The Web of Life: 2013

Wednesday, October 09, 2013

The Dancing Grasses

Pennypack meadows in the fall. © Beatriz Moisset. 2009

That autumn day, it was windy but sunny and pleasant in the meadows of Pennypack. The fields looked more alluring than ever, dressed on their ochres, tans and scarlets. The breeze played fantastic tricks on the assortment of tall grasses planted in recent years to restore the meadows to their former glory before farming and mowing had converted them into dull lawns.

Sunlight puts a sparkle on the grasses. © Beatriz Moisset. 2009

Each gust of wind made the grasses dance, sometimes a slow minuet, others a wild disco. We stood there mesmerized. No manicured meadow could produce the glorious spectacle that we observed that day.

It is fall again. When the rain ceases, we will visit the meadows and fill our hearts on their beauty and peace. Perhaps a swallow will slice the sky in its way to South America. Perhaps we'll hear the buzz of a late bumble bee before it retires to its winter sleeping place. The dancing grasses are calling us.

The wind sends the grasses dancing. © Beatriz Moisset. 2009

List of Articles

Beginners Guide to Pollinators and Other Flower Visitor

© Beatriz Moisset. 2013

Tuesday, October 08, 2013

Goldenrods and their Dependent Fauna

Blue-winged wasp on goldenrod

Goldenrods are magnets for a wide variety of animal life. I am talking about the six-legged and eight-legged fauna, insects and spiders.

I enjoy leading walks in the fall to observe all the bounty of tiny wildlife buzzing, zipping along, and crawling and hiding in the goldenrod patch. I call this program "The goldenrod zoo". My favorites are the pollinators; but I also like to point out the various kinds of galls and their amazing makers and residents.

Goldenrods used to be regarded as weeds in North America; many people still see them that way. Recently I heard a gardener, an organic gardener at that, who wants to eliminate them from her property. This made me think about the beneficial qualities of goldenrods, both to wildlife in general and to gardens in particular. So I started a list.

Goldenrod round galls in winter. One of them has been opened by a chickadee

Round galls are produced in the stems of tall goldenrods by a species of flies (the goldenrod fly). Gail Eichelberger described the fly’s life cycle in "The Gall of That Goldenrod" in "Beautiful Wildllife Garden." She also mentioned how the gall fly larvae can serve as food for chickadees and downy woodpeckers during the winter months. I will simply add that you can tell which of these two birds has opened each gall. Downies skillfully chisel a clean hole, while chickadees are sloppier, and destroy a good part of the gall to get to the prize.

There are a few other types of galls, produced by moths or flies, many of these insects also provide food for birds.

Sweat bee Agapostemon

Sweat bee Augochloropsis

Let us take a look at the goldenrod flowers visitors. There are at least 380 species that visit just one species, the Canada goldenrod (Solidago Canadensis). Not all of them are pollinators and many visit other flowers besides goldenrod. But they all benefit from these flowers’ nectar and pollen.

Syrphid fly, a good aphid control

Feather-legged fly, Tachinidae

Leaf-footed bug. Notice the tachinid fly eggs on its head

Here I am listing a few whose larvae feed on other insects, so they provide an important ecosystem service as biological controls. The larvae of some Syrphid flies feed on aphids. Tachinid flies lay their eggs on other insects especially on stink bugs or related bugs which feed on plants.

Potter wasp

Wasps of many kinds are very abundant in the fall, so perhaps they are the most common visitors of goldenrod flowers. They include not just the more familiar and feared ones, hornets and yellow jackets, but also many solitary ones, which are less likely to sting. All of them catch insects or spiders to feed their larvae.

There is one in particular that has become a favorite of mine, the large and colorful blue-winged wasp, Scolia dubia. It is rather hairy and heavy-bodied, unlike most wasps. Its wings are supposedly blue, as the name suggests. But you need a little imagination, or the sunlight hitting them just right; otherwise they look smoky. The body is very dark blue-black, except for the last few segments of the abdomen which are reddish or orange with two bright large yellow spots.

The nice thing about this wasp is that its offspring feeds on the larvae of June beetles. The females spend a good deal of time searching the ground for beetle larvae and digging them out; this earns them their other common name: digger wasp. When a female wasp finds a grub, it paralyzes it. Then it digs a little deeper, builds a small chamber, and lays an egg on its victim. Gruesome, yes, but effective.

And here comes the best part: The blue-winged wasp has developed a taste for Japanese beetles and treats them the same way as June beetles. We all know that one of the most serious problems with introduced pests such as this is that they have left most of their enemies behind in the old country, so they can multiply unchecked. The USDA tried unsuccessfully to introduce some relatives of this wasp as biocontrols of the Japanese beetle. So it is wonderful to see that a native insect has become an enemy of the invasive pest.

Blue-winged wasp

Here’s to the blue-winged wasp and to the goldenrods that sustain it in the fall!

First published in "Native Plants and Wildlife Gardens" as "Goldenrod, a Weed or a Treasure?"

List of Articles

Beginners Guide to Pollinators and Other Flower Visitors

All photos by Beatriz Moisset. All rights reserved
© Beatriz Moisset. 2013

Friday, August 09, 2013

Mile-a-Minute

In my walks along some local trails, especially the Horsham power line right-of-way trail, I often see a weedy vine called mile-a-minute. The name is a humorous reference to its speedy growth. Exaggeration or not, it can enshroud entire trees and shrubs to the point of killing them. Wherever it goes, it changes the landscape. You can recognize it easily by its triangular leaves and its thin stems armed with insidious minuscule barbs that cling to your clothes or hands if you dare to come near, and by the thick mats of vegetation on the ground or climbing up trees.

It arrived from East Asia in the 1930s, accidentally introduced to York Pennsylvania along with horticultural stock. From there, it started an inexorable march across Pennsylvania and nearby states. With the help of birds that carry its seeds, it spreads to disturbed areas, such as power line clearings and roadsides. Now, I know why it is so abundant along the Horsham trail. Its seeds can also be carried by water, enabling it to spread along rivers. Since its arrival, it has spread to surrounding states and shows no signs of slowing down.

Notice the triangular leaves full of holes

Like with many other invasives, the reason for its success is that it left behind the natural enemies that kept it in check in its native land. This is why I was surprised when I began to notice leaves full of holes. Who is eating this invasive plant? Did a local insect develop a taste for this unfamiliar food? Not so, it turns out that an ancient enemy of the vine, a small weevil, has been intentionally brought from East Asia.

Mile-a-minute weevil at the tip of the vine

Before bringing this beetle from overseas, horticulturists needed to make sure that it would not start eating other plants, causing more damage than benefits. The Forest Service launched a program of testing the beetle, which they dubbed the mile-a-minute weevil of MAM weevil for short. In 2004, when researchers were confident enough of the results, they began introducing batches of this beetle to several sites in New Jersey. The results were encouraging; the beetle is reproducing well and it seems to have some impact on the plant. In recent years the beetle has been released in many other sites in ten states.

Mile-a-minute weevil (Rhinoncomimus latipes)

Armed with this knowledge, I started my search for the mile-a-minute weevil in areas where I had seen leaf damage. It didn't take me long to find it. I was surprised at how small it is, less than one eighth of an inch, just a reddish grey dot. It chooses to eat only the tender leaves at the tip of each stem. Almost every plant I looked at had some weevils. In one case I found six of them in the same cluster of new leaves. They were busy mating and I was happy to photograph them. Despite all the holes in the leaves, the plants looked quite healthy. Perhaps, it would take a few more years for the mile-a-minute weevil to multiply in numbers high enough to have an impact on this weed. So, I congratulated the happy couples and let them go forth and multiply.

Busy beetles to the rescue

List of Articles
Guide to Pollinators and Other Flower Visitors

Friday, July 12, 2013

Milkweeds, Monarchs and More: The Milkweed Community

Monarch butterfly, adult female. It nectars on a variety of flowers

Monarch caterpillar, It feeds only on milkweeds

Monarch butterflies capture our hearts with their beauty and intrepid globe trotting. We have learned that the caterpillars need milkweeds to grow into the magnificent winged creatures. As a consequence, many gardeners gladly grow these plants in their yards and welcome the arrival of the travelers. They eagerly follow the appearance of the tiny caterpillars, their growth and final metamorphosis.

This leads many to learn more about these plants, their toxicity and the other visitors attracted by the overpowering sweet aroma of the flowers. Some gardeners don’t see them as weeds anymore but as nice additions to their butterfly gardens. Did you know that there are more than 100 species of milkweeds or Asclepias in North America? Did you know that monarchs are not the only ones that depend on milkweeds? Many other insects do. The whole story is infinitely more complex than just milkweed plant/monarch butterfly. A patch of milkweed plants is a community with many herbivores taking advantage of it, followed by carnivores, not to mention numerous pollinators.

Some of the members of this community depend exclusively on milkweeds while others benefit from these plants, but have other food choices. Pollinators and predators, fall in the second category.

Let us take a look at those that are dependent on milkweeds, those which need these plants to complete their development from egg, through immature or larval stages to adulthood. Some eat leaves; others go for stems, roots or seeds. Their tastes can be highly selective, feeding on only one or at most two species of milkweeds. Others, like the monarch butterfly, have broader tastes and accept most species of milkweeds or even some related plants. It is the growing insects that are dependent. The adults, in turn, may not need milkweeds, but they frequent these plants to lay their eggs on them.

Milkweeds have developed an assortment of defenses, such as sticky latex, hairy leaves and powerful toxins, against the cadre of hungry feeders. The eaters, in turn, have gradually found ways to overcome every one of these barriers. Milkweeds respond by producing more latex, hairier leaves, and stronger toxins. In this eternal arms race nobody wins, but nobody loses either. Like a carefully choreographed ballet, the equally matched enemies continue this dance of life and death affecting each other and in turn influencing the other members of the community.

Delicate cycnia (Cycnia tenera)

Its caterpillars feed on milkweeds

The best known, of course, is the monarch butterfly. Let us not forget its close relatives, the queen and the soldier butterflies. It is worth mentioning that a few other relatives live in South America and Africa. They are all fairly flexible and can resort to more than one species of milkweed.

Milkweed tussock moth caterpillar
feeding on common milkweed

Among the moths dependent on milkweed, the delicate cycnia (Cycnia tenera), with a very appropriate name, relies only on common milkweed and swamp milkweed. The milkweed tussock moth (Euchaetes egle) has broader tastes and can live on several species of milkweed.

Red milkweed beetle (Tetraopes tetrophthalmus)
feeds on common milkweed

Moving on to other dependents we find beetles. We are most familiar with the milkweed longhorned beetle, often found on common milkweed. If we translate the scientific name of the most familiar one, Tetraopes tetrophthalmus, we would call it the four-eyed four-eyes, although it is known as the red milkweed beetle. The peculiar eyes of all the Tetraopes beetles are divided by the base of the antennae, hence the name. But it gets more complicated because instead of just one species there are at least 14 related and similarly looking species of four-eyed milkweed beetles. Each species sticks to only one or at most two species of milkweed. For instance, the red milkweed beetle feeds only on common milkweed, the red-femured milkweed borer on showy milkweed, and the blackened milkweed beetle on swamp milkweed.

The list goes on and on. It includes beetles of several families. For the sake of briefness see images of a few of them.

Swamp milkweed beetle larva (Labidomera clivicolis)
feeding on milkweed

Dogbane beetle. Larva feeds on dogbane or milkweed

Milkweed stem weevil (Rhyssomatus lineaticollis)

Larvae of several species feed on milkweeds

Small milkweed bug (Ligaeus kalmii)

Large milkweed bugs (Oncopeltus fasciatus)

Let us take a look at the milkweed bugs. The most familiar ones are the large milkweed bug (Oncopeltus fasciatus) and the small milkweed bug (Lygaeus kalmii). Curiously, despite their names, they are not entirely dependent on milkweed. They have been seen feeding on other plants, and even on other insects, in the case of the small milkweed bug.

Milkweed aphid (Myzocallis asclepiadis)

feeding on common milkweed

Several kinds of aphids attack milkweeds. Two of them are dependent on common milkweed. They are Aphis asclepiadis, and Myzocallis asclepiadis; no common name for these either.

All these and many more feed on milkweeds, some on only one species, others on several or many.

When we nurture monarch butterflies by planting milkweeds we are doing more than aiding the butterflies. We are helping the entire milkweed community or series of communities. The members of such communities or ecosystems interact with each other and, in turn, with a wide arrangement of other participants of this intricate play, such as neighboring plants and soil organisms. By preserving the habitat of monarchs, we are also preserving biodiversity. All species are important and we need to respect these communities and learn more about them.

Large milkweed bugs (Oncopeltus fasciatus)

See also:
Food Chain in the Milkweed Patch

References

Milkweed Community

Milkweed Guide

What is native? What is not? When does it matter?

Monarch Butterfly, a Case of Mistaken Identity
List of Articles
Guide to Pollinators and Other Flower Visitors

Wednesday, May 08, 2013

Stinging Nettle. Food for Butterflies and Food for Us

I went for a walk yesterday morning, May 7, and noticed the nettles growing fast and furiously. The tender leaves are an invitation to gourmets who enjoy this healthy vegetable. I have never tasted it, but I think it is time to do so. I tried collecting a few leaves, but soon found out the sting was surprisingly powerful. I have picked up leaves in other occasions with little consequence. I may have to go back wearing gloves.

I found many recipes in the Internet. Garlicky pesto sounds promising. I will try that. Stinging nettle soup also looks tempting.

Early May is perhaps the best time to collect leaves. The plants are already tall and vigorous and, when I collected them yesterday, they seemed free from hungry visitors. However, I am surprised the next day when I look at the leaves in their plastic bag. They are now crawling with tiny aphids. Last year I found aphids eagerly sucking juices from these plants on May 12. Close observation of the aphids under a microscope led me to notice the impressive structure of the stinging hairs. Interspersed among the regular hairs, considerably larger but still small enough to go unnoticed by the bare eye, the stinging hairs look remarkably different. They are shaped like hypodermic syringes and bursting with fluid, ready to pierce the passerby's skin.

Aphid and stinging hairs

Insect activity grew significantly by June of last year. These plants turned into a zoo of sorts. Aphids abounded on many plants. Large, fat caterpillars were feeding on leaves. Some were hiding within neatly folded leaves shaped as tents. Others had already turned into immobile, colorful chrysalides.

Red admiral caterpillar

Red admiral pupa or chrysalis

Adult red admiral

I was happy to learn that such caterpillars would turn into the lovely admiral butterfly. Nettles can feed several other varieties of caterpillars, the comma butterfly and the spectacular Io moth among them.

Comma butterfly on winter attire

In summary, stinging nettles can enrich a diet and be a worthy addition to a butterfly garden.

List of articles

Saturday, January 26, 2013

Plastics are not part of the web of life

A view of garbage.

Let me repeat this: Plastics are not part of the web of life. They do not truly recycle but downcycle. They inexorably accumulate despite the best efforts at recycling because the circle cannot be completed, so this cannot be called recycling. At best what we are doing is downcycling, modifying used plastics into lower grade plastics that can be used once or at most twice in some other form. After that, they reach the end of the line.

The consequence is that plastics keep accumulating in the landscape. Horrific examples abound: dead albatrosses with stomachs full of plastic fragments; turtles and other wildlife chocked to death by plastic rings; fish full of plastic. Worse yet, the smaller fragments are out of sight, but not entirely out of the picture. Some may be inert but many others are potential carcinogens and toxins. If they are eaten by animals, they become part of the food chain. Are we eating our own plastic garbage? We probably are.

Dead albatross chick.

What to do? We may not be able to eliminate plastics entirely. Some plastics are useful, even highly valuable and we don't have to give all of them up. But we could start with the disposable, one-use only plastics, such as grocery bags and water bottles. They represent the largest bulk of plastic waste and there are easy ways to cut down on their consumption.

One-use bottles

Two great books should be helpful if we commit ourselves to the task of plastics: "Plastics, a Toxic Love Story by Susan Freinkel gives abundant information on plastics, their history, uses and recycling."Plastic-Free:How I Kicked the Plastic Habit and How You Can Too" by Beth Terry is equally informative. It is also packed full of suggestions on how you can reduce plastic usage. It also provides numerous useful links.

As for me, I have been taking steps toward reducing plastics. I take my reusable bags wherever I go, not just to grocery stores, but also other stores. Sometimes the cashier of a book store or drug store automatically reaches for a plastic bag, without noticing that I am holding my bag in front of him or her. In such cases, I promptly stop them with a smile and tell them: "We have to help the environment any way we can". I say it loud enough that other people in the line can hear me. I used to be embarrassed, but no more. I do my best to be cordial and to emphasize the word "we".

When eating out, I carry my own container and bag. When the waitress offers a doggy bag, I tell her I don't need one. I am not surreptitious about it anymore. Once again I speak loudly about helping the environment.

Biodegradable plastics.

I still don't know what to do with all the grocery items that come in plastic containers; although I am beginning to keep track of "green" stores that make an effort to provide egg cartons rather than Styrofoam ones, cardboard salad containers and similar items. But there is still a long way to go.

What suggestions do you have

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