Spider Milkweed

Spider Milkweed, Asclepias viridis, is my favorite of the milkweeds at Blue Jay Barrens. The flower head is both showy and not showy. The lime green corolla lobes are conspicuous from a distance, which is considered to be showy. However, that color makes you think of a sickly, poorly performing plant, which is a failure as far as producing the attractive side of showiness.

This is one of those southern plants that reaches its northern limits in Southern Ohio. The population here has been increasing slowly over the past 20 years. I don’t think it’s in danger of dieing out, even though a few plants turn up missing every time we have a particularly cold winter.

It makes its home in the prairie openings. Full sun and dry conditions seem to best suit its needs. It also seems to do best in areas with minimal tall grass. I haven’t found any of these milkweeds growing in the thick Indian Grass, or Big Bluestem areas.

Flowering stalks are usually around 18 inches tall. Without the flower, they blend neatly with the other vegetation and are hardly noticeable. The lean is typical. I rarely find any flowering stalks that are completely vertical.

Ants are the only insects that I see regularly visiting the Spider Milkweed flowers. It’s odd that other milkweed species are so attractive to bees, butterflies and flies, but none of those fliers visits the Spider Milkweed. Ants may be the prime pollinator for this plant.

I found these larvae munching away on the corolla lobes. I didn’t have much luck with a positive ID, possibly because these guys are still so young.

I’ll give the larvae a few days to put on some size and then take another look at them. I just hope I can find them again later. It seems common for young larvae to begin life by eating the more tender parts of the plant, such as the buds or flowers. As they get larger, they move on to the leaves. If I have my typical luck, I’ll find nothing when I go back. We’ll see.

Larva

I’ve always been fascinated by moth and butterfly larvae. The rush to get from egg to adult is often fast enough to satisfy even the most impatient of us. Unfortunately for me, the larvae are often hard to find. It’s always a surprise and a delight to happen upon an interesting individual, such as this larva I found in the woods on a Leatherwood shrub.

I initially made the classic mistake of misidentifying which end was the head. The enlarged posterior end certainly appeared head-like at first glance.

The side view quickly cleared things up and showed me the proper orientation. Unlike with humans, there is no right or wrong way in which a caterpillar must be positioned.

Here’s the head. It’s really quite obvious once you take a close look.

The results of a little observation make me think that this is a caterpillar out of place. A bright orange larva on a glowing green plant is much too conspicuous. A bird should have made a meal of this guy long ago. There’s also the fact that I could find no evidence of leaf damage anywhere on the plant. If this is the larva’s proper place, there should have been some chewed leaves.

I examined several Leatherwood shrubs in the area and found no evidence of feeding on any of the plants. I also found no additional orange caterpillars. I suspect that it fell out of a nearby tree and has had trouble finding its way back to the proper host plant. Possibly, it’s on a journey to locate a suitable site for pupation. Whatever it’s doing, I don’t think it has yet found the proper place to be.

Edwards' Hairstreak Larvae

I visited some small oaks in hopes of discovering eggs of the Edwards’ Hairstreak butterfly and found a newly hatched larva instead.

With my hand in the background, you get a little better idea of the size of this newly hatched caterpillar. What I found odd was the absence of any Allegheny Mound Ants attending this little guy. Maybe they’ll be along soon.

Not much growth on these small oaks to feed a newly hatched caterpillar. The tree in the center hosted the larva, but the buds hardly looked as though they were beginning to swell.

On a second tree, I found more larvae along with their ant protectors. The larvae are busily feeding on the bud. They’ll be adults by mid-June, so their development should proceed at a fairly rapid pace.

The ants will guard the larvae and resulting pupae up to the point of adulthood. During the early stages of development, the larvae will spend most of their time on or next to the buds. At some later instar, the ants are supposed to escort the larvae to a protected area at the base of the tree for safety during daylight hours and then take them back up the tree to feed during the night. I have yet to witness this activity, but I’m going to try hard to catch it this year.

The tree doesn’t look like much, but its existence is essential for the survival of the Edwards’ Hairstreaks living in this small prairie opening. Click on Edwards’ Hairstreak from the list in the sidebar for more information on this interesting butterfly.

Ash Eaters

I came across a small Blue Ash that was playing host to a number of leaf eaters. Parts of the leaves had been completely consumed while other parts had lost just the outer layers. I think of this last as the leaf eater’s version of a filet. The consumers of the greenery were not readily apparent.

There was plenty of frass evident on the leaf surface, so the little herbivore had to be nearby. Viewed from the side, the curled edge of the leaf appeared to have been manipulated to conceal a snug little hide away.

A webbed tunnel neatly held the leaf edge in a permanently curled position. Inside the tunnel was the larva responsible for the leaf damage. The larva is perfectly patterned to avoid detection. The green color is a good match for the green of the leaf and the black spots mimic the rows of frass.

Most leaves had at least one leaflet that harbored a larva. If these larvae get much larger, they could probably come close to defoliating the tree. A loss of leaves would not severely stress the tree this late in the season.

Blue Ash is my favorite ash, at least from an identification point of view. The young twigs are four angled and look square in cross-section. It’s always nice when a plant with many close relatives has a distinctive trait that splits it from the rest.

This Blue Ash was one of many growing in the woodland understory. It’s interesting that none of the others showed any signs of insect damage. Eggs are normally scattered between many individual plants which reduces the chances of the plant being damaged or the young being lost to a predator. Variations in behavior within a species are just as common as variations in color and patterning. These differences are a way of surviving changes that threaten the standard methods of behavior.

Onosmodium Insects

At this time of year, I become most curious about the identity of this particular insect. I’ve mentioned this larva before. It feeds on the False Gromwell, Onosmodium molle var. hispidissimum, and travels through web tubes that it constructs on the plant. I’ve never found anything laying eggs on the plant. The larva apparently leaves the plant to pupate, since I’ve never found pupae or pupal skins in the web tunnels. Larvae raised indoors will pupate on the plant, but I’ve had no luck producing adults from the pupae. Netting the wild plants has only resulted in dead larvae in the bottom of the net. I suspect the wild larvae may pupate on or in the ground. I’ve raised False Gromwell in pots with the thought that I could cage the entire pot once larvae appeared on the plant, but none of my potted plants has ever hosted larvae. I’d really like to see an adult.

Whatever this thing is, it must be fairly common. Typically 60 to 70 percent of the plants are infested with larvae. A single plant may contain a half dozen larvae. I’ve cut a flower pot in half and plan to enclose the base of a plant containing larvae. With the pot filled with soil and the plant completely netted, I may capture a pupa. We’ll see what happens.

The frass from feeding larvae covers the lower leaves. Lower leaves are not consumed by larvae, but they never seem to remain healthy. While examining this plant, I found another neat little insect.

I believe this to be a nymph of the Spiny Assassin Bug, Sinea spinipes. There are a couple of similar species that can be readily separated as adults, but the nymphal descriptions made it difficult to be certain. There’s no doubt of it being an interesting little creature.

This clump of Gromwell was consumed by larvae the past two years. This year the leaves are blemish free. Feeding damage occurs late in the season and the loss of leaves doesn’t appear to hurt the plant or reduce seed production. Finding the adult form of this larva may be one of those things that’s going to have to wait until I have time to stay with the plant and catalogue visitors.