Predators and Parasites on Oleander (Milkweed) Aphids

My milkweeds are hopping these days.  Sadly, I've only seen one monarch caterpillar, but I am still fascinated by all the insect life that I am seeing.  Most of my observations have been on tropical milkweed (Asclepias curassavica) simply because I have several big, healthy plants in pots on my back patio and they are easy to check on and photograph, but I'm fairly certain that what I'm seeing isn't unusual for other milkweed species.

The orange-yellow oleander aphids (Aphis nerii) are common on these plants.  A week ago, when many of these photos were taken, the aphids covered about 2-3" of the top of every shoot.  This week their numbers are much reduced, with just a few hardy individuals remaining where hundreds dined last week.  This is at least the second rise and fall of aphid numbers on my plants this summer.  I'm sure they will go through at least one more population cycle up and down before frost comes this autumn.

So what's keeping the aphid populations from exploding out of control?  If you look closely at the photo above, you can begin to see the answer.  Specifically, here are some of the candidates I've been seeing....

Each milkweed shoot with its covering of yellow aphids near the tip seems to also have at least one or more of these blobs of gray and white protoplasm which, I am pretty sure, are actually syrphid fly larvae.  Although the blobs are stationary when I usually see them, I have occasionally seen one "hightailing" it from one area to another.  Looking on BugGuide.net, this looks like the larva of the syrphid fly, Ocyptamus fuscipennis.  I have certainly noticed syrphid flies that look like these adults hovering around the aphid clusters.  There is no common name for this little fly that I know of, but the BugGuide link will allow you to see what the adult looks like, so that you can notice if your milkweed aphids are attracting attention from this species, too.

Less common, but still easy to find, are these little bumpy caterpillar-like animals that are also, I believe, syrphid fly larvae.  I've not been able to figure out which species or even genus these guys belong to, but I do find it fascinating that two different species of syrphid flies are munching on my oleander aphids!  The only way to really tell for certain would be to raise up some of these larvae to adulthood, which sounds like a fun project when the boys get a little older.

If you ever see a piece of trash seeming to move on your plant, look a little more closely....

You may be seeing a green lacewing larva, which hides under a pile of debris that includes its castoff skins from earlier molts. 

If you look closely in the photo above, you can easily see the yellow oleander aphid being eaten...by the actual lacewing larva at the bottom of the pile of debris.  Lacewings are fierce aphid predators as both larvae and adults.

Not uncommonly among my aphid populations, I will see a dark brown aphid that doesn't move.  This is an aphid mummy.  Tiny parasitic wasps lay an egg in an individual aphid and the developing wasp larva eats out the insides of the aphid, leaving the aphid a literal shell of itself.  Only one baby wasp per aphid, but each female wasp can then go on to lay eggs in many aphids, so aphid mummies are welcome sights on my milkweed plants.

There are other more generalist predators that I'm seeing around my milkweeds, too, which may or may not be preying on the aphids.

I often see tiny, longlegged flies, for example, flying around and landing on milkweed leaves for short periods of time.  Longlegged flies (Family Dolichopodidae) are iridescent green or brown and are known to be predators in both the larval and adult forms.  Although I have never seen one pay attention to, let alone eat, an aphid, I can still hope.  They've got to be eating something!

Clad in the red-orange and black colors of the classic milkweed insect, milkweed assassin bugs (Zelus longipes) are another generalist predator that I see these days, both on milkweeds and on other plants around the yard.  I see the milkweed assassin bugs hunting up and down the plants, sometimes hanging out in the flowers, but just as commonly walking up and down the stems or inspecting both sides of each leaf.  Their eyesight is superb and it can be hard to sneak up on one to take its picture.  At first it will simply duck to the other side of a stem or leaf or flower cluster, but if you persist, it will readily fly away.

The final predator I've been consistently seeing around my milkweeds in recent weeks is a damselfly.  Again, I don't know if this dainty creature is eating winged aphids or not, but I doubt it would turn one down.

So, as you look at the aphids on your milkweeds in horror and dismay, look a little closer - there's a good chance you'll see some other, interesting insects drawn in to the feast that they represent in the animal world!

A Trickle of Native Insects Begins to Appear....

FINALLY!  We've lived here for about 16 months now and at last I am beginning to see a greater variety of  insects attracted to and living in our yard.  It's so exciting to go outside and see native pollinators nectaring at the few little blooms we have scattered around, or predatory insects patrolling the foliage and flowers.  It sure goes to show that changes don't have to be big or dramatic to have an impact.  Every little bit counts.

So here are some of my recent finds....

Gulf fritillaries (Agraulis vanillae) are gorgeous butterflies, with silver patterns on the undersides of their wings and an almost fluorescent orange coloration on the top side.  The fresh individual in the top photo was nectaring at garden phlox (Phlox paniculata), while the tattered one in the lower photo is nectarying at Flyr's Nemesis (Brickellia cordifolia), a rare wildflower in Florida that has recently become available at some native plant nurseries, including 7 Pines Native Plant Nursery in DeFuniak Springs.

Out and about, I'm seeing more gulf fritillaries flying everywhere these days, presumably due to the time of year.  However, I'm starting to count on seeing them regularly in our yard since we finally have some caterpillars eating the maypop vines (Passiflora incarnata) that we planted on the lower terraces last spring.  Just as monarch caterpillars only eat milkweeds, plants in the genus Asclepias, so gulf fritillary caterpillars only eat maypops and passionflowers, plants in the genus Passiflora.

Predators are pretty rare in the yard still.  It took me around 5 years to start noticing them regularly in my Kansas gardens, so I'm trusting that they'll increase in number as I garden naturally here.

With a lake right out the back door, however, we do have several dragonfly and damselfly species.  One of the species I've just started to see is the eastern amberwing (Perithemis tenera).  A male and a female have staked out the small patch of powderpuff (Mimosa strigillosa) in the front yard and I can count on finding them there essentially every day.

Although this species is quite small for a dragonfly, the male eastern amberwing, shown above, is easy to spot since he's dramatically colored, with shining amber-colored wings and a darker amber body.  Up close, the camera captures yellow markings on the thorax and abdomen that the eye generally misses.  The female, however, is much different....

...and much drabber.  Her darkly blotched wings and more sober colors don't attract the eye as her mate's colors do, but that's probably the point.  She, too, has yellow markings on her thorax and abdomen. 

These small dragonflies are said to eat "tiny, flying insects", which I interpret to mean mosquitoes.  Hopefully my male and female eastern amberwings will produce lots and lots of baby eastern amberwings to patrol my yard even more thoroughly!

Another colorful species that I've observed, photographed, and been able to identify is the metallic green bee, Agapostemon splendens.  I've always loved the metallic green bees, especially the ones that are entirely green, because of their vibrant coloring.

Shown above, the females of Agapostemon splendens are especially beautiful to my eye and earn their "splendid" moniker based on the beautiful shadings of blue and green on their abdomen.  Note:  I have no real idea why this species was labeled the splendid green metallic bee, but I think the abdomenal color IS splendid.

Here's another, closer look at that gorgeous color.  Look, too, at the pollen load that this little bee is carrying - the pollen from this species of flower is white, not yellow, and that's a LOT of pollen clustered on her hind legs!  She still has to finish her load and, most importantly, fly back to her nest with her carefully gathered provisions.  Like many other native bees, the Agapostemon bees nest in the ground, usually in a tunnel dug by the female.  After digging the tunnel, the female gathers together a ball of pollen and nectar, lays an egg on it, seals off the cell, and repeats the process several times.

Interestingly, like the eastern amberwing dragonfly above, Agapostemon splendens is another dimorphic insect species, with the male looking significantly different from the female.  The photo above is a male of the same species.  While the thorax is similar to the female's, the abdomen is completely different - males sporting a natty black and yellow stripe pattern that is vibrant, but not as pleasing to my eye.  This little guy was fun to watch.  He seemed to perform head stands as he fed, diving deeply into the flower to get his prize.

Unlike the colorful green metallic bees, the next bees I want to share with you are somber black with a few white markings.

Another native bee, this is a carpenter-mimic cuckoo-leaf-cutter (Coelioxys dolichos) - a name that seems more interesting than the bee looks, at least on first appraisal.  That's the bloom of a wild lettuce (Lactuca sp.) that she's feeding on.

What drew my attention to this bee was the pointed abdomen, which is very distinctive.  Cuckoo bees are parasites on other bees.  The females of this genus of cuckoo bee, Coelioxys, use that sharp abdomen to break into the nests of their host species and lay eggs on the pollen and nectar stored there for the host's eggs.  Because female cuckoo bees don't have to provision their own nests, they don't have pollen baskets and they aren't seen carrying pollen;  they do, however, still have to feed themselves.

This particular species, the carpenter-mimic cuckoo-leaf-cutter, is a parasite on a single bee species called the carpenter-mimic leaf-cutter bee (Megachile xylocopoides). Ironically, when I went to look up M. xylocopoides, I recognized the pictures as showing the same species as another, unidentified bee species in my recent photos!  I even took the photos of the two different species within a few feet of each other, just 1 day apart!

Here is the male carpenter-mimic leaf-cutter bee (Megachile xylocopoides), also feeding on wild lettuce blooms.  Did the two bees, the predator and the prey, hatch out of the same nest?  There's probably a good chance of it.  At the very least, it would appear that the nests were nearby.

There are many more sightings I'd love to share, but this post is long enough for now.  Hope you're seeing lots of interesting insects in your gardens, too!

The Milkweed Community Beyond Monarchs

My attempt to rescue 4 monarch caterpillars that were about to eat out their food source seemed to fail, despite my provisioning them with 6 white milkweed and 2 swamp milkweed plants from 7 Pines Native Plant Nursery.  The last - and largest - of the caterpillars curled up in a question mark on the soil surface one day and then disappeared overnight.  Eaten?  Probably.  Pupated somewhere?  Possibly.  At any rate, I have no more monarch caterpillars to watch right now.

However, I do have my 8 milkweed plants.  Making me quite sure that these plants weren't being treated with neonics, my milkweeds came pre-supplied with bright yellow aphids.  A little research on BugGuide.net informed me that these aphids are oleander aphids, Aphis nerii.  Oleander aphids are actually native to the Mediterranean area, but they have become common around the globe, having traveled everywhere on oleander plants.  Oleander aphids are especially common on oleander and on milkweed plants, although they are known to feed on several other types of plants as well.

As I was looking for the monarch caterpillars, I noticed a fly hovering about 6" from the milkweed plants. Watching more closely, I noticed there were actually about 6 flies, and that occasionally one would dart in, look like it was depositing something, and return to hovering.

So I got my camera and tried to take a photo.  After a long time - and many attempts - I hadn't managed to get a nicely clear photo, but I had managed to get a couple shots where I was able to at least get a feel for the flies I was seeing.

Between the blurry photos, the gestalt I had, and the research I did, I think that this little fly is a species of syrphid fly, Ocyptamus fuscipennis, known both for its dark colored wings and its diet of aphids in the larval stage.  That's just my best guess, however.  It's not a verified identification.

As I was trying, again and again, to get a clear photo of one of the syrphid flies, I suddenly noticed a couple tiny, tiny wasps walking among the aphids.  As I looked through the camera lens, I watched one of the wasps curl its abdomen and seem to poke the aphids individually.  This was a little odd, because the wasp curled its abdomen relatively far away from the aphids, but I was sure that it was laying eggs on them.  Again I took photos, but again I didn't get any good shots - to get clear photos of such minuscule insects, I needed a tripod for stability and a windless day with no sway in the plant stems.

Despite my lack of good photos, I saw enough to have a good idea of what was going on.  After more research, I suspect that the small wasps were braconid wasps, which parasitize aphids by inserting an egg in an individual aphid.  The egg hatches and the larval wasp eats the aphid from the inside, killing the aphid and leaving an "aphid mummy", which is essentially the shell of the aphid with the larva, then pupa, of the wasp inside.  When the wasp emerges from its pupal stage, it cuts a hole in the aphid mummy and emerges, to repeat the cycle.  If you click on the link I've highlighted, you'll see a great photo posted on BugGuide.net of one of these wasps in egg-laying stance, ready to lay an egg on an oleander aphid.

Note:  Looking at several of my photos from this series, there are many little dots on them.  The dots were only visible when I enlarged the images and they only occurred in the middle of the milkweed plants.  I don't think it was a dirty lens (although I will certainly be cleaning it to verify).  There is also a small, beetle-like insect on the vein of the milkweed leaf in the very bottom right of the photo above, which I haven't identified.  I think it might be some sort of weevil, but that is simply another guess.

So right now, with no milkweed blooms to be had, I've already got 4 species that are relying on my milkweeds for the basis of their life cycle:  monarchs, oleander aphids, a syrphid fly, and a braconid wasp.  I've also seen examples of herbivory (monarch caterpillars and oleander aphids), predator-prey relationships (syrphid flies and aphids), and parasitism (braconid wasps and aphids).  Pretty cool for February!

Another Wasp Player in the Garden

I'm starting the process of going through the photos from 2014, the ones that I didn't have time to edit or identify during gardening season.  There are SOOO many to go through!  And most of them are of insects.

Anyway, luckily I don't have many insect photos from January, February, or March. So I'm already on April.

I have to laugh.  You'll probably recognize the first insect I needed to identify, since it commonly comes to porch lights in spring time.  I took this photo on April 21st.  The greenery is Eastern Redcedar (Juniperus virginiana).

I recognized it as an ichneumon wasp, but I didn't know much more than that.  I've seen many, many of these over the years.  None have ever acted aggressively; I don't know if they are capable of stinging or not, but since they are wasps, I don't push the matter.  Anyway, I still don't know a lot more about them, but the little I learned tonight made me laugh - is EVERY insect I learn about a predator?!

Anyway, this beastie is a short-tailed ichneumon wasp, Ophion sp.  Their larvae are caterpillar parasites - one larva per caterpillar.  The caterpillar does not survive the encounter.

So, in the future, if you see one or more at your porch lights, you should rejoice.  This is natural pest control at its finest!

Another Worry for Cicadas: Cedar Beetles

Kermit the Frog always said, "It's not easy being green."  Well, I've decided that it's not easy being a cicada either.

My dogs absolutely love to munch cicadas and have been known to catch them in mid-air.  If they find one on the ground, they'll often hold it in their mouth for a little bit to get it to buzz before they chomp down and eat it.  A canine "Fizzy", I guess.

Then there are more "normal" predators like birds and, especially, the huge wasps known as cicada killers.  Female cicada killers hunt down a cicada, sting it to paralyze it (but keep it alive), drag it back to their nest in the ground, carry it below ground, lay an egg on it and seal the brood cell off.  When the egg hatches, the larval wasp eats out the paralyzed, living cicada, pupates, and emerges the next year to repeat the cycle.  An effective population control mechanism for cicadas, although it's extremely unsettling to think about.

I suspect that moles eat a fair number of cicada nymphs, too, as the nymphs feed and mature underground.

Now, I've learned about another animal that feasts on cicadas, specifically on the nymphs while they are still underground - the cedar beetle, Sandalus niger, also descriptively known as the cicada parasite beetle.  I've been observing these large beetles all around the yard over the last few days.  Most often, I'm seeing them on honeylocust trees.

These are fairly large beetles - many are close to an inch in length.  I first noticed one when I saw a big brown beetle being eating by 2 wheelbugs.  I've never seen TWO wheelbugs eating the same beetle before!  I took photos and tried to identify the beetle, but I couldn't quite make it out.  It looked somewhat like a longhorn beetle, but I didn't see long "horns" (antennae) on it.

While I was photographing this interesting vignette, Greg called me over to a nearby lacebark elm, saying that he'd just seen a big black beetle fly into it.  He showed me where she had landed and I took several photos of her;  she appeared to be laying eggs on the underside of a dead limb.

I started to go back to taking photos of pollinators on asters, when I felt something on my shoulder.  Looking down, it was a large black beetle with one of the elytra (thickened wing covers) missing.  I brushed her to the ground, where I photographed her, wondering how she had lost her elytra.  Then I picked her up and put her in the elm tree, thinking she probably got interrupted during egg laying.

Only when I edited the photographs this evening did I notice that all the white "innards" showing were actually larvae(?) or pupae(?) of some other insect that were massed inside her.  I have no idea what they are...but I'm submitting the photo to BugGuide to see if anyone there can help identify what was going on with her.  (Parasites eating parasites.  Sometimes the natural world is really complex in its creepiness.)  Did the larvae have anything to do with how she lost her wing cover?  I have no idea.

Next, I noticed another, similar looking beetle being eaten by a wheelbug on a nearby honeylocust trunk.  As I stood and took photos, I heard and felt yet another big beetle - the 5th one - fly by my head.  It was a male, judging by its smaller size and more slender body, and it landed on the tree trunk right in front of me and starting searching all around.  Its antennae were really interesting, especially when the beetle fanned them all the way out.

While all of these beetles were grabbing my attention, I was also hearing a clicking noise that sounded very much like the rhythmic pattern of a field sparrow, which is often likened to the sound of a bouncing ball.  This noise, however, was more "insect-like" than a bird call, if there is such a thing.  I never did find out what was creating the sound, but I don't recall having heard it before and I wonder if it was some sort of mating call between the cedar beetles.

Before I went in for the evening, I took several more photos of each of the different beetles I'd observed, and  I also found a 6th beetle on the underside of a honeylocust branch. This was another female, based on the size and shape, but I didn't get any clear photos of her.

Looking through Insects in Kansas, by Glenn A. Salsbury and Stephan C. White, I found the tentative identification of my beetles, which I confirmed on BugGuide.net.   They were all the same species, Sandalus niger.  Insects in Kansas had noted that males often had blackish-brown wing-covers, rather than black, and on BugGuide, I saw the difference in antennae between the males and females.  There wasn't a lot of information given about the species on its information page at BugGuide, but it was noted that the adult beetles are very short-lived.

I've gone back and picked up the "empty" beetles discarded by the wheelbugs after they were through eating them so that I could examine them more closely, plus I've been able to find a couple more dead specimens.  Sunday, October 19th, was the only day that I saw so many living individuals, although I've seen one or two more each day since then.  I have not heard the clicking noise again.

I have seen one more instance where two wheelbugs were eating the same cedar beetle.  Do wheelbugs do this with any large insect, or is it only with cedar beetles?  I'll be keeping my eyes open to see what I observe in the future.

Isn't the complexity of life fascinating?! 

The Fly and the Caterpillar: Not a Love Story

As I was doing a quick look-see in the vegetable garden yesterday, I heard a fly buzzing.  Why a buzzing fly caught my attention, I really can't tell you, but it did.  Perhaps it was because the noise was coming from the top of a tomato plant, which isn't normally fly country.  Anyway, I stopped to see what was going on.

At first I didn't see anything, then a movement attracted my attention.  Was that a smallish horn worm? 

I kept looking, finally able to see the outline of the caterpillar against the underside of one of the tomato leaves tucked in a ways.  Suddenly I saw a quick, dark movement and the caterpillar thrashed wildly.  What was going on???

As I watched, it became obvious that a fly was attacking the hornworm.  Every time the fly circled around and came near, the hornworm would move.... Trying to defend itself?  Trying to attack the fly?  Trying to keep the fly from landing?  I couldn't really see what was going on, but I took a series of photos, hoping to capture something with my lens that my eyes couldn't see.

Here are the best shots from the encounter...

The hornworm when I first saw it.

The first view of the fly.

Another "fly by" by the fly.  (Look carefully - you can see the fly's legs above the caterpillar;  the body of the fly is mostly hidden by the tomato stem.)

The fly comes back for another go-around.

And another attack - Fly attack #4...

This one lasted a little longer and the fly seemed to land on the caterpillar's body, despite the hornworm's thrashing and attempts to defend itself.

Fly attack #5.....  (You can just see the eyes of the fly coming into focus to the left of and slightly below the caterpillar.)

Fly attack #6...

Now there's fluid on the back of the caterpillar;  the fly has definitely made contact.

Still the fly comes back again....

But this seems to be the end of the attack.  A drop of "blood" on the back of the caterpillar remains, but the buzzing fly is gone.

According to my camera's time stamp, all of these photos were taken within a 2 minute window.  I don't know how long the attack had been going on when I chanced upon it.  Still, overall, the action didn't last that long.

I am assuming that the fly was a female and that she laid at least one egg in the caterpillar.  Judging from the fly's hairy abdomen that I could see in the photos, this was probably a tachinid fly.  If that's the case, the hornworm will go back to eating as if nothing has happened, but when it goes to pupate, the fly larva that has grown inside it will take over and kill the developing moth.  The hornworm pupa will actually only produce one or more fly pupae, which will, in their turn, produce more tachinid flies to carry on the cycle.

I knew that tachinid flies were parasitoids of caterpillars, but this is the first time I've actually witnessed the interaction between the caterpillar and the fly.  I see many, many tachinid flies in the garden, especially in the fall when they are feeding at my asters, so I knew this sort of event had to be occurring.  Adult tachinid flies are pollen and nectar feeders...and good pollinators.  Hornworms, while I think they are cool and interesting, are pests on tomato plants.  This is natural predator control at its most basic.

Life is not particularly gentle, but it tends to balance itself when allowed to do so.  Sometimes the variety of feeding strategies truly boggles my mind.   What predatory insects have you seen in YOUR garden lately?

Learning Another (Fly) Stitch in the Tapestry of Patchwork Prairie

After all the hoopla of the holidays, I'm finally getting back to my projects, particularly the one where I'm learning to identify the different insects that I've photographed in the yard over the last 7 years.

With that goal in mind, I've started posting some of the insects that I can't identify on bugguide.net.  This wonderful site has generous volunteers that identify the insects they can in photos shared by people from all around the country.

The last time I posted any photos on bugguide.net was almost 2 months ago, so I was rather surprised recently to get a message in my e-mail box saying that someone had added comments to one of my submissions.  Checking it out, I learned that one of the flies I had posted from early November had been identified as a particular species of tachinid fly, Archyatus marmoratus.  Which meant exactly what?

I had been pretty sure that the fly, which I observed feeding on aromatic aster blooms, was a tachinid.  And it was.  Tachinids are rather large flies that look like very hairy, even bristly, house flies.  Despite their homely appearance, they are considered a beneficial insect.  In their larval stage, they are parasitoids, because their larvae grow inside a variety of other insects and kill those insects as they grow.  Often the species parasitized is specific to the species of tachinid fly, so finding out the species of tachinid fly gave me a good chance of learning how this particular insect fit within the community of plants and animals in our yard.

Googling was in order...and rapidly accomplished.

I didn't find a lot on Archyatus marmoratus during my quick Google search, but what I did find was reassuring, even exciting.  This tachinid species is not completely host specific, but it does parasitize caterpillars in a specific group of moths, Noctuids, particularly within a group of caterpillars that includes armyworms, budworms and other pest species.  The female fly lays her eggs in the area where host caterpillars are likely to occur and, after the eggs hatch, the young fly larvae hitch onto appropriate host caterpillars when they come by.  Each caterpillar that picks up a tiny fly larva eventually gives up its life, producing one adult tachinid fly in the process.

So, for every adult fly I see, an armyworm or budworm gave its life.  For every adult A. marmoratus fly I see, an armyworm or budworm didn't make it to adulthood to reproduce.  For every adult A. marmoratus I see, a new generation of tachinid flies has a good chance of appearing to help keep next year's armyworm and budworm populations under control.  And along the way, my asters get some extra help in pollination.

All in all, it's a mighty sweet deal, despite being all wrapped up in a pretty homely package.

Learning Another Beneficial

I rather like this photo for a couple reasons.

First, it's a great example of mimicry. The insect on the left is a goldenrod soldier beetle. Note the banding on its abdomen? That sort of banding is mimicking the banding on bees and wasps - this species of beetle is essentially trying to puff itself off as bigger and badder than it really is!

Secondly, the insect to the right in this photo is a fivebanded tiphiid wasp. Kind of a funny looking thing, isn't it? I've seen them many times, but hadn't looked them up to hang a name on them until tonight. When I did, I learned that tiphiid wasps are nectar feeders as adults, but they parasitize the small white grubs of scarabaeid beetles (aka June bugs) as larvae.

So, the more tiphiid wasps I see, the fewer white grubs I should have in my lawn! I love learning this stuff! Best of all, I love learning this stuff right in my own backyard!