Sunday, August 17, 2014

Ladybugs, Praying Mantis, and other So-called Beneficials. Are They?

The native polished lady beetle, a good one
I recently published an article on ladybugs, better called lady beetles, in Native Plants and Wildlife Gardens. My purpose was to explain that not all lady beetles are beneficial. Unfortunately some are introduced species which disrupt the ecosystems, competing with and even killing some of the native ones.

Spotted lady beetle larva (Coleomegilla maculata)

In writing the article and later reading people's responses, a more serious problem caught my attention. Companies that sell lady beetles are causing more damage than good. Well-intentioned gardeners buy them without realizing the consequences of introducing non-native lady beetles or the pests that they carry.

An invasion of Asian lady beetles. More trouble than they are worth
This led me to want to learn more about other bio-controls or biological pests controls being sold to unwary gardeners. I will be writing in the future about praying mantis and their commercialization. This seems to be a bigger problem than that of lady beetles. For now, just look at these pictures. More coming up later on.

Tenodera sinensis sinensis (Chinese Mantid)


© Beatriz Moisset. 2013


Friday, July 04, 2014

Hidden Life on a Pear Tree



Bradford pear in bloom, attracting numerous pollinators
© 2014 Beatriz Moisset
Spring finally arrived, although a little later than usual. At the end of April, the Bradford pear trees in front of the Abington Library were in full bloom, white clouds against a sapphire sky. Hordes of little bees eagerly visited the sweet flowers.

Pollinators were not the only visitors to the trees. Surprisingly, life was also present in places you wouldn't think to look at. A cluster of bright yellow dots in a bark's crevice caught my eye just by chance. Afterwards, I began to see many similar clusters, partially hidden by the bark's irregularities. I knew them as lady beetle eggs, so I wasn't surprised to see some adult lady beetles engaged in romance or in search of potential nurseries for their babies.


Lady beetle eggs
© 2014 Beatriz Moisset
 A solitary green aphid painstakingly climbed the tree trunk, probably in search of tender shoots to feed on its juices. What was it doing so far from its traditional food? Perhaps, it had fallen to the ground and, obstinately, was engaged in the arduous voyage back to distant branch tips.

I puzzled at the lady beetles' choice of egg-laying sites. The tree trunk may offer refuge for the eggs, but not food for the newborns. The tiny larvae would have a long way to go to find nutritious aphids. Perhaps, just like the lost aphid, they could manage the perilous trek successfully.

I visited the trees a week later. They were still blooming, although slightly past their peak. I looked for the lady beetle eggs and found many of the clusters still in place. Some had darkened, a sure sign that the larvae inside would soon emerge, hungry for aphids. Others had become food for unknown predators and were gone.


An incipient aphid colony
© 2014 Beatriz Moisset
 Once again, I wondered where they would find food and looked at the new growth, the clusters of flowers which were already beginning to leaf out. Aha! Just as I suspected, the green aphids were there, small colonies of young and adults, wingless and even some winged ones. I would have never noticed them if I hadn't suspected their presence because of the lady beetles.

Aphids have a way of multiplying at great speed. One female can produce many babies in a mere week and the babies start reproducing in an equally short time. The small colonies I observed would become huge by the time the new leaves reached full size. They would be numerous enough to damage the new growth.


Aphid in search of food
© 2014 Beatriz Moisset
Would something keep the aphids in check? The mentioned lady beetles had their job cut out for them. But they would need lots of help and I was pleased to see other aphid enemies. I caught a glimpse of a parasitic wasp. These tiny wasps lay their eggs inside aphids and their larvae feed and kill their hosts in the process. Another great helper became apparent later on, on further observation. Some minute greenish grubs were thrashing about in the midst of the aphid colony. A syrphid fly had chosen this place to lay her eggs. The recently emerged blind and apparently helpless larvae were busy devouring their favorite food, juicy aphids. They grow fast on this nutritious diet and soon metamorphose into small flies, ready to lay more eggs.


Syrphid fly maggot feeding on aphids
© 2014 Beatriz Moisset
 The accidental sight of the lady beetle eggs led me to the related findings, aphids and their predators—an entire mini-ecosystem well hidden in bark cracks and flower clusters of a pear tree. A month later, I visited the trees again and found no traces of this entire food chain. The stems appeared too tough for the aphids; the winged ones had moved elsewhere. The lady beetles and other predators also took their leave in their perennial search for nourishment.

List of articles

© Beatriz Moisset. 2014

Tuesday, March 18, 2014

You can help pollinators in your own garden

Bumble bee on Helenium © Beatriz Moisset
Plant a pollinator garden. Turn some of your lawn into a wildflower meadow. One major objection of gardeners, the fear of stings, doesn’t need to be a serious concern. Most native bees are quite different in this respect from honeybees and hornets; they hardly ever sting and if they do, it is very mild. In fact there are some, such as the Andrenids, that are incapable of doing so. Their stingers are too small to penetrate human skin.

Avoid pesticides or if you absolutely need to use them, inform yourself carefully about the specific pesticides that kill only the target species, rather than decimating many others unintentionally. Furthermore, avoiding pesticides may not be as bad as it sounds since nature has its own checks and balances and manages to keep most pests under control without resorting to pesticides. There are some cases in which use of pesticides backfires by destroying these checks and balances. Avoid herbicides also; they can be bad for pollinators. They either deprive them of food or poison them.

Fritillary on butterfly milkweed © Beatriz Moisset
Plant native flowers, that is flowers that grow locally, not just native to the United States; these are best for pollinators. Some bees may be able to adapt to non-native plants, such as many fruit trees or some of the less fancy cultivars. But native pollinators and native plants have become mutually adapted through millions of years, so they make the perfect match in most cases.

Small bee on fruit tree blossom © Beatriz Moisset
Grow a variety of flowers that bloom through the seasons. This is good for native bees; fortunately this is also what most gardeners aspire to have in their gardens. However highly selected cultivars or those with doubled-flowers don’t take care of the needs of pollinators. In general they have lost all the cues that pollinators need, such as scent. In some cases, they have also lost the pollen or nectar and so they don’t provide any food to bees.

Sunflower and bee © Beatriz Moisset

Plant the kind of lawn that provides habitat beneficial to bees. A perfectly manicured, pesticide saturated lawn is a desert to wildlife, including pollinators. Reducing the size of the lawn would benefit native pollinators. But it is also possible to have a lawn that is good for bees while being esthetically pleasing. As mentioned before, stay away from pesticides and herbicides as much as possible. Second, allow some small wildflowers; the look of your lawn may change as a result but it will continue to serve its purpose. Clover is great food for native bees; it also fixes nitrogen cutting down the need for fertilizers. Other small plants that benefit bees are ground speedwells (Veronica), wood sorrel (Oxalis acetosella), smartweeds or knotweeds (Polygonum), wild strawberries (Fragaria, several species), etc. Rather than calling them weeds we should call them grass companions or pollinator food.

Nests of solitary bees © Beatriz Moisset

Provide housing for bees. A simple bare spot here and there (no mulch or grass, just bare soil) may be enough for a few hard-working soil nesters. A sand pile may be even better. It bears repeating: There is no real need to worry about stings from solitary bees.

Dead logs or snags can supply housing for bees. You probably can’t have a dead tree on your property, but it is possible to keep a stump or a standing log and use it as an attractive planter; perhaps it will in turn provide housing for some little bees. Drilling holes on an old post or even a tree trunk would also make good nesting sites. They should be 3/32” to 3/8” in diameter and at least 4” deep.

Or you can make your own bee houses. It is possible and relatively easy to build one by following instructions posted in several websites. Or you can buy one; some resources listed below. I have discovered that watching the comings and goings of those busy mother bees can be as much fun as observing a bird house. Once again, stings don’t seem to be a real problem; I have had my face right in front of their houses and have even let them climb on my finger without any consequences.

Hollow tubes, just about the size of drinking straws, can also be used as bee nests. Some of the suppliers listed sell them. You can also tie up a bunch of hollow twigs, such as elderberry, or paper drinking straws (plastic ones are no good) together or pack them into a container such as a small milk or cream carton and place them horizontally. They should be closed at one end with the open end facing south or southeast. If you have trouble figuring out where the south is, step outside sometime between 10 AM and 1 PM and face the sun. That is how you want to place the nests. (See links below for instructions).

You can let some of your ornamental grasses stay all winter; they can be quite handsome and add variety to your winter landscape while providing nesting to your friendly native bees.

Helping the native bees would benefit us because of their invaluable services to the environment and to our gardens.

Pollinators and their multiple benefits © Beatriz Moisset


Resources
Ross, Edward S. (2003) Pollinator Conservation Handbook. The Xerces Society and The Bee Works. Portland, Oregon ISBN 0-9744475-0-1. (Bee gardens, bee houses, etc.)
The Xerces Society Guide (2011). Attracting Native Pollinators. Storey Publishing. ISBN 978-1-60342-695-4 (Everything you want to know about pollinators and their conservation)
Urban Bee Gardens. Berkeley University
Nests for Native Bees. The Xerces Society
Bee houses. National Wildlife Federation. (How to build a bee house)

Sellers of bee houses
Knox Cellars.
Mason bee homes.


List of articles
Beginners Guide to Pollinators and Other Flower Visitors


© Beatriz Moisset. 2014

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?"


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


Mile-a-minute climbing up a tree © 2013 Beatriz Moisset
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
© 2013 Beatriz Moisset

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
© 2013 Beatriz Moisset

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)
© 2013 Beatriz Moisset
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
© 2013 Beatriz Moisset

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)


References