Are Cabbage White Butterflies Poisonous to Humans? Debunking Myths and Facts

Cabbage White butterflies are a common sight in many gardens, with their elegant white wings and black spots. While they primarily feed on plants, a person may wonder if they are poisonous to humans.

Fortunately, Cabbage White butterflies pose no threat to humans as they are not poisonous. These delicate creatures are even admired by many for their beauty and contribution to the ecosystem as pollinators.

Are Cabbage White Butterflies Poisonous to Humans
Cabbage White butterflies

Are Cabbage White Butterflies Poisonous to Humans?

Toxicity of Cabbage White Caterpillars

Cabbage White caterpillars, also known as Pieris rapae, feed on cabbage plants containing certain compounds.

These compounds are toxic to some insects but not humans. Cabbage White caterpillars can consume these plants safely due to their immune system.

Isothiocyanates in cabbage plants:

  • Toxic to some insects
  • Cabbage White caterpillar’s immune
  • Not poisonous to humans

Human Reactions to Cabbage White Butterflies

Cabbage White butterflies, belonging to the Pieridae family, are not poisonous to humans. They do not bite or carry any harmful substances.

People may experience a bitter taste when touching a cabbage white, as the isothiocyanates can be transferred from caterpillar to adult butterfly.

Comparison: Cabbage White Caterpillars vs. Butterflies

FeaturesCaterpillarsButterflies
Poisonous to humansNoNo
BiteNoNo
Consume toxic plantsYes (cabbage plants containing isothiocyanates)N/A
Transfer taste to humansPossible bitter taste through contact with isothiocyanates from plantPossible bitter taste through contact with isothiocyanates from plant

Understanding Cabbage White Butterflies

Brief Overview and Habitat

Cabbage White Butterflies, also known as Small Cabbage White or Small White butterflies (Pieris rapae), are common butterflies found across Europe, North Africa, Asia, and North America.

They primarily inhabit gardens and fields, where they lay their eggs on plants within the Brassicaceae family, such as bok choy and other cabbages.

Wingspan and Physical Characteristics

With a wingspan ranging between 1¼ – 1¾ inches, Cabbage White butterflies are relatively small. Males and females are white, displaying dark wingtips.

Female butterflies have two black spots in the center of their forewings, while males only have one.

Main features:

  • Wingspan: 1¼ – 1¾ inches
  • Color: White with dark wingtips
  • Additional markings: Males have one black spot, and females have two

Generations and Lifecycle

Cabbage White butterflies have multiple overlapping generations in a year. They begin as eggs, which hatch into larvae (cabbage worms). These green caterpillars then feed on the host plants before turning into pupae.

Finally, the adult butterflies emerge from their chrysalis and start the cycle anew. The abundance of these butterflies in a natural range is partially due to their preference for agricultural areas with Brassicaceae plants.

Lifecycle stages:

  1. Egg
  2. Larva (cabbageworms)
  3. Pupa (chrysalis)
  4. Adult butterfly

Comparison table: Cabbage White vs. other butterflies

FeatureCabbage WhiteOther Butterflies
Wingspan1/4 – 1/2 inchesVaries
Primary ColorWhiteDepends on species
Black Spot(s)Males – 1, Females – 2Not all species
HabitatGardens, fieldsVarious habitats
Caterpillar Host PlantsBrassicaceae family plantsVaries

Ecology and Agricultural Significance

Role in Nature

Cabbage white butterflies (Pieris brassicae) play a role in nature as pollinators, feeding on nectar from various plants in the Brassicaceae family.

However, their larvae, known as cabbage worms, feed on these plants, causing damage to crops like cabbage, broccoli, and cauliflower.

Impact on Agriculture and Pest Infestations

Cabbage white butterflies significantly impact agriculture, particularly in Brassicaceae crops. In their larval stage, they can create holes in the leaves and heads of cabbage, broccoli, cauliflower, and turnips.

Some areas where they are invasive species, such as New Zealand and North Africa, suffer economic losses due to infestations.

Comparison Table: Cabbage White Butterfly vs. Imported Cabbageworm

CharacteristicCabbage White ButterflyImported Cabbageworm
OriginEurasiaEurope
Food sourceNectar (adults); Brassicaceae plants (larvae)Brassicaceae plants (larvae)
Genetic diversityHigher5Lower6
Method of controlBiological control program, crop management, environmental controlsSame
Damage to cropsHoles in leaves and headsSimilar

Prevention and Control Strategies

To manage infestations and reduce cabbage white butterfly populations, several methods can be employed:

  • Biological control: Introducing natural predators, such as parasitic wasps or ladybirds, helps limit cabbageworm populations.
  • Crop management: Rotating crops, removing crop debris, and planting trap crops (e.g., mustard, thyme) help lessen the risk of infestation.
  • Environmental controls: Using row covers, screens, or reflective mulches, deters egg-laying and suppresses larval development.

These strategies can be combined to create an effective control program against cabbage white butterflies, ultimately protecting Brassicaceae crops and reducing economic losses.

Cabbage White Butterfly Research and Citizen Science

Spread Through Human Travel and Trade

Cabbage white butterflies (Pieris rapae) are not native to North America but have spread widely due to human travel and trade. Factors contributing to their spread include:

  • Human travel along ancient Silk Road routes
  • Trade and migration of agricultural crops like mustard and canola

Pieris Project and Genetic Testing

The Pieris Project is a collaborative scientific effort to study the genetic variation in cabbage white butterflies. Researchers from different fields, such as invasion biology and evolutionary biology, contribute by:

  • Collecting historical data on the butterflies’ spread
  • Sampling DNA from existing populations

The project aims to understand the loss of genetic diversity due to domestication, invasive pests, and other human-induced changes in the butterflies’ environment.

Involvement of Citizen Scientists and Online Communities

Citizen science projects like the Pieris Project involve the public in the research process through:

  • Providing DNA sampling kits for participants
  • Encouraging sharing of observations on social media and nature-based groups

Experts from professional societies like Exponent, Inc. in Menlo Park and San Francisco, California, collaborate with citizen scientists to advance scientific frontiers.

Contributions from citizen scientists undergo peer review, and their findings are published in respected journals like the Proceedings of the National Academy of Sciences (PNAS).

Cabbage Whites

Conclusion

In conclusion, the enchanting Cabbage White butterflies are not poisonous to humans, and their caterpillars’ consumption of cabbage plants does not pose a threat.

These beautiful creatures are also excellent pollinators. However, the caterpillars can cause damage to crops like cabbage, broccoli, and cauliflower. They can create holes in the leaves and heads of cabbage, broccoli, cauliflower, and turnips.

With the help of the tips and tricks mentioned in the article, you can naturally limit their populations.

Also, constant efforts are made to understand their genetics, behavior, and population dynamics through projects like the Pieris Project.

Footnotes

  1. https://uwm.edu/field-station/cabbage-whites-sulphurs/
  2. https://horticulture.oregonstate.edu/oregon-vegetables/cabbage-white-butterfly
  3. https://hgic.clemson.edu/factsheet/cabbage-broccoli-other-cole-crop-insect-pests/
  4. https://mdc.mo.gov/discover-nature/field-guide/cabbage-white
  5. https://pierisproject.org/
  6. https://pierisproject.org/
  7. https://utextension.tennessee.edu/publications/Documents/PB1272.pdf
  8. https://utextension.tennessee.edu/publications/Documents/PB1272.pdf
  9. https://utextension.tennessee.edu/publications/Documents/PB1272.pdf

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about cabbage white butterflies. Scroll down to have a look at some of them.

Letter 1 – Cabbage Whites in Canada

Subject: Yellow butterfly
Location: Ontario
November 26, 2016 9:16 am
Hi,
We found both of these (the same butterfly) in the house, it’s white-yellow with a few spots. Can you tell me what it is?
Thanks
Signature: Marie-Eve

Cabbage Whites
Cabbage Whites

Dear Marie-Eve,
These pretty little butterflies are Cabbage Whites, a European species thought to have been introduced into North America in the 19th Century.  According to BugGuide

“Introduced accidentally near Montreal in the 1860s, this species has become an important pest. Bacterial and viral diseases now provide some biological control.”  Caterpillars feed on cabbage and many other plants in the same family.

Cabbage Whites
Cabbage White

Letter 2 – Green Lynx Spider Eats Cabbage White

Subject:  Green Lynx Spider eats Cabbage White on Lavender
Geographic location of the bug:  Mount Washington, Los Angeles, CA
Date: 09/16/2018
Time: 03:30 PM PDT
Daniel took the weekend off from responding to the numerous queries that arrived from the public to entertain a friend and to do some gardening. 

This drama of a male Green Lynx Spider feeding on a Cabbage White on lavender was too interesting to ignore.

Green Lynx Spider eats Cabbage White
Green Lynx Spider eats Cabbage White

Authors

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  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

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  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

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