Monarch Watch Update - February 16, 2004



1) Welcome!

2) Conservation Perspectives

3) The Western Population & Continuous Counts

4) Status of the Population

5) Tag Recovery Fund

6) Cold-Hardiness and Related Issues

7) Video Conferencing with Monarch Watch

8) New Life Cycle Poster

9) How to Unsubscribe from this Update


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2) Conservation Perspectives

"What can be done to stop the illegal logging?"
By Jordi Honey-Rosés
World wildlife Fund, Mexico

Monarch season is in full swing in Mexico with tourists climbing up and down the Transvolcanic Mountains, journalists calling regularly for a quote on the latest controversy, and researchers avidly jotting observations inside the colonies with notebook, compass, camera, and GPS in hand.

A late January storm has caused some Monarch mortality in the colonies although much less than the severe freeze of 2002 and by no means should affect the visitors’ spectacular experience at the overwintering sites the remainder of the season. The biologists of the Monarch Butterfly Biosphere Reserve (MBBR) will be finishing the count of dead butterflies and releasing the final mortality numbers soon.

The press in Mexico picked up on the mortality story immediately and along with the story came questions about the illegal logging inside the protected area. The questions about the illegal logging in the Monarch Butterfly Biosphere Reserve are without a doubt the most difficult and complex to answer. However to ignore the illegal logging issue would be just as problematic. The organized and illegal extraction of trees is probably the primary threat to the habitat of the Monarch Butterfly in Mexico and not to address the issue would make any interdisciplinary and long term conservation plan incomplete and bordering on irrelevant.

To the Mexican government’s credit, they have recognized the Monarch region as one of the most contentious natural areas in the country. Mexico’s Minister of the Environment Alberto Cárdenas grouped the Monarch region in the same category as the Montes Azules Biosphere Reserve in Chiapas, which serves as campground and hideout for ski masked Zapatista revolutionaries. Cárdenas also included in this category the forests of Guerrero -- infested with drug traffickers and armed revolutionaries of their own. Not bad company for the Monarchs. We could call this trio, Mexico’s Axis of Illegal Logging.

So clearly the Mexican authorities recognize the magnitude of the illegal logging in the Monarch Butterfly Protected Area. And also to their credit, money is being channeled into the region accordingly. The Mexican Park Service (CONANP) has more than doubled the budget of the Protected Area since 2000 under the leadership of Ernesto Enkerlin. This increase of funds has been noticeable in the area and executed through the hard work of the Reserve Director Marco Bernal and Subdirector Eduardo Rendón.

Still, the illegal logging continues and is self evident. To better visualize the dimension of the illegal logging, a group of Mexican decision makers, researchers and journalists participated in aerial flights above the Monarch Butterfly Biosphere reserve this past January 21st and 22nd. The flights were possible thanks to the non-profit organization Lighthawk and its network of volunteer pilots. Passengers included Michoacán State Delegates of SEMARNAT (Secretary of Environment) and PROFEPA (Environmental Attorney General’s Office) as well as the Regional Director of the CONAFOR (Mexican Forestry Service) and the Municipal Presidents of Angangueo, Ocampo and Senguio.

The flight passengers saw not only the dire effects of the logging, but also witnessed the logging occurring in real time, where at least four trucks were seen inside the Monarch Biosphere Reserve driving through a devastated area of what only two years ago was dense oyamel forest.

These powerful aerial images were shown later that night on Mexico’s national news channel Televisa. The news clip on the illegal logging also featured an interview with the long time researcher Dr. Lincoln Brower. The prime time news report denouncing the illegal logging created quite a controversy and was followed up by an opinion article written by Mexican poet and conservationist Homero Aridjis and published in Mexico’s most widely read newspaper Reforma also denouncing the continued illegal logging in the protected area. ("Crespúsculo de la monarca" Reforma, Febrero 1, 2004)

So all of this brings us to the most important and difficult question: What can be done to stop the logging? And more specifically what can independent and non-governmental organizations do? Aside from the police and judicial work in the hands of the Mexican authorities, the appropriate actions to halt the illegal logging can be broken down into three groups 1) Empower local community efforts, 2) Document the illegal extraction, and 3) Denounce the illegal activities to the press.

First and foremost, the agrarian communities that own this forest need to be empowered to protect what forest they have left. In the long run only a strong local commitment for protection will stop the illegal logging. External efforts will never be a substitute for this local commitment. Fortunately, within each community there is always a group who would like to stop the logging, but who don’t have the means to do so, or who feel powerless before the network of illegal loggers. These individuals need to be empowered. Local community forest watch groups need to be better equipped, and if they are doing a good job, they should be paid for their time spent protecting the forest. Interestingly, field research in the forest could be an indirect way to support the community forest watch groups. It has been seen that illegal loggers are less likely to enter an area if there are people present in the forest. Lastly, when local community members request forest protection help from the authorities, independent groups can follow through on their request to be sure that the correct action is taken.

Second, conservation organizations and researchers can and must document the status of the logging. The use of aerial photography and high resolution satellite images have recently allowed specific areas to be identified for action. Also, written documentation must be gathered that describes the logging activities and what is being done (or not) to stop it. The analysis and conclusions generated, such as the most affected areas, the access points for loggers, and the patterns of illegal activity should all be shared among conservation organizations and authorities to find more effective means to stop the illegal activity.

Lastly, there comes a time when the illegal activities needs to be made public and denounced in the press. Going to the press can help pressure for a deeper political commitment at a higher level of government but also risks a negative twist in the message by the press, or generating ill will from local government agencies. Criticism should be used carefully so as to address specific problems and not fall into sweeping statements or condemnation about the status of the Reserve as a whole.

All three courses of action require close coordination between conservation groups, researchers, local communities and the government authorities. A recent initiative designed to catalyze this coordination is the Monarch Butterfly Regional Forum whose website is temporarily being hosted at (Spanish)

The Forum will bring most of the major Monarch conservation groups to the table to share their work-plans and map them in a Geographic Information System and database. Hopes are high that this latest effort may help diminish the illegal logging.

For years the discussion on illegal logging has lacked site specific evidence to focus the debate. Finally, new technology is allowing this debate to become more specific and quantitative. Conservation organizations, researchers and the public at large are not the authority to directly confront the illegal logging, but there are specific actions that may be taken. The time has come for a more open dialogue with Government agencies in Mexico to jointly find solutions in order to ensure an intact and permanent habitat for the Monarch butterfly.

About the Author
Jordi is from Sunnyvale, California and graduated from the University of California, Berkeley. He joined World Wildlife Fund (WWF) in Mexico City in November of 2001 and since has been privileged to join the trinational conservation efforts to protect the overwintering habitat of the Monarch Butterfly. When not chasing after Monarch Butterflies, Jordi enjoys triathlon training and reading about Mexican and European history.

Conservation Perspectives
Conservation Perspectives will provide regular and accurate updates on the local conservation issues at the Mexican overwintering sites of the Monarch Butterfly. This space will be a forum for discussion and sharing. The updates will serve as conduit for ideas and stories that are rarely heard from Mexican side of the border, especially those successes by local Mexican inhabitants to protect the forest of the Monarch Butterfly.


3) The Western Population & Continuous Counts: Is it Worth the Effort?

By Mia Monroe, Park Ranger, Muir Woods National Monument

The size of the western monarch population is estimated by a one-time count at each of the overwintering sites. These counts occur around Thanksgiving each year. This year, stewards at the Ellwood Main overwintering site have been conducting counts throughout the season. The hope is that the ongoing monitoring at the Ellwood Main overwintering site will help us understand how a site protects monarchs during storms, sunny days when monarchs venture out to nectar and sip dew, and when unseasonal conditions render a site inhospitable. However, these ongoing counts could have bigger applications as well.

John Goldwasser, a mathematician, and his daughter, Shama Cash-Goldwasser, are monarch lovers from West Virginia. They visited Ellwood Main in January and were told the overwintering population numbered approximately 8,000 butterflies (this number was obtained during early November). This number seemed low to John and Shama and they conducted their own count. They estimated a population of 25-35,000 butterflies. After returning home, they shared this information with Monarch Watch. Monarch Watch then asked western monarch observers to comment. Due to continual monitoring, Ellwood Main Stewards Chris and David Lange were able to confirm that numbers had increased from the beginning of the season. The initial count (in early November) indicated the site hosted 8,000 monarchs. By the end of November (11/23) the site hosted 13,400 monarchs. Counts on 12/05 and 1/13 showed 18,400 and 22,000 butterflies (respectively), indicating the overwintering population at Ellwood continued to grow as the season progressed.

We generally don't expect overwintering populations to increase much after mid-November. What happened at Ellwood? Well, we don't really know. November counts can be misleading since butterflies from temporary sites continue to join the main sites as the season progresses. Weather may have been a factor as well. Perhaps monarchs from less protected sites moved into Ellwood after the bruising holiday storms coastal California experienced. Monarchs were virtually absent from the extremes of the overwintering range (Baja, San Diego, LA, and Marin Counties) later in the season; these counties were hit by severe winter storms and conditions chilled. It is possible that the core counties, including Ellwood, took in monarchs as they fled the chilled counties. One explanation is that other regional sites are "weaker" structurally (from a monarch's point of view) and "feed" the main, or at least more meteorologically stable, sites such as Ellwood throughout the season. Another possibility is that a break in the weather encouraged monarchs to forage out of site range. Later, when cloud cover moved in earlier than expected, they dashed for the closest site - Ellwood! It is interesting to note that nearby overwintering clusters in the East Bay counties, such as Ardenwood, Alameda Golf Course and San Leandro Golf Course, were able to hold on to their monarchs throughout the same winter period.

A good way to explore these theories is to develop a continuous monitoring program at nearby sites and to begin a tagging program that would help monitor intra-site movement. The Thanksgiving Count has been invaluable through the years to give us an idea of the size of the western population. However, it is now time to think about a continuous monitoring effort throughout specific regions, as this could help us understand population dynamics and trends. Clearly, the Ellwood counts this season demonstrate the value of identifying sites in California to use in a tagging program and to monitor carefully throughout the season to determine whether "gain and loss" at these sites can be correlated with environmental factors.

What's next for the Western population? Thanks to the early spring we're experiencing, the mating season will be underway over Valentine's Day weekend (quite a heartwarming sight at Natural Bridges SP, Pacific Grove, Pismo Beach or Ellwood). In just a few more weeks the overwintering season will come to a close and the butterflies will be heading north and east again.

Edited by Sarah Schmidt, Monarch Watch Program Assistant


4) Status of the Population - by Chip Taylor

There is good news and bad news this month, first, the good news. The measurements of the monarch colonies by the personnel of the Reserva Biosfera de la Mariposa Monarca (RBMM) show that the total area occupied by all the colonies to be 11.12 hectares (27.48 acres). This is the third largest overwintering population since the colonies were first systematically measured in 1993. We had expected an increase above the 8 hectares reported last year based on reports from observers and taggers throughout the fall migration. The weather conditions during the migration were also favorable, decreasing the likelihood of significant mortality during the migration. Given that only 20-25% of the population survived the winter storm of 2001-2002 the size of the population this year signals a remarkable recovery over the past two breeding seasons.

The bad news is that it's happened again. For the third time in four years the overwintering monarch colonies in Mexico have experienced severe mortality due to winter rains followed by snow and clearing skies and temperatures in the 20s (F). There appear to have been two episodes of cold weather, one starting on the 17th of January and the other occurring at the end of the month. The details of these events are unclear. We need data from monitoring sites in the colonies and reports of the chronology of the weather changes from residents of the area. On the 3rd of February we posted a report on the effects of the first storm to Dplex-L. This report from the RBMM (published in the popular newspaper Reforma) indicated that only 10% of the monarchs had died as a result of the freeze. However, subsequently I learned of the claim by one resident familiar with the colonies that the mortality was "twice as bad" as in 2002. Since 75-80% of the monarchs were killed in 2002, I wasn't sure how to interpret what was meant by "twice as bad". In addition, it wasn't clear when this person had visited the colonies. On Wednesday, 11 Feb., I received another report from a Mexican observer who visited the colonies on the 9th. He indicated that the mortality was indeed quite severe and that only a few trees at both Sierra Chincua and El Rosario contained monarchs. The numbers of live monarchs seen at each site was extremely low. This observer also thought that the mortality was greater than in 2002 and that many butterflies were buried alive in the masses that had fallen from the trees. The colonies appeared to be all but wiped out - gone. That night I didn't sleep well and periodically got up to send off emails in the middle of the night. On Thursday, I was busy with lots of details and teaching but late in the day I received an express mail letter from Dr. John Wenzel from Ohio State University. I'll quote portions of the letter (dated 11 February) relevant to the mortality issue. John visited Chincua on 2 February. "I just got back from Michoacan. - Chincua was particularly beautiful. We rode a couple of miles, crunching through icy puddles on the path, to a point that became too steep for the horses. Then we hiked down a steep face to where the monarchs were in the forest. One of our guides said they had counted about 300 trees festooned with them (well he didn't use the word festooned but anyway -) --- The storm that knocked them from their perches on 30 January did NOT kill them, and by Feb 2 millions upon millions were back in the trees where they belong, although they were slightly displaced from the area where Lincoln Brower had apparently been two weeks before and marked many trees (not far, same hillside). Yes, there were tons of butterflies on the ground, but if they were not wet they are usually not dead either. We put many (thousands?) in sun spots and they warmed and moved around, and some took flight. --- Anyway, in addition to the tags, I just wanted to pass along the information that I was there after the snowstorm, and I doubt the butterflies really suffered great mortality despite news reports to the contrary. The ones that didn't get stepped on seemed to be okay, and most were back up in the trees after a few days." This was certainly a more positive perspective and I slept better the next night. It is common for the survivors of these catastrophic storms to move and reform colonies at some distance from the original site.

The task that remains is to assess the true extent of the mortality and to estimate the number of survivors. The later is particularly important since it gives us a view of what to expect in the future. Estimating the mortality is difficult because many dead butterflies remain lodged in the trees and large numbers still alive after the storm are nevertheless seriously damaged and take many days to die. According to Jordi's account above, the RBMM is in the process of reassessing the mortality and I've also learned that Jordi is working with a group of international students to assess the numbers of dead butterflies in the colonies. To sum this up, all I can tell you at this point is that it is certain that the mortality was much higher than the 10% previously reported but probably lower than the 90% I had envisioned from the first two eyewitness accounts. We will know more in a few weeks.

The occurrence of catastrophic winter mortality in three of the last four years, with both of the last two events being extreme in their severity, is of great concern. In the past, most episodes of weather related mortality have affected only a few of the colonies. In 2002, and this year, all of the colonies were impacted and the proportion of the population lost to these two weather events is unprecedented in the twenty-nine years these sites have been observed by scientists. Global climate change is a reality, and, in the case of central Mexico, the models predict increasing winter rainfall. Normally, winter is the dry season in Mexico but there is no doubt but that winter moisture has been increasing in recent years. This has been a particularly rainy winter, and it is rain followed by falling temperatures that devastates the population. The increase in rainfall is consistent with the climate change models and Karen Oberhauser and Town Peterson recently predicted that over the next 50 years there will be a significant increase in the conditions that contribute to winter mortality such that it will threaten the very existence of the eastern migratory population. Global climate change is upon us and this may already be happening. Should this pattern continue, the monarch could become a poster symbol for the effects of global warming - not a happy thought.

Oberhauser, K and A. T. Peterson. 2003. Modeling current and future potential wintering distributions of eastern North American monarch butterflies. PNAS 100:14063-14068.


5) Tag Recovery Fund

Last month we appealed for more contributions to the tag recovery fund. This was before the storms. Now we have a crisis. Many of the local residents have 100s of tags found on the monarchs killed by the late January storms. We don't have the funds to buy the number of tags available. Donations to the tag recovery fund for this year were $2,371. As you know, we pay 50 pesos (approximately $5) for each tag recovered - a reasonable compensation, since it normally takes 1-3 hours to find each tag among the dead butterflies on the forest floor. After the big chill of January 2002 (fall 2001 tags) we spent approximately $12,000 recovering tags with the help of Dave Kust and others. This resulted in 31 pages of data entries in the 2001 Season Summary. We recovered many more tags the following year and we could have bought more had we anticipated the large number of tags that still remained as a result of the storm in 2002.

We will match up to $5,000 in donations from our operating budget but even $10,000 may not be enough to recover all the tags available. If you can help us with the tag recovery fund, your tax-deductible contributions would be greatly appreciated. Checks may be sent to us at:

Monarch Watch
University of Kansas
Entomology Program
1200 Sunnyside Avenue
Lawrence, KS 66045-7534

If we have the money to buy the tags, many of the taggers will have their tags recovered and we will learn more about the patterns of the migration.


6) Cold-hardiness (cryoprotectants), mortality due to winter storms, why monarchs overwinter at lower latitudes and related issues.

By Chip Taylor

The text for this topic was written for inclusion in the January update but was left out due to the overall length of the email message. It is even more appropriate for this month's update...

The February 2002 Update started with the following statement:
"A massive moisture-bearing weather system moved into central Mexico late on 11 January 2002 which was followed by clearing skies and overnight lows in the mid to low 20s (F) (-7 to -2C) on the mornings of 14-16 January. What followed was unprecedented mortality at the monarch overwintering sites." A subsequent survey of the mortality by Lincoln Brower and his associates suggested that at least 75% of the monarchs in the two main overwintering colonies, Sierra Chincua and El Rosario, died as the result of the storm. Monarchs are not known for their cold-hardiness. In fact, the tropical origins of monarchs and their inability to survive freezing temperatures for prolonged periods is often given as an explanation for the origin of the migratory behavior and the overwintering in Mexico.

In Mexico, the monarch colonies generally form in oyamel fir forests on southwesterly slopes at elevations that exceed 10,000 feet. The climate at these forested sites is relatively uniform from day to day, compared to lower elevations or open areas at the same elevations. The temperatures within the canopy of the forest seldom exceed 65F (18C) or lower than 32F (0C) during the wintering period. Lower temperatures (<23F/<-5C) frequently occur at ground level, and monarchs caught on the ground overnight sometimes freeze. During daylight hours, higher temperatures occur in open areas, possibly above the canopy on some occasions, and at lower elevations. On days during which the temperatures are high enough (low 50s F (10+C) in sunlight or nearly 60F (16C) with wind and clouds) monarchs become active and frequently fly to watering sites (see #4 in the Update for January 2003 for another interpretation of the value of such flights). Generally, the monarchs are relatively inactive during the winter months and their rate of metabolism, lower than when sexually active in the breeding season, allows them to live off the stored energy in their fat-bodies without feeding at flowers for the balance of the winter season. In most years, the colonies survive the winters quite well. Mortality probably increases late in the winter when the water sources dry up (and the dew point is seldom reached), particularly during El Nino years, forcing the monarchs to search extensively for water.

Winter storms are a bigger threat. The most severe winter mortality seems to follow storms that start as warm, moisture-bearing air masses that sweep in off the Pacific and are succeeded by strong cold fronts and clearing skies. At the higher elevations, as the warm air masses move in, rainfall occurs as a result of the cooler temperatures. Rainfall during the winter at these north temperate latitudes is uncommon as this is the dry season. Most of the rains during the winter are light and are followed by short cool periods or gradual warming. Occasionally, these warm air masses are followed by cold air masses from the north or northwest. This appears to be what happened in mid January 2002. Rains began early on the morning of the 12th and continued for over 30 hours. The rains eventually turned to light snow followed by clear skies and rapidly dropping temperatures. The exact low temperatures reached in the vicinity of the rain soaked clusters of butterflies is not clear, but it was probably in the mid twenties, certainly low enough to kill the wetted butterflies.

This dramatic event, and similar episodes of catastrophic mortality, raised questions about how and why the monarchs died. We can also ask what monarchs lack that leaves them vulnerable to freezing while other insects survive harsher conditions. Dry monarchs appear to be able to survive temperatures as low as 18F (-8C) for short periods (a few hours). Wet monarchs are more vulnerable and die at temperatures just below freezing. (In contrast, the Mourning Cloak (Nymphalis antiopa), a butterfly of similar size and mass, overwinters as an adult throughout the north temperate region

Mourning Cloak Photo:

This species is common in regions in which the winter lows sometimes exceed -40F (-40C). But, what does it mean to freeze, or, stated another way, what is it about the below freezing temperatures that kills the butterflies? The answer is the formation of intracellular ice crystals that break down the cell walls, stopping all physiological functions. It is also possible that the formation of ice crystals withdraws water from the cells and disrupts cellular function. In the case of the rain soaked monarchs, evaporative cooling and the water facilitated ice crystal formation, accelerating the freezing process. But, why do monarchs die at temperatures in the 20s (-7 to -2C) when some insects survive temperatures of as low as -60F(-51C)? What keeps north temperate and sub arctic insects from freezing?

To survive extreme cold an insect must remain liquid. That is, it must keep its cells from freezing. This is accomplished by the synthesis of compounds that act as cryoprotectants. Cryoprotectants either lower the freezing point of insect tissues, reduce the likelihood that ice crystals will form, accelerate the formation of small ice crystals or keep ice crystals from becoming large enough within cells to break down the cells or damage cellular mechanisms. There are several classes of compounds that provide these protective functions; polyols (alcohols) such as sorbitol, manitol and glycerol (a 2 carbon polyhydric alcohol) are thought to act like an antifreeze both reducing the freezing point and retarding ice formation. In fact, glycerol, the most common of these compounds in insects, was once used as antifreeze. (Today, similar compounds, ethylene glycol (a sweet tasting 2 carbon polyhydric alcohol associated with antifreeze poisoning, particularly of pets) and propylene glycol (a non-toxic compound frequently used as a food additive) are now the predominant antifreeze/cooling agents used in cars.) Other protective compounds are the insect blood sugar trehalose, lipids of low molecular weight, amino acids, ice nucleating proteins and antifreeze proteins.

Insects appear to have two patterns of adaptations for remaining liquid under freezing conditions. These patterns have been characterized as freeze avoidance and freeze tolerance. Many insects avoid freezing by synthesizing and accumulating cryoprotectants, particularly glycerol. In response to decreasing temperatures, and perhaps cues such as changes in photoperiod, some insects increase the proportion of glycerol in their tissues. Glycerol increases to 20-30% of the wet mass in some cases in preparation for winter and decreases, and may disappear entirely, as the weather warms in spring. These compounds have the effect of decreasing the freezing point. However, the chemical constituents of the cells, extracellular fluids and hemolymph not only reduce the freezing point but allow the liquids to "supercool" and reach temperatures below the freezing point without freezing. If the internal temperatures reach this lower point, the supercooling point, ice crystals will form and the insect will die. In some species, death occurs before the insect reaches the supercooling point. When wet, monarchs held at below freezing temperatures, yet above their supercooling points, died after two to three hours (Larsen and Lee,1994). Supercooling points in some species can be lower than -40F (-40C).

Freeze tolerance is a complex adaptation that allows up to 65% of the water to freeze without killing the insect. This is accomplished without freezing the cells. The extracellular water that bathes the tissues and cells freezes within the insect, including the hemolymph (blood). In the extracellular water and hemolymph, ice-nucleating proteins aid in the rapid formation of small ice crystals and antifreeze proteins appear to keep the ice crystals from getting large enough to damage cells. These extracellular processes tend to withdraw water from the cells, further reducing the freezing point. The cells themselves are protected by high concentrations of cryoprotectants, particularly polyols such as glycerol. Since the hemolymph is frozen and the muscles controlling oxygen/carbon dioxide exchange through the tracheal (breathing) system are inactive under these conditions, survival of the semi-frozen insect is dependent on maintaining low cellular respiration and further loss of cellular water. Again, glycerol, which binds to water, serves to reduce water loss.

Monarchs don't appear to fit into either of these patterns. In fact, they should probably be characterized as "freezing susceptible." Anderson and Brower (1993) have shown that the tolerance of monarchs to low temperatures is greater in migratory and overwintering monarchs than that of reproductive monarchs but the difference is relatively small, about 3 degrees C. Further, monarchs do not appear to have ice nucleating proteins, although these proteins would be more likely to be found in freeze tolerant rather than freeze avoiding species; monarchs are more likely to employ the latter strategy. Whether monarchs possess polyols and antifreeze proteins has not been determined. The fact that monarchs die as a result of relatively short-term exposures (<24 hours) to temperatures in the mid 20s (-7 to -2C) suggests that they do not differ substantially from other summer insects that die from similar exposures. The slight increase in freeze tolerance of migratory and clustering monarchs relative to reproductive summer monarchs may be due to changes in lipid metabolism and trehalose levels in the blood and tissues rather than the synthesis of cryoprotectants such as polyols and proteins. This interpretation is partially supported by the findings of Troyer, Burks and Lee 1996. Troyer, et al. demonstrated that monarchs lacked polyols and trehalose levels were higher in migrants than reproductive monarchs although the difference was not significant. The possible roel of trehalose and other blood components is also suggested by the finding that active overwintering monarchs were less freeze- tolerant than clustered butterflies (Anderson and Brower (1993). As I pointed out in the January '03 Update, monarch activity during the winter could be related to the need to increase body temperature through flight to facilitate the metabolism of fats and raise the levels of trehalose in the blood. On the other hand, Larsen and Lee (1994) found that subjecting monarchs to +4C for only one hour induced rapid cold hardening allowing >80% of the monarchs to survive exposure to -4C for 24 hours. Less than 40% of the untreated monarchs survived this exposure. Although this response is consistent with the synthesis of cryoprotectants, a subsequent study by Troyer,et al. (1996), failed to establish the presence of polyols in fall migrants. In the absence of polyols, further studies are needed to determine if the slight increase in tolerance to freezing observed in these studies is a consequence of seasonal, or cold induced, changes in lipid physiology and blood chemistry.

As to why monarchs aren't more tolerant of freezing conditions, the answers might involve the frequency of exposure to freezing temperatures and physiological constraints. Selection tracks past events and one explanation for the lack of greater freeze tolerance may be that the monarch, as a species with a large and widespread population, hasn't experienced freezing conditions with sufficient regularity to acquire the cryoprotectants needed to resist freezing temperatures. On the other hand, one has to wonder whether the synthesis and accumulation of cyroprotectant compounds is compatible with the relatively high metabolism and activity levels of overwintering monarchs. Whatever the explanation, monarchs appear to be restricted to overwintering environments in which the frequency of freezing temperatures is relatively low and the temperatures seldom drop below 25F(-4C).

Additional Reading:
Anderson, J. B., and L. P. Brower. 1993. Cold-hardiness in the annual cycle of the monarch butterfly. Biology and Conservation of the Monarch Butterfly (ed by S.B Malcolm and M.P. Zalucki), pp 157-164. Los Angeles County Museum of Natural History

Anderson, J. B., and L. P. Brower. 1996. Freeze-protection of overwintering monarch butterflies in Mexico: critical role of the forest as a blanket and an umbrella. Ecological Entomology 21:107-116.

Calvert, W. H., W. Zuchowski and L. P. Brower. 1983. The effect of rain, snow and freezing temperatures on overwintering monarch butterflies in Mexico. Biotropica 15(1): 42-47.

Larsen, K.L., and R. E. Lee Jr. 1994. Cold tolerance including rapid cold-hardening and inoculative freezing of fall migrant monarch butterflies in Ohio. J. Insect Physiol. 40:859-864.

Troyer, H. L., C. S. Burks and R.E. Lee, Jr. 1996. Phenology of cold hardiness in reproductive and migrant monarch butterflies (Danaus plexippus) in southwest Ohio. J. Insect Physiol. 42:633-642.



7) Video Conferencing with Monarch Watch

We have posted a couple of pages online that summarize our early experiences with video conferencing over the internet and provide a "getting started" guide for those of you that would like to participate. We are still looking for classes/groups to connect with so if you are interested in setting up a session please read through the information we have online at

and then contact us at and we'll set up a time to connect.

The iChat software that we use runs on Macintosh hardware; however, the latest beta version of iChat AV supports audio and video chatting with PC computers running Windows XP and AOL Instant Messenger 5.5 - for more information about the PC requirements for "Video Instant Messaging" visit

If you have any questions about this please feel free to drop us a line anytime!


8) New Life Cycle Poster

We have added a new poster to our educational offerings in our online storefront. It is a beautiful 14" x 20" photo montage created by artist and monarch enthusiast Ron Brancato. The poster illustrates the entire life cycle of the monarch butterfly and includes descriptive captions, making it the perfect blend of art and education. This poster is available in laminated and non-laminated (suitable for framing) formats for $15.

You can order the poster now, but we will not begin shipping it until March 15th. To view and/or order the poster visit:

Alternatively, you can do a quick search for "monarch butterfly poster" in Gulliver's Gift Shop (our online storefront) at

Remember, each and every purchase you make in "Gulliver's Gift Shop" supports Monarch Watch!


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