BUTTERFLIES, BATS, AND POLLINATION

September 12, 2003
Texas State University
San Marcos, Texas

Dr. Jeffrey Glassberg (naba@naba.org or 973-285-0907), President of the North American Butterfly Association, gave a presentation on the role and protection of butterflies, key players in pollination.

He explained that butterflies were more than a "little blip" in the natural world, but could be the way that the public might get interested in nature and engaged in its protection. People naturally love the beauty of butterflies and the fascination of their metamorphosis from caterpillars, so butterflies can serve as an easy entry point for people's exploration of the entire natural world.

While there has been a traditional interest in charismatic megafauna, this doesn't need to exclude the possible interest in quite small creatures like butterflies. For instance, a grizzly bear at 300 yards is no bigger, in appearance, than a butterfly within 2 feet. Dr. Glassberg offered the E=MC2 "formula" as a useful reminder: Excitement = Mental stimulation x Closeness-squared. Further, unlike the grizzly, butterflies aren't threatening - they don't sting or carry disease, and polls have shown that they are the kind of wildlife that most people want near their home.

Also, there is great diversity among butterflies to reward people's study - there are green butterflies and blue ones, large ones the size of a melon, and smaller ones the size of a fingernail, showy ones and camouflaged ones.

Dr. Glassberg also finds that butterflies are useful as an environmental early warning system, a type of canary in the coal mine, since butterflies' populations are found in most climates and terrains, are very sensitive to temparature and contaminants, and can have 100-fold swings in a single year. As an example, some scientists are seeing the northward shift of the Italian Fritillary as an effect of climate change.

Also, since butterflies are so intertwined with their surroundings, the study of butterflies is a great window on both plants as a food source and pollination factor, and on the insects that butterflies compete with.

Butterflies are also easy to approach (they are not frightened by people standing in their midst), and easy to attract (gardening with milkweeds and other plants can pull in butterflies).

For all these reasons, the North American Butterfly Association has seen rapid growth: in 1990, NABA conducted 119 July 4th butterfly counts with 586 participants, while in 2000, it coordinated 422 July 4th counts with 5143 participants.

Dr. Glassberg then discussed the life history of butterflies, explaining their cycle of side-by-side mating, egg-laying (sometimes in stacks under leaves), hatching of the eggs into caterpillars, pupal stage, metamorphosis and emergence of the butterfly.

Interestingly, the life cycle of many butterflies brings them to Texas in migration or residency. To give an idea of the popularity of Texas with butterflies, Dr. Glassberg asked us to consider this chart:

In addition, 10% of resident butterfly species are only found in Texas.

As a result of the importance of Texas in butterflies' life, NABA has committed to building the NABA International Butterfly Park in a Lower Rio Grande Valley site near Mission, Texas, Bentsen State Park and the World Birding Center. 83 acres for the Park have been donated (a value of $1.5 million), and a remaining 70 acres are available for purchase from the donors. Overland Partners, the San Antonio architectural firm responsible for the Lady Bird Johnson National Wildflower Center headquarters, has been retained to design the building. The City of Mission has committed $100k for roads and irrigation.

Dr. Glassberg concluded by reminding TEGG that the Greeks equated the butterfly and the soul, that "psyche" referred to both, and showed that people and butterflies had long been linked.

Q: What are the best times to look for butterflies? Dr. Glassberg said that October and November were best, though 75-100 species could be seen in any season.

Q: Are there predators that eat butterflies? Merlin Tuttle said that bats ate moths. Dr. Glassberg said that dragonflies, spiders, parasitic wasps, and human collectors preyed on butterflies.

Q: What effect do collectors have? Dr. Glassberg replied that collectors were few (prior to 1985 there were less than 100 active field "butterfliers") and had minimal impact.

Q: What is the lifespan of a butterfly? Dr. Glassberg said that it varied from as short as 1 week to as long as 9 months, with an average of 1 month.

Q: Is artificially propagating or "farming" butterflies for collections a good or bad thing? Dr. Glassberg said that he was unsure, that the jury was still out. NABA works mostly with wild butterflies so this hasn't been a focus for him.

Q: What is the impact of genetically engineered corn on monarch butterflies? Dr. Glassberg said that he thought it highly unlikely that genetic engineering would harm the monarchs, at least in comparison with more immediate threats, such as vigorous mowing of road rights-of-way, or bans on planting milkweed. Dr. Tuttle was less sure that genetically engineered crops were so benign.

Merlin Tuttle (512-327-9721 or www.batcon.org), founder of Bat Conservation International, followed Dr. Glassberg's talk with a presentation on bats and their protection. Dr. Tuttle said that bats were critical to the pollination and propagation of many plants, especially desert species such as agave, organ pipe cactus, and saguaro cactus. Since such bat-pollinated plants as agave have economic value (as the source of tequila), and other plants, like the saguaro cactus, have ecological value (as the nest home for gila woodpeckers), it is important to protect bats. Other examples of bats' key pollination role abound: bats are responsible for the pollination of baobab trees, the famous African "tree of life", and for the fertilizing of the balsawood tree and numerous fruits. It's estimated that 70% of tropical fruits are pollinated by bats, including the banana, avocado, cashew, date, mango and durian.

It should not be surprising how critical the bat is to the web of life: Dr. Tuttle explained that there are over 1100 species of bats, and bats make up 1/4 of the world's mammals. The concentration of bats in some locations is astounding: Bracken Cave near San Antonio hosts 20-40 million bats, representing 270 tons of bats, clustered at 200 to 500 bats per square foot, able to eat 200 tons of insects nightly, and produce prodigious amounts of guano. The ability and agility of bats is impressive as well: bats learn to fly within 4 to 5 weeks of birth, and must fly within 3 seconds of launch in the midst of thousands of emerging bats.

The economic value of bats was long understood (guano was the most valuable Texan mineral export prior to the petroleum), but its full value is only now starting to be seen, with the help of Doppler radar that show the clouds of bats moving into central and coastal Texas to eat agricultural pests. Scientists now estimate that 1 bat consumes 20,000 moths per year, removing the need for $32 in pesticides. In total, bats are expected to save farmers $1 billion per year in losses in the US alone. Bats also contribute to tourism: 1.5 million Mexican free-tailed bats live beneath the Congress Avenue bridge in Austin, and bring in $8 million per year from visitors to the area.

Nevertheless, there is a bias against bats. There is a wide misconception that bats bite and infect humans, though no one with one of the 100,000 bathouses in North America has had this happen.

To turn around this misunderstanding of bats (bats are reputed to be the least-studied mammal, with only 5% of their species even described), Bat Conservation International is training field biologists, and so far has funded scholarships for 1000 students in 17 countries.

To promote protection of bats and their roost sites, BCI is helping mining companies gate, rather than close, their abandoned shafts, reducing liability for human visitors, but still allowing bats' access. To date, 1000 mines have been gated (often by cavers, a rather vilified group) and preserved as bat roost sites. Not only are these gates helping avert the "kill-it, scoop-it, bury-it" attitude among companies frightened of endangered species liability, but they are also making a very real difference in the survival of bats. For instance, the rare Indiana bat has tripled in just 3 years after the restoration of one mine, and may no longer need listing as an endangered species. Similarly, the grey bat, which was listed as endangered in the early 1970s, now numbers 2 million and is under consideration for down-listing.

In general, BCI seeks cooperative, nonconfrontational approaches. Dr. Tuttle said that they have never sued, threatened, or boycotted.

Mr. Tuttle concluded with the thought that it is not sufficient to save only bats or butterflies. We must save "all the pieces".

Questions and Answers

Q: Has BCI had ever conducted Halloween events? Dr. Tuttle said that they had: the Fikes Foundation had provided money for bat fact cards to be distributed at Halloween.

Q: Did BCI have a role in the recent USPS bat stamps? Dr. Tuttle said, "yes", they had lobbied for the stamps (less popular than and created after snakes' stamps), and had provided the photos.