Butterflies, often admired for their beauty and grace, play a crucial role in our ecosystem as pollinators. Understanding their dietary needs is essential for their conservation and for creating habitats that support these delicate creatures. This article focuses on the Painted Lady butterfly (Vanessa cardui), exploring its dietary preferences during both its larval and adult stages.
The Importance of Host Plants for Painted Lady Caterpillars
In the world of nature, certain species rely heavily on specific plants for sustenance and survival. In the realm of Lepidoptera, the relationship between butterflies and their host plants is a fundamental aspect of their life cycle. When discussing the captivating Painted Lady butterfly (Vanessa cardui), understanding the concept of a "host plant" is very important. Host plants serve as the primary food source for the larvae, or caterpillars, of these unique insects. Host plants play a critical role in the lifecycle of Painted Lady butterflies (Vanessa cardui) and their caterpillars by serving as the primary food source and habitat.
Female Painted Lady butterflies carefully select host plants on which to lay their eggs, typically preferring species such as thistles, mallows, and various legumes. Upon hatching, Painted Lady caterpillars feed voraciously on the leaves of their host plants, rapidly growing and developing through multiple instars. The nutritional content of the host plants is essential for the caterpillars' growth and metamorphosis into adult butterflies.
Preferred Host Plants: A Closer Look
Painted Lady caterpillars (larvae) exhibit a voracious appetite for a variety of host plants, each offering essential nutrients crucial for their growth and development. One common choice is plants belonging to the Asteraceae family, such as thistles. Thistles are characterized by their prickly stems and distinctive, often purple, flower heads. Another favored host plant family is Malvaceae, with mallows being particularly favored. Mallows are known for their showy, cup-shaped flowers and soft, lobed leaves. Additionally, various legume species, belonging to the Fabaceae family, serve as favored host plants for Painted Lady butterflies. Legumes such as alfalfa (Medicago sativa) and clover (Trifolium) are among the preferred choices. These plants are characterized by their nitrogen-fixing abilities and compound leaves with small, clustered flowers.
In addition to thistles mentioned above, another preferred food choice for Painted Lady caterpillars comes from the Malvaceae family, particularly mallows (Malva). Mallows are recognized for their cup-shaped flowers and soft, lobed leaves. The lush foliage of mallows serves as a nutritious feast for the caterpillars, contributing to their robust development. Additionally, various legume species within the Fabaceae family, such as alfalfa (Medicago sativa) and clover (Trifolium), are favored by Painted Lady caterpillars.
Read also: Foraging Strategies of Painted Buntings
Nectar Sources for Adult Painted Lady Butterflies
Painted Lady butterflies (Vanessa cardui) display a preference for nectar-rich flowers, which serve as their primary food source during adulthood.
Favorite Nectar Flowers: A Detailed Overview
Asters are characterized by their daisy-like appearance and come in various colors, providing abundant nectar for Painted Lady butterflies. Another favored choice among their diet are plants within the Lamiaceae family, including lavender (Lavandula). Lavender is recognized for its fragrant, purple-hued flowers that attract a myriad of pollinators, including Painted Lady butterflies. Furthermore, Painted Lady butterflies are attracted to plants within the Fabaceae family, such as legumes like clover (Trifolium) and alfalfa (Medicago sativa).
These plants offer abundant nectar reserves housed within their clustered flowers, making them enticing feeding spots for Painted Lady butterflies. Additionally, they are also known to visit plants from the Boraginaceae family, such as borage (Borago officinalis).
Butterfly Anatomy and Flower Preferences
I believe that the anatomy of the butterfly plays a role in which flowers attract them for feeding. The head has many sensors and on the bottom part of the head is the proboscis, which is like a skinny straw that the butterfly uses to reach down into a flower to drink the nectar. The compound eye is made up of thousands of eyes that help the butterfly see at wide angles (Prairie Frontier 2009). Butterflies can see a large spectrum of color, including ultraviolet light, and Painted Ladies have four types of color receptors so they can see patterns in flowers that we can't see (Stokes 1991). Because of its eyesight, a butterfly may be attracted to a particular color flower more than another color, or see the details in a flower's structure that attract it and cause it to show a preference for feeding on that flower.
The characteristics of flowers may also play a role in how they attract a butterfly for feeding. The flower has to be able to support the weight of the butterfly, and its legs have to be able to latch on to sit on the flower because butterflies don't hover while they feed (Boriqua 2009, Roth 2001). The shape of the flower or its blossom arrangement may also be a factor in attracting butterflies for feeding. Clustered flowers and flowers with spikes that have small, closely packed blooms may attract butterflies because they offer more sips of nectar in one visit. Daisy-type flowers might attract butterflies in this same way because the "button" in the center is really a group of miniature petal-less flowers packed close together (Roth 2001). But some large single flowers will attract butterflies too, although they have a limited amount of nectar in one flower. "Something important to think about is the length of the tube of the flower because the butterfly has to be able to reach its proboscis inside to drink the nectar" (Boriqua 2009).
Read also: Weight Loss with Manga
Another important fact affecting a butterfly's behavior is that they are cold-blooded so they need warmth to be active, usually above 50°F. When the Sun shines, the butterfly spreads its wings to bask and gain energy. They are more active, including feeding, earlier in the day when it is warmer and sunnier, and at nighttime or on cloudy days they rest with their wings folded to conserve energy (Kracht 2009, Ortho 2001).
Research on Flower Preferences of Painted Lady Butterflies
I thought of my project idea, did some reading research and then conducted interviews with specialists from the butterfly pavilion at the Desert Botanical Gardens in Arizona. The research question I asked is, Do Painted Lady butterflies have a preference for what flowers they feed on? My hypothesis was: Given a choice of flowers to feed on, the Painted Lady butterflies will display a preference for certain flowers because of the color or the structure of the flower, rather than feeding randomly. The dependent variable was the number of times a butterfly feeds on a flower. The two independent variables studied were flower color and flower structure. There were several constant variables: (1) type of butterfly (Painted Lady, Vanessa cardui ); (2) age of the butterfly (less than two weeks old); (3) habitat (size, materials, setup, feeding apparatus); (4) testing conditions (outdoor temperature above 50°F, sunlight); (5) length of the feeding time (three hours); (6) flowers (naturally grown, not cut from a florist).
The design for this project included 12 testing subjects (Painted Lady butterflies) split evenly into three groups. Each group participated in three experimental trials for each independent variable (color and structure), which were conducted over six days, with three hours of data collection each day.
Experimental Setup
Set up habitats indoors and raise caterpillars following the instructions (Insect Lore, 2009). Raise caterpillars in culture cups (Figure 2). Build an apparatus to hold flowers for feeding. Cut wood and Styrofoam according to the materials list. Construct the apparatus (Figure 4) by attaching a foam block at each end of a wood strip with the wood positioned toward the top of the foam. Repeat, and this time position the wood toward the bottom of the foam so this wood strip can fit under the other. Position these two wood strips with foam blocks like a cross. Poke two holes in the top of each foam block to hold the flowers. One day after the caterpillars hatch from their chrysalises, move four butterflies each into its own testing habitat . These will be the testing subjects for Group I. Leave the others in the growing habitat. Feed butterflies with the sugar water solution as follows: Wet a paper towel with solution. Crumple the paper towel and place it on a plastic lid or paper plate in the bottom of the habitat. Repeat when paper towel is dry. Important: Butterflies in the growing habitat are fed continuously.
Testing Methodology
Testing: Check weather.com in the morning. Plan testing to start after 50°F when there is good sunshine. Vary the time to get the best conditions. At the decided time, set up the testing habitats by cutting and attaching flowers (Figure 5) to the feeding apparatuses according to testing schedule (see Figure 6). Criteria for feedings: A feeding is counted when the butterfly inserts its proboscis into the flower. Separate feedings are counted if the butterfly flies off the flower and then returns to it to feed again. At the end of the three-hour testing session, remove the apparatuses and throw away the flowers. Testing is complete for the group of four subjects after three trials of both color and structure. Place four different butterflies into the testing habitats as Group II subjects. Repeat Steps 3-6 and follow the testing schedule.
Read also: The Truth About Ladybugs' Diet
Results: Flower Color Preference
Data from all trials for Groups I to III testing what color flower butterflies prefer to feed on is in Table 1. Results show that Painted Lady butterflies prefer to feed on purple flowers and like white flowers the least. They fed on purple flowers 45% of the time, red flowers 24%, yellow flowers 22% and white flowers 9% of the time (Graph 1). Overall, the results show that Painted Lady butterflies do not feed randomly; they have a preference for feeding on purple flowers.
Results: Flower Structure Preference
Table 2 shows the data from all of the trials for Groups I to III, which tested which flower structure the butterflies prefer to feed on. Results show that Painted Lady butterflies prefer to feed on clustered flowers and like the large single flower the least. They fed on clustered flowers 65% of the time, spiky flowers 20%, daisy-like flowers 10% and the large single flowers 5% of the time, as shown in Graph 2. The results show that Painted Lady butterflies do not feed randomly; they show a preference for feeding on clustered flowers.
Additional Observations
To get extra information about which flowers were the butterflies' favorites, data was also recorded when a butterfly landed on a flower but did not feed at all, and when butterflies stayed to feed on a flower longer than three minutes at a time. Results in Tables 3-6 show that butterflies most often "landed only, without feeding" on white flowers (22% of the time) compared to purple flowers (1% of the time); and on large single flowers (71% of the time) compared to clustered flowers, which they never landed on without feeding (0%). They fed longer (greater than three minutes) on purple and red flowers (both 6% of the feedings) compared to white flowers (less than 1% of the feedings); and longer on clustered flowers (4% of the feedings) compared to large single flowers, which they never fed on for longer than three minutes (0%).
Discussion of Results
The data from this project answers the research question and supports the hypothesis. It shows that given a choice of flowers to feed on, Painted Lady butterflies do display a preference for certain flowers depending on the color or structure of a flower. They prefer to feed on purple flowers (45%) compared to other colors, and prefer clustered flowers (65%) to other structures. I was not surprised because my background research made me think that a clustered flower is a good choice because it gives a place for the butterfly to land and can support its weight, and also provides many sips of nectar close by to make feeding very efficient. Purple is a favorite color, and this may be because of the butterfly's eyesight. Butterflies can see ultraviolet light, and purple is the wavelength of visible light closest to ultraviolet, and that may be why butterflies are most attracted to purple. Purple may also stand out better against the green leaves of a plant. There was a large difference between these results, and the butterflies feeding on the white flowers 9% of the time and large single flowers only 5%. White is all of the visible colors being reflected, and maybe the butterfly cannot see that color as well and so is not attracted to it. I believe that the butterflies do not like large single flowers as much because they do not offer much nectar in one visit, and it may be hard for the butterfly to reach its proboscis deep inside because it is a bigger flower.
Another observation from my data collection was that when a butterfly fed on a flower it liked, it often stayed on that flower longer to feed. If it was an unpopular flower, it often just landed on the flower without feeding. Butterflies have sensors for tasting on their feet, so when they land on a flower they can decide right away if they like that flower or not. The data for landing only, without feeding, give extra support to show what their feeding preferences were. Purple flowers were a favorite of the butterflies, who landed on them only 1% of the time without feeding, compared to 22% for white flowers. Clustered flowers were a definite favorite, with no occasions in which a butterfly landed without feeding, compared to 71% of the time on the large single flower. They also fed longer on purple flowers and clustered flowers, which shows that they really do prefer these flowers.
I made many interesting observations during my data collection. At the start of this project, I planned on doing the testing inside because I knew that butterflies need light and warmth to be active. The room would be at a constant warm temperature, and I would have the lights on a schedule. I thought those would be the best conditions, but I observed that the butterflies were feeding very little or not at all, and mostly rested with their wings closed. I thought that maybe the butterflies need the light and warmth from the Sun to be active and feed. The moment I carried the habitats outside, they opened their wings to bask and soon became active. I also observed changes in their feeding habits depending on the weather; they fed more when it was sunny than when it was cloudy outside. If I could do this experiment again, I would do it in the spring when there are more types of flowers in bloom so I could have a wider selection to test. An idea for a future project would be to use different color flowers or different flowers that fit in the structure categories. It would be interesting to see what the feeding preferences are of a different species of butterfly, and how that might compare to Painted Ladies.
The Importance of Butterflies and Biodiversity
Biodiversity is the variety of all living organisms and the ecosystems that they are part of. It helps provide the basic human needs such as food, shelter, and medicine. It composes ecosystems that maintain oxygen in the air, enrich the soil, purify the water, and regulate climate. (CIEL 2009)
Because human society is growing quickly and uses a huge amount of resources, there has been a sharp increase in the loss of biodiversity, so it is important to remember that every living thing on Earth has a part in the circle of life. Insects are an important part of our world because they have the largest number of species and the largest number of individual organisms; "their combined biomass represents an important food resource for other animals, and they contain much of the raw materials for the energy and nutrients that are cycled through ecosystems" (Schappert 2000). So insects are a very important part of biodiversity. Studying butterflies is important for general scientific learning. "It also gives important information about ecosystems because we don't completely understand what the role or impact of butterflies might be. Information learned can be helpful to preserve and restore habitats, as well as provide adequate food in migration pathways or exhibits" (Kracht 2009). Because insects have a reputation for causing problems, many people are not concerned about their conservation. Luckily, people are not as unsympathetic about butterfly conservation as they are about other insects, because butterflies need our help. Along with problems like weather, pollution and predators, butterflies are at risk because of habitat loss and ecosystem damage caused mostly by people. Butterflies need a lot of host plants to lay eggs on in order to reproduce well, and they also need flowering nectar plants to feed on. Without good habitats that provide both of these things, there will not be enough homes for butterflies, which could lead to a decline in their numbers and make them more vulnerable to extinction (Schappert 2000).
Raising Painted Lady Butterflies: A Practical Guide
Are you interested in raising painted lady butterflies? Painted ladies are an easy and magical way to learn about butterflies.
Essential Supplies
Prepared food - If purchasing from a science supply house, the prepared food will come with the larva. If using wild-caught larva, be sure to secure their larval host plant for a food source. If possible, collect food from the same plant they are found to be eating. Be a bug Scientist! If you have ordered larva and are hatching butterflies, use this journal to document your experience!
Preparing the Habitat
Once you have your caterpillars you will need to prepare habitat cups that will hold the larvae until they pupate. In a small condiment cup with lid, place a small amount of prepared food on the bottom or side of the container (this will be approximately ¼-inch in thickness). Place a small piece of tissue paper, coffee filter, or thin paper towel over the top of the cup and place the lid on. DO NOT PLACE THE CUPS IN DIRECT SUNLIGHT. The cups can become overheated and cause the larvae to die. It is best to maintain a consistent temperature of 68-78 F.
Caring for the Larvae
The larval stage will span approximately 5-10 days. Taking larvae out of the cup to handle them or touch them may injure the larvae or make them sick. You will enjoy observing your caterpillars through the cups. Depending on temperature, the process of growing from a tiny caterpillar to chrysalis to adult can take up to three weeks, so you may want to be sure you’ll be around when they emerge as adults. After all chrysalises have formed, leave the cups undisturbed for an additional 1-2 days. Using tape or safety pins, attach the chrysalises to the inside of the mesh butterfly house.
Feeding Adult Butterflies
To feed the butterflies, a sugar-water solution can be prepared and placed in the bottom of the butterfly net in a small dish (adult butterflies require a liquid diet). Butterflies also enjoy fruit, including oranges and mashed bananas. Enjoy your butterflies! After releasing the butterflies, cages and equipment can be cleaned with warm water and a very mild dish detergent. What did you like about this project? Your chrysalis has formed already? Congratulations!
The Role of Painted Lady Butterflies in Pollination
Painted Lady Butterflies play an important role in the pollination of fruit trees, contributing significantly to the health and productivity of many fruit-bearing plants. As they flutter from flower to flower in search of nectar, they transfer pollen from one blossom to another, aiding in fertilization and the formation of tasty fruit. While bees are often considered the primary pollinators of many crops, butterflies also provide essential pollination services, particularly in gardens and orchards where they enhance biodiversity. By supporting the pollination of a wide range of fruit trees, such as apples, cherries, and citrus, Painted Lady butterflies and their counterparts help maintain healthy ecosystems and ensure abundant harvests.
As fruit ripens, it undergoes a transformation that not only enhances its flavor and aroma but also makes it a tasty source of nourishment for Painted Lady butterflies. The over-ripening process releases sugars and fermented compounds, which appeal to these pollinators seeking both nectar and other nutrients. Butterflies are particularly drawn to the fermented, sweet scents of overripe fruit, which can act as a feeding hotspot. This attraction not only benefits the butterflies, providing them with an essential energy source, but also plays a role in the natural dispersal of pollen as butterflies continue to move between flowers and fruit.
Fruit Preferences of Painted Lady Butterflies
Citrus Fruits
Oranges attract Painted Lady butterflies and many other species due to their sweet fragrance, vibrant color, high sugar content, and soft, juicy texture. The sweet, citrusy scent of ripe oranges is particularly powerful, as butterflies are drawn to fragrances that signal the presence of nectar or fermenting fruit. The high sugar content found in the fruit, especially as it begins to ripen and ferment, provides the necessary energy for butterflies to fuel their flight and reproduction. Other butterfly species that are known to favor citrus fruits, including oranges, include the Common Buckeye (Junonia coenia), the Orange-tip (Anthocharis cardamines), and the Gulf Fritillary (Dione juno). These butterflies are commonly found in regions where citrus fruits are grown, such as the southern United States, parts of South America, and the Mediterranean.
Bananas
Surprisingly, bananas are highly attractive to Painted Lady butterflies and many other species despite the last of liquid juices. This is due to their sweet, sugary aroma and soft, easily digestible flesh, particularly when overripe or starting to ferment. The strong, sugary scent signals a rich source of energy. These fruits, which are abundant in tropical and subtropical regions, are commonly found in areas like Central and South America, the Caribbean, and parts of Southeast Asia, where they attract butterflies seeking both nectar and fermenting fruit.
Melons
Cantaloupe is attractive to Painted Lady butterflies and other species due to its high water content and sweet, sugary fragrance, which draws them in for nourishment. The soft, juicy flesh provides an easy source of hydration and energy for butterflies, especially in hot climates where moisture is scarce. Watermelon attracts Painted Lady butterflies and other species due to its high water content and sweet, refreshing taste, offering both hydration and energy. The soft, fleshy texture makes it easy for butterflies to feed on, particularly in hot climates where moisture is needed for survival.
Berries
Strawberries attract Painted Lady butterflies and other species due to their sweet, aromatic fragrance and rich, sugary content, which provide a terrific energy source. The soft, juicy texture of ripe strawberries makes it easy for butterflies to feed, particularly in areas where fresh fruit is abundant.
Stone Fruits
Peaches attract Painted Lady butterflies due to their sweet, juicy flesh and fragrant aroma, which serve as an excellent energy source for growing butterflies. The soft, tender texture of the fruit allows butterflies to easily access the nectar and moisture they need, especially in hot weather. Nectarines are fruits that are similar to peaches, but without fuzz on the skin. Nectarines attract Painted Lady butterflies and other species due to their sweet, aromatic flavor and high moisture content, making them an ideal food source for butterflies in need of hydration and energy. The smooth, juicy flesh of nectarines is easy for butterflies to access, particularly during hot weather when fresh fruit provides much-needed sustenance.
Purple, powerful plums attract Painted Lady butterflies and other species due to their sweet, juicy flesh and high sugar content, which provides both hydration and energy to keep butterflies soaring and happy. The soft texture of the fruit allows butterflies to easily access its tasty nectar and refreshing moisture, particularly in warm climates.
Other Fruits
As I'm sure you've noticed, butterflies love a slice of apple as a snack! Apples attract Painted Lady butterflies due to their sweet, slightly tart flavor and high water content, making them an excellent source of hydration and energy for butterflies. The soft, fleshy interior is easy for butterflies to access, especially when the fruit is overripe or fallen, providing a quick food source. Passionate about pears? So are butterflies! The soft, juicy flesh of pears also offers a high moisture content, giving Painted Lady butterflies hydration and a big energy boost. Butterflies are also attracted to the subtle fragrance of the fruit.
Mangoes attract Painted Lady butterflies and countless other species due to their sweet, tangy flavor and high sugar content, which provides a rich energy source for butterflies still learning to use their new wings. The soft, juicy flesh of the mango is easy to access with the butterfly's tubular proboscis, making it an ideal food source in tropical and subtropical climates. Last but not least, Painted Ladies are picky for Pineapples! These prickly fruits attract Painted Lady butterflies due to their sweet, tangy taste and high moisture content, making them an excellent hydration and energy source. The soft, fibrous texture of the fruit is easily accessible, particularly when overripe or cut, allowing butterflies to feed with ease.