Showing posts with label invasive species. Show all posts
Showing posts with label invasive species. Show all posts

Wednesday, May 18, 2016

I Brought 1000's of Invasive Insects to Live in my Yard

We have just introduced a colony of invasive insects to our yard. While we ordinarily think of invasive species as harmful, there are actually many beneficial species that were not native to North America. Among these are honeybees.
Italian Honeybees, Apis mellifera lingustica
Photo by Brad Sylvester, may be used only with a link back
to whatlivesinmyyard.blogspot.com


That's right. There were no honeybees in North America before they were intentionally brought to Virginia around 1622. Incidentally, that's a year before the first of my ancestors (Edward Hilton, Dover, NH) reached North America, but let's stick to the topic of honeybees. Today there are many species and sub-species of honeybees in North America. All brought over either intentionally or unintentionally to help pollinate crops and to provide honey. The climate and biosphere were so suitable to the honeybee that they spread throughout the continent.


So accepted are honeybees that most think of them as native to our nation. When the population of this invasive species began plummeting in recent decades, there were widespread cries of alarm. Plainly, not all invasive species are harmful.


We purchased a three pound package of bees which included a mated queen bee. We introduced them into a hive and within 24 hours, we can already see that they are building combs on the starter frames that we placed inside the hive. The combs that the bees build are used for several purposes. Of course, we all know about honeycombs which are combs used by the bees to store honey. The queen bee will lay her eggs in combs as well. Not honey combs, but brood combs. Once the eggs are laid in the combs, they hatch into larvae. Larvae are fed and cared for by the worker bees until they pupate and emerge as adult bees. It takes about 21 days from the time the egg is laid until an adult bee emerges.


The main reason that bees make honey is because that is what they eat during the winter when fresh nectar is not available. They store it in the honey combs and then use it as food during the winter months. That means that if we take all the honey out of the hive, the colony will starve to death. So we need to be careful to leave an adequate supply of honey for the bees at the end of the season.


In the lower section of the hive, the queen will lay her eggs. At some point, moving upward from the bottom, there is a brood/honey dividing line with honey storage above and brood combs below. This divide makes it possible for the bee-keeper to remove honeycombs without disturbing the next generations of worker bees.


Quick Facts About Honeybees:



How do honeybees survive the winter? During the winter, honeybees will stay in the hive tucked into empty comb cells clustered around the center of the hive. Although they are cold-blooded like all insects, they group together to try to conserve what heat is available. They don't truly hibernate and may come out of the hive on particularly warm days. Even in the dead of winter, a knock on the side of the hive will result in a buzzing from within as the bees react to the noise.

What do honeybees eat? Honeybees eat nectar from flowers when it is available and honey during the months when flowers are not available. They also need water to drink and will sometimes be seen visiting birdbaths or a pet's water dish during the summer if other sources of fresh water are not available.

Why do honeybees swarm? Honeybees swarm when a hive gets too crowded and a second queen emerges from the hive. This is the natural way for honeybees to create new hives and reproduce. When a hive swarms, about half the bees will leave with the new young queen and the remainder will stay with the old queen. This leaves two small hives that will gradually build up their populations again. Beekeepers often discourage swarming because a depleted hive will produce less honey because it has fewer worker bees collecting nectar.

Are worker bees boys or girls? Everyone knows the queen bee is female, but few know that the worker bees are also female. Drones are males. The queen bee mates during the swarming flight, the drones that mate with her die, and the queen remains fertile for the rest of her life. The hive is ruled by the females and not just the queen. At the end of the summer as the weather turns colder, the female worker bees will drag the larger drones out of the hive to die. Because the drones are so much larger, they'd use up too much of the stored food during the winter.

What is colony collapse? Colony Collapse Disorder is the name given to the rapid disappearance of the majority of the worker bee population of a hive. Without worker bees, the entire hive dies. In recent years, colony collapse has become widespread vastly reducing the number of honeybees throughout the country. It affects both wild honeybees and those in domesticated hives. It is well documented that Colony Collapse Disorder is caused primarily by pesticides that contain nicotinoid compounds. Because these pesticides are commonly used on corn, and beekeepers feed their bees high fructose corn syrup (which carries the pesticide from the corn plant), beekeepers can lose their entire stock of hives in a single season. Wild bees pick up the pesticide directly from the flowers of treated crops. The link between pesticides and Colony Collapse Disorder was unknown for years, but is widely accepted now due to convincing evidence such as this 2012 Harvard Study.



Taxonomy of Honey Bees
Honeybee Hive with syrup feeder
Photo by Brad Sylvester, may be used only with a link back
to whatlivesinmyyard.blogspot.com

Kingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Hymenoptera

Family: Apidae

Genus: Apis

Species: Apis mellifera

Subspecies (for Italian Honeybees): Apis mellifera lingustica


Wednesday, April 25, 2012

Which One is a Harmful Invasive Species?

Five animals found while turning and sifting the soil in
my garden to remove an old strawberry bed.
Photo by Brad Sylvester, copyright 2012.
One of the tasks I had to take care of today was pulling out an old strawberry bed to prepare the plot to become a vegetable garden this year. I moved a number of new strawberry plants to a new plot last fall. Pulling out the old plants involves shoveling and sifting roots out of the soil. Well any good garden soil is home to a community of organisms and mine is no different.

As I turned over the soil and pulled out the old roots and plants, I found a number of tiny creatures living in the soil and I put a few of them aside to detail for this blog. Each will get its own entry, but I just wanted to take a minute to show you what I dug up. Mind you I wasn't really searching carefully and I undoubtedly missed a number of smaller creatures.

Nevertheless, there are five distinct animals in the picture. Although, to be fair, it's possible that fewer than five species are represented if any of the grubs are larval beetles. I don't think they are, because I'd expect each species from a given sample plot to be in close to the same stage of development at this point.

Without going into research to formally identify theses species, I can tell that at least one of them is an invasive species to New England brought over from either Europe or Asia (depending upon which of several species it turns out to be) and is potentially a harmful invader to forests like those in my backyard. Which one is it? Believe it or not it's the earthworm although there may be others in this group as well. I haven't closely examined or identified them yet, but the smaller white grub in the top center of the picture could be a Japanese beetle larva which would make it a harmful invasive species as well.

While earthworms might be good for the garden, several common varieties are quite bad for forested eco-systems, but I'll dig into that a bit more on the individual species page when I post it.
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Monday, September 12, 2011

Western Conifer Seed Bug Nymph (Leptoglossus occidentalis), A True Stink Bug


Western conifer seed bug nymph (Leptoglossus occidentalis)
Photo by Brad Sylvester. Copyright 2011. Do not copy.
When is a bug not a true bug? When it doesn't belong to the suborder Heteroptera (True Bugs). To qualify as a true bug, there are eleven basic criteria according to bugguide.net. (Nine really, with two more that apply only to some groups of true bugs.)

  1. True bugs do not pupate. They change into adult stage gradually with successive molts.
  2. Nymphs may have different coloration and much smaller wings, but otherwise look pretty much like adults of the same species. The wings often get larger with each instar stage.
  3. True bugs often have a flattened body
  4. Wings are beetle-like, but fore-wings may be partly thickened and partly membranous.
  5. Hind-wings are membranous and used for flight (as in beetles which are NOT true bugs).
  6. When folded at rest, wing-tips overlap or cross.
  7. True bugs (and some beetles) have a prominent scutellum (triangle-shaped part of the thorax between the wings).
  8. Mouth is beak-like and made for sucking.
  9. Antennae have 4-5 segments.
  10. *Some true bugs have simple eyes (as opposed to compound eyes)
  11. *Some true bugs (including the western conifer seed bug) have defensive scent glands.
Adult Western Conifer Seed Bug: note the overlapping wings,
four antenna segments, and prominent scutellum that are
indicators of a true bug. Also note the leaf-shaped extensions
on the rear legs that make this a leaf-footed bug.
Photo by Brad Sylvester. Copyright 2012
As you can see, true bugs share some traits with beetles and many somewhat resemble beetles. If you are trying to identify an insect that you think is a beetle, but it doesn't match any that you can find, consider that it might be a true bug (Heteroptera) instead.

All of which brings us to today's find: the western conifer seed bug. This true bug was particularly difficult to identify (for me), because most guides use only pictures of the adult form and while this immature specimen is similar to the adult, the differences are enough to cause problems and, of course, I started out with beetles instead of true bugs.

Finally, I figured out that this was a nymphal form of a true bug, and from there arrived at a juvenile western conifer seed bug (Leptoglossus occidentalis). Notice that it has full wings (lacking in my specimen) and a longer, narrower body, but is otherwise quite similar. Once I had arrived at this species, I could confirm the species' presence in my yard by the adult's typical behavior and my previous observations. (Note: I added the adult photo which I took in my yard on October 20, 2012). You see, the western conifer seed bug likes to spend the winter indoors, in human houses. It doesn't breed, burrow, or eat in the house, but just likes to be indoors to stay warm in the winter. In the winter it isn't unusual for an adult specimen of the western conifer seed bug to buzz down from the rafters of my house.

Quick facts about the western conifer seed bug:

Leptoglossus occidentalis, an invasive species in New England
Photo by Brad Sylvester. Copyright 2011. Do not copy.

Range: The range of the western conifer seed bug, according to the Connecticut State Agricultural Experiment Station website, has expanded to the northeast United States only as of the mid-1980's making it an invasive species, but one that migrated here naturally over time from the West.

When is it here? The western conifer seed bug resides here year-round, over-wintering in the adult form. However, it prefers to overwinter inside human houses for protection from the winter cold. This insect may be a case of an invasive species whose continued existence here relies on human help. Although it is possible that it might be able to survive the cold under pine bark.

Diet: Leptoglossus occidentalis sucks plant juices from many species of evergreen seeds, green cones and, less often, needles.

Habitat: Pine forests.

Lifecycle: Eggs are laid in spring on pine needles. Once hatched, Leptoglossus occidentalis molts through five instar stages before reaching adulthood around August.

Lifespan: Unknown

Other facts: As mentioned above, the western conifer seed bug is one of the true bugs that has scent glands for defense. If you crush these bugs in the home, they may give off an unpleasant odor. They are sometimes called "stink bugs."

Taxonomy of the Western conifer seed bug:

Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hemiptera
Family: Coreidae
Genus: Leptoglossus
Species: Leptoglossus occidentalis

 

Thursday, July 14, 2011

Beneficial Invasive Species - Drone fly (Eristalis tenax)

Drone Fly (Eristalis tenax) is a honeybee mimic
Photo by Brad Sylvester, copyright 2011, all rights reserved
We are used to thinking of invasive species as bad things, but the drone fly (Eristalis tenax) appears to be a case of an introduced species that is actually good for the new environment. The only downside that I could find is that if you eat the maggots, you'll get sick... so, please entomophages, leave this one alone.

Bugguide.net tells us that the drone fly also known as the European drone fly, was introduced to the United States before 1874. It apparently found North America to its liking and is now well established from Alaska to Florida and point seven remotely close to being between them.

With a good look at it, the drone fly is relatively easy to identify even though its behavior and appearance mimics that of a honey bee. It is decidedly less hirsute than the average honey bee, for one thing. The drone fly does, however, fly from flower to flower pollinating them as it feeds on nectar.
The drone fly is quite common and is responsible for the pollination of many flowers and garden vegetables. Although the National Audubon Society Field Guide to North American Insects and Spiders  says it prefers compound flowers, I found it on a wide variety of plants in my yard.

The Audubon Guide also suggest that the drone fly may have fooled Ovid, Vergil, Solomon and the author of the Bible's Book of Judges (or at least the protagonist of the book, Samson). All of whom represented in their writings what must have once been a common wives' tale that honeybees rose from the carcasses of dead animals. The drone fly, a notorious honeybee mimic, does, in fact, lay its eggs in either stagnant pools or on rotting meat left in damp locations. Someone passing by and not looking too closely might mistake the drone flies, on a lion's carcass, for example, for a swarm of honeybees.

The larva or maggot of the drone fly is called the rat-tailed maggot. it has a long tail-like tube extended from the back of its abdomen that it sticks up through the surface of the stagnant water in which it lives to breathe. The rat-tailed maggot eats just about any decaying organic material that it can find, then crawls out of the water to a more dry area to pupate and become an adult drone fly.

Occasionally, if people drink fetid water or eat spoiled meat containing the egg or larval form of the drone fly, the maggot can actually live in the intestine for a while causing intestinal pain according to at least one report at the website of the Journal of Clinical Microbiology.

The Drone Fly, then, becomes the first invasive species from my yard recorded in this blog.

Quick facts about the Drone Fly (Eristalis tenax)
Life Cycle: Twenty or so eggs are laid in a group in foul water or decaying flesh. When ready to pupate, the larva climbs from the water to drier ground to form a cocoon and become an adult drone fly.  Britain's National Insect Week website says, as I suspected, that drone flies hibernate like house flies, and may wake on warmer days in the late winter.
Diet: Nectar as adults, rotting organic matter as larva.
Range: All of the continental United States, Alaska, and sub-arctic Canada.
IUCN Redlist Status: Prevalent, not-listed
When are they here: Drone flies are present all year round hibernating as adult flies in the winter, and emerging to lay eggs in the spring. Aside from the occasional warm winter day, drone fly adults are active from April through October.