Thursday, October 8, 2015

Helping Monarch Butterflies?

The inquiries began last Spring after the announcement of another low monarch butterfly overwintering population in Mexico. "Where can I find monarch eggs to grow to help the population?" Well, the answer seemed easy at the time - grow a large milkweed patch and they will come. Earlier we updated the Southwest Monarch Study webpage with links to local milkweeds as well as a special link on creating a Monarch Waystation with plant recommendations by elevation. But the emails for eggs and larvae continued. And continued. And continued.

Over the summer months we heard about large mass rearing of monarchs in some states. In some cases where larvae were distributed for everyone to have a monarch caterpillar grow in their yard, they weren't healthy. Some didn't survive, others couldn't fully eclose (emerge from its pupal case), were very small or had difficulty flying.

In late July in Phoenix with temperatures hovering around 110°, we received a call from a ranger who reported a monarch along the Salt River. She sent a photo to be sure it was a monarch (it was) and she was laying eggs on Desert Milkweed, Asclepias subulata. A few of us went to monitor the area and counted her eggs. None of the 15+ eggs developed even though they looked fertile.

In early August we received an email requesting a large number of tags by a person who said she had large numbers of monarchs in her yard. This was only days before our record 117° heat wave. After monitoring monarchs in the Phoenix area for many years we have a good idea of their range of absence/presence and monarchs are absent during the summer months. But we are always open to rare sightings. Upon further investigation I learned this individual was a butterfly farmer. A butterfly farmer will raise butterflies and sell them. The problem was monarchs do not thrive or naturally reproduce successfully in Phoenix with our high summer temperatures. Normally monarchs are found in the higher elevations during the summer months where it is cooler.

In early August we received a request from a teacher in the middle elevations of Arizona to visit their classroom to share information about monarchs. They had already ordered monarch larvae from a butterfly farm but they all died, so they were receiving a second batch by mail for the students to watch grow. A Southwest Monarch Study volunteer visited the classroom and brought a wild monarch to tag when she saw the condition of a freshly eclosed monarch from the butterfly farm. So we discussed her concerns and talked her through how to test for OE. Out of 40 larvae, only six successfully became an adult. Of those many had high levels of OE and others did not look healthy. We are sending the samples to Monarch Health for confirmation.

In our recently published, "Status of Danaus plexippus in Arizona" we found that while Ophryocystis elektroscirrha (OE) levels were low in Arizona at 4% in the wild monarch population, in the few tested farmed monarchs they were much higher at 29%. While we do not know the current OE levels for other states in the Southwest, based on our experience here in Arizona, we would urge caution until more is learned. Sick or infected monarchs are often still well enough to breed and can spread diseases unnecessarily.

As a result of the increase of communications requesting a source for monarch eggs and larvae to help increase the population as well as the increase in reports of OE in farm monarchs, the Southwest Monarch Study has joined other monarch scientists and conservationists in recommending against encouraging mass breeding of monarchs in the wild or obtaining farm monarchs due to the increasing chances of spreading diseases to our healthy population here in Arizona. While we applaud the intentions of those who would release monarchs to replenish the dwindling population, releasing infected butterflies may be doing more harm than good. Please take a few moments to read the full statement on Captive Breeding and Releasing Monarchs here. This doesn't mean you shouldn't protect monarch eggs or larvae in your yard in an enclosure if you wish and then tag and release them afterwards. Just be sure to follow the protocols for safe rearing to keep your cage healthy and enjoy them.

How can you best help monarchs? Grow milkweed. Grow spring nectar plants to nourish monarchs when milkweed is up but not yet in bloom. Grow stands of fall nectar to fuel their migration.

Thursday, September 24, 2015

A New Monarch Highway Through Arizona

Monarch at Buffalo Park, Flagstaff in early July
The clues were there in spring. Sightings of monarch butterflies were reported in late April and May in Sedona followed by early sightings in Flagstaff. At the time we were thrilled to have new eyes looking for monarchs and larvae in those areas. But as I mentioned in the last post, monarchs were scarce along the east-central portion of Arizona, most notably near the Little Colorado River where the population flourishes especially during August and early September when orange wings are usually everywhere you look. Not this year. Instead a new monarch highway developed.

In general monarch sightings were unusually low throughout the state while the population appeared higher than earlier years in New Mexico, Nevada, even Utah. Reports from the state of Washington also seemed robust. So what happened here? It's unclear. Maybe a late freeze in the last days of May and early June in the higher elevation eliminated the spring migrants in the area. The cooler than normal spring as well as rain could have slowed reproduction and milkweed availability. Or strong monsoon winds could have shifted movements.

Grand Canyon Butterfly Count
While numbers were lower than usual in early August, there was an uptick in numbers as the premigrants moved south through the state in mid August and early September. This movement is a precursor to the main monarch migration appearing about 30 days prior to the peak migration by latitude. Usually this southward moving pulse of monarchs are breeders laying eggs as they move through and their offspring will mature in time to join the main migration. That is exactly what happened as more and more people began reporting monarchs throughout the state beginning in the Grand Canyon where we easily counted 35 monarchs each day three weeks ago with at least six females laying eggs in eye view. Last week they reported more large fifth instar monarch larvae than they've seen all summer.

Steve Plath, Signature Botanica, Sept 23, 2015
So where are the monarchs in Arizona? The pattern appeared in August with numerous sightings in the Grand Canyon, Sedona, followed by increasing numbers in Prescott as the month progressed. Yesterday, Steve Plath of Signature Botanica in Wickenburg was excited to report a monarch in his shade house on Arizona Milkweed, Asclepias angustifolia. But he didn't just have a monarch visit - she was laying eggs. This year it looks like the main thrust of monarchs is in west-central Arizona. Everyone living along this monarch highway may likely see more monarchs than usual, so get your tags ready!

Canelo July 2015
Yes, there are monarchs now throughout the state of Arizona. A monarch and larvae were reported in Mesa the second week of September and Adriane Grimaldi found monarch larvae on Desert Milkweed, Asclepias subulata, in north Scottsdale. A week later Mary Klinkel reported a monarch in the Tucson area followed by a report of another at Tohono Chul that was promptly tagged by Andy Hogan. There are more monarchs in southeast Arizona as well, although the numbers are still lower than recent years. But, so far, the largest density is following the west-central route through Prescott.

The main migration this year seems late. Strong southerly winds could have easily caused a bottle-up in southerly movement. We are watching the skies and reports that filter in. Last year the monarch migration was also two weeks late. Warm temperatures in the southern deserts this weekend could also have slowed their progress. Our paper, Status of Danaus plexippus in Arizona published last June showed that we had the most recoveries (sightings in another location) when upper level winds blow from the northwest to the southeast or from the northeast to the southwest. This was a statistically significant finding.

Enjoy this special time of year as temperatures eventually ease and monarchs move in. Don't forget to report sightings to the Southwest Monarch Study Facebook page and if you are interested in tagging in the southwest there is still time to get tags before the main migration moves through.

Note:  Three monarchs were sighted at Boyce Thompson Arboretum in Superior recently. If we see any monarchs we will tag them as part of this Saturday's Butterfly Walk at Boyce Thompson Arboretum near Superior beginning at 9 a.m.

Wednesday, August 12, 2015

Summer Status of Monarch Butterflies in Arizona and the Southwest

Every summer we look forward to visiting the larger monarch breeding habitats in the higher elevations of Arizona. Not only does this offer us a good opportunity for an annual habitat assessment, we can also observe when the breeding season is in progress and compare monarch adults, mating, ovaposition and larvae presence from year to year. June and July are also wonderful times to get away from the greater Phoenix area as desert temperatures soar, so we are always eager to hit the road. Here is a brief overview of some of our findings so far this year.

Queen Butterfly on Dogbane
White Mountains. In mid-June we visited Show Low and Springerville. In some years monarchs were already present in these locations, but not this year. However, both Showy Milkweed, Asclepias speciosa, and Horsetail Milkweed, Asclepias subverticillata, were up and looking healthy. We found over 20 queen butterflies, Danaus gilippus, in Springerville nectaring on Dogbane, Apocynum cannabinum, the premier nectar source for butterflies this time of year.

Pearl Crescents nectaring on A. tuberosa
Canelo. An early visit to Turkey Creek in the southeast part of the state on July 5 found the fields filled with hidden Horsetail Milkweed, A. subverticillata, but none yet in bloom. However, we found healthy Butterflyweed, A. tuberosa, packed with pearl crescent butterflies. After walking through the otherwise empty fields, we spotted one lone queen butterfly and were just about ready to leave when a spark of orange dipped in the grasses. Sure enough, there was one worn female monarch ovapositing on the A. subverticillata woven in the grasses. This is often the largest monarch breeding ground in the state, so this worn female gave us hope for a good breeding population.

Grand Canyon. July 12 found us at the Grand Canyon and we searched several common breeding areas. We only found one male monarch near the South Rim Bright Angel lodge. Still, it was early in the season and the milkweed, A. subverticillata, looked good and was in bloom. By August 3, Robb Hannawacker reported one female laying eggs and four males. A year ago during this time-frame we tagged over 30 monarchs in this same area.

Buffalo Park, Flagstaff
Flagstaff. Later in the day on July 12 we stopped by Buffalo Park in Flagstaff. There was one large male speeding through the abundant Horsetail Milkweed through the center of the park. A few days later another observer noted one monarch at the same location.

Female monarch nectaring on A. subverticillata near Show Low

White Mountains. We returned on the
weekend of July 25 to Show Low, Springerville, Eager, Rudd Creek and other White Mountain locations where the monarch population is normally firmly established by this date. In the past we noted over 20 monarchs at some locations by this time of year with several females laying eggs at each site.This year, we found only one lone monarch in Springerville and another was reported at nearby Becker Lake. The next day,  we were ready to leave the field outside of Show Low when movement in the distance caught our  eye - a worn female laying eggs - but after hours walking this normally monarch rich location, we found only this one.

Sedona & Prescott. Reports began coming in from both Sedona and Prescott the weekend of August 1, especially after a well-attended (over 100 people!) monarch presentation at Watters Garden Nursery in Prescott. Reports from Sedona (north of Prescott) began first, followed by Prescott area several days later.

Female Monarch Butterfly laying eggs on A. subverticilatta
Canelo. On August 4, three of us returned to Turkey Creek to monitor the breeding population. By now the presence of monarchs and larvae should be notable. Instead, we found only three:  one monarch was flying by the road when we first drove in, a male was on a tree branch and one female laying eggs. We did not observe any larvae, patrolling males or monarchs in quantity like previous years. Queens were notable with over 20 flying in the fields and at least five queens ovapositing. The area was very dry - the creek was dust - and only approximately 30% of the Horsetail Milkweed, A. subverticillata, was in bloom. Normally this cienaga calls for boots to slosh through the grasses. Although rains were abundant in nearby Sierra Vista and other locations, this location slipped through the monsoon's cracks. A few A. tuberosa were still in bloom and only limited A. subverticillata nectar was available in this normally rich breeding area.

Fields of verbena outside Show Low
Much can and will change over the upcoming days and weeks before the migration. Soon Horsetail Milkweed, blending well and hidden in the grasslands, will be in bloom. The rains will return and lush growth will likely follow. There are likely larvae and pupae hidden in the fields that will mature.

Each report of a monarch or immature (egg, larva or pupa) is especially important this year. Be sure to post any sightings on the Southwest Monarch Study Facebook Page or Email Southwest Monarch Study with location information and/or photos. The numbers are low, but don't panic. Remember the monarch migration will likely sweep monarchs from further north and east as well through Arizona and the Southwest. So far indicators are that many parts of the West (especially Washington) and Southwest (especially Nevada and New Mexico) are having an exceptionally good breeding season for monarchs. Our local numbers could be lower because our late Spring cool spell and freezes in the mid and higher elevations could have affected our local summer breeding population. Soon a wave of breeding monarchs will begin sweeping through the entire state about a month before the peak migration for each latitude. This will help repopulate monarchs in each region and their offspring will in time join the migration in September and October.

In case you missed it, be sure to read our paper recently published in the Journal of the Lepidopterist Society in June,"Status of Danaus plexippus in Arizona". Or you can read a condensed version, Top Ten Key Findings.

Want to tag? Tagging helps us determine monarch migration destination but also where they may spend the winter locally. Tagging also helps us learn monarch absence/presence. Email the Southwest Monarch Study for tags if you live in Arizona, New Mexico, Nevada, Utah, western Colorado or the deserts of California. Act soon - over 1,000 tags have already been distributed. The monarch migration is right around the corner!

Saturday, January 17, 2015

Tropical Milkweed - Friend or Foe?

Tropical Milkweed, Asclepias curassavica
This week, several news articles appeared based on a recent study questioning the wisdom of planting Tropical Milkweed, Asclepias curassavica. In many cases the headlines were sensational and pointed fingers at home gardeners as villains. I'd like to take a few moments to sift through some of the misunderstandings and urge calm garden practices. The study is very well done but only focuses in areas home to Eastern monarchs where native milkweeds die back each winter. Even so, it is important to review their findings and see how it applies to us in the Southwest.

Monarch larva in Zitacuaro
Scientists have long voiced concern about the increasing number of monarch butterflies overwintering in the southern United States, particularly in Texas and the Gulf Coast. We all know monarch butterflies are dependent on milkweed (Asclepias) as their only host plant. The recent plummet in the monarch population has encouraged more people than ever to grow milkweed to help the monarch population increase. But native milkweeds aren't always easy to find. More and more stores are now only selling Tropical Milkweed, also known as Bloodflower (and other common names), Asclepias curassavica. This milkweed is native to Mexico and is also found near the overwintering sites. Last winter in late February we found monarch larvae at the hotel where we were staying in Zitacuaro in Mexico shortly after finding monarchs mating at the nearby overwintering sites.

Tropical milkweed is easy to grow from seed and so it has become popular with home gardeners. Monarchs love it, in fact many people feel it is monarch candy - monarchs can't resist it. In most parts of the country, native milkweed dies back during the winter months. Tropical milkweed is frost tender and will die back in areas with a hard freeze, so it is grown as an annual in the northern states. But in some areas in the south,  A. curassavica can thrive during the winter months. Breeding monarchs will find the milkweed and lay their eggs profusely, often devouring all the leaves, stripping branches bare.

So what's the problem? Enter in the rising concern about Ophryocystis elektroscirrha (O.e.). Studies have shown that high levels of O.e. are lethal to monarch butterflies. O.e. is higher in year round monarch populations. Mating with an infected monarch spreads O.e. Spores from an infected monarch can be present on milkweed leaves and then ingested by monarch larvae increasing the incidence of O.e. in the population as well. It is a rising concern and exactly why this study was done.

I've received many emails and FB posts on the Southwest Monarch Study Facebook page with people in a panic, urging everyone to rip out A. curassavica in their gardens. I'm seeing good-hearted and passionate people creating a great divide and finger pointing. But in this time of low monarch populations, I'd like to urge everyone to take some time to step back and think things through a bit. First, everyone who is growing milkweed, no matter the species, should be commended for their efforts to grow the monarch butterfly's only host plant. Right now increasing habitats is number one and you are part of the solution. Second, we need to urge plant nurseries to grow more native milkweeds. There is a serious lack of options in many parts of the United States.

Desert Milkweed, Asclepias subulata
Native milkweed seeds can be difficult to grow, more tutorials (both written and in videos) need to be available for optimal success. We recently posted one on our Southwest Monarch Study Facebook page featuring an easy way to start Desert Milkweed, Asclepias subulata, that does not require cold-stratification. In order to do this, more native milkweed seeds need to be available. Luckily, the Xerces Society recently stepped in to help with their Milkweed Seed Finder. Or, you can order milkweed plugs from the successful Monarch Watch Milkweed Market.The Southwest Monarch Study will offer free Desert Milkweed seeds soon on our FB page.

Why am I urging calm here in the Southwest? For one simple reason. So far, here in Arizona, O.e. levels are very low, an average of 4.3% over four years. The infected monarchs were all in Southeast Arizona breeding grounds, not in the small number of overwintering monarch populations. In the West, O.e. levels are predicted to be about 30%. We recently included this information in part of a larger paper for publication that is currently in peer review. In the chart below, only category 3, samples with more than 100 spores are considered highly infected by Monarch Health.
Results of O.e. testing by Monarch Health of monarchs in Arizona

 There are three important questions that need answers:
  • Is it Tropical Milkweed, Asclepias curassavica, that is a concern, or is it any milkweed? In the Southwestern low deserts we have four native evergreen milkweeds: Desert Milkweed (A. subulata), Pineleaf Milkweed (A. linaria), Arizona Milkweed (A. angustifolia), and Asclepias albicans. It isn't uncommon to see a few late monarch stragglers fly through and lay eggs on these milkweeds in December and January. We offer a unique opportunity here in the Southwest to learn more about monarchs during the winter. We are currently monitoring two sites and hope to share this information in the future.
    Pineleaf Milkweed, Asclepias linaria
  • What is the effect of temperature on monarch breeding in the fall? 2014 was the warmest on record. Is it the presence of milkweed or is it warmer temperatures that trigger breeding in late eclosing monarchs in November and December?
  • Where is Tropical Milkweed naturalizing? So far in Arizona, Asclepias curassavica is only an irrigated garden specialty. We have no evidence of naturalizing in our extreme dry climate and temperatures. Continued monitoring is crucial as this could change over time. Furthermore, native evergreen milkweeds far outnumber the small amount of Tropical Milkweed available.
Desert Milkweed, Asclepias subulata
What should you do?
  1. Plant milkweed! If you only have Tropical Milkweed, add natives this Spring. Several are now available in Tucson, Phoenix and Yuma. Native Desert Milkweed, Asclepias subulata, is a monarch favorite. It is a common landscaping plant as well.
  2. Monitor monarchs using your milkweed as a host plant. If you have larvae, test freshly eclosed adult monarchs for O.e.
  3. Encourage your local plant nursery to carry NATIVE milkweeds! We are so lucky to have so many native species that thrive in our hot, dry climate in full sun.
  4. Grow native milkweed and share them with friends, relatives, coworkers, etc. Encourage your workplace, church, nature center and city parks to include milkweed in their plant selections. If they are adding plants for a more pleasing landscape, why not native milkweeds?
  5. If you grow Tropical Milkweed be sure to cut it back periodically.
I hope this helps. I want it to be clear I am not in disagreement with this study, in fact I'm very supportive and glad this is finally published. So let's use this information to benefit the monarchs and learn more about their life cycle here in the Southwest.