The Milkweed Habitat
The common milkweed is a habitat all by itself. Many organisms depend on the milkweed plant for food, shelter, space, water and even air.
FOOD/WATER These organisms have special adaptations or characteristics that allow them to live and reproduce on the milkweed. For example, Monarch caterpillars, milkweed bugs and aphids are able to consume the milkweed without being harmed by the milky substance that is toxic to many other organisms. The milkweed sap provides both food and water. They have different adaptations to acquire the sap (see bottom of this page).
Look at the video about the ants below. They are can't eat the milkweed because it's toxic to ants. But not for aphids! So the ants depend on their food and water by consuming the liquid waste (honeydew) of the aphids. In return, the ants provide shelter to the aphids by protecting them from predators such as the ladybug. The ladybug gets its food and water by consuming the aphids using their scissor-like mandibles (see bottom of page). [Mandibles are specialized mouthpart adaptations, which makes them a physical adaptation.]
AIR Since plants are photosynthesizers (organisms who make their own food using the energy of the sun to combine water and carbon dioxide into a sugary food called glucose), the "waste" product of photosynthesis is oxygen, which all consumers such as animals need for respiration (or turning food into their energy.)
SHELTER The milkweed provides shelter to the organisms that live on it. To live on the milkweed, these animals have different types of adaptations, such as the suction cup-like pseudopods (false feet) of the Monarch caterpillar, or hooked legs to grasp the leaves. Spiders use the milkweed to build their webs. When insects are attracted to the milkweed for nectar or to consume the sap and leaves, it also helps the spider by attracting food to its web. Interestingly, the milkweed sap, which is poisonous to most animals, helps protect the aphids and Monarch caterpillar because, when they consume the sap, they also are consuming the toxin. This transfers the toxin to their bodies and, in turn, makes them poisonous to most, but not all, predators.
Click on the image to the above to see some other animals that depend on the milkweed.
The milkweed depends on some of these animals:
FOOD/WATER These organisms have special adaptations or characteristics that allow them to live and reproduce on the milkweed. For example, Monarch caterpillars, milkweed bugs and aphids are able to consume the milkweed without being harmed by the milky substance that is toxic to many other organisms. The milkweed sap provides both food and water. They have different adaptations to acquire the sap (see bottom of this page).
Look at the video about the ants below. They are can't eat the milkweed because it's toxic to ants. But not for aphids! So the ants depend on their food and water by consuming the liquid waste (honeydew) of the aphids. In return, the ants provide shelter to the aphids by protecting them from predators such as the ladybug. The ladybug gets its food and water by consuming the aphids using their scissor-like mandibles (see bottom of page). [Mandibles are specialized mouthpart adaptations, which makes them a physical adaptation.]
AIR Since plants are photosynthesizers (organisms who make their own food using the energy of the sun to combine water and carbon dioxide into a sugary food called glucose), the "waste" product of photosynthesis is oxygen, which all consumers such as animals need for respiration (or turning food into their energy.)
SHELTER The milkweed provides shelter to the organisms that live on it. To live on the milkweed, these animals have different types of adaptations, such as the suction cup-like pseudopods (false feet) of the Monarch caterpillar, or hooked legs to grasp the leaves. Spiders use the milkweed to build their webs. When insects are attracted to the milkweed for nectar or to consume the sap and leaves, it also helps the spider by attracting food to its web. Interestingly, the milkweed sap, which is poisonous to most animals, helps protect the aphids and Monarch caterpillar because, when they consume the sap, they also are consuming the toxin. This transfers the toxin to their bodies and, in turn, makes them poisonous to most, but not all, predators.
Click on the image to the above to see some other animals that depend on the milkweed.
The milkweed depends on some of these animals:
- for reproduction (bees & butterflies help to pollinate the plant so it can make seeds; the milkweed attracts pollinators by making nectar - a sugary liquid food),
- for protection (spiders or grey tree frogs help to reduce the population of insects that consume the plant, and ladybugs love to consume damaging aphids);
- for fertilizer (If you've ever seen the droppings of a monarch caterpillar as it grows larger, you know that some of those big droppings will fall back to the ground, dissolve in the rain water and get drawn up in the water through the plant's roots, providing nutrients (NOT food) to the plant);
- for carbon dioxide (The animals take up oxygen provided by the milkweed, and eliminate carbon dioxide, which is the waste product of their respiration. Respiration is needed to turn food into energy. Animals and all organisms that respire help all photosynthesizing plants by providing them the carbon dioxide as one ingredient necessary for photosynthesis, or the process by which plants make their own food.)
A simple diagram showing how plants and animals depend on each other for their energy
Plants use the energy of the sun to combine water and carbon dioxide to make a food called glucose. The "waste" product of photosynthesis is oxygen. Because they make their own food, plants are called "producers."
Organisms that must consume living things to get their food are called "consumers." Food is a source of energy and must be turned into energy using a process called "respiration." Here, glucose is combined with oxygen (a plant's waste product) to produce that energy. The waste product is carbon dioxide and water, which can then be turned back into glucose by the plant using photosynthesis. It's a cycle!
Pollination
Pollination is how many flowering plants reproduce and make seeds. Many flowers make a sugary nectar to attract pollinators such as butterflies, moths and bees. The nectar is food for the pollinator (not the plant). When the pollinator drinks the nectar, typically with an adaptation called a proboscis, pollen sticks to the feet and body of the pollinator. When they fly to another flower, some of the pollen is rubbed off onto the next flower, which travels down into the flower where seeds are made for reproduction. Milkweed pollination is a bit tricky for pollinators and can even be deadly. The video above (right) explains how.
Grasshopper
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There are many different species of grasshopper that live in Wisconsin, and many of them look very similar, so I went to the folks at BugGuide.net with this photo and asked if they could identify it. We are still not certain, but their best "guess" based on the photo is a 2-striped grasshopper. The grasshopper is unable to consume the toxic milkweed, however, it can use the milkweed for shelter.
Earwig
Earwigs are also known to live on milkweed using their big pincers to (among other things) grab prey such as the aphids. They also have jaw-like mandibles for consuming both dead and live vegetation as well as other insects.. In our own observations over the years, we have found them on milkweed, so I suspect they are hunting for prey. I've never observed them actually eating the milkweed plant.
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Milkweed bug
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We discovered a large group of 15-20 milkweed bugs at different stages of development - called instars. In the "Buzzle" article on milkweed bugs, learn everything about this interesting "true bug". These are categorized as "true bugs," because they use a sturdy proboscis to pierce the milkweed leaves and pods to withdraw the sap for food and water. They have are specially adapted to be immune from the toxin.
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Monarch caterpillar
One of the 3 habitats the Monarch occupies is the milkweed plant. Monarch butterflies will lay eggs on this plant and the larvae (caterpillar) will eat the plant using its mandibles until it forms its pupa (chrysalis). These caterpillars are called "specialists" because they eat only one kind of food. Interestingly, by consuming the toxic milkweed (which does not harm them), the toxin is transferred to their body, making them toxic to most (but not all) predators as well. This, too, is a special physical adaptation.
As adults, Monarch butterflies consume the nectar of the milkweed flower using their proboscis, but they can and do consume nectar from a variety of prairie flowers. They are "generalists" because of they can consume nectar from many plant species. Interestingly, the butterfly has a completely different mouthpart from the caterpillar. The proboscis is adapted to withdrawing nectar (like a straw), and the caterpillar mandible is adapted to cutting and chewing the milkweed leaves. See more about the Monarch by clicking on this page. |
Long-legged fly
Well, I narrowed this metallic green insect down to a long-legged fly, however, there are thousands of species of this type of fly, 1500 of which have been identified in North America. The closest genus I could find to the one we spotted on the left is the Condylostylus. I sent the photo to the experts at the BugGuide.net and they confirmed my suspicion and thought it might be a male Condylostylus nigrofemoratus. Click here to find out more about long-legged flies (whose "family" name is Dolichopodidae).
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What adaptations are used to "consume?"
We've been talking about how some of the organisms we've found "consume" their food. Not all organisms have mouths with teeth, do they? But they still need food. So how do they get the food into their body? Monarch butterflies, aphids, and milkweed bugs have a special adaptation called a proboscis. It is a tube-like structure, much like a straw, that allows the organism to withdraw nectar or plant juices. As you can see, the proboscis of the aphid and milkweed bug are sturdy enough to pierce the milkweed leaf. But the Monarch butterfly's proboscis is bendable so it can reach into the nectar tube of prairie flowers. Here are some close-up images that show the different proboscis adaptations of some of the milkweed animals.
Some organisms have jaw-like mouth parts called "mandibles." The mandibles operate like a pair of scissors, but can also vary in structure depending on what they are used for. The monarch caterpillar (left) and the earwig (right) are able to chew on leaves using this adaptation. The ladybug uses its mandibles to grasp and "chew" the aphids. The ant uses its mandibles to consume the aphids' honeydew.