Letter from Dr. Jeffrey Glassberg to members of the North American Butterfly Association (NABA) with IBBA responses.

IBBA Responses may be excerpts from full statements made in other reports on IBBA’s website under “What the Experts Say” section.

NABA: Butterfly Releases: Action You Can Take

It has been almost three years since the editorial “There’s No Need To Release Butterflies-They’re Already Free” appeared in this space. The editorial (by Jeffrey Glassberg — president of the NABA and author of Butterflies Through Binoculars, Paul Opler — author of Peterson Field Guide to Butterflies, Bob Pyle — founder of Xerces Society and author of Audubon Society Field Guide to Butterflies, Bob Robbins — curator of Lepidoptera at the United States National Museum, Smithsonian Institution and Jim Tuttle — then president of the Lepidopterists Society) explained why releasing commercially raised butterflies into the environment — at weddings and other events — is truly a terrible idea.

At NABA, we are often contacted for permission to reproduce the editorial, and for information about butterfly releases. It is clear that the editorial, and NABA’s continuing efforts to educate the public about the potentially devastating effects of butterfly releases has had a significant impact. Many, many individuals have reconsidered their own plans to release butterflies into the environment after reading the information from the NABA. The fact that the commercial butterfly breeders who encourage these releases are constantly attacking NABA is a clear measure of the impact that we are achieving.

IBBA’s Response

Many commercial butterfly breeders are members of the NABA. We do not attack the NABA. Dr. Glassberg’s opinion concerning the release of butterflies is unsubstantiated by any scientific data.

There is now an opportunity for all NABA members to personally make a contribution. As was mentioned in the earlier editorial, the United States Department of Agriculture (USDA) has taken the position that it is appropriate for the USDA to regulate the interstate shipment of live butterflies, since butterflies are potential agricultural pests.

The USDA is now reconsidering it’s regulations regarding the interstate shipment of live butterflies. My understanding is that the USDA is likely to propose regulations significantly weakening the already unacceptably lax regulation of these shipments. Currently, the interstate shipment of live butterflies requires a permit from the USDA. The USDA will consider issuing permits for shipping nine butterfly species – Giant Swallowtail, Zebra Heliconian, Gulf Fritillary, Mourning Cloak, American Lady, Painted Lady, Red Admiral, and Monarch. The regulations being considered would allow interstate shipments of American Ladies, Painted Ladies and Red Admirals without any permit.

What Can You Do? Because the USDA listens to public opinion, it is important that you contact the USDA and express your views regarding this threat to wild butterfly populations. Write to: Wayne F. Wehling, USDA – Aphis, PPQ PRA, Unit 133, 4700 River Rd., Riverdale, MD 20737; or send an email message to him at Wayne.F.Wehling@usda.gov.

In addition, The National Invasive Species Council, in the Dept. of Interior, has published an Invasive Species Draft Management Plan that is open for public comment. You can comment about this plan, saying that it needs to consider the effects of interstate shipment of butterflies, by writing to: National Invasive Species Council, U.S. Dept. of the Interior – South, 1951 Constitution Ave. NW, Suite 320, Washington, DC 20240; or by sending an email message to invasivespecies@doi.gov. Written letters are more effective than emails.

Please let the USDA and the Dept. of Interior know that you object to the interstate shipment of commercially-raised butterflies intended for release into the environment. Here are some of the reasons you can provide to them why these shipments and releases should not be provided:

Because butterflies are pollinators, they are an important component of plant ecosystems, not just potential plant pests. Heretofore, the USDA has viewed their authority to regulate the shipment of butterflies as stemming only from their potential as plant pests. However, butterflies are a major part of the pollination community. Although the efficiency of butterfly-induced pollination is lower than bee-induced pollination, the cumulative importance of butterfly pollination is probably important to many plant communities. From personal observations, I would conclude that for particular plants in particular areas, butterflies are probably the major factor in pollination. Because any threat to butterfly populations is a threat not only to the butterflies themselves, but also to plant communities, the USDA does have the authority to regulate potential threats to butterfly populations.

IBBA’s Response:

The release of butterflies at special events increases public awareness of the magnificence of this insect. Hopefully, people will become involved in putting a stop to the unbridled destruction of butterfly habitat, the indiscriminate use of insecticides and they will develop a desire to modify their landscape to include larva host plants and nectar plants. Butterflies are the ambassadors of goodwill for the insect world.

Releases of commercially-raised butterflies may spread disease and epidemics to native butterfly populations. This issue is critical. All known biological organisms are affected by diseases and parasites. The spread of diseases from one area to another has decimated populations. For example, American chestnuts almost became extinct due to the introduction of a fungus from Europe. The transmission of measles from European populations of humans to New World populations of humans killed more Native Americans than did any wars. The lesson here is that not all populations of the same or related species have been exposed to all diseases that may affect that species. Our knowledge of butterfly diseases is rudimentary, but we do know that there are many species of viruses, including many baculoviruses and nuclear polyhedral viruses, many bacteria, and many fungi that cause diseases of butterflies. Such diseases have been found to be prevalent in shipments of commercially-raised butterflies.

Shipping butterflies from California to New York, or from Florida to New York or California and then releasing the butterflies into the environment would allow a California disease to spread to wild butterfly populations in New York, or a Florida disease to spread to California. The fact that Red Admirals can be found in Florida and in California does not preclude the likelihood that some diseases or parasites of Red Admirals and other butterflies are currently limited in their range to, for example, Florida, or to California.

In the late 1940’s, House Finches, a bird that until then had been found only in western United States, were released onto Long Island, New York. These few birds have now spread throughout the entire eastern United States, demonstrating that although a particular species may currently be found in only one section of the United States, there is no guarantee that it will not thrive in a different region if introduced into that region. If this is true of a bird, it can be just as true of a diseases-causing organism.

The practice of shipping live butterflies around the country and releasing them into the environment carries with it the possibility of unleashing invasive diseases. Large-scale commercial operations foster the spread of disease and the generation of new diseases that can devastate butterflies. It is well known that agriculture and animal husbandry, by increasing densities of an organism, create conditions that are extremely favorable for the spread of disease-causing agents of that organism. In addition, these conditions encourage the creation of new disease-causing organisms

IBBA Comment:

Dr. Glassberg cannot cite one documented case of a shipment of commercially raised butterflies carrying and transmitting any disease to the wild population. Nor can he document an example of a new disease-causing organism resulting from the activities of commercial butterfly breeders. There is no scientific data that commercially raised butterflies spread diseases and epidemics to native butterfly populations. To the contrary, commercial butterfly breeders must be meticulous to prevent the spread of diseases from the wild population to their butterfly stock. If this happens, their stock will be completely wiped out and they will have no butterflies to release.


In the last 32 years, Insect Lore has shipped out over 8 million Painted Lady larvae; and Monarch Watch Program has shipped 250,000 Monarch larvae in the last 8 years. No damage to local butterfly populations nor to the environment has been reported to have occurred as a result of this livestock being sold, raised and released.

The fitness of local butterfly populations may be decreased by interbreeding with released individuals. A recent report in Nature (Moore, P.D. 2000). “Conservation biology: Seeds of doubt” Nature 407: 683-685.) highlights the unexpected findings that, released into the environment, individuals that originate non-locally, will breed with local individuals and decrease the fitness of the local population, by introducing genes that are not optimal for the local environmental conditions.

IBBA Comments:

The science of population genetics proves the fitness of local butterfly populations is not decreased by interbreeding with released individuals. Dr. Bruce Walsh, associate professor, University of Arizona, a renowned population specialist, has posted on the d plex on several occasions that this does not happen. Please refer to the IBBA website’s “Expert Answers to Butterfly Concerns” item No. 6 comment to “Do captive raised monarchs that are released somehow weaken the wild population? No!” — This is a very thorough discussion as to why captive raised butterflies do not weaken the wild population. (www.butterflybreeders.org)

Scientific studies and observation by butterfliers are confused by butterfly releases. The movements and migrations of butterflies are still very poorly understood. Scientists, trying to track, for example, northward movement in the spring of Painted Ladies, now are confused by Painted Ladies being released into the environment. Butterfliers, who would be thrilled to see a Zebra Heliconian in North Carolina are cheated out of a satisfying experience because now the butterfly may well have occurred there unnaturally.

IBBA’s Comment:

The release of captive raised butterflies does not confuse proper scientific studies of local population structure. Please refer to “Expert Answers to Butterfly Concerns”. A population geneticist explains scientifically, why this does not happen.

The commercially-raised and released butterflies often suffer. These butterflies often arrive dead or dying, and then are often released into hostile environments at inappropriate times of year.

IBBA’s Comment:

For any commercial enterprise to survive, they must market a quality product at a competitive price. Commercial butterfly breeders are meticulous in the raising, packaging and shipping of live butterflies so they arrive healthy and vigorous. They’re not shipped at inappropriate times of the year. The USDA and the State Departments of Agriculture will not permit butterflies to be shipped and released in areas they do not normally occur. Butterfly farmers adhere to USDA permitting regulations and ship butterflies interstate for release to the environment ONLY where they occur naturally.

Butterflies are living animals, not toys. There is something ethically wrong with treating butterflies as if they were mere playthings for humans. They are not toys, or to use a Bob Pyle phrase, “living balloons.”

IBBA’s Comment:

Many elementary school students raise and release butterflies as part of their science education program. This is a magnificent introduction into the wonders of nature for the small children and is not looked upon as a toy or playing. The release of butterflies at funerals, weddings and other events is a very worthwhile, spiritual and emotional experience. It is not looked upon as playing with toys.

We do not allow those who like birds to ship chickadees around the country and then release to them into the environment. There no reason to allow butterflies to be treated any differently.

IBBA Comment:

The intentional release of native birds, without obtaining proper permits, was outlawed in 1947. Thousands of permits to release native birds are issued every year to individuals and municipalities. The USDA has similar regulations with respect to transporting and releasing of butterflies.

For all of the above reasons, please make your voice heard.
Jeffrey Glassberg

IBBA Follow Up

What can you do to save butterfly releases for school children and adults alike?

The USDA is committed to issuing regulations that are based on science. The extremist opinions and statements of Jeffrey Glassberg are not founded in any provable science.

It is interesting to note that in the last 32 years, Insect Lore has shipped out over 8 million Painted Lady larvae; and Monarch Watch Program has shipped 250,000 Monarch larvae in the last 8 years. No damage to local butterfly populations nor to the environment has been reported to have occurred as a result of this livestock being sold, raised and released.

You are invited to contact the USDA and urge them to base their decisions and policy making in science, and allow commercial butterfly breeders to continue raising and shipping butterflies for release to the environment.

Write to: Wayne F. Wehling, USDA – Aphis, PPQ PRA, Unit 133, 4700 River Rd., Riverdale, MD 20737; or send an email message to him at Wayne.F.Wehling@usda.gov.

In addition, The National Invasive Species Council, in the Department of the Interior should also be encouraged to base their decision making in science with regard to butterfly releases. Write: National Invasive Species Council, U.S. Dept. of the Interior – South, 1951 Constitution Ave. NW, Suite 320, Washington, DC 20240; or send an email message to invasivespecies@doi.gov.

The IBBA website (www.butterflybreeders.org) contains answers about butterfly concerns, from noted scientists and butterfly authorities. Their answers are based in science and demonstrate clearly there is no harm being done to the butterflies nor the environment.

Thank you for your support in helping save the opportunity for people to have a first-hand experience with the beauty of butterflies.