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10 PERFECT CHRYSALIS'S ARE HERE

9/11/2021

We now have 10 perfect chrysalis's. As caterpillars in their 5th instar they each moved up the stick, to the roof of the caterpillar castle. From there they wandered around seeking a place to make their button and form their 'J'. My caterpillar castle has been used for several years, being washed from time to time between caterpillars. Somehow each caterpillar generation congregates into the same corners as their forebears, to set up their J's. They weave their silk, across a small section of the cloth, before making a secure button to set themselves into for hanging. Once in the J, the caterpillar hangs for about 24 hours before forming their chrysalis (see here).

I wait for 2 days after the chrysalis has been formed, until it has firmed enough to gently handle, before I transfer it onto a toothpick so it can hang safely until it emerges as a butterfly.
So now my little charges are all hanging on toothpicks, marked with the date they formed the chrysalis. I keep their details in a notebook, so I can check how long until they'll emerge as a butterfly. It differs at different times of the year and in different temperatures.
At this time of year it's 9-10 days. So now we're waiting........... 🦋

*Click on the first picture and then click through to see them all larger...................

CATERPILLARS READY FOR CHRYSALIS'

5/11/2021

Our 10 Monarch Caterpillars are growing bigger by the minute.
They’ve got to the contrary stage, being big enough to get some attitude. Several are climbing up the stick in readiness of creating their chrysalis on the roof of the caterpillar castle.
The others will follow suit in the next day or two.

When I have them in a caterpillar castle, I place a stick in the centre of the plants, to give them something to climb up to the roof where they will make their button and hang in a 'J' shape prior to forming their chrysalis. The system works well.

Click on each picture to see a larger view..............

UPDATE: MONARCH CATERPILLARS ARE HUGE NOW

3/11/2021

UPDATE:
Our Monarch caterpillars are growing so rapidly and all are almost at the stage of forming their chrysalis. By golly they eat a lot during this last stage of caterpillarhood.

2022 SEASON HAPPENING IN OUR CORNER OF NEW ZEALAND

1/11/2021

One month ago I observed a Monarch butterfly laying eggs on our swan plants (milkweed) so I dug up 2 plants and transferred them to a large pot. I set up a little wooden frame and draped a pink mosquito net over it and placed the pot with plants, into that.

My aim was to stop butterflies laying more eggs on the plants, because there aren't many swan plants in my garden that are mature enough to feed caterpillars for an extended time.
As the days passed, a few caterpillars hatched and began to eat their way through the leaves.
But then more and more kept hatching and soon there were 12 caterpillars.
They grew well under the pink net until, two days ago, I noticed a wasp had got into the enclosure and had already sucked out one of the caterpillars.

I swung into action and removed the caterpillars from the plants, taking them indoors to plants I had put into the large caterpillar castle.
So there they now are. There are 11 altogether. Unfortunately one fell off the plant and has died however the others are going strong and, even in 2 days, have grown quickly.

Here are some pictures I took this morning..........................
click on the first one and then click through the gallery 🐛

Here's a little movie of them - so busy eating all they can 🐛

NEW SEASON: FIRST MONARCH IN THE GARDEN

2/10/2021

It's 2 October 2021 and our first Monarch of the season flew into the garden today.
She flitted around the flowers and trees, stopping to lay eggs on the small swan plant (milkweed), then flitted out again. She came back 3 times during the day to do the rounds again and again - it was a joyful sight.

That got me into action because we are already seeing wasps in the garden too.
I picked off 5 eggs and have them under cover. I potted up some mature swan plants and set them under the mosquito net, to stop butterflies from laying more eggs on them. My reasoning is because these plants will need to be food for the caterpillars that emerge from the 5 eggs and there aren't enough mature plants to feed any more caterpillars as yet.
As more swan plants come on stream, I'll look at bringing more eggs inside. I know from past experience that any eggs left outside are quickly dealt to by wasps or other predators such as ants, earwigs, shield bugs and others. I also have to keep a close watch for aphids because we usually have a big problem with them decimating swan plants, in this area, as summer progresses.

So, I'm getting in quick and will raise a few early caterpillars for now, while the swan plants are in good condition, and see how it goes as summer progresses.

🦋 🦋 🦋 🦋 🦋 🦋 🦋

Click on each picture below to see a larger size........................

I VISITED A BUTTERFLY HOUSE LAST WEEK

22/8/2021

2 x One-spotted Prepona (Archaeoprepona demophon) and a Blue Morpho (morpho peleides)

As you may know I'm in New Zealand and we don't have a lot of butterfly species here.
It's Winter right now so the main way to see any butterflies is to visit a heated butterfly house.
Last week I was away for a few days and was lucky enough to be able to visit one of those in Dunedin. The exhibit is called "The Tropical Rain Forest" and is set within the Otago Museum in Dunedin city. They have many species of butterflies that would normally be seen in more tropical areas of the world, along with a few Zebra Finches and Java Finches that are kept in the butterfly house to keep spiders down.
It's a fabulous experience.

***Click on the first picture, below, and then click through to see the pics in a larger size***

Caterpillar of the Owl Butterfly (Caligo memnon)

A MID-WINTER BLUE BUTTERFLY FLEW BY TODAY

4/7/2021

LONG TAILED BLUE (Lampides boeticus)

What a delightful surprise to see a LONG TAILED BLUE (Lampides boeticus) enjoying the winter sunshine and flowers, in a little out-of-the-way bay near Russell (Far North of New Zealand) today. It's mid-winter here, so seeing a blue butterfly flying about at this time of year was a surprise. Having said this, I also recall seeing a Monarch Butterfly fly through. We see Monarchs all the time during winter, but I've never seen a blue butterfly.

Our New Zealand butterflies go into diapause during winter, basically meaning they don't mate. Today's sighting of a blue was quite historic for me. The butterfly had slightly ripped wings, but was otherwise fine. Hopefully it will get through until Summer when it can mate.

LONG TAILED BLUE (Lampides boeticus)

QUESTION: SHOULD INFECTED MONARCH POPULATIONS BE ENHANCED?

2/7/2021

I'm sharing this perhaps controversial article by American Monarch Butterfly scientist, Andy Davis. He poses some interesting questions that are especially interesting to me being in New Zealand (if you read his article you'll see why).

For some time, now, I've been concerned about the numbers of Monarch Butterflies being reared indoors by New Zealanders. I used to do this myself, because of our huge wasp problem here, but then I began wondering if it might be setting up an artificial situation that would eventually breed weak butterflies. These days I leave it all to nature.

I know there are many many different opinions and ideas on the subject, so I find the scientific findings of people like Andy Davis very interesting.
I do hope you'll read his article, below, then come back to tell me what you think?

Cheers - Julie 😍

*** Now read Andy's Article -

Greetings everyone,

Get ready to put your thinking caps on - there have been some recent happenings in the monarch world that involve the parasite, OE, and these have had me thinking. Today, I'm going to provide more details of these events, and then, let you know of my thoughts on this topic. As you can see from the blog title, this is a post that covers a rather controversial topic...

Before I begin, I hope all readers know what OE is by now. I've covered the OE parasite that infects monarchs in many previous blogs, and, there are lots of online resources where people can learn more about it. So at this point, there is no excuse if you don't know what I'm talking about here, especially if you are involved with monarchs. One thing that I will emphasize here though, is that all scientific evidence we have thus far suggests that this is a naturally-occurring parasite, that has likely co-evolved with monarchs for thousands of years. This is important to keep in mind going forward.

This month, there was an interesting new study published on OE in monarchs, that didn't get much press, at least here in North America! In the journal, Ecological Entomology, two scientists (Philip J. Lester, Mariana Bulgarella) published a paper describing OE in monarchs in New Zealand!

Yes, monarchs in New Zealand - it's not clear exactly when monarchs colonized this island country, or exactly how big this population is, but monarchs are certainly present there now, just as they can now be found in a number of places around the world. And, these are truly monarchs, i.e. Danaus plexippus. In New Zealand, the authors report that the monarchs breed mostly on introduced hostplants, balloon milkweed and tropical milkweed. In prior genetic studies, monarchs from these outlying populations have been studied, and the evidence shows that the North American monarch population seems to be the "original, ancestral" population, and the rest of these global subpopulations appear to be its offshoots. And, this same research shows that the offshoot populations are not as genetically diverse as the ancestral one. This is especially true for the New Zealand population, which appears to have a low genetic diversity (which is typical of small populations). This is another way to say that there is some inbreeding going on...

This new paper reports on a very new, informal citizen science project that was stimulated by some anecdotal observations by NZ citizens a few years ago. People had been reporting seeing deformed monarchs in their yards, and this apparently motivated the researchers to start this program, as a way to investigate the cause of these deformities. They knew from prior research that the OE parasite can cause deformities, so this program seemed like a logical thing to do. Through social media, they asked people to send them tape samples of monarchs throughout the country. Their program provided instructions for "taping" a monarch, which involves pressing scotch tape to the monarch abdomen to get a sample of the OE spores. Also interesting to note, is that this program really coincided with the COVID lockdown in that country, and so maybe this gave everyone something to do!

I'm going to fast-cut to the results of the project here. After examining over 500 tape samples of monarchs, the researchers report that about 60% of the monarchs in New Zealand were heavily infected! They also report that the OE prevalence across the country did not necessarily predict the prevalence of deformities - surprise! They appear to suggest environmental factors as a cause, though I think more research is needed here.

I'll paste the main figure from the paper below, which shows the prevalence of OE and deformities across the country.

OK, now that I've given you the gist of this paper, I want to talk more generally here about the overall infection prevalence in New Zealand, since this is the number that had got me thinking. Sixty percent is a lot - in other words, 3 in 5 monarchs have a heavy parasite infection in that country. Since we don't have any historical records of OE from there, we don't really know if this number is growing or not. There was a small sample of 6 New Zealand monarchs from some years past that showed 3 were infected (50%), though this sample size is just too small to draw meaningful conclusions. Actually, it doesn't really matter if the number is growing or not, because the real question to ask here, is what should be done about it now? Anything? Nothing? This gets to the question at the top of the blog. While the authors of the study didn't specifically mention this, they did imply that people in NZ are actively trying to bolster the monarch population there, either by establishing hostplants, or even captive-rearing. But should they, is the million-dollar question.

I know there are some people who would take a very simplistic view of monarchs and their conservation, and feel that ALL monarchs should be conserved and ALL populations should be enhanced, period. This may sound good in spirit, but, I tend to think that OE changes things. And, in this case, we're talking about a lot of OE.

Actually, there are a number of places in the world where this same question applies, like in southern California, or the state of Florida. In those places, OE prevalence is through the roof right now: 70-90 percent of all adult monarchs are infected in these regions! And, the same thing is happening there, where well-intentioned people are working to enhance these local populations by adding milkweed, establishing butterfly gardens, or releasing reared monarchs. And in these places, it seems to be working - the local monarch abundance in these areas appears to be increasing (I've seen the data). But on the other hand, so too is the spread of OE. There is no actual historical data to point to here, but I can tell you that in Florida, for example, it used to be that only the southern tip was the region of high infection, but now, it's the entire state! And this spread is undoubtedly because people are helping the monarchs there.

I guess the question I'm getting at, is do we really want these local, highly infected, populations to grow or spread? With New Zealand being an island, their monarchs probably won't spread, but in Florida, this issue is more relevant, because their monarchs can easily spread further inland to the main, mostly-healthy, monarch population.

Think of it this way, when doctors find that a person has a tumor, their first course of treatment is to cut it out, so it doesn't spread. Why isn't this a viable, alternative, conservation strategy for monarchs? I'm not talking about actively wiping out infected populations with poisons or anything, as that would be cruel. But what about a strategy of gradually reducing (as opposed to adding) the available hostplants? Someone else may have a better idea here, and truly, I've not really given this part much thought. And remember, this is really a more of a thought-provoking question, and I have no illusions of being able to convince anyone to actually do this!

One of the problems when talking about OE and monarchs is that people seem to fail to grasp how much the OE is affecting the local monarch population. This is especially true in Florida and California, where people can easily see lot of monarchs flying around, despite the fact that OE prevalence is through the roof. In other words, they can't grasp why this matters so much.

Here is one way to understand how it matters. In 2019, a study was published by some of my colleagues (and one who I'm married to!), which was a very technical, theoretical, statistical analyses of OE prevalence data in areas of the southern US where there are local hotspots of high infections. Here is a link. This study addressed a number of research questions, but one important one was asking how OE was affecting the local monarch population size. Through a series of modelling (fancy statistics) the researchers concluded that OE reduces the local monarch population by 50%! In other words, if OE was not present in these areas, there would be twice as many adult monarchs present! Importantly, this same finding would apply to anyplace where monarchs are resident and have a high infection level, such as California, Florida, or New Zealand!

So after hearing this, hopefully you can see where I'm coming from, and then maybe this doesn't sound so crazy. If (big if) we could ever eliminate, or drastically reduce OE in these hotspot areas, the net effect could be an increase in monarchs, which is what everyone wants. But here's the rub, the only way to truly eliminate OE in a monarch population is to first eliminate the infected monarchs!

I've heard many people claim that if we were to do this in heavily-infected areas like Florida, this would effectively eliminate the entire Florida monarch population! This is correct. It essentially would, but, I think the local population would eventually rebound from the simple process of immigration. If you think about it, this is essentially what happens each summer throughout the core eastern population. Every summer, the adult monarch population builds, along with the OE prevalence, and then the monarchs all leave in the fall. The monarchs which return the following year tend to be uninfected, and these rebuild the local population. And similarly, if the diseased monarchs in Florida (or California) were eliminated, there would indeed be fresh uninfected monarchs arriving each fall. We already know this happens in both cases.

While I'm at it, let me also address another commonly-mentioned argument about OE in Florida, California, or other places like New Zealand: people who rear monarchs for release into these populations usually go to great lengths to prevent their reared monarchs from getting infected, by bleaching all the eggs and milkweed they use. This does reduce OE from captive stock, for sure, but there is something important that these people forget here. Even if you release dozens or hundreds of OE-free monarchs into these populations, those healthy females you released will eventually lay their eggs onto OE-contaminated milkweed. When there are so many infected monarchs in a population, that also means that just about every milkweed leaf has hundreds of OE spores. So, even if those females themselves were healthy, their (hundreds of) offspring will be infected. So really, those healthy monarchs you released are only enhancing the local OE spread.

Last thought - recall that I mentioned earlier that we know that OE is a naturally-occurring parasite. On the one hand, one could argue that this means the parasite is not something that we need to actively manage or interfere with (i.e. because it belongs here). Unfortunately, we also now know that we humans have artificially enhanced the spread of this natural parasite, both locally, and throughout the world. Recall the paper a couple years ago showing how OE is being transported around the world by the butterfly house industry (link here for blog). And don't even get me started about how many infected monarchs are being released each year by home-rearing...

So when it comes to heavily infected monarch populations, we have a bit of a conservation conundrum. If people work really hard, they can indeed enhance and help these populations, by supplying habitats, hostplants, and even by adding more individuals, but is all of that really helping? It is helping the infected population, for sure. But there's the rub. Now we have more infected monarchs because of it.

Hope this post got you thinking! What is YOUR answer?

PS: HERE is a link to the original data and article provided by NZ scientists Mariana Bulgarella from Victoria Univerity of Wellington. New Zealand.

************************************************************************
Here is a direct link to Andy's blog entry:

https://www.monarchscience.org/single-post/food-for-thought-should-heavily-infected-monarch-populations-be-enhanced
************************************************************************

BUTTERFLIES IN MID-WINTER: WOW

29/6/2021

I enjoyed a most unexpected surprise yesterday, when I saw several butterflies flying about enjoying the sun.

That's not unusual, you might think, however I live in New Zealand where, right now, it's mid-Winter and quite cold. There were three butterflies, one white and two blues. All three were in beautiful condition so must have emerged from their chrysalis's at the start of our Winter.

It's not usual to see Monarch butterflies flying about at this time of year, as they cluster about in tall trees until Summer, however I don't think I've ever seen a white butterfly or a blue butterfly in Winter before. Nevertheless, there they were. All in pristine condition.

What a joy it was to see them and, as you can see, I took plenty of pictures despite not having my correct 'butterfly' lens with me.

Look here 🔽 (click on each pic to see it larger)

MEXICO AND TAGGED MONARCHS - A NEW TWIST

18/6/2021

This is the latest Blog Post written by Andy Davis, suggesting an interesting twist to the tale of Monarch Tags found in Mexico. He poses some interesting questions about how tagging might affect a Monarch's flying ability.

He asks........
"Are the tags themselves leading to the monarch deaths?
Think about it. We already know that the stressors monarchs face during migration are immense - like cars, loss of nectar, storms, etc. What if the weight of the tags, even if it is incredibly minor, is causing monarchs to burn slightly more energy during flight every day, so that they arrive in Mexico with not quite enough fat to survive the winter. Or, maybe the minor weight of the tag causes the monarchs to not flap as efficiently as it would have normally. Or, maybe the tags are leading to slightly, but chronically-elevated metabolic rates. Or, for all we know, there is a behavioral issue at play here - maybe the white tags cause the tagged monarchs to be shunned by their untagged friends, and the tagged monarchs are then prevented from joining the rest of the monarchs in the safe tree clusters. Who knows?
The point is, we really don't have any data on the effect of tags to monarch physiology, flight mechanics, or behavior to say anything about this, but, given this new evidence (about increasing mortality at the winter sites), I might want to take this issue up in my own lab, and maybe other scientists should too."

I encourage you to read Andy's Blog Post, below...................

Recoveries of Tagged Monarchs in Mexico
- what do they really mean?
by Andy Davis ** 17 June 2021

Greetings everyone,

Summer is just about here and by now everyone has seen lots of adult monarchs in their yards and maybe eggs or caterpillars. Before you know it, thoughts will start leading toward the fall migration, and starting our tagging efforts! Well, before that happens, I'd like to spend today talking about the data that is generated by tagging, and tell you about some recent research focused on the tagging and recovery data. So this is a post that needs to be read by anyone who has ever tagged a monarch. Most taggers generally know that these tags are "used to help track the migration", but really, this is an oversimplification. In reality, it is much more complicated than that, as you'll see from this post.

First, let's start with the basics, just in case any readers here have never done this. Tagging monarchs essentially involves placing a numbered sticker on the wing of an adult monarch, as pictured above (from MonarchWatch.org), and then releasing it. If that monarch is spotted or found again by someone who can read the number, they then report where the monarch was found. This allows us to place two dots on a map (release location and recovery location), and then draw a line connecting them. This is a rather archaic technology, considering the recent advances in GPS tracking, but on the other hand, this is the way that the Mexican overwintering locations were tracked down years ago - by drawing lines on a map. So it is really thanks to a lot of tagging efforts by citizens back in the 60s and 70s (who were recruited by Fred Urquhart), that we now know where that all-important location is.

I bet a lot of folks reading this have even had one of "their" monarchs recovered in Mexico. If you tag long enough, this will happen eventually. My friend Don Davis is a legend for having lots of tag recoveries in Mexico! Anyway, this is usually something that is celebrated, and you even get a certificate in the mail when this happens. People like to post their recoveries on their favorite monarch facebook site too. I've always been a little uneasy about this celebratory nature of it though, since it seems to turn this very important scientific endeavor into something akin to a lottery.

After Fred Urquhart stopped running it, the monarch tagging (in the eastern N. American population) has been run by MonarchWatch for the last 20 years or so. I've always said that these tagging data are very important for the conservation efforts, since they tell us where the migration flyways are, and where in these flyways are the more critical locations. In fact, I even published a paper stating this. But recently, I've begun to question whether these data are as useful as I thought. I explain below.

Last year, a group of scientists, led by folks from MonarchWatch, conducted a formal analysis of 18 years of tagging data, the results of which were published in the journal, Frontiers in Ecology and Evolution. This paper is fully online, and a link is here. The intent of the paper appeared to be a test of something called the "migration mortality hypothesis", which is an idea that basically came from my lab. Essentially, it goes like this: since the size of the Mexican overwintering colonies has been declining over the past two decades, but, the counts of adult monarchs in the breeding range has not declined, therefore, there must be increasing mortality during the fall migration that is leading to the Mexico decline. Incidentally, this hypothesis has a fair amount of support from a variety of different studies now. Anyway, the MonarchWatch paper was intended to be a kind of test of this hypothesis. The researchers examined the rates of Mexico recoveries (from the tagging records) over 18 years. The rate is simply the number of tagged monarchs that were recovered in Mexico, divided by the total number of tagged monarchs. Typically it is something like 1-2 percent. The researchers figured that if migratory mortality were truly increasing over time, then there would be a corresponding decline in Mexico recovery rates over time. They did not find this, based on their own analyses of the tagging data. Their analysis showed that recovery rates have varied a little, but overall showed no real trend. Therefore, they concluded that the migratory mortality hypothesis was busted (or "debunked" as I read in one press release).

Now, here's where it gets interesting. After they published their paper, another group of researchers - James Fordyce (U. of Tennessee), Chris Nice (Texas State), and Matt Forister (U. of Nevada) - took issue with their study, and then published something called a "rebuttal" paper. This is kind of like a small study that refutes the first one, or maybe provides a different look at the data. These typically get published alongside the first paper, so that people can read the arguments from the rebuttal authors, and then make up their own mind about the original paper. Sometimes, the rebuttal paper is then followed by a counter-rebuttal by the original authors. I happen to know that there will be no counter-rebuttal forthcoming for this paper though. Anyway, this rebuttal of the MonarchWatch paper is now fully online, and is linked on the same page as the original paper - link here.

Let me give you the gist of this rebuttal. The Fordyce et al. group took issue mainly with the way that the MonarchWatch group statistically analyzed the recovery data. There were a number of different tests performed in the MonarchWatch paper, but the most important was the test that examined recovery rate over time. The original group had basically run a correlation test, to see if the recovery rate per year has changed over time (comparing recovery rate versus year). This seems fair at first, but the Fordyce crew said that this approach does not take into account the vast differences in population size each year, which may affect how many monarch monarchs are tagged, and/or recovered. So, they ran their own analysis using the same data as MonarchWatch (which had been posted in the original paper as tables), and their analysis took into account this size variation. In essence, they still were examining if the recovery rate has changed over time, but now this approach factored in the population size variation.

Shockingly, their analysis showed that tag recovery rates in Mexico have steadily increased over the last 18 years! What? Yes, it's true. I recently reached out to my friend Matt Forister, who pointed out to me what they did. I just crunched the numbers myself and it seems solid.

To be honest, I'm just as shocked as you are about this. On the one hand, this new information seems to refute the original paper's analyses (big time), so in other words, they were wrong. On the other hand, this this new evidence certainly seems to go against the migration mortality hypothesis too. How can recoveries in Mexico be increasing - can the monarchs' fall migration be getting easier over time? No, that's just stupid.

In their rebuttal paper, these authors made a few suggestions for why they think this might be happening. For one, they pointed out that the recovery data from Mexico is dependent on people looking for tags (more on this below), and, we really don't know if this "search effort" has increased over the years. If it has, then this might explain the apparent increase in recoveries. But, Taylor and colleagues have argued very firmly that they don't believe the tag search effort has increased, so there's that.

They also pointed out another possibility, and this is one that I am inclined to believe. They suggested that there might be a general increase in mortality of monarchs at the overwintering colonies (due to stress from in increasingly harder migration), which is leading to more tags being found over time. This makes a lot of sense to me, but first, let me unpack this idea a bit further. Something that most people seem to forget, especially when they get one of these celebratory certificates, is that a tag recovery in Mexico means that your tagged monarch died there! And, therefore it did not remigrate north in the spring, have offspring, or contribute to the overall population at all. Tags are found by locals who search through the forest floor, surveying the dead monarchs, not by looking through the living clusters with binoculars. In fact, the local monarch guides are the ones who usually find the tags. There was a neat essay a number of years ago on this, which was posted on Journey North (link here).

Reading it, you can see that the locals essentially sell the tags back to MonarchWatch. So, this means there is a monetary incentive for them to collect these tags. Below is a neat picture from that essay, showing two youngsters holding a bunch of tags, waiting to get paid!

So, when you consider that tag recoveries are essentially deaths in Mexico, you can start to picture what might be happening - increasing tag recoveries over time really means increasing winter mortality in Mexico. Probably not a good thing.

Now, here's a question that will really throw you for a loop - are the tags themselves leading to the monarch deaths? Think about it. We already know that the stressors monarchs face during migration are immense - like cars, loss of nectar, storms, etc. What if the weight of the tags, even if it is incredibly minor, is causing monarchs to burn slightly more energy during flight every day, so that they arrive in Mexico with not quite enough fat to survive the winter. Or, maybe the minor weight of the tag causes the monarchs to not flap as efficiently as it would have normally. Or, maybe the tags are leading to slightly, but chronically-elevated metabolic rates. Or, for all we know, there is a behavioral issue at play here - maybe the white tags cause the tagged monarchs to be shunned by their untagged friends, and the tagged monarchs are then prevented from joining the rest of the monarchs in the safe tree clusters. Who knows? The point is, we really don't have any data on the effect of tags to monarch physiology, flight mechanics, or behavior to say anything about this, but, given this new evidence (about increasing mortality at the winter sites), I might want to take this issue up in my own lab, and maybe other scientists should too.

OK, so to sum up this post, we now have two competing groups of researchers, who have each looked at the rates of monarch tag recoveries over time. A simplistic analysis of the data from the first group indicates that tag recoveries have not changed over time. A more comprehensive analysis from the second group shows that it has, which raises lots of questions, like why monarchs would be dying more frequently when they get to Mexico.

If there is one thing that this whole experience (the original paper, plus the rebuttal) has demonstrated, it's that interpreting trends from monarch tagging data is surprisingly hard to do. So the next time someone tells you that these tags "help scientists track the migration", tell them that it's more complicated than that!

That's all for now.

**This article has been reproduced with permission from Andy Davis, a research scientist at the Odum School of Ecology in the University of Georgia - link to the Davis lab website here. Andy has been studying monarchs, especially their amazing migration since 1997, and is the editor-in-chief of a scientific journal devoted specifically to animal migration. Andy is the author or coauthor of 35+ scientific studies on monarch biology.

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