Hairy-legged Fly, a Gardener's Friend

Female Trichopoda pennipes. © Beatriz Moisset

Unsung insect heroes of the native plant garden abound. Pest fighters such as lady beetles, praying mantises and lacewings are receiving growing attention. But pest fighting doesn't end with the three above mentioned. Wasps and flies of many sorts provide invaluable pest control services. Let us look at one of them, the hairy-legged fly (Trichopoda pennipes).

Male Trichopoda pennipes. © Beatriz Moisset

The abdomen of the colorful hairy-legged fly is bright red or orange on the male and with a black tip on the female. Both wear funny looking bell-bottoms on their third pair of legs. This flare is made of a tuft of hairs that gives these flies their name. Like all other flies, they have only one pair of wings. The back wings have been reduced to small balancers, called halteres, hard to see in most species. This fly is the exception. The halteres are relatively prominent and bright orange. If you have been struggling to identify flies by the number of wings and the presence of halteres, you want to start with this example.

They are often seen visiting flowers and drinking nectar. Thus they may perform some pollination. But their most important role in the garden is what they do to feed their young. They hunt a variety of insects on which they lay a single egg. When the baby or larva emerges from the egg, it drills into the hapless bug and proceeds to eat its insides.

Green stinkbug, Chinavia hilaris. © Beatriz Moisset

Two insidious pests are among its favorite hosts: the green stink bug and the squash bug. The green stink bug attacks a number of crops, including corn, cotton and soy bean. The squash bug feeds on squash and related vine crops.

Squash bugs, Anasa tristis on pumpkin. © Beatriz Moisset

The hairy-legged fly deserves more recognition than it gets. If you want to encourage it to visit your garden, reduce or eliminate pesticides and provide native flowering plants that bloom through the seasons so the adults find nourishment. If you are helping pollinators you are probably doing all this already.

Male Trichopoda pennipes. © Beatriz Moisset

References
Just the fly for your pumpkin patch


For more on pollinators and other flower visitors read the e-book:
Beginners Guide to Pollinators and Other Flower Visitors

List of articles

© Beatriz Moisset. 2014

The Importance of Native Pollinators

Bumble bee visiting a sunflower. © 2010 Beatriz Moisset

At the risk of repeating myself, I want to discuss once again the widespread erroneous belief that we depend entirely on honey bees for the pollination of one third of our food and that we would all die if they were to disappear. Honey bees are not the only pollinators. We must value all the others and we should learn to take advantage of them for our crops' pollination.

We must remember that 4,000 species of native bees populate this country; 20,000 the entire world. They vary in size, appearance, season of activity, flower preference. . .  Some live in colonies similar to those of honey bees, but most are solitary and nest in holes in the ground or in hollow tubes inside soft pitted canes or in holes left behind by beetle larvae.

All of them combined are tremendously important, not just for the pollination of wild flowers but also of some crops. In fact, all the crops pollinated by honey bees could be taken care of by one or another of the numerous species of wild bees.

A few examples of the marvelous things native bees do

*Bumble bees and several solitary bees pollinate tomatoes, peppers and eggplants. Only they know how to manage their flowers. Honey bees cannot do it

*The alfalfa bee and the alkali bee pollinate 80% of the alfalfa flowers they visit. Several bumble bees do just as well. The batting average of honey bees is a mere 20%

*A single southern blueberry bee can pollinate $20 worth of blueberries (probably more at current rates). Honey bees don't come even close

Osmia  sp., a mason bee. © 2007 Beatriz Moisset

*An acre of apples can be pollinated by 250 female orchard mason bees. This task would require 1.5 to 2 honey bee hives—approximately 15,000 to 20,000 bees

Squash blossom. © 2014 Beatriz Moisset

*Squash bees are up early in the morning, when squash flowers are at their peak. Later on, when bumble bees and honey bees arrive, most of the pollination has already taken place

*When the weather is bad, too cold or wet, some native pollinators go out anyway. A few work before sunrise or after sunset. The honey bees prefer to stay home under these conditions

An assortment of pollinators provides a degree of insurance. When the population of one species  declines, as it is bound to happen some years, other species take over the slack. This is one of the advantages of diversification. We have depended for too long on just one species.

Despite the advantages of this variety of native pollinators, farmers often resort to honey bees because the wild pollinators are, well, wild, not easily controlled. Honey bees provide a large task force that can be managed and transported where needed. They are perfect for large monocultures, with only one kind of food temporarily available and nothing else the rest of the year.

We shouldn't ignore the contributions of native bees. They can do a superb job at small or medium sized farms. Managing them would require a healthier habitat and less pesticides. A polyculture, the opposite of a monoculture, would also be important.

We are reaching a point in which we cannot rely entirely on just one species of pollinator. The task of changing cultivation practices is huge but it can be done and it needs to be done. The Xerces Society and some universities are committed to developing the ways of putting native pollinators to good use. The results have been highly encouraging.

Long-horned bee on sunflower. © 2007 Beatriz Moisset

 

Additional readings

One Bite our of Three
Don't Underestimate the Native Pollinators

Will We all Die if Honey Bees Disappear?

Bring Back the Native Pollinators! We need them more than Ever

Farming with Pollinators, the Xerces Society
Wild Pollinators, Agriculture’s Forgotten Partners. WildFarm Alliance
Native Pollinators. Wildlife Habitat Council

List of articles
Beginners Guide to Pollinators and Other Flower Visitors

© Beatriz Moisset. 2014 

Lady Beetles. Not all are Welcome in the Garden

Asiatic Lady Beetle (Harmonia axyridis).

It poses a threat to native ones and it is a nuisance

when it gathers in large numbers

in winter in human habitations

………

 As I discussed in Native Plants and Wildlife Gardens on July 7th, not all ladybugs or lady beetles are beneficial. Some have been introduced from other lands and create trouble for the native species. Moreover, the sale of lady beetles as biological controls deserves thorough examination. You may be spending money for nothing or, worse yet, doing harm rather than good (Ladybugs,Lady Beetles or Ladybird Beetles. How Good are They?)

Mexican bean beetle (Epilachna varivestis). Stephen Ausmus. USDA

 Here are a couple of lady beetles which will surprise you. Not all lady beetles feed on other insects. A few feed on plants and may even be pests. The Mexican bean beetle (Epilachna varivestis) is just as cute as some of the most beloved lady beetles. Sadly it feeds on beans, peas and other plants of the pea family. The only consolation is that it also likes to eat that dreadful Japanese invasive plant, Kudzu.

Alfalfa Lady Beetle (Subcoccinella vigintiquatuorpunctata)

Luis Miguel Bugallo Sánchez/ Wikicommons

………

I also want to mention another pretty one, the Alfalfa Lady Beetle (Subcoccinella vigintiquatuorpunctata). It was introduced from Asia and feeds on alfalfa and an assortment of plants, such as bouncing Bet and campion. 

Another introduced species

 Seven-spotted Lady Beetle (Coccinella septempunctata)

………

List of articles
Beginners Guide to Pollinators and Other Flower Visitors

Plume Moths: More Little Known Pollinators

Himmelman's Plume Moth

The plume moths or Pterophoridae get their name because of their feathery wings. Their aspect is quite unusual for a moth. The wings are narrow and fringed by bristles. When resting they spread their wings looking like the letter T. Their wing span ranges from ½ to 2 ½ inches. Most have a pattern of broken colors, tan and white or brown and white. The legs also present bristles. The combination of these colors and their shape makes them look like a piece of dry grass. Probably this helps them to escape predators' notice. They are easily missed by this photographer although in plain view. You may have seen one resting on your window screen where they are easier to notice

There are about 150 species in North America; most are hard to tell apart. A very common one is the Himmelman's Plume Moth or Geina tenuidactylus.

They are seen at flowers frequently, so they may be pollinators; although I don't know of any studies about it. More is known of their role as pests of some ornamentals and as biological control to keep in check some introduced invasive plants

Himmelman's Plume Moth

Moths as Pollinators
List of articles
Beginners Guide to Pollinators and Other Flower Visitors

© Beatriz Moisset. 2012

Bugs in the Garden. Hornworm: Friend or Foe? Friend and Foe

Do you grow tomato plants? Who is your worst enemy in that case? Probably the tomato hornworm or the tobacco hornworm. Those fat green caterpillars with a funny looking horn at the rear end, red in the case of tobacco hornworms, blue in tomato hornworms. Besides that minor difference they look very similar; they both attack your precious plants with gusto and grow healthy and vigorous in such a diet. They also feed on tobacco, potato, peppers and other plants of the Nightshade family.


The moths that emerge from those caterpillars after they are done growing and after a period of rest called pupation are called hawk moths or sphinx moths. They are very beautiful, mostly brown and white with orange markings on the sides of their bodies, five in the tomato hornworm and six in the tobacco one; once again not a big difference.

Naturally you hate the worms, fear to find and infestation of them in your garden and would like to exterminate them forever. Fortunately, Nature has provided a few enemies of hornworms that help you in your battle for control but you are very likely not to know them and even accidentally eliminate your little helpers in an effort to combat the worms. So, it is important to know both.

Occasionally you find a hornworm all covered with white little oval things that you might mistake for eggs. Those are not eggs at all; they are your friends. It is fascinating to learn how they got there, although I must warn you: be prepared for some gore.


There is a tiny wasp, so small that if you drop a handful of them on a white piece of paper they look like the marks you could make with a regular pen, no bigger than some scribbles. This wasp lays its eggs inside the body of a caterpillar. The poor thing feels the prick and goes back to eating and growing for a while, without knowing that it is doomed. Eventually it becomes lethargic and later catatonic. It stops moving but continues to cling to the stem of one of your tomato plants.

In the interim the wasp’s eggs have turned into minute grubs that start doing a lot of eating and growing of their own at the expense of the caterpillar. When they are fully grown, something out of the movie “Alien” takes place. Remember a scene, early in the movie? An astronaut, that had suffered an encounter with the alien creature, seems fully recovered. Then, all of the sudden, he screams and writhes in pain. A blood covered hideous creature, a parasite, the alien in question, bursts out of his chest and scurries away. They must have gotten the idea from the parasitic wasp.

The full grown grubs emerge from the body of the caterpillar after making little holes. They cling to the body for safety, and spin cocoons around themselves. By then the caterpillar is too far gone to care. The wasp’s larvae need a period of repose inside their cocoons to turn into winged adults. They emerge in a few days ready to go and infest another caterpillar. I told you that it wasn’t pretty!


But it works to your benefit. Be thankful to the wasps that keep the population of hornworms down and prevent serious damage to your tomato plants. Hold the pesticides! You don’t want to kill these friends of yours along with your enemies.

There is still another twist to this story. As I said, the unwanted pest that devours your plants turns into a handsome moth. The transformation is so complete that people even end up calling it by a different name; in the case of the tobacco hornworm it becomes the Carolina sphinx moth. It flies at night visiting flowers such as morning glories, sweet potatoes, Nicotiana, etc. in search of nectar. It hovers on front of them, unfurls its long tongue and drinks deeply. In doing so it pollinates them. It has gone from foe to friend, from tomato destroyer to pollinator. We have to think twice about our desire to eliminate the hornworm entirely. Perhaps Nature works best by keeping a delicate balance by means of parasites.

THE WEB OF LIFE. The Bear, the Waxwing and the Bee

You may be wondering what bears, waxwings and bees have in common. We'll get to that later.

Let us start with a black bear, the formidable resident of forests and broad spaces. An encounter with one of them can be an unforgettable experience. It is surprising to realize that an animal built up with such powerful claws and jaws is seldom a hunter; in fact perhaps only 10 or 15 percent of its diet consists of animal matter and a good part of that is carrion or insects. So, what does a bear eat? With great versatility it finds a wide range of plant food in the course of the year. In early spring, fresh out of hibernation it may find skunk cabbage to its liking as well as sprouts from plants in the pea family, horsetails and sedges. Later in the season it will find the growing cow parsnips and dandelions, as well as flowers of several kinds. It may supplement this vegetarian diet with some animal protein, from caterpillars to the occasional newborn elk; but still about 80 percent of the summer diet is vegetable. In the fall, it is the time to feast on berries; blueberries, raspberries and everything in between. It can devour enormous quantities of this food because it needs to fatten for the long winter ahead. It is hard to believe that such diet can become many pounds of fat in the short period of a couple of months.

And now for cedar waxwings, those attractive birds that are so much fun to watch. They are especially interesting when they are engaging in their peculiar tradition of passing berries from one to another. Cedar waxwings eat an assortment of berries through the year. In summer, when they are raising young, they enrich their diet with insects; but berries are the main staple of their diet.

Finally, let us talk about bees. Let us make it clear that I am not referring to the domestic honeybee but to any of the numerous native bees and bumblebees that feed on pollen and nectar of wild flowers. If we want to be more specific we can choose the blueberry bee. This industrious little bee is very specialized on the pollen it chooses to feed her family. It goes almost exclusively to blueberry flowers. When doing so it carries some pollen from flower to flower and from plant to plant, providing the plant an invaluable service, pollination. Once the flowers are pollinated they can start setting seeds and developing fruits.

Now, you see the link between bees and birds such as the cedar waxwing and larger animals such as the black bear. They feed on the berries that have been pollinated by the bees or, in the case of the bear, on other plant parts that also require pollination to multiply.

Experts on pollination remind us frequently that one third of our food comes to us courtesy of pollinators; most fruits and vegetables require the services of these little go-betweens, most of them bees. What they forget to mention is the large number of other species that also depend on pollinators for a good part of their diet. The bear and the waxwing are just two examples of a very long list that intertwines the little bees with the more visible birds and mammals.

Another twist in this intricate web, the bear and the waxwing digest the berries but not the seeds. So they end up dropping them farther from the mother plant and surrounded with an amount of excellent fertilizer. So, the pollinator, in turn, also depends on the seed dispersers.

But the final, and perhaps most marvelous twist, is that the plants, so dependent on pollinators and seed dispersers are actually making use of them. They are very skilled in attracting their attention and supplying their needs, either with rich pollen and nectar or with juicy, nutritious fruits. At the same time, they make sure that not all the pollen gets eaten and that the seeds can safely go through the intestines of the berry gluttons.
Thus the web is complete: flowering plants need the pollinators and the seed dispersers; bees need the flowers and the seed dispersers and, finally, bears and birds need the plants and the pollinators. When you walk through the woods or the meadows, think about this invisible web and what it is doing to make everything possible.

Bear feeding: BearDiet

Cedar waxwing feeding: Appalachian Mountain Club: Bird of a Feather...

FLOWER FLIES. Very Good Friends of the Gardener

There are some little flies that visit flowers with great frequency. Naturally, they are called flower flies; although the British prefer the name "hover flies", which describes their behavior very accurately. They are very numerous in the garden; but if you dislike house flies you don't need to worry about flower flies; they are rather pretty. You probably didn't notice their presence thinking that they were bees, rather than flies.They are excellent impersonators of stinging insects such as bees and wasps and they probably fool hungry birds into thinking that they may get stung but these little "bees". This strategy seems to work very well for them, so they can go feeding on flowers unmolested by these winged predators.

Sphaerophoria

In their visits to flowers they accomplish some pollination. They may not be as efficient as bees, but their sheer abundance makes them important pollinators of wild flowers. But there is something else that these flies do that makes them very welcome in the garden: The larvae of some of them feed on aphids.


This is such an important task that they deserve more attention than they get from plant lovers. We don't appreciate them enough.