Who needs fireworks? Native Azaleas and Tiger Swallowtails

Have you been to a wild azalea grove?

 

 

 

 

 

 

 

 

Every year there are a couple of azalea groves I love to visit in early spring. One is in the Boat Rock preserve in South Fulton County, and another is in the back acreage of our forest at Beech Hollow. And every year the groves are fireworks of flowers and Tiger Swallowtails.

The Tiger Swallowtails always seem to be one of the first butterflies to be up and out in the cool of early spring, and the azaleas are one of the few nectar sources available at the very beginning of spring. It is truly delightful to sit and watch the yellow winged males and the blue-black winged females delicately sip nectar all the while fanning their wings, slowly working their way across the azalea grove in loopy arcs.  There are plenty of native bees visiting the flowers as well; they flit past the arched stamens and pistil to burrow down into the corolla and access the nectar.  Those stamens and the pistil don’t come close to brushing the bees as they pass.

Here’s the thing: How would the bees pollinate the azaleas? The anthers and pistils flare out, well away from the nectar. Bees that access nectar alone won’t necessarily make contact with the stamens or pistil. In 2015, Mary Jane Epps, Suzanne E Allison, and Lorne M Wolfe published a paper about wing pollination by tiger swallowtails of Flame Azalea (Rhododendron calendulaceum) in the Blue Ridge. Very cool! Could our Piedmont Azaleas be pollinated in the same way?

Last spring, Jessi and I decided to take a look for ourselves in our grove of Piedmont Azalea (Rhododendron canescens) up by the boulders in the back of Beech Hollow. While we sat, a male Tiger Swallowtail was on patrol at the grove, waiting for a female. He looped around the grove, from flower to flower, fanning his wings as he nectared. He was such a pale yellow that it was hard to tell if he had gathered any pollen on his wings. Then a female swallowtail came by, and:

 

 

 

 

 

 

 

Above, on the left, female Tiger Swallowtail (Papilio glaucus) with her wings brushing the anthers of Piedmont Azalea.  On the right, several minutes later,  the same female with pollen visible on her wings.

This is an observation, not a scientific study. But it does appear that the same type of wing pollination that was recorded by scientific study in Flame Azaleas may also be occurring in Piedmont Azaleas.

That same spring at Boat Rock Preserve in Southwest Fulton County my husband Michael Williams was taking photos in the Piedmont Azaleas and caught this critter, a Hummingbird Clearwing moth, (possibly Hemaris thysbe) hard at work in the  azalea flowers:

I wonder if this species is also capable of wing pollination?

Here is the citation for the 2015 article on wing pollination:

Epps, Mary Jane, Allison Suzanne E., and Wolfe, Lorne M. Reproduction in Flame Azalea (Rhododendron calendulaceum, Ericaceae): A Rare Case of Insect Wing Pollination. The American Naturalist, vol 186, No. 2. August 2015.

 


The Monarchs are Coming

March 17: Spring has warmed the mountains of Michoacán in the State of Mexico.  As I write this, the noon temperature in that alpine forest is 74 degrees Fahrenheit. The monarch butterflies that have been hibernating in tall fir trees have started leaving their mountain roosts to voyage north on their yearly migration in search of milkweed host plants for their young.  By the end of March, all of them will have left Mexico to journey north.
 
As early as this January and February, Monarchs have already been sighted on the Gulf Coast of Alabama, Mississippi, and throughout much of Florida.  They will be in the Georgia Piedmont soon, and as you read this, fragile orange wings are flapping and fluttering against air currents to make their way here. By the time the Monarchs have reached Beech Hollow in late March and early April, the journey will have been roughly 1500 miles.

Why do they migrate?  The timing of the butterflies’ northward migration follows the seasonal availability of the larval host plants that monarchs need to feed their young.  They will migrate only as far north as the milkweed grows.  However the timing of the southward migration has the insects traveling well ahead of cold winter temperatures that they cannot survive.  And as they travel south during the late summer through the fall, there are still plenty of nectar plants for them to forage on to fuel their journey to the alpine forests in Mexico.  How’s that for travel planning? From the summer range in southern Canada to Mexico’s alpine forests, the total journey averages 2500 miles.

Rough timing of Monarch migration stops: When the female Monarch arrives in the southern United States between February through April, she will lay her eggs, and only upon Milkweed plants. Her caterpillars feed on the Milkweed, grow, pupate, and hatch. It takes anywhere from 4-7 weeks for the second generation of butterflies to mature enough to take up this generational relay. 
 
This second generation of new Monarchs flies into the northern United States and Southern Canada in late spring.  When the butterflies arrive, the females lay the eggs of generation number three on Milkweed plants.

In August and September, Monarch generations three and four will start flying southward, retracing their flights back to the mountains in Michoacán and the State of Mexico.  When the butterflies arrive, they overwinter in large fir trees and wait for the return of spring.

Habitat needs:  A garden with native plants which provide nectar for the adult butterflies is important.  Even MORE important for Monarch butterflies is the availability of their larval host plant: Milkweed. Supporting their full life cycle by providing host plants for their caterpillars will ensure the return of these intriguing insects year after year.  Milkweed species that are recommended by the GPCA (Georgia Plant Conservation Alliance) and native to the state of Georgia are: 

  • Clasping Leaf milkweed, Asclepias amplexicaulis
  • Poke Milkweed, Asclepias exaltata
  • Pink Milkweed, Asclepias incarnata
  • Butterfly weed, Asclepias tuberosa
  • and Whorled Milkweed, Asclepias verticillata

Please Provide Water, everyone needs clean water, even insects.  A ceramic plant saucer with large pebbles or a sand ramp in it will allow butterflies to approach the water without being drowned.
 
Minimize use of toxic chemicals, such as pesticides, which can sicken or kill unintended, or “non-target,” wildlife.  If you must use a pesticide, be aware of your larval host plants and other pollinators, apply pesticides carefully to avoid destroying your beneficial insects.

Websites with additional information:

https://www.fs.fed.us/wildflowers/pollinators/Monarch_Butterfly/migration/index.shtml

http://www.learner.org/jnorth/maps/monarch.html

https://www.fs.fed.us/wildflowers/pollinators/Monarch_Butterfly/biology/index.shtml#migrgen

Annual generational lifecycle:

https://monarchlab.org/biology-and-research/biology-and-natural-history/breeding-life-cycle/annual-life-cycle/

Western Monarch Information:

https://www.westernmonarchcount.org/about/