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Showing posts with label Asclepias syriaca. Show all posts
Showing posts with label Asclepias syriaca. Show all posts

Monday, May 21, 2018

Common Milkweed Hosting Larvae of Unexpected Tiger Moth

My first encounter with the Blue Jay Barrens population of the Ohio endangered Unexpected Tiger Moth, Cycnia collaris, formerly Cycnia inopinatus, was seven years ago.  My encounters with this species have increased each year since then, and this year is no exception.

Unexpected Tiger Moths are a milkweed dependent species.  Last fall, a few larvae were found on Common Milkweed, Asclepias syriaca, growing in the narrow strip between my driveway and Water Garden.  When larvae of this species are ready to pupate, they move into the plant litter at the base of the host plant and pupate near the soil surface.  I am assuming that this is exactly what occurred last September.  This spring, the adults emerged and apparently laid masses of eggs on the young milkweed plants emerging at the time.

The larvae are present in numbers many times greater than what I saw last year.    The amount of plant damage occurring from feeding larvae is readily apparent.

Most of the feeding is occurring on the young leaves at the growing tip of the plant.  There are about 10 larvae working on the particular plant.

Plants with more larvae show more leaf damage.

There are at least 20 larvae working on this plant.  The milkweed can’t grow quickly enough to stay ahead of these ravenous caterpillars.

Many of the larvae are moving out to begin feeding on the older leaves.  This intensive feeding won’t harm the milkweed.  This batch of larvae, the first of two yearly broods, will soon mature and leave the plant to pupate.  The plant will recover and be ready to hopefully host another batch of larvae in August.


The video shows feeding activity in one of the areas of highest larvae concentration.  Click HERE to view the video on YouTube, which usually provides a clearer image.  Click HERE to view earlier posts concerning this species.
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Tuesday, August 14, 2012

Common Milkweed Activity

I’ve been admiring some of the Common Milkweed plants that have put on luxuriant growth despite the super dry conditions.  This one has topped out at about seven feet.

Most plants are carrying six or eight seed pods.  Tendrils on the surface of the Common Milkweed seed pod present an alien appearance.

It looks like it’ll be a bumper year for Milkweed seeds.  All of the pods are large and full.  It won’t be long before the seam separates to release the ripe seeds.

Monarch butterflies are around loading the plants down with eggs.  I watched this female lay 17 eggs on a clump of three milkweed plants.

It may be warm now, but this egg is in a race to produce a mature butterfly before cold weather arrives.  Monarchs will not survive an Ohio winter.  In order to survive, the mature butterfly will have to emerge and make its long migratory journey to the south.

The Monarch is not the only insect depositing its eggs on the Milkweed leaves.  These orange gems were left by a female Milkweed Bug.

Here’s the likely source of those eggs.  This is an adult Small Milkweed Bug, a species that specializes on eating milkweed seeds that are still held within the pod.

The nymphs form colonies on the milkweed plants.  They are most likely to be found congregating on the seed pods where they use long, tube-like mouthparts to probe deep into the pod to access the hidden seeds.

The nymphs will shed their skins several times before emerging as an adult.  To avoid being damaged during this vulnerable time of their lives, the little bugs will move away from the pack and pick a secluded spot in which to shed.  After a while, shed skins can be found just about anywhere on the plant.  The variety of interesting activities occurring on milkweeds makes the cultivation of this plant a rewarding endeavor.
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Wednesday, June 30, 2010

Milkweed

Milkweeds are champions at attracting a wide variety of insect species. There are the casual visitors that come to the plant just for food, as well as an entire menagerie of species that are intimately tied to milkweeds for their survival. When out walking, I always check the milkweeds to see what animal life can be found. A variety of tiny flies were visiting this bloom.

Common Milkweed, Asclepias syriaca, is a plant of the open fields. Many people tell me that milkweeds growing in the field are a sign of mismanagement. It seems to confuse them when I suggest that the presence of milkweeds only signifies poor management if you are managing for a condition that doesn’t include milkweeds. Milkweeds in a pasture or hay field indicate poor management, but milkweeds in a field being managed for diverse native grassland species do not, so don’t use that as an argument that I’m not caring for my fields. This is the point at which I turn the conversation towards the weather, which my daughter says is the only subject I’m capable of handling in social situations.

The fully opened milkweed blossom is a nectar factory that feeds a multitude of different species. I’m especially interested in pollinators and spend a lot of time watching the native bees. A few weeks ago I was with some backyard fruit growers who were lamenting the decline of the European Honeybee and wondering how their flowers would be pollinated if things didn’t improve. When I suggested they try managing for native bees that could provide the same pollination service, they looked at me as if my hair had caught fire. Apparently, any acceptable substitute had to share the honeybee’s ability to work on demand as well as produce a marketable byproduct.

This grasshopper is eating a portion of the flower. Milkweeds contain steroid glycosides and other toxic substances that make the plant unpalatable to all but a few species that have evolved to deal with the toxins. The concentrations of toxins vary throughout the plant, so the grasshopper may be feeding in a less dangerous area. The tiny white spot on the grasshopper’s back is the empty skin of a tachinid fly egg. The larva has recently hatched and made its way inside the grasshopper, where it will feed until ready to pupate. The grasshopper will not survive the activities of this parasite. Perhaps milkweed toxin is a remedy to tachinid fly infestation.

The flowers are even attractive pre-bloom. Like many plants with multiple blooms, the flowers develop and open in succession, so the blooming and pollination activities occur over a long period.

The underside of the Common Milkweed leaf reminds me of a thick carpet. You certainly wouldn’t imagine these tough, hairy, poisonous leaves to be something edible. I wonder what was after these plants that made them evolve such a collection of defensive mechanisms.
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