A Northwoods Almanac for August 5 – 18, 2022

 A Northwoods Almanac for August 5 – 18, 2022  

 

Sightings – Wood Frogs, Dragonhunters, and Red Raspberry Slime

            Dan Lucas sent me a couple excellent photos of young wood frogs. He noted, “Our yard has lots of baby wood frogs. They are in the longer grass. And for little guys/gals, they move fast and can leap 10 to 12 inches. A beauty of nature! . . . We have a small marsh/bog by the lake and are serenaded by wood frogs and spring peepers every spring. We live to hear it.”

            As you can see from Dan’s photo, wood frogs are tiny – from 1.5 to 2.5 inches. The dark brown mask through and behind the eyes is distinctive for ID purposes. 

photo by Dan Lucas

            Wood frogs have the shortest breeding season of any Wisconsin frog, starting right after ice-out on ephemeral ponds and lasting a mere two weeks. Then the adults meander off into the woods, leaving the eggs to hatch and the young to go through metamorphosis all on their own, hopefully before the pond dries up in early summer.

photo by Dan Lucas

            Chip Steele on Nelson Lake in Boulder Junction shared a photo he took at a boat landing in Land O’ Lakes of a dragonhunter dragonfly who had just captured another dragonfly. “He ( or she?) was able to fly with his catch and landed on a dead spruce bough to chow down. I heard a little crunching as he dined!”

photo by Chip Steele

            Dragonhunters average 3.3 inches long – they’re huge! They’re a fierce predator, whether as a larval nymph in the water or as an adult. The adults are known to capture and eat large butterflies, including monarchs and Canadian tiger swallowtails, and they eat other dragonflies, too, including fellow dragonhunters!

            Most folks have never seen the emergence of an adult dragonfly from its larval body, though this is a very common phenomenon. The aquatic nymph emerges from the water and clings to a vertical or diagonal surface like a plant stem, tree trunk, or pier support. Soon the skin at the back of the head breaks open and eventually splits down the back as the adult unfolds itself from within its larval case. The newly emerged juvenile pumps blood into its wings, and then rests, letting its wings dry out for an hour or so before taking its first flight. 

            The empty, dry larval shell is left behind with a hole in its back, and remains attached to the site where it crawled out until a wind blows it off. I’ve seen dozens of these “exuviae” attached to bullrush or cattail stems along various rivers we’ve paddled over the years.

            Dragonflies are full-sized once they emerge – they won’t grow any bigger.

            This process of transformation doesn’t take long, but it’s estimated that up to 90% of the young are immediately predated upon by birds who apparently know all about dragonfly emergence. The other source of mortality is boat wakes. A wave coming ashore during the hour-long drying period will wash the juvenile into the water where it dies – all the more reason for slow, no wake zones near shorelines.

            Finally, Mary, Callie and I found a patch of red raspberry slime mold in the Giant White Pine Grove State Natural Area east of Three Lakes. You have to be a real plant/fungi geek, or in junior high, to appreciate slime molds. Slime molds actually aren’t fungi or plants, but are amoeba-like life forms – plasmodiums – that can locomote around via oozing through their habitats. They feed on microorganisms that live in dead plant material and contribute to their decomposition, so while “creepy,” generally speaking they’re “good guys.” They’re usually found on the forest floor or more commonly on downed logs. In a city, you might see them on compost piles, mulch, or in roof gutters – places where moisture is consistent.

photo by John Bates

Sundews – A Beautiful Trap

            Last week, Mary, Callie and I paddled McKinley Lake, an undeveloped lake east of Eagle River, looking for “bog logs,” which are old fallen tree trunks laying in the water that have been colonized by mosses and various plants, but dominated in particular by sundews. Sundews attract our attention because they’re one of four families of plants in the Northwoods that are carnivorous – pitcher plants, bladderworts, and butterworts comprising the other three. 

photo by John Bates

            We were looking in particular for roundleaf sundew – Drosera rotundifolia. "Droseros" is Greek for “dewy” and refers to the glistening, sticky drops on the tips of the leaves, while "rotundifolia" comes from the Latin, meaning “round leaves.”

            The multitude of dew drops make the sundew a breathtaking beauty and a sticky death trap for small insects. The drops of “dew” are actually sweet smelling and sticky drops of mucilage that the plant secretes in order to attract its prey. Bugs land on the plant thinking that they have found a sweet meal, but become stuck in the goo and turn into a meal themselves! The plant responds by folding the leaves around the prey with the rapidity of response depending on what is being devoured, with more rapid response when the victim is actively struggling. 

            The prey is digested when the shorter hairs on the inner surface of the leaf secrete a mucilage containing digestive enzymes and an anesthetic that debilitates the prey. The captured insect then becomes digested into soluble materials that are absorbed into the leaf cells and later distributed to other parts of the plant. One late 19th century naturalist thus referred to the sundew as a “bloodthirsty little miscreant”.

            Sundew does photosynthesize like most other flowering plants, but the high acidity in bogs discourages the growth of fungi and bacteria, thus retarding decomposition and creating a chronic shortage of nutrients, such as nitrogen, that the plants need for growth and reproduction. 

            Henry Lyte’s botanist book “New Herbal,” published in 1578, coined the plant’s name; “the Dewe of the Sonne, or Sonnedew.” 

            Erasmus Darwin, Charles Darwin’s grandfather, hypothesized quite mistakenly in 1791 that the dew was a means of protection from predators. Later that year, William Bartram concluded quite the opposite – that the dew was a means of attracting and purposefully capturing insects. 

            It took Charles Darwin himself to conclude the carnivorous nature of sundews in his 1875 book Insectivorous Plants. Writing a botanist friend, Darwin mentioned caring more about sundews than anything else: “. . . at this present moment I care more about Drosera than the origin of all the species in the world.”

            He described them as being more sensitive to touch and taste than the animals species he had studied, and mused that they were really animals in disguise. Darwin experimented at length on sundews attempting in one set of experiments to feed inedible substances to the sundew, whereupon the sundew, after a brief embrace, would drop the false hope and patiently wait for its next opportunity. 

            Historical uses and beliefs about sundew were wide-ranging and, shall we say, imaginative. The ‘dew’ of round-leaved sundews once formed the basis of anti-ageing potions as people believed it was a source of youth and virility – the sundew itself glistening and moist even in the most fierce sun. Later on, the plant was also used as a love charm because of its power to lure and trap helpless insects. Sundews were also used as a red ink, a wart and corn remover, an antispasmodic, and as a natural flypaper to be hung indoors.  

            The small, white flowers were just coming into bloom when we paddled the lake on 7/25. The tall flower stalk helps prevent pollinating insects from getting caught in the leaf traps below, a conflict of purpose evolution cleverly chose to resolve.

            The extent to which sundew depends on its insect prey for nutrition depends on the site. Studies have shown that the proportion of nitrogen derived from carnivory varies from about a quarter to about half. 

            Midges and other small flies reportedly constitute roundleaf sundew's main prey, but they do capture mosquitoes, so hooray!

            

Loon Social Gatherings

            As August progresses, loons start gathering in social groups on our larger lakes. So, just what are they up to? Walter Piper, long-time loon researcher in our area, says this:

            “These “flotillas” – consisting of a territorial pair and from one to a dozen intruders – might appear to be friendly get-togethers. They are not! In fact, in order to understand social gathering, we must first recognize that the loons attending them comprise three distinct sets of stakeholders with mostly opposing interests. These stakeholders are: 

            “The territorial pair that owns the lake – this male and female want nothing more than to be rid of their visitors . . . because young adults without territories (termed “floaters”) spy on breeding pairs, find their chicks (as a measure of territory quality), and then return the next year to evict the pair member of their sex. 

            “Floaters seeking a territory –  these youngsters spend their second, third and fourth years learning about breeding territories. They then seek to settle on a territory that: 1) resembles their natal lake in size and pH and 2) produced chicks in the previous year. If they locate chicks in a territory, they try to boot a pair member off of the lake and take its place, forming a breeding pair with the mate of the bird they evict. 

            “Neighbors visiting from a nearby territory –There are two possible benefits [for a breeding pair to visit their neighbors breeding territory]. Neighbors without chicks show a strong tendency to visit neighbors that had chicks the previous year, probably because they hope to “trade up” from their failed territory nearby to one with a good track record. On the other hand, neighbors with chicks themselves apparently leave those chicks hiding at home and go visiting for a very devious purpose. By temporarily abandoning their own chicks in Territory A, the breeders of Territory A hope to lure floaters in the area to join them in a social gathering at Territory B, induce the floaters to spot the Territory B chicks, and thus set the stage for floaters to evict the Territory B pair members, not themselves! This . . . is a hypothesis based upon the strong statistical tendency for loon pairs raising chicks to target their intrusions mostly into other territories with chicks. We call this idea the Spotlighting Hypothesis.”

            See Walter’s blog posts for a deep well of information on loons (https://loonproject.org).

 

Celestial Events

            August 7 marks the midway point between summer solstice and autumn equinox. 

            The Perseid meteor shower occurs from 8/8 through 8/14, but peaks in the predawn of 8/12 – look for up to 60 meteors per hour, or one per minute.

            The full moon, however, occurs on 8/11, which will unfortunately wash out the best viewing conditions for the Perseids. Here’s what the “Earthsky” website recommends: “Note that this shower tends to rise to a peak gradually, and then fall off rapidly after the peak. That means you can watch for Perseid meteors in the week or 10 days before the peak. You won’t see as many meteors as you would in a dark, moon-free sky at the peak. But, in 2022, we don’t have a moon-free sky at the peak. Also note that the Perseids strengthen in number as late night deepens into the wee hours of the morning. The shower is often best before dawn. So, in 2022, we recommend you start watching in early August, from late evening to dawn. Watch on multiple mornings, until the waxing moon – brighter each night, and up for more hours – drives you back inside.”

            On 8/15, look after midnight and until dawn for Jupiter about two degrees above the waning gibbous moon.

 

Thought for the Week

            If spiritual growth and maturing of mind are what count, the dream of fulfillment is always within reach. The longing for Hudson Bay is behind me, but the grandest dream of all, entering the vast world of comprehension and knowledge, is still alive. Sigurd Olson, Reflections From the North Country

 

Please share your outdoor sightings and thoughts: e-mail me at manitowish@centurytel.net, call 715-476-2828, snail-mail at 4245N State Highway 47, Mercer, WI, or see my blog at www.manitowishriver.blogspot.com.