you talk to, some species can live 75-200 years. I'd feel bad eating something that old.

Thursday, July 26, 2012

The Clouds and the Lake

Meryl, Carlos, and the Canada geese

What: I've now paddled the Salmon Hole to downtown Burlington loop about 7 times, this last time with my sister, Meryl, and our friend Carlos. It's amazing that I can walk my boat three quarters of a mile, paddle, 16 miles, and then walk 2 miles home. With all the rain we had the other night the river level was considerably higher and I had a blast running the rapids at Salmon Hole. The wind was also much stronger. The following day (Wednesday) we had fair weather, with a nice blanket of cumulus clouds settled over Vermont and New York. With a different perspective of being on the lake I was struck by the noticeable absence of clouds over the water.

Panorama showing absence of clouds over Lake Champlain
Ecological notes: My theory is that we had lots of rain on Monday, followed by warm temperatures. Already when the rain was falling it was evaporating and there was a beautiful mist carpeting the understory of Centennial Woods. As the warm moist air rises it reaches cooler air. When enough water vapor cools enough degrees (the birds and bees of making a cloud) it can reach what's called the dew point. Dew point is the point just beyond 100% relative humidity where water vapor condenses out onto a solid substrate, like dust or grass or your tent. An easy example is a cold glass of water on a warm humid day. As the air comes in contact with the glass it cools rapidly. Cold air can "hold" less water vapor, so the air in contact with the glass reaches the dew point and little water droplets form on the glass (but not on your much warmer skin). 

Turkey Vulture enjoying the warmth

In the atmosphere, as that warm air rises, the water vapor can condense and will appear to us as a cloud. So the greater the difference in temperature between the ground and the sky, the lower the elevation at which clouds should form, because they'll reach that dew point much sooner.

Rolling cumulus with Camel's Hump in background

We started paddling on the lake around 9:45am and I guessed the clouds were around 3000'. Once we rounded Apple Tree Point we had a great view of Camel's Hump and a little more than the summit (4081') was covered, so the clouds were probably closer to about 3500'. About an hour later it was considerably warmer outside, and more warm air had already risen into the atmosphere, thus, the air around Camel's Hump had warmed as well. This should have raised the dew point and the elevation at which clouds were forming. Sure enough, by about 11:15am, the top of Camel's Hump was exposed, indicating that the clouds were at about 4100'.

Rolling cumulus with Camel's Hump in background

So why no clouds over the widest parts of the lake? The temperature of the lake is more stable and cooler, so the temperature gradient between water and air is far less. Because there is a lower temperature gradient, the air rises at a much slower rate, allowing for water vapor to reach equilibrium rather than condensing out.

Where: Lake Champlain & the mighty Winooski River

Meryl and Carlos paddling in front of the silver maples

Other notes: The sunlight on Tuesday was stunning - those soft sunset golds. The winds were kicking up the leaves of the silver maples that line the Winooski River. I could never understand why they were called silver maples until I saw this a few years ago. The undersides have a much paler color and when the winds dance them around exposing their bellies the whole tree takes on this ethereal silvery sheen. Someone must have named it in the sunset after a good summer storm.

Monday, July 23, 2012

Bees and gender in Insects

Male honeybee (drone)

What: I've been thinking more about my last post and the importance of words in relation to our understanding of the world around us. I was telling a friend about the woodchuck that's growing fat off our kale, and how he had gotten the broccoli too. My friend asked how I knew it was a "he" and then pointed out how it was weird that animals automatically and unconsciously becomes "he" when the gender is unknown (I'm always conscious of when someone uses the pronoun "she" in a gender neutral situation). The pronoun "it" lacks so much emotion and humanity, like describing an automaton, so, because we like to anthropomorphize animals (e.g. Bambi), we assign gender to them. I even hear people refer to my bees and egg laying chickens as male.

As a naturalist my first questions are often around identification, particularly with insects. I posted an ID request to the bugguide.net community. John Carr sent a response "It's a female dolichopodidae." Well female is awfully specific, but animal scientific classifications ending in -idae (-aceae for plants) are family groupings, which are pretty general (Curculionidae, the weevil family, contains over 40,000 species). This is from a guy who specializes in IDing midges and their relatives, and he could get gender but only ID down to family. So what was he cuing into that said female and not male? Turns out the answer is more about what makes a male a male.

Female honeybees guarding the hive

Ecological notes: So even with the vast evolutionary divergence of insects into every ecosystem around the world, some morphological adaptations are still conserved or at least have converged. One of those things is a male's ability to detect a female, and they do this in a variety of ways, like hearing, smelling, or seeing females from a great distance. Male mosquitoes, for example, have enlarged antennae to pick up that horrendous and penetrating bzzzzzz sound the females make as they look for that perfect patch of skin. What I'll call foot moths (and cover in a future post) have huge antennae for "smelling" the sex pheromones from females.

Male honeybees, aka drones, have enlarged eyes to spot a queen before other males do. The first picture in the post is a drone; note how the eyes are so big that they actually touch in the middle of the head. The next picture shows a bunch of females at the entrance to the hive, their eyes considerably smaller and not touching on the tops of their heads. Drones are pretty much useless to the colony other than for reproduction. They hanging around feeding on honey, begging for food, and grooming themselves. When the timing is right they'll start going for exploratory flights to breeding sites. These change frequently, so a male needs to be able to spot one from a distance. The story is far more complicated than this, but it's a neat start and I"m tired, maybe more later...

Where: My backyard

Other notes: Ryan Morra and I noticed a whole bunch of female worker bees crawling around on the ground near the hive. I went back with my camera after he left and spotted one a worker dragging another, much lighter colored worker out of the hive. At one point the lighter one started to fly and the other one held on and pulled it back down. Once it got to the edge of the platform the darker one left the lighter one to die on her own. In the middle of summer, this generation of worker bees have the shortest lifespan of just a few weeks (c.f. winter life span can be several months). Kicking out unproductive bees is essential, I guess, to maintaining efficiency.

Friday, July 20, 2012

A gaggle of nouns

A deer stopping for water in the 90 degree heat
Where: Winooski River (still). Zac and I just got back from another paddling adventure to complete my last trip from Bolton to Salmon Hole, this week from Salmon to Skinny Pancake. Another perfect day of paddling!

An outburst of water striders
Other notes: This time of year has the most overlap across life stages for animals. You may have noticed not just one crow perusing the lawn for food, but a mini-flock of 4 or 5, or a sudden flush of 30 robins sweeping through a honey suckle thicket. As nesting season winds its way down (com on goldfinches, hurry up and finish nesting already), lots of family groups are out and about feeding, the males are less territorial trading the stress of land disputes for the comfort of extra sets of eyes to be vigilant. It was hard enough on the trip to identify the many different species of birds, flowers, and trees I was passing by. Throw into the mix the different names for males, females, juveniles, and even collective nouns, and I was a bit over my head trying to keep it all straight. I got curious about what the different names for groups of different animals might be (and is there a term for a herd of cottonwoods? a "stand" is so boring, "grove" gets better, but there's a whole world of opportunity here).

A scuttling of mergansersA motoring of ducklings
A ring of ring-bills A dastardly of F-16s
I've long been fascinated by names and the naming of things. I was first introduced to the quirks of latin names by my love of gray squirrels, and indeed Sciurus carolinensis was the first scientific name I learned. Turns out Sciurus derives from the Greek words skia (shade) and uros (tail). The Greeks must have thought that squirrels their tails much like one might find respite from summer heat under the cover of a parasol. They were wrong, but thanks to the convention of naming things, their error is preserved in our scientific lexicon.

A flapping of kingfishers

Contemporary naturalists seem to have a certain fondness for collective nouns used to describe groups of animals. Being able to call a flock of crows a murder, starlings a murmuration, or vultures a committee is a sure sign of esoteric adeptness when it comes to being naturalist. It's like the painfully obvious difference (to those in the know) between a tourist ("Bar" for Barre, "Shar-let" for Charlotte) from a Vermonter ("Bare-ee", "Shar-lot"). There is delight, beyond proving ones worth in the often ridiculous and colorful phrases. Some are probably grounded in some sense of the animal's natural history, while others, it appears, are from the fanciful imagination of the 15th century British author Dame Juliana Berners, or at least were first recorded by her. She was the prioress of a nunnery, where she kept up her passion and dedication to fishing, hunting, and other outdoor pursuits. Her book, The Boke of St Albans, is damn near impossible to read (much like Canterbury Tales). It includes three sections - on falconry, hunting, and heraldry. In her section on hunting she publishes a lengthy list (3 pages worth!!) of collective nouns. The most famous to make it from her pen to our vernacular is murder of crows, but the rest are just as inventive.

A lonesome of bald eagle
It might be easy to chalk the lengthy list up to the poetic musings of one more skilled in writing than shooting, but I think Berners, like other hunters, had stories that got bigger and bigger with time: "I once caught a fish th-------------------------is big." I imagine that sport hunting was a hobby for the finer and fancier of folks, a well-educated bunch that would lounge around the hearth in their parlors recounting hunting tales from days of yore. "If you think today was good, you should've been here yesterday, we caught a suit of mallards, a muster of peacocks, a covey of partridges, and a bevy of girls."

A hawking of kingbirds
Language reflects what's important to the culture that uses it. Thus, the Yup'ik Eskimos, for example, use the word kanevvluk for fine snow particles, natquik for drifting snow, aniu for snow on the ground, and have other distinct lexemes (like a root word) for variations of snow. So if your culture values hunting and the pride that comes with it you might expect a distinct lexicon to accompany it, much like any subculture develops its own language to describe shredding the gnar, sick pow-pow, etc.

An awkwardness of herons
Since her writing, many more collective nouns have sprung up, some useful and serious, others amusing and useless (a clutch of auto mechanics). In the captions for each picture, I've thrown my hat into the ring, vying for a few new collective nouns.

A flotsam of jetsam
As a side note, the publishing of Boke of St Albans made Berner the first published woman in England.

Berner's list of collective nouns in its original format

Wednesday, July 18, 2012

Storm + Winooski River Paddle Revisited

Bonus post: Just wanted to post a quick video I put together from that epic thunderstorm last night. For a better synopsis of conditions leading up to and during the storm, check out The Weather Rapport.

What: Last Wednesday and Thursday I paddled the Winooski River from Bolton Dam down to Salmon Hole in Burlington (about 30 miles or so). There are a couple of great paddling guides online (1) (2) that give a sense of what to expect from the conditions on the river, but do little to describe the sheer joy of getting lost in the meandering freedom of the Winooski's bends and folds. Only occasionally did the old span bridge or rumble of a semi's engine break remind me of the thin border of silver maples separating me from the faster pace of asphalt and clocks.

Turkey vulture hanging out along the Winooski River

Ecological notes: I was particularly fascinated with the enormity and odd grace of the committee of turkey vultures that seemed to defy my cultural expectations of what a vulture should be (on Friday I'll post more about collective nouns, like committee, for animals). Wednesday evening I came to a fork in the river where it split around an island. I saw a turkey vulture circling low on the south stretch of the island and so I set down that direction. As I slowly approached, another turkey vulture landed on a gravel spit about a quarter mile down from me, followed shortly by three more. I tied up my boat and crept slowly along the shore line to get a better view. As I rounded the bend I was treated with a spectacular view of about 25 turkey vultures either sunning themselves on the rocks or perched up in the trees preening themselves.

Turkey vultures sunning themselves on the Winooski River

In that late afternoon heat I wanted nothing more than to spread my own arms out and sun myself on the rocks with them. I couldn't help but wonder if that was the ultimate motivation for the turkey vultures' behavior. When I got back, Callan and I came up with a pretty short list of reason why we thought the vultures (and other birds) might do sun themselves. Here's what we came up with:
  1. Kill bacteria by drying them out (they're detritivores, an animal that eats dead stuff, which is probably a source of all kinds of nasty bugs)
  2. Kill other parasites, like taking a dust bath
  3. Produce Vitamin D
  4. Warm themselves up before going to bed
  5. Warm themselves up to increase metabolic rate, digest food faster
  6. Visual display of power to other turkey vultures
  7. Dry off
Double-crested cormorant sunning itself

I've also seen cormorants do this (see photo above), pelicans, and green herons. Some quick research shows that many birds do this, but their posture is different from the vultures and cormorants shown above. Indeed only a few others, like anhingas, storks, and other herons, do this standing up with wings spread. The ring-billed gull colony I encountered the following afternoon had about 300 individuals (plus a small handful of mergansers) all standing facing the sun, but with wings closely tucked in).

Colony of ring-billed gulls on the Winooski River

Some patterns in the list of birds that sun themselves standing up with wings out emerge: many are aquatic, they tend to be darker, they're carnivores, they're very large birds, they live longer than most birds, and most are in the stork order, Ciconiiformes. After writing this I looked up the order of pelicans (Pelicaniformes) to see if it used to be included in Ciconiiformes, and sure enough Pelicaniformes is often proposed as part of Ciconiiformes. What's even cooler and more surprising is that new world vultures (as opposed to buzzards and their old world kin) are close cousins of the storks. So if this behavior of standing up and sunbathing is monophyletic (occuring only in one evolutionary branch of birds), then it might be reasonable to assume it originated in a single ancestor of new world vultures, herons, storks, cormorants, and pelicans. The behavior might then serve a unique purpose among these birds.

I didn't find anything conclusive, but it looks like birds will sunbath for all the reasons that Callan and I came up with. A 1957 paper on the topic indicates that birds might also sunbathe socially; if one starts sunbathing then others will join her/him. I'm not sure what the primary purpose of sunbathing is for these birds, but I'll bet spending lots of time in/near stagnant water (for cormorants, herons) and eating carcasses (vultures) makes these birds susceptible to parasites so having a way to kill them would be good (maybe the black of a vulture heats their feathers up to a higher more lethal temperature).

Additionally, vitamin D deficiency can pose skeletal problems, making large body size a critical reason to sunbathe. Ciconiiformes and vultures don't migrate far, so in the winter they're not getting as much vitamin D as say migratory song birds might. Vitamin D deficiency prevents an animal from absorbing calcium from food. Prolonged deficiency (as with people in northern latitudes) can result in weakened bones that bend and curve under the body's weight (like the stereotypical bow-legged Eskimo). Sunning would be an effective way of producing vitamin D.

Another source says that warming up feathers "resets" their curvature, bringing them back to their most efficient shape, an obvious advantage for a turkey vulture, which spends most of its time soaring looking for food. But I couldn't verify this with any reputable sources. 

Where: Winooski River, about 2 miles upstream from Richmond.

Monday, July 16, 2012

Mourning doves

What: We've got a pair of mourning doves (Zenaida macroura) that started to build a nest in a boxelder (Acer negundo) at the end of our street. I watched the male bring supplies to the female all morning. It was a hot and listless day and the female was yawny waiting for the male to return with sticks (for more on how to identify male vs. female, check out: The Secret Life of the Mourning Dove by Michele Patenaude; in short males are larger, have rosier chests, and have more irridescent heads).

As is evident in the video, it appeared as though the male was testing the strength of each twig/pine needle to be added to the nest by banging it against the ground. Flimsy ones were discarded, sturdier ones brought back. It was fun to watch him pick through the bounty of needles and twigs in search of the perfect ones. I was in and out all morning, but I'm pretty sure the male worked on this for about 6 or 7 hours before my sister and I left the house. By the following afternoon it was abandoned for whatever reason.

A finished mourning dove nest is kind of a disaster so it was hard to tell that it had even been abandoned. I found one a few years ago with Ian Worley and I asked if it was old because it looked like it was in awful shape. He said that was par for the course and the active nests I've seen since then look almost like the birds don't really care at all for craftsmanship or aesthetics. But I guess if you're building a nest in a scraggly tree like a boxelder you build a scraggly looking nest to blend in.

Ecological notes: The nest went unfinished and I think they selected a nearby site over the next couple of days after the video. Last Sunday, Brian was outside and watched the doves attacking a red squirrel. I went out and the red squirrel was coming down a white pine with feathers clinging awkwardly to its mouth. At least one of the mourning doves, and I can't really think of a more docile bird, were going crazy. So the video is from July 1st, 7 days before "the attack". I suspect that they rebuilt and soon after laid eggs. I don't know that the eggs had hatched yet, but my guess is that the doves defended their nest from the red squirrel and the red squirrel might have bit back, but not been actively hunting the doves.

Where: Burlington, VT in my backyard.

Other notes: The red squirrels have been extra bellicose the past couple weeks. It's amazing, I hadn't really seen any of them in my back yard for about two months - just an occasional sighting. But now that the fruits on our black walnut (Juglans cinerea) are swelling, they've been fighting off the gray squirrels like that's the last food source on earth. They start wailing at dawn and don't really stop. What's interesting is that the gray squirrels, though they are certainly submissive, have been equally vocal.

Also, there was a robber fly in my backyard today. I couldn't tell what kind it was nor could I tell what it was eating, but it was fun to watch it devour its meal in fits and starts.

Friday, July 13, 2012

Long Trail

What: Last week Brian and I led a three-day backpacking trip for 11 & 12 year olds. We started at Lincoln Gap and finished at Appalachian Gap. We hiked about 14 miles total and stayed at Battell Shelter our first night and Glen Ellen the second night. The video shows some of the scenery and inside of Glen Ellen Shelter.

What else: This blog is primarily run by me, but we also have guest contributors and this fall we'll have students from Crow's Path programs updating it. We volunteer our time because we love sharing the natural world with others. If y'all enjoy it and learn a thing or two about the world around you, it'd be awesome if you could make a small donation by using the link to the right. 100% of donations support our programs directly through buying tools and gear or providing scholarships for kids. Any amount helps.

Ecological notes: On our last day, as one of the kids and I were walking down from Mt Ellen to the parking lot at Appalachian Gap, David asked how far we had to go. He remembered the parking lot at Lincoln Gap is at 2428', and suggested the Appalachian Gap was probably the same (he was right, it's 2375'). To answer his question, I just looked around me. The ridge line (about 3800'-4100' in elevation) smells so pristine with the scents of moss and spruce mixing in the updrafts blowing off the lake. As we descended, I pointed out a new plant that had started to appear, hobblebush. As we looked at the flowers, I told him that it won't grow much above 3000', so just 600' to go to the parking lot. I told him that we'd start seeing beech trees at about 2700' in elevation. I described the smooth gray (gray in America, grey in England) bark, which can look like an elephants foot, and the stiff papery leaves with perfectly straight veins. He spotted the first one, and I told him to keep his eyes peeled for more - 300' to go. The light broke open in the now overwhelmingly deciduous canopy and he started running towards the parking lot.

Where: Lincoln Gap to Appalachian Gap along the Long Trail.

Other notes: I just got back from a 30 mile paddle along the Winooski and saw some amazing things, including a roost of about 25 turkey vultures! I'll post on that in a couple of days.

Monday, July 9, 2012

The Monarch Grows Older

Feeding sign from monarch caterpillar

I went out yesterday looking for the monarch caterpillar (Danaus plexippus, see notes below for the sordid story behind the latin binomial). It wasn't where it hatched so I set out to find it. I spotted the feeding marks on a leaf which made it a lot easier. The shadowy figure taking respite from the heat was actually a moth. When I flipped over the leaf and I was pleasantly surprised with not one but three critters (one is not pictured.

Monarch caterpillar feeding on milkweed leaf

I watched the caterpillar chew an outline into the leaf (you can see it in the above photo) and when I came back the section of leaf had been entirely removed. With a voracious appetite, the little caterpillar is about 4x as big as it was last Wednesday. It's also taken on the typical coloration of monarch caterpillars. I wonder if in their first instar (each molt of the exoskeleton is called an instar) they don't have any warning colors because they haven't ingested any toxin from the milkweed yet. What's interesting is that two other species that depend on milkweed in their life history also have bright colors - milkweed or oleander aphids (Aphis nerii) and small and large milkweed bugs (Oncopeltus fasciatus and Lygaeus kalmii, respectively). Neither of these have appeared on the milkweed yet this year, but were present last year - maybe they'll show up later in the summer.

Milkweed flower buds with feeding sign from monarch caterpillar

When I went back out today the monarch caterpillar had move up to the top of the plant and was gnawing on the flower buds. You can see a chewed bud at 9 o'clock in the above photo, which is actually what drew my attention in and I spotted the monarch second (the caterpillar is kitty-corner at 3 o'clock). I went back a few hours later and took the shot below. It had moved on to another bud and was gnawing on the stem of the bud. An hour later the bud was still detached but the sagging over. The caterpillar is bigger than it was yesterday!

monarch caterpillar feeding on milkweed flower buds

Etymology notes: Danaus comes from the Greek mythological figure who had 50 daughters (monarchs have multiple generations in a year). He was the twin brother of the more well known Aegyptus (they were descendents of Io, the woman the ever-womanizing Zeus turned into a heifer to hide from the ever-jealous and vengeful Hera). Aegyptus went on to become the king of Egypt and sired a convenient 50 sons, all of whom - save one - were killed by the Danaids (the collective name for Danaus's 50 daughters, like a flock of crows is a murder, buzzards a wake, coyotes a band, and house cats a clowder - more here). 

While there are several Plexippuses found in Greek mythology, it's not difficult to narrow down the namesake to the Plexippus that was one of Aegyptus's sons. The sons drew straws (well, sort of) to marry one of the daughters. Danaus had no interest in letting his daughters marry his twin brothers sons so they 51 of them fled to Argos. The Aegyptus and his 50 jilted sons tracked them down. Danaus readily submitted, not wanting harm to fall upon Argos, but told his daughters to kill their husbands on the first night of their marriage. Plexippus married - and was murdered by -Amphicomone

One daughter, Hypermnestra, spared her husband, Lynceus, as he alone respected his wife's desire to remain a virgin. As you can imagine, he was pretty irate at the fate of his brothers and killed Danaus. He and Hypermnestra remained wedded and started the lineage of rulers of Argos (which includes such notables as Perseus). The other daughters chose new husbands by holding footraces.

Other milkweeds or tigers (the common name for members of the Danaus genus) have specific epithets (the second part of the latin name) that derive from other sons of Aegyptus (like chrysippus).

Thursday, July 5, 2012

Monarch butterfly

What: The milkweed has certainly got my attention this time of year. I spotted a monarch near the milkweed in the front of my house and my heart immediately skipped a beat with the anticipation that it might lay an egg on one of the stalks. Sure enough it did!! I told my mom I'd get her a monarch chrysalis for her birthday, so hopefully these little caterpillars will make it to the pupal stage. The eggs hatch in about 4-5 days, so and I took the above photo on Saturday. Yesterday when I went out in the evening I took the photo below:

In about 2 weeks the caterpillar will begin the process of metamorphosis, and 10 days later it will emerge a beautiful butterfly (and die 2-6 weeks later after giving birth to the next generation). Given the timing of this hatch, this should be the 2nd or 3rd generation of the year. The 4th generation is born in the fall and migrates down towards Mexico. This generation will live around 6 months.

Monarch egg on underside of milkweed leaf

I tried to catch a video of the monarch laying its egg, but I didn't have much success. They only land on the leaf for a couple of seconds and then they're off flying in crazy, unpredictable patterns (possibly to make it harder for birds to catch them on the wing?). She would lay an egg, then flap around for a few minutes before returning to lay another egg (one at a time, I watched her lay about 2 dozen in 20 minutes). The eggs were all on the under side of the leaf and always on milkweed. A couple of times she landed on a nearby Jerusalem artichoke or a beggars tick, but far more often than not it was on milkweed.

Ecological notes: I was impressed with the number of other insects making use of the milkweed. There were more tortoise beetles, some ants, an ear wig, a cabbage moth, a spider eating what looked like a June bug, and lots of long-legged flies (Dolichopodidae).

Where: Milkweed patch in my front yard.

Other notes: More cicadas singing, plus a pair of mourning doves making a nest in the boxelder across the street. I'll post more on that soon.