Category Archives: lepidoptera

Bats Use Sonar, but Butterflies?

hawk moth, Pablo PadronButterflies and moths are small, but mighty. They have numerous ways of thwarting predators, namely bats. Only recently have lepidopterists (moth and butterfly scientists) understood the defensive sonar-jamming capabilities of some species. In a recent collaboration by scientists at the University of Florida and Boise State University, lepidopterists scoured jungles from Borneo to the Amazon. They observed and collected hawk moths in thirty-two countries. Echolocation experiments and lab experiments used more than 700 moths, and found that nearly half generated ultrasonic sounds with their genitalia. Tiger moths, however, use tymbals, vibrating membranes located on their thorax to produce the sounds. Similar radar jamming is used in human warfare, allowing pilots to be invisible to the enemy. Further study of moths’ ultrasonic sound production should help improve human use of sonar.

Recently, Akito Kawahara at the University of Florida and Boise State University biologist Jesse Barber released a second study reporting that luna moths have learned to use their tails to confuse the sonar calls of bats. Noticing the large diversity in nocturnal moths, Kawahara studied certain species of moths with long tails. Bringing brown bats and several moth species to the Florida Museum, the team set up high-speed infrared cameras and ultrasonic mikes and found those with tails were more likely to survive a bat attack than those without. Bats appear to target the moth’s long tails instead of the head in 55 percent of all interactions, assuring the moth’s survival.

There is still much to learn about the biodiversity of nocturnal species. Yes, moths attracted to your patio lights, or munching caterpillars in the garden can be a nuisance, but we must not discount the small and mighty moth.

Ref: May 2015 study Proceedings of the National Academy of Sciences, lead author Akito Kawahara, assistant curator of Lepidoptera at the Florida Museum of Natural History  flmnh.ufl.edu/mcguire/kawahara; photo credit: Pablo Padron

 

Disappearing Monarchs

monarch-sunflower-lacreek-nwr-tome-koerner-usfws-300[1]Ubiquitous no longer describes the beautiful monarch butterfly. Experts say over the past two decades, population has declined from about one billion butterflies in the mid- nineties to just 35 million individuals last winter. Jaret Daniels, associate curator and program director at the McGuire Center for Lepidoptera, estimates the monarch butterfly population has declined by as much as 95%. The U S Fish and Wildlife Services will announce in December whether federal protection will be extended to the beautiful pollinator.

What is causing the decline? Herbicide maker Monsanto’s popular weed killer Roundup is blamed for wiping out most of the milkweed plants on farms across America. Monsanto has introduced Roundup Ready crops which resist the herbicide. Farmers, in a race to fill demands for ethanol fuel, are planting more herbicide-resistant crops.

Soy and corn fields across North America were once filled with milkweed, the Monarchs’ host plant, on which they lay eggs. Each species of butterfly has a specific host plant, the only one the caterpillar will eat. On their route to specific over-wintering sites in Mexico, then back home again, Monarchs rely on the milkweed to lay the next generation, and for flowers to nourish them along the migration route.

What can I do to help the iconic Monarch butterfly? Plant milkweed! Learn which of the 103 types is suitable in your area. I recently learned that what I had planted in my North Florida yard was doing as much harm as good, because it did not die back early enough in the fall, delaying Monarch migration. I will be planting an aquatic species of milkweed this year. I am not ready to pull up what I have growing, but will certainly cut it back early in the fall. Plantings along roadsides and fence lines would mmonarch-caterpillar-courtney-celley-usfws-300[1]ake good service projects. Farmers would do the world a service by leaving surrounding rows unplanted and unsprayed so that milkweed can co-exist with herbicide resistant plantings. And we can always pray. But prayer without action is just a wish. bto