Northern Minnesota phenology report: November 2009

By John Latimer, KAXE Radio, Grand Rapids

The last of the meadowhawk dragonflies will put in an appearance in early November. These small, bright red, insects are among the last to fly about in the fall. A warm day or two in the early part of the month will send them out in a last and probably fruitless search for other flying insects.

Flickr photo “Ruby Meadowhawk” by Jim Frazier. Original.

If you have been observing them throughout the fall you may have noticed them flying in tandem with the female periodically touching her abdomen to the grass. She is depositing eggs. Her strategy is to place her eggs on stalks of grass that will be inundated in the spring. Once awash the eggs will begin to develop and the larval stages will terrorize the shallow ponds and lake edges until late summer when they will emerge and terrorize the flying insects.

Those eggs mistakenly laid in the grass that may be your lawn will likely never develop. No one is perfect and least of all the meadowhawk dragonflies, but what they lack in foresight about those areas likely to flood they make up for in sheer numbers of eggs laid. Some of them will end up underwater and the species will survive.

Flickr photo “Dragonfly” by Chris Coomber. Original.

In the case of the meadowhawk dragonflies they survive the winter as eggs or larvae, but what about the Compton’s tortoiseshell or Mourning cloak butterflies? How do they survive the cold? They over-winter as adults and without an approach to overcome the cold they would freeze and die. For many insects the strategy is freeze avoidance.

There are three elements to freeze avoidance. First, the insect produces an anti-freeze which circulates in the blood. These special proteins bind with any ice crystals that may form keeping them small and preventing them from doing damage.

Second, they produce sugars and sugar based alcohols which act to lower the freezing point of any water in the body. These typically take the form of glycerols that by mid-winter may constitute 20 to 25% of the insect’s total body weight.

Flickr photo “Chionea species” by C Wood. Original.

The final part of a freeze avoidance strategy involves finding a dry location. Staying away from water and the resulting ice is imperative. Ice can act as a nucleator for the development of further ice crystals. The butterflies must find secure dry locations, other insects might construct waterproof cocoons or some other personal protection, but the butterflies lack this ability. This perhaps explains why I find so many of them in my garage.

John Latimer is well known throughout northern Minnesota for his phenology work. He appears weekly on KAXE radio in Grand Rapids, and audio and twitter archives are available here. His work is a frequent feature on MyMinnesotaWoods.  This article also appeared in the Duluth Senior Reporter.  It is printed with the author’s permission.

Northern Minnesota phenology report: October 2009

By John Latimer, KAXE Radio, Grand Rapids

Fall color from Oberg Mtn. Allison Eklund photo.

The arrival of fall is best announced by the leaves of the trees turning color. For many years it was assumed that these colors were in the leaves from the beginning and that as the tree prepared for winter it stopped producing chlorophyll and the intrinsic colors were revealed. Recent studies have shown that the colors are not in the leaves and must be produced by the tree.

From an evolutionary perspective simply turning color would be a waste of energy because the pigments produced are lost when the leaves fall. There must be a reason why the trees would invest in the color change. Two theories have emerged as possible explanations.

One theory is that the color is a signal to insects to stay away. Many insects approach trees in the fall to lay their eggs and in the spring these eggs will hatch and begin an attack on the tree. There is some evidence that insects avoid the most colorful trees. The trees with the brightest colors will self select because they will experience the least insult from pests. Ultimately these trees should come to dominate the forest. That they don’t is the source of much conjecture.

The problem is that some trees do not turn color in the fall. Rather they just drop their leaves while still green. Scientists that support this protectionist theory contend that there is always going to be some natural variation within the plant community. Research indicates that those trees under the greatest pressure were the ones that evolved to have the brightest colors.

Jack pine needles about to drop in fall. Esagor photo.

Other scientists have noted, especially here in the far north, that by the time trees begin to turn color the majority of their insect pests have perished.  Where then is the pressure to turn color for defense? They contend that the trees turn color to mitigate the effects of sunlight on the leaf as it shuts down.

The entire photosynthetic process must be shut down in the fall. The tree needs to carefully dismantle the chemicals used in the process, nitrogen, and phosphorus among others will be maintained in the tree to be used again in the spring. All this housekeeping requires energy that comes from photosynthesis, yet this is the process that is shutting down.

Leaves cannot use all the energy striking their surfaces in the fall and the excess can cause damage. Anthocyanins, those molecules that cause leaves to turn red, act as a sunscreen allowing the leaf to get its work done without destroying the chemicals the tree is trying to extract.

Scientists produced trees in the laboratory that were unable to produce the colors associated with fall. While these trees prospered in the greenhouse they were unable to ship nutrients to the tree for storage in the fall. This supports the sunscreen theory, but the sunscreen is only present in those trees that produce anthocyanins. The trees that turn yellow manufacture a chemical called carotenoid and this has no effect on sunlight. Currently they are arguing that there is another, as yet undiscovered, chemical doing the screening.

So it goes, the two sides concede that the other may be partly correct. Possibly the leaves turning color may accomplish more than one task. I am just glad that they do turn color in the fall. Whatever the reason it is a time of stunning beauty.

John Latimer is well known throughout northern Minnesota for his phenology work. He appears weekly on KAXE radio in Grand Rapids, and audio and twitter archives are available here. His work is a frequent feature on MyMinnesotaWoods.  This article also appeared in the Duluth Senior Reporter.  It is printed with the author’s permission.

Northern Minnesota phenology report: July 2009

By John Latimer, KAXE radio, Grand Rapids

Swamp milkweed. Flickr photo by Anita Gould. Click for original.

July 1, 1991 The first pin cherries are turning red. I wouldn’t call them ripe because it will take a bit of time before the sugars in the fruit really begin to develop. I ate my first ripe raspberry today so as I wait for the pin cherries to ripen I won’t starve. The water hemlock has begun to bloom. Another flower seen blooming today is the swamp milkweed. The beautiful red flowers are a delight to the eye.

July 14, 2002 The Atlantis fritillary winter survival must have been great because I can’t remember seeing this many before. They can be told from the great spangled fritillary by the presence of a black border along the trailing edge of both wings. The absence of the black border on the trailing edge of the wings and the broad stripe of yellow on the underside of the wing set the great spangled fritillary apart from its close cousin the Atlantis fritillary. The day of the butterflies ends with an observation of the Harris checkerspot.  All three of these butterflies are mostly orange, though the smaller checkerspot has more black than the others.

Atlantis fritillary. Flickr photo by Jerry Oldenettel. Click for original.

July 25, 2007 There are two Eastern pondhawk females sitting on a rock wall near Prairie Lake. They are startlingly green with black on the last few segments of the abdomen and the very tip is touched in white. The smooth aster, Canada goldenrod and the pearly everlasting are all beginning to bloom today. The Canada goldenrod is a favorite among the goldenrod gall flies. The select this variety almost exclusively to lay their eggs upon. Their feet taste the plant when they land, and they can tell whether or not this is the proper species.

A warm sunny day can be a perfect time to observe butterfly behavior. The males of many species are quite territorial. The sulfur butterflies are a good species to watch defend their area. A male will spend a good deal of energy and time flying after other males that attempt to infringe upon his space. These skirmishes usually involve a spiraling flight that begins low near the ground and can climb to fifty feet or more.

Eastern pondhawk. Flickr photo by Vicki DeLoach. Click for original.

Puddling is another behavior that can be seen without great effort. Sometimes just driving around after a rain storm will afford a chance to watch as males gather and share a drink at the edge of a puddle. Or if you have ever seen butterflies congregate on feces and wondered just what was going on, both of these activities are related. Typically these are male butterflies and they are attracted to these spots in search of trace minerals.

One of the current hypotheses about this behavior is that the males, by concentrating these trace minerals; make themselves more desirable to the females. The females need these minerals as well and can get them from the male during copulation. This transfer, think of it as a dowry, allows the female to spend more time and energy developing the eggs that will be the next generation of the species.

One hot July day I spent an afternoon moving a pile of bricks that had been salvaged from some demolished building. I was re-acquainted with a world I had left behind as a child. There was an entire ecosystem living in there. Ants, salamanders, spiders, millipedes, beetles of unknown names, were all living in the crevices surrounding the bricks. It was a menagerie of the miniscule.

Some of these insects are remarkably well defended. Ants carry chemicals which alert one another to the presence of danger. The millipedes secrete hydrogen cyanide through pores located near the legs. This poison is strong enough to deter almost all of the predators they are likely to encounter. Among the beetles are the bombardiers whose scalding hot spray can be selectively shot in any direction. And the spiders, those wolves of the insect world, stand ready to attack anything that crawls or flies into their range. They use chemicals to subdue and liquefy their chosen prey. For all of the innocence of its appearance it is a dangerous world down there among the rocks, bricks, and leaves.

If you are one of those people who like to tramp the woods all year around then in July keep a look out for the blue bead lily or yellow clintonia. This lily is quite common across the eastern half of the United States and can be found as far south as Alabama. The bright blue berries are a most tempting sight but close observation will reveal few if any attempts at eating them. That is because they contain calcium oxalate crystals. Sharp microscopic needles, these crystals imbed themselves in the flesh of the mouth and throat and cause pain and swelling. Look for a cluster of two to five or six berries at the top of a single stalk above a pair of lily-like leaves. And then avoid the temptation to taste them.

Pin cherry fruit. Flickr photo by George Bott. Click for original.

As July comes to a close there will be several tasty fruits ripe and ready to tempt you. The blueberries will be ready, though much depends on the weather leading up to the end of July. A frost at the wrong time or the wrong amount of moisture can wipe out a crop. Pin cherries ripen in July. Some find these a bit tart, but if you can wait and the birds don’t eat them all, they become quite sweet. And if you are a wine maker you should be watching the chokecherries. They are a bit too astringent for my palate, but they make a wonderful wine.

John Latimer is well known throughout northern Minnesota for his phenology work. He appears weekly on KAXE radio in Grand Rapids, and audio and twitter archives are available here. We hope his work will be a frequent feature on MyMinnesotaWoods.  This article also appeared in the Duluth Senior Reporter.  It is printed with the author’s permission.

Northern Minnesota phenology report: May 2009

By John Latimer, KAXE radio, Grand Rapids

There is no place I’d rather be than northern Minnesota in May and June. The rush and rebirth of life in the fields and forests is astonishing. Birds sing from every tree, shrub, and thicket. These same perches are bursting forth with life of their own. Leaves, flowers, and fruits develop with a speed that deceives. Though they seem slow and measured the flowers and fruits race to complete their mission, which is to spread seeds to insure survival. Now is the time to walk amid all this ruckus and observe its magic.

Photo: Flickr/~flutterby~

Purple clematis blossoms drape from the shrubbery. The lovely pale purple, bell-like flowers are quite large, perhaps two and a half to three inches long. The vine climbs and twists through the understory. The plant has no tendrils to support its stems, relying on the leaf petioles to wrap around supporting structures. These petioles turn woody and remain attached to the branches even after the vine has died away.

Clematis are not plentiful. The greatest populations occur here in northeast Minnesota, though even here they are never abundant They are somewhat shade tolerant but will not grow in the darkest thickets. They prefer moist, slightly acidic soils and I find them most often in the company of aspens. Often the vines will climb on young aspen, or hazelbrush, and I have seen them draped all over downy arrowwood. From the middle of May until the end of the first week of June look for the lovely bell shaped purple flowers of the clematis. You won’t be disappointed.

Photo: Flickr/guppiecat.

While the clematis bloom the painted turtles will be wandering about search out the perfect spot to lay their eggs. Wandering is perhaps not the right word, since the gravid females often return to the same locations year after year. Open sandy sites are selected and an urn shaped chamber is dug with the hind legs. Once the chamber is completed she lays eight or nine eggs on average, though she may lay as many as twenty.

The eggs are leathery and white. They are slightly oblong averaging an inch and a quarter long by three quarters of an inch wide. The developing turtle inside takes about eighty days to mature. Many of the hatchlings will remain in the nest throughout the winter. This explains the presence of the tiny turtles found in the spring well before the females have had a chance to lay their eggs. One nest studied by scientists experienced temperatures as low as twelve degrees, yet the turtles emerged unharmed in the spring.

Sea (not painted) turtle eggs. Photo: Flickr/muhawi001

Another effect of temperature on developing turtle eggs is its ability to determine the sex of the embryo. If the nest is in a sunny location and the temperature climbs above eighty-four degrees most of the turtles will be female. Conversely temperatures below this mark will produce mostly males. Inventories of populations reveal a nearly one to one relationship between males and females, so the system seems to be in balance.

It is estimated that fewer than two percent of the eggs laid each year result in adult turtles. There are many critters out there searching for a meal of fresh eggs. Fox, skunks, and raccoons destroy many nests. Hatching is only the beginning of the gantlet that they must run. Crows, mink, garter snakes, fish and even larger turtles all will make a meal of these tender morsels. And if that weren’t bad enough there are all those roads to cross. Who hasn’t seen the carnage that results from inattentive drivers. For three hundred million years turtles have faced these depredations and survived. The Painted Turtle can live for forty years in the wild, so as we move into spring, and they gather on logs to bask, let’s try to give them a brake.

John Latimer is well known throughout northern Minnesota for his phenology work. He appears weekly on KAXE radio in Grand Rapids, and audio and twitter archives are available here. We hope his work will be a frequent feature on MyMinnesotaWoods.  This article also appeared in the Duluth Senior Reporter.  It is printed with the author’s permission.

Northern Minnesota phenology report: April 2009

By John Latimer, KAXE radio, Grand Rapids

NC Native Plant Society photo

Leatherwood remains one of my favorite plants. Its lovely yellow flowers festoon the shrubs under the sugar maples, basswoods, and red oak in late April. It is one of the most shade tolerant shrubs found in Minnesota. Shortly after the snow melts leatherwood blooms, and shortly after the blossoms appear the leaves begin to emerge. This early start takes place before the canopy overhead has had a chance to close off the sun’s light.

Since leatherwood doesn’t colonize open areas, nor does it respond well to fire disturbance, a healthy population is often an indicator of a climax forest. A forest that has a stable plant community with an established dominance of species and remains unchanged over time may be said to have reached its climax. Leatherwood can be the gauge of final successional stability on soils that are deep, rich in nutrients, and remain moist. So this spring as you gaze at the lovely yellow flowers check out the other plants and think about a forest that may go unchanged into the future.

May is truly the month of spring in northern Minnesota. The month begins with the blooming of the spring ephemerals, those early flowers on the forest floor that must get their blooming done before the trees leaf out. These flowers include hepatica, bloodroot, bellworts, and wood anemones, among others. Once the canopy begins to close in, the early spring flowers whither and the plants concentrate on leaf growth and food storage. Most of these early bloomers work from a root designed for storing energy. Without this reserve few would achieve this early start.

Flickr photo by Ian Marsman

Hepaticas light the woods beginning in late April or early May. Once the bumblebees shake off their lassitude they quickly hone in on the blooms and perform the pollination.  Hepatica’s furry stems arise from the leaf litter seemingly without leaves. The leaves are there, they’re just buried under last summer’s forest debris. Hepaticas have evergreen leaves. After the blossoms fade new leaves replace the old. Walk the same forest in the fall and these leaves shine bright green while all around them other vegetation fades to brown.

The flowers of the hepaticas may have as many as twelve sepals, and they may present nearly as many colors. The nineteenth century naturalist John Burroughs said of the hepatica: “What an individuality it has! No two clusters are alike; all shades and sizes; some are snow white, some are pale pink, with just a tinge of violet, some are deep purple, others the purest blue…” The one constant key to identity remains the dense fuzz on the stem.

Walking the forest and admiring the wildflowers may be its own reward, however it pays to stop and listen to the bird songs erupting all around. May brings an influx of birds like no other month. Perhaps the most anticipated, aside from the robins who came in late March, remain the ruby throated hummingbirds. These tiny dynamos of raw energy buzz into the northland around the first week in May.

Flickr photo by Laura Erickson

I try to have my feeders out and ready by May fifth.  I use a mixture of four parts water to one part sugar and no food coloring. It’s unnecessary and may actually do harm. Honey or brown sugar are also not recommended. I never let the nectar stand more than a week, at which point I will replace it with a fresh mixture. When I wash out the feeder I use a tiny amount of bleach to retard the growth of mold. It seems a little fussy but the hummingbirds are so small and sensitive that even the least amount of contamination can be lethal.

John Latimer is well known throughout northern Minnesota for his phenology work.  He appears weekly on KAXE radio in Grand Rapids, and audio and twitter archives are available here. We hope his work will be a frequent feature on MyMinnesotaWoods.  This article also appeared in the Duluth Senior Journal.  It is printed with the author’s permission.