November 19, 2009 at 7:13 am (plant-eating insects)
Tags: Acer nigrum, Acer saccharum, black maple, Caloptilia, Cameraria, leaf miner, Maple Grove, Meacham Grove, sugar maple
by Carl Strang
Recently I reported the results of my survey of black/sugar maple leaves in the forest understory at Maple Grove and Meacham Grove Forest Preserves. Each year I measure the incidence of four groups of leaf miners on those trees at those preserves, continuing a study I began in the 1980’s. Having found very few leaf miners of any type on the low saplings in September, I returned in November to gather data from fallen leaves, nearly all of which come from the canopies of mature trees.
Linear mine on a fallen leaf
As in the understory, canopy leaves had relatively few leaf miners. The highest incidence in any 300-leaf sample was 11 leaves bearing blotch mines of Cameraria caterpillars at Maple Grove. In comparisons between canopy and understory incidences, none were statistically significant. Comparisons between canopies of the two study areas likewise revealed no differences.
I also compared leaf miner incidences between 2009 and 2008. The only statistically significant changes were decreases in Caloptilia boxfolds at Maple Grove, both in the understory (a drop from 42 to 9) and in the canopy (a similar drop from 32 to 9).
It is worth noting that I found low numbers of all four mine types at both preserves this year.
Cameraria mine in a fallen leaf
This is the first time since 2006 that the sample included Cameraria at Meacham Grove.
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November 17, 2009 at 7:43 am (insects (other), plant-eating insects)
Tags: basswood, Erannis tiliaria, linden looper, Mayslake, oak, Quercus, Tilia americana, winter moth
by Carl Strang
Last year I arrived at Mayslake Forest Preserve at the beginning of November, and went through that first month without seeing any. We’re halfway through November a year later, and I still haven’t found one there, though I’ve spotted them elsewhere in DuPage County this month. I’m talking about winter moths.
Look at the eyes on that dude! Despite the slender looking antennae, I know it’s a dude rather than a dudette because the females of the species are wingless. The winter moth, Erannis tiliaria, is a member of the inchworm family (Geometridae). The adults wait until November to emerge, and I love them despite their drab color. When the males fly through the forest in that cold air, their slowed flight gives them a dreamlike, drifting quality as they pass among the stark tree trunks of the leafless woods.
Much of their adult structure seems geared to a cold-weather emergence. Females don’t waste energy building wings. Males must fly in the warmer daytime, and apparently use a combination of enhanced vision and pheromone detection (on relatively minimal antennae) to find the females.
Winter moth caterpillars are fairly straightforward, if a little more colorful than most inchworms: white beneath, bright yellow on the sides, and pinstriped brown, white and black down the back behind the red-brown head. I’ve seen them, but never with camera in hand. Like many moth caterpillars, they consume a wide range of tree species. Their other common name, linden looper, suggests a preference for basswood. That tree is rare at Mayslake, but winter moth larvae are known to eat the leaves of many trees, including oaks, which are common there. So, I continue to look for this ghostlike moth on November days in Mayslake’s savanna and brushy woodlands.
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November 2, 2009 at 7:09 am (plant-eating insects)
Tags: Acer nigrum, Acer saccharum, black maple, boxfold, Caloptilia, leaf miner, linear mine, Maple Grove, Meacham Grove, Phyllonorycter, Stigmella, sugar maple, tent mine
by Carl Strang
In a series of posts last winter I outlined my results to date in a study of several species of leaf mining moth caterpillars that occur on black/sugar maples at Maple Grove and Meacham Grove Forest Preserves. This study, begun in the 1980’s, continues to be worth pursuing; I put in a total of about one full field day per year.
Tent mine formed by Phyllonorycter larva
One aspect of the study is a comparison of leaf miner occurrence in the canopy versus the understory. Today I’ll report this year’s results for the understory, having gathered those data in September. The story can be told simply, as I found very few leaf miners of any kind at either study area. Out of the 300-leaf samples from each preserve, the greatest number of leaves bearing a leaf mine type was 9 (Caloptilia boxfolds at Maple Grove). That number itself represented the only statistically significant change from 2008, having dropped from 42 leaves in last year’s Maple Grove sample. In comparisons between study areas, only the linear mines which I believe are produced by Stigmella showed a difference. Technically, however, the 8 leaves at Maple Grove versus 0 leaves at Meacham do not meet the criteria for the statistical test I use.
So in the understory the maple leaves were about as clean as I have ever found them. I’ll go out to collect the canopy data soon.
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October 23, 2009 at 6:18 am (plant-eating insects)
Tags: bitternut hickory, Carya cordiformis, defensive mimicry, eye spots, Geranium maculatum, leaf miner, Meacham Grove, Pachyschelus purpureus, sibling species, Ted C. MacRae, wild geranium
by Carl Strang
Last winter I described a leaf-eating beetle, Pachyschelus purpureus, which has a diet contrary to the usual rules governing leaf-eating insects. My past observations have been that, instead of eating a variety of tree leaves, or focusing on a group of herbaceous plants with similar defensive chemistries, this beetle scrapes holes in the surfaces of both wild geranium and bitternut hickory leaves at Meacham Grove Forest Preserve.
I was interested, then, to read in Missouri entomologist Ted C. MacRae’s blog, Beetles in the Bush, that he has studied beetles in genus Pachyschelus. Through e-mail correspondence I have learned from him that purpureus larvae are leaf miners, known to develop in geranium leaves. Ted encouraged me to continue observing these beetles, to see if indeed there is a particular connection between them and bitternut hickory.
The above photo I took in the late summer. I found only a few scattered Pachyschelus this year, and though they were resting only on geranium and bitternut hickory leaves, none were feeding. Thanks to Ted I now know that purpureus adults are known to feed on a variety of tree leaves. My observations simply may be of beetles taking a bedtime snack before finding winter shelter. In the spring they will emerge and lay eggs on larval host leaves. I want to continue studying this beetle at Meacham Grove, however. I want to learn to recognize their mines. Our expectation is that these will be limited to geraniums, but if I were to find them in bitternut hickory as well, that would open the possibility that incipient sibling species, separating to specialize on two separate larval hosts, may be evolving.
Incidentally, take another look at that last photo. While searching for the beetles this year I was struck by the white spots on the elytra, how they resemble eyes (complete with antenna-like extensions). A bird grabbing for the apparent head end might find its beak sliding off the hard pointed tail end of the beetle, which then could escape by flying away in the opposite direction, its dark color in the shaded forest no longer highlighted against a pale leaf.
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October 7, 2009 at 5:45 am (botany, ecology, plant-eating insects)
Tags: ermine moth, Euonymus obovatus, Meacham Grove, trailing strawberry bush, Yponomeuta multipunctella
by Carl Strang
A continuing study that I began in the 1980’s regards a low forest shrub, the trailing strawberry bush (Euonymus obovatus), at Meacham Grove Forest Preserve. Last year I outlined the history of this study. The plant’s nemesis, colonial web-spinning caterpillars of a tiny ermine moth, have been absent from the scene since 2002, and did not return in 2009. The photo below shows a caterpillar-free sprig this past June.
September is when I make my annual check of Euonymus patches at Meacham. Leaf consumption by herbivores was minimal in 2009, less than 10% in 14 of 16 surviving patches. The other two patches lost around 10%. Though the plants were affected by a controlled burn in 2007, the net effect for them appears to have been positive as competitors were hurt more than were Euonymus. Of the 16 patches, 14 showed growth in 2009, one was the same size as last year, and one was smaller. The median product of patch length x width is 5.5 m2, an increase from last year’s value of 1 m2. Since these patches are rather sprawling, containing a lot of empty space, a better measure is the rough coverage if the scattered elements of the patch all were brought together. In 2009 the range was 0.01 – 2 m2, median 0.25 m2. Even 2 m2 apparently did not provide enough photosynthetic power for fruit production. I have not seen fruit at Meacham since 2002.
However, if growth continues I expect to find the beautiful fruits of these plants returning in the next few years.
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September 25, 2009 at 6:22 am (birds, botany, geology, insects (other), plant-eating insects, reptiles and amphibians)
Tags: aspen, beauty, Bombus impatiens, Bombus ternarius, bumblebee, false hemlock looper moth, Michigan, Muskallonge Lake State Park, Nepytia canosaria, pileated woodpecker, smooth green snake, Tahquamenon Falls, Upper Peninsula, Whitefish Point
by Carl Strang
In this final chapter of my Michigan vacation account, I will bring together assorted observations of other animals and sights. None of this truly counts as inquiry, except that travel and the exposure it gives us to new places leads us to make comparisons with our familiar environment. Such comparisons often lead to questions and inquiries on down the line.
At Muskallonge Lake, after completing my investigation at the beach, I went for a walk along the state park’s trails.
There were spectacular views of Lake Superior from elevated points, and flocks of migrating songbirds to investigate.
Tahquamenon Falls State Park is named for various waterfalls along the Tahquamenon River. Especially spectacular are the upper falls.
After a summer in which I made good progress in my knowledge of Illinois bumblebees, I was interested to find that in that part of the U.P., as back home, only one common species of short-tongued, generalist bumblebee is active at this point in the season. Here it’s Bombus impatiens; at the tip of the U.P. it was the beautifully marked Bombus ternarius.
B. ternarius is a northern species that does not extend its range down to Illinois.
One of the more charismatic birds that one hears and, sometimes, sees in the north woods is the pileated woodpecker. Here is a tree that has been well worked by that species.
Beauty on a smaller scale, which provided a reminder of the season in transition, took the form of this aspen leaf lying on a trail.
I spent most of my time at Whitefish Point. Here is a small scene I found especially compelling.
As I walked out from the point to the parking lot for the final time, I found an enchanting little animal crossing the trail.
Smooth green snakes occur in many places, but are so well camouflaged that we seldom have the good fortune to see them.
On my final morning at the Tahquamenon Falls campground, I found that a large number of moths had been drawn to the restroom building’s lights.
These were nearly all males of the same species, emerging all at once.
Nepytia canosaria, the false hemlock looper moth, is a common northern species whose larvae feed on a wide range of coniferous species including firs, hemlock, pines and spruces.
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August 7, 2009 at 6:17 am (botany, history (human), plant-eating insects)
Tags: blue lettuce, Cacalia atriplicifolia, early goldenrod, Eupatorium purpureum, Eupatorium rugosum, Helianthus hirsutus, hispid sunflower, Lactuca floridana, leaf miner, Mayslake, pale Indian plantain, phenology, purple Joe Pye weed, Solidago juncea, white snakeroot
by Carl Strang
The list of flowering plants I have encountered at Mayslake Forest Preserve has grown to an impressive length. I look forward to next year, when I will be able to compare the first flowering dates between years. As I mentioned in an earlier post , flowering dates indicate the biological impact of climate in a given year. Today I will add to the list of native species blooming in woodlands.
A sure harbinger of autumn is the first of our goldenrods, appropriately named early goldenrod.
A magnificent towering beauty is the pale Indian plantain. This one once was rare and local, but restoration stewards enthusiastically have spread it to appropriate habitats across the county.
The blue lettuce is a beautiful plant topped with spreading arrays of blue flowering heads.
One that shouts to you from a distance with its large yellow flowers is the hispid sunflower.
Two species in the diverse genus Eupatorium have made their appearance in Mayslake’s woods: purple Joe Pye weed,
and the notorious white snakeroot.
The last plant was established, decades after the fact, as the one responsible for milk sickness. In some but apparently not all populations of white snakeroot, the plants produce a defensive poison which, when eaten by cows, becomes concentrated in their milk. Few herbivores consume this plant. One exception is a leaf miner .
Among the people killed by milk sickness in the 1800’s was Abraham Lincoln’s mother.
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July 29, 2009 at 6:10 am (birds, botany, ecology, gardening, insects (other), plant-eating insects)
Tags: Asclepias tuberosa, Bombus bimaculatus, Bombus griseocollis, butterfly weed, Danaus plexippus, garden, gardening, monarch, nectar thief, royal catchfly, ruby-throated hummingbird, Silene regia
by Carl Strang
Our yards are habitats for wildlife. We have no choice in that. We can, however, influence what kinds of wildlife will visit us or live with us on the land. This is true even for a tiny yard like mine. Here are some examples from my prairie flowerbeds, which are approaching their peak now.
I have planted royal catchflies all out of proportion to their presence in our local prairies.
As a result, I can count on regular visits from ruby-throated hummingbirds in July and August. Here is this year’s happy camper, photographed through the kitchen window.
I kind of like this impressionistic view of the same bird.
Red tubular flowers shout “hummingbird” to ecologists, and to the birds themselves. I wonder if royal catchfly flowers also have evolved the means to defeat nectar thieves.
This Bombus bimaculatus bumblebee behaved as though it were in one of those sticky-slow-motion nightmares. The hairs on the royal catchfly calyx either were affecting it chemically, or physically had grabbed it. It wasn’t struggling strongly, so I suspect the former. As far as I know, no bumblebee has a tongue long enough to reach the nectaries of this flower from the front. Bumblebees are known to pierce such flowers from the outside, getting nectar but bypassing the anthers, therefore not serving the plant’s need for cross pollination. Such nectar thievery could provide selective pressure favoring any adaptation in the plant that might prevent the would-be perps from being successful.
In any case, I have plenty of bimaculatus visiting my other flowers, and also a few Bombus griseocollis.
A final species for this time is the monarch.
This half-grown caterpillar is doing well on one of my butterfly weed plants.
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July 27, 2009 at 6:13 am (insects (other), plant-eating insects)
Tags: banded hairstreak, black swallowtail, Danaus plexippus, Haploa reversa, large milkweed bug, Mayslake, monarch, Oncopeltus fasciatus, Papilio polyxenes, red milkweed beetle, reversed haploa, Satyrium calanus, Satyrium favonius, southern (oak) hairstreak, Tetraopes tetrophthalmus
by Carl Strang
A couple days ago I updated the dragonflies and damselflies I have been finding at Mayslake Forest Preserve in my first year there. Today I’ll continue with newly sighted butterflies and a moth. These include black swallowtails, both female
and male.
I have not seen larvae, but there are plenty of Queen Anne’s lace and other members of the family Umbelliferae that are potential food plants. When I saw the following hairstreak, I made sure to get photos.
This proves to be a banded hairstreak. A year ago I was alerted by Forest Preserve District invertebrate biologist Tom Velat to watch for southern or oak hairstreaks. That alert was prompted by the following photo I took of that species at Fullersburg, which I failed to identify correctly.
The hairstreaks require a close study of patterns in the lines of dots beneath both wings, and the arrangement of colors in the corner of the hindwing. I have one moth to share this time, the reversed haploa.
Haploa is a genus of tiger moths. I’ll close with three insects of milkweeds. The first is a familiar butterfly, the monarch, here visiting a purple coneflower in Mayslake’s Historic Garden.
Monarch caterpillars feed on the leaves of milkweeds, in the process sequestering defensive poisons which then protect the specialist insect from its own consumers. Other insects have solved the milkweeds’ chemical challenge, and gone on to advertise their own poisonous status with bright colors. Two species in this category which recently have appeared at Mayslake are the red milkweed beetle
and the large milkweed bug.
I’m sure I have barely scratched the surface of Mayslake’s Lepidoptera.
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June 15, 2009 at 6:15 am (plant-eating insects)
Tags: Euonymus obovatus, trailing strawberry bush, ermine moth, Yponomeuta multipunctella, Meacham Grove, black maple, sugar maple, Maple Grove, mourning cloak, Nymphalis antiopa, Tortricidae, Choristoneura rosaceana, caterpillar, parasitism, Acer saccharum, Acer nigrum, Campaea perlata, tortricid
by Carl Strang
Last winter over an intermittent series of posts I summarized some of my research on leaf-eating insects in DuPage County forests. Most of that work was in the 1980’s, but I have continued a couple of studies to the present day. One of those is following leaf miners of sugar/black maple leaves . In my study forests I found that the maples host a long list of leaf consumers. Each year the parade of them begins with the tortricids. Here is the adult stage of one of those moths, Choristoneura rosaceana.
The wingspan of this mounted specimen is three-quarters of an inch. Its small larva looks like this:
The caterpillar bites through the major veins of the maple leaf at the base, so that the leaf wilts.
This presumably cuts off the leaf’s ability to produce defensive chemicals, and also provides a shelter that protects the caterpillar from birds, which focus on more easily gleaned prey. When the caterpillars become abundant, their numbers get knocked back by parasitic wasps. I found that the wasps’ eggs are readily visible in the parasitized caterpillar.
This year I decided to go back to my study areas and see what the tortricids are up to. The bottom line answer is, not much. There were a few, but in my random samples of 20 maple saplings per preserve I found only one tortricid caterpillar, at Maple Grove. There were none at Meacham Grove, though I did see a few on saplings outside the sample. This compares to the peak year of 1982, when 63 percent of maple saplings at Maple Grove and 88 percent at Meacham Grove hosted at least one tortricid caterpillar. I plan to continue taking this measurement in coming years.
Incidentally, while sampling Meacham Grove I checked out the trailing strawberry bush (Euonymus obovatus) plants to see if they have ermine moth caterpillars this year (I reviewed this study last winter). The plants all were clean and green.
At one point I looked down and saw this.
Sticking out beyond the edges of the enchanter’s nightshade leaf were moth wingtips. I tried holding the camera underneath and taking a photo without looking through the viewfinder.
The pair of moths apparently had mated the previous night and were waiting out the day. Having acquired my contingency photo, I carefully inverted the leaf. The male moth took off, but I was able to get a clearer shot of this beautiful pale green, leaf-mimicking Campaea perlata female.
On the way out of Meacham Grove I got the opportunity to photograph this mourning cloak caterpillar.
All in all, this was an enjoyable return.
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