Thursday, April 15, 2010

Earth Day is soon - plant Milkweed!

 Earth Day is just a week away. Learn something new and see how you can make the world a better place to live. Love the great outdoors? Well, there is something you can do to make your yard more wildlife friendly. The number of monarch butterflies are dwindling, but you can help them by planting milkweed, plants in the Asclepias family. Here is a link to a segment from 12News Valley Dish yesterday where you can learn how to create a monarch butterfly rest stop in your yard:

Join these upcoming events to learn more about monarch butterflies:

Boyce Thompson Arboretum in Superior 
Sunday Monarch Butterfly Lecture - And New Asclepias Plants!
April 18 at 1:00 p.m.

Just in! As of Tuesday we have at least four varieties of Asclepias plants you can purchase and plant Sunday following Gail Morris' Monarch Butterfly lecture. Lynnea Spencer and Preston Cox just stocked-up with Pine Leaf Milkweed (A. linaria), Desert Milkweed (A. subulata), Butterfly Milkweed (A. tuberosa) and Bloodflower (A. curassavica) for members and visitors to bring home and plant in order to help restore Monarch butterfly populations (potted milkweed plants will range from $5-$10 each). Colorful Monarchs are a garden delight -- and the seemingly delicate insects' mysterious migration is an international puzzle to scientists. Monarch numbers have plummeted  over the past year, according to Chandler resident and BTA Member Gail Morris, but Arizona residents can plant milkweed species to encourage Monarchs to lay eggs and rebuild their populations. Learn more about these regal insects during a one-hour slideshow in our Smith Building Lecture Room. The talk is free for our annual members; for nonmembers the presentation is included with regular daily admission of $7.50 for adults, $3 for ages 5-12. At the end of the slideshow we will have a planting demonstration so you can ask your milkweed planting questions.
For more information see:
Verde Valley Birding & Nature Festival in Cottonwood, AZ
Workshop:  Arizona’s Monarch by Gail Morris
Saturday, April 24    

10:30am – 11:30am Cost: $5
This year the World Wildlife Fund declared the Monarch butterflies’ migration ‘an endangered phenomena’ primarily due to loss of habitat. Some scientists feel if nothing changes, the monarch will lose their magnificent migration within 25 years. Are there monarchs in Arizona? You bet! The Southwest Monarch study tagged over 2,000 in 2009. Learn first-hand how we can help preserve the monarch migration directly from Gail Morris of the Southwest Monarch Study. She will be bringing free milkweed seed packets for anyone who wants to plant them to secure a monarch habitat on their flyway through Arizona.

For more information about the festival see:

Tuesday, April 13, 2010

Monarch Caterpillars in Phoenix!

When I visit the Desert Botanical Garden I always look for monarch butterflies or caterpillars first. As our temperatures begin to warm, the morning hours are the best time to catch a glimpse of butterflies nectaring, especially on lavendar. It is also the ideal moment to spot caterpillars hungrily munching on milkweed. In the morning, caterpillars usually crawl and feed at the top of the plants so they are easy to spot. Every week brings something new.

On Friday I walked through the Herb Garden and ran into Denny Green taking photos of monarch caterpillars on Tropical Milkweed, also known as Bloodflower, Asclepias curassavica. We counted seven larvae on two plants. One milkweed in a shady location had two larvae, another in a sunnier spot had five. The caterpillars were very large, 5th instar. With our warm temperatures by now they have likely formed a chrysalis. All photos in today's post are by Denny Green unless otherwise noted and used with his permission.

It was just two weeks earlier that these same milkweed plants were filled with queen caterpillars. While queen and monarch caterpillars have similar coloring, there are striking differences.

Queen caterpillars have three sets of filaments, one pair at each end and one pair near the middle of the larva. Often you can see a red tinge at the end of the filament.

In comparison, monarch caterpillars have two pairs of filaments, one set at each end.

When I spotted the monarch caterpillars, a few questions popped to mind. Could these caterpillars possibly be from eggs laid by the faded female monarch butterfly I saw on March 15th? This was almost three weeks later, longer than normal for their growth stage. During this time period some of our temperatures in the Phoenix area were much cooler, with a few lows in the upper 30's and low 40's. While now a warm 85, I couldn't rule out the possibility since monarch larvae grow only between the temperatures of 52.7 and 91.4 degrees.

Did one or more monarchs lay these eggs?  It is interesting to note that all seven caterpillars are about the same size, so they were likely from the same female monarch. Only one seemed to have a smaller body, but the filaments were as long as the others, one of the indicators of instar size.

The coloration of a monarch caterpillar gives us clues to whether it is hot or cold outside. Look at this picture of a monarch caterpillar on Desert Milkweed, Asclepias subulata, taken by Laura Miller last Fall. Temperature readings at that time were hovering in the middle 90's with mid-60's to 70's at night. When it is warm, the caterpillar adapts with wide bands of white, and thinner bands of black and yellow. In this case the black is almost pencil-thin. When it is hot many of us like to wear light colors to keep cool. The monarch larva does the same.

In comparison we can see how thick the black and yellow stripes are in the monarch caterpillars at the Desert Botanical Garden last week. The darker coloration helps them keep warm by absorbing more of the sun's heat during a cool time of year - just like we are more comfortable wearing darker colored clothing on a chilly day.

How wonderful to see monarch caterpillars in the Phoenix area, the first sighting of Spring!

Monday, April 5, 2010

The Spring Migration in Phoenix

Last Friday, April 2, a male monarch butterfly was spotted at the Desert Botanical Garden in Phoenix 2:15 in the afternoon. It was a sunny day with temperatures in the low 70's. Earlier we had a few days of strong winds from the south that could have thrust him into the Phoenix area. Monarch butterflies love to hitch a ride on thermals and gust fronts. While we have no way of knowing for sure that this is the case, it is interesting to record and note.

If you look closely at the color of the monarch butterfly in this picture, the orange color is rich and the wings look new. This male is likely a freshly emerged monarch rather than one that traveled from overwintering sites in Mexico or California. In comparison, the female spotted laying eggs on March 15 was faded and a tad tattered from her journey. Of course this raises the question, WHERE did he emerge? This monarch butterfly likely came from the first generation of a monarch that either overwintered nearby in Arizona, or flew from Mexico or California and laid eggs on available milkweed.

On Friday the male monarch was "patrolling" the milkweed in the Herb Garden. Male monarchs will often fly over milkweed patches looking for a female mate, driving off other butterflies to protect his field. In this picture he took a rest to sun on a plant for a moment, but was quickly back in the air cruising the thicket. Its interesting to just sit back and watch their flight pattern that resembles a jet in a flight hold over an airport, circling around and around. Today I returned to see if he was still at DBG, but he was gone, likely moving north or northeast. In fact I didn't see a butterfly of any kind that morning despite the sunny and delightful temperatures. So often what we see is a matter of timing.

We watched the three monarch eggs deposited on a milkweed plant at the Desert Botanical Garden on March 15.  One egg developed into a tiny caterpillar with its large dark head, but was gone two days later. The other two eggs never developed. Monarch eggs have a high mortality. Studies indicate only one egg of ten becomes a monarch butterfly. The numbers are even lower if more predators are present.

Several milkweeds are beginning to bloom: Tropical Milkweed (Asclepias curassavica), Narrowleaf Milkweed (Asclepias angustifolia), Pineleaf Milkweed (Asclepias linaria). Desert Milkweed (Asclepias subulata) will likely bloom in the next few weeks savoring the warmer temperatures and also extending the milkweed availability for migrating monarchs.