Monday, July 31, 2017

Elephant Mosquito: The First Mosquito I'm Glad to Find in Our Yard!

It's hard to decide what I love the most:  photographing insects and other animals around my gardens or identifying the insects I see and then learning about how they fit into the patterns of life around me.

Once again I want to sing the praises of and its community of volunteer entomologists for their help and expertise.

A few days ago I was doing my afternoon walkabout, using my newly "discovered" tripod, and capturing the images of just about any animal I could find.  One of those animals was a fly that looked suspiciously like a very large mosquito, over 1/2" in length.  Thanks to the tripod, I was able to get a reasonable series of photos and look at the little beastie with a more discerning eye.

As I took the photos, one thing I noticed with my "naked eye" was that, as it fed, the insect seemed to be signalling by raising its hind legs, first one side and then the other, showing off a white "bootie" on the end of each leg.

Since the signalling was done slowly and methodically, I was able to capture pictures of it without trouble.  As I looked at the photos, though, I was not a happy camper.  Damn.  Despite all my mental attempts to make this animal into a non-mosquito-type insect, the images revealed that it simply was, indeed, a very large mosquito.  "That's all we need here in the yard," I thought, "an extra large mosquito joining the ranks of the more normal sized, always-seemingly-hungry, stealth mosquito squadron."

However, this mosquito, which appeared to be a female due to its non-feathery antennae, was obviously feeding on the nectar in the mountain mint flowers.  Hmmmm.  Was that normal?

I tried wading through the images of mosquitoes on BugGuide to learn more, but I simply wasn't getting anywhere because I really didn't know what features to focus upon.  So I asked for identification help earlier today.  Within a few hours, I had my answer - and what an answer it is!

My giant mosquito is known as the Elephant Mosquito or Treehole Predatory Mosquito.  In scientific parlance, that's Toxorhynchites rutilus.  As larvae, these mosquitoes are actually predators on other mosquito larvae!  Best of all, the adults feed at flowers, as mine was doing, and the females do not appear to require a blood meal to lay eggs!  I didn't have the slightest clue that predatory mosquitoes existed, so this has really made my night.

What a truly marvelous world we live in!

Friday, July 28, 2017

Red Aphids on Milkweed?

Many years ago I found aphids infesting a little milkweed plant I'd purchased but had yet to plant.  I didn't want to spray chemicals, but I was concerned that the little plant wouldn't make it - and I was concerned that the aphids would spread to all the other plants in my garden.  Feeling very noble and "green", I hooked up a strong sprayer to the hose and simply, carefully, sprayed all those little yellow aphids off the plant.  Ah, I'd saved it!

Except that when I got to looking at the milkweed plant after I'd washed the aphids off, I noticed a lacewing egg on its willowy stalk.  I'd washed off all the food that the lacewing mother had planned for her offspring to eat and thus I'd managed to kill the beneficial-predator-to-be.

Note:  The photo above is of a lacewing egg, but on a tree leaf, rather than on a milkweed.  The egg on the tip of the stalk is diagnostic, as far as I know, of a lacewing egg.  Sadly, I don't appear to have photographed my little milkweed/aphid/hose experiment, but I thought you might be interested in what a lacewing egg looks like.

Back to the story.....   Feeling a little sick at heart after spraying off the aphids and finding the lacewing egg, I took to the web to do some research.  WHY didn't I do that research BEFORE I reached for the hose sprayer?

It turns out that most aphids are pretty species specific regarding their host plants.  The little yellow aphids with black legs on milkweed are oleander aphids (Aphis nerii) and are found primarily on milkweeds and oleanders.  These little aphids were never going to be a problem on my asters or Echinacea or garden vegetables. 

Interestingly, oleander aphids are not native to North America.  They were brought here along with oleanders, which are also not native.  Luckily, unlike with many other non-native insects like Japanese beetles, there ARE predators and parasites that will help keep oleander aphid populations under control.

In this photo, for example, it's easy to see both the yellow oleander aphids and the aphid-eating syrphid fly larvae on the tropical milkweed.  The syrphid fly larvae are some of the predators on oleander aphids.

Fast forward to recent days.

Evidently, with so many more people planting milkweed for monarchs these days, a lot of folks are suddenly noticing oleander aphids on their milkweeds.  Questions abound about how to kill these aphids without jeopardizing the monarch caterpillars.

In my experience, thanks to the work of predatory insects, the populations of oleander aphids on milkweeds will cycle up and down, but will almost never hurt the plant.  Since I think chemical alternatives do far more harm than any possible good, I freely share my experiences whenever it seems appropriate.

In the above photo, for example, there are at least two aphid mummies and two syrphid fly larvae among the aphids. 

The aphid mummies (round, dark brown remains of aphids) are what happens when small wasps parasitize the aphids.  Each aphid mummy produces one new adult wasp.

The syrphid fly larvae feed exclusively on aphids and look like moist bird droppings to me.  You can also see the out-of-focus, brown ball of another aphid mummy in the upper left hand corner of this closeup, too.

Going back to the original photo above, here is a closeup of the second syrphid fly larva in the upper left corner.  This looks like a different species of syrphid fly larva to me.

Yellow colored, oleander aphids are the only kinds of aphids I've ever noticed on milkweeds, so imagine my surprise the other morning when I went out and found a cluster of what looked suspiciously like bright red aphids on one of the flower clusters.  What in the world?!  I couldn't help but think of Sheldon Cooper when he exclaims, "Oh, what fresh hell is this?!"

After photographing my unusual "red aphids", I realized they were actually newly hatched nymphs of the large milkweed bugs (Oncopeltus fasciatus) that I've been seeing on my milkweed plants in recent weeks, regularly having x-rated fun.  It surprised me a little bit, as I was under the impression that large milkweed bug nymphs primarily eat milkweed seeds and these were on flower bud clusters.  However, insects don't read instructions on what they are supposed to do, as we all learn daily.

Now I'm curious to see if I can tell what predators will show up to help thin the ranks of the young large milkweed bugs.  How could anyone ever be bored in a garden?!