Growing up Monarch – 3

“Growing up Monarch” is an on-going segment in the River Bend blog that follows the lives of several monarch butterflies as they grow from egg, to caterpillar, to chrysalis, to adult. We’ll be updating with photos and fun facts and observations throughout the summer!
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All three River Bend caterpillars are 5th instars. Photo credit: Stephanie Rathsack

 

Another week has gone by and our three resident monarchs have grown an immense amount! When last we checked in, they were all what is known as 4th instars, meaning that they had shed their skins three times, and would have several distinct features: bold yellow triangles on their heads, “chunkier” bodies with dark banding, and long front tentacles (antennae) that go beyond their head capsules. By Friday the 9th all three caterpillars had shed once again and become 5th instars.

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When shedding and during windy days a monarch caterpillar will produce silk (similar to spiders) in order to anchor itself to the leaf. Silk is one of the strongest natural fibers and it’s thought that pound for pound it is stronger than steel. Photo credit: Stephanie Rathsack

 

As 5th instars our caterpillars are in their final stage as larvae. This means that within just a few short days they’ll be preparing to pupate. The 5th instar stage is marked as being the largest of all the stages, and their front tentacles will be extremely long, becoming noticeably “droopy” past the head capsule. Another key feature though sometimes more difficult to distinguish is a velvety appearance to the black stripes along their bodies.

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The black stripes on 5th instars are very large and almost velvety in appearance.
Photo credit: Stephanie Rathsack

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The front tentacles of 5th instars are extremely long and are distinctively droopy towards the ends. Photo credit: Stephanie Rathsack

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The facial markings of 5th instars are bright and clearly visible. Note the large triangle in the center. Photo credit: Stephanie Rathsack

 

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Between May 30th (2nd instar) and June 10th (5th instar), just 12 days apart, our caterpillars have dramatically increased in size. Photo credit: Stephanie Rathsack
And while the caterpillars at this stage are very close to completing their time as larva, they still have a little bit of growing to do and a little bit of weight to gain and so of course that means…more eating! They have continued to feed almost nonstop (except to molt and produce frass). However, this constant feeding is noticeably slowing compared to their feeding habits as 3rd and 4th instars. More often they can be seen resting on the leaves—perhaps preparing their bodies for the big changes that are about to occur. In fact, scientists have dissected caterpillars at this stage to discover that several butterfly organs are already starting to form. And so even though these changes are not visible to us, we can imagine the amount of energy it would take to go from an animal that crawls on the ground to one that is capable of flying up to 2,000 miles (anyone would need a nap!).
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Although nearly full size, the 5th instar caterpillars can still be seen feeding fairly frequently. Photo credit: Stephanie Rathsack

With three caterpillars sharing an enclosure it’s never a surprise when overnight entire leaves will be consumed—not a single scrap being left (not even the stems)—leaving an empty tank with three very hungry caterpillars looking for seconds, thirds, and fourths. For this reason, rearing monarchs can be a very demanding job, requiring frequent trips to collect fresh leaves no matter what the weather may be.

 

 

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Being larger doesn’t make you invincible. While 5th instars are notably more bold and more likely to explore their environments than their smaller counterparts, they will still consistently take shelter on the undersides of leaves, perhaps to prevent being spotted by predators. Photo credit: Stephanie Rathsack

 

And while rearing caterpillars can be an immense amount of work, it is also a very rewarding process, allowing you to view them at every stage, and also witness infrequent or short-lived behaviors that would be difficult to spot in the wild if not impossible. One such behavior that the author witnessed on Saturday the 10th was especially interesting. With three large caterpillars all relatively close together it soon became apparent that this species is by no means gregarious, and has no instinct for companionship. Quite the opposite actually—they are notably aggressive towards those of their own kind, behaving in a manner that you would expect to see exhibited towards potential predators and not towards other caterpillars (who are so similar in size and appearance they may as well be identical). When one caterpillar wandered too close to its neighbors, close enough to brush up against them, the former responded by violently thrashing their head towards the intruder. This motion was repeated several times with a clear “back off” message similar to that of a lunging dog, but the recipient of these “attacks” appeared completely oblivious and merely continued on its way. Eventually the trespasser moved along far enough, and it would seem that touch was the catalyst for this behavior, for as soon as contact was removed, all normal activities of feeding resumed as though nothing had happened.

 

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The caterpillar in the center wandered too close to its neighbors and was punished for doing so by both individuals on either side of it. When touched, the caterpillars will rear their heads and lunge at the intruder—perhaps to drive them off.
Photo credit: Stephanie Rathsack

 

It’s likely that this behavior is completely instinctual, rather than decision-based. It would seem that caterpillars are “wired” to rear up at unexpected physical stimuli, that is, to throw themselves at things that touch them. This would effectively make them look larger (and probably less appetizing) to would-be predators. It’s behaviors such as this that allow these caterpillars to survive their long lives in this vulnerable stage. For while they are toxic, not all animals have learned to associate the bands of black, yellow, and white, with danger, and will therefore feed on monarch larva before finally understanding that they all are unpalatable. This defensive behavior may also tie in with the necessity to roam. As the caterpillars continue to grow they will soon cease feeding altogether, just as they had when preparing to molt. This time however will be different, and the caterpillar will be searching for a very special location.

 

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The large tentacles of 5th instars may be useful in sensing the environment, especially when exploring an unfamiliar location. Photo credit: Stephanie Rathsack

 

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When large enough, the caterpillars will stop eating and begin to move around more—even leaving their host plant entirely in search of a safe place to pupate.
Photo credit: Stephanie Rathsack

 

It’s important that the location chosen is perfect—protected both from the elements as well as from predators, as the next stage, the chrysalis, is by far the most vulnerable of all its stages. As a chrysalis, the monarch will be completely unable to move or defend itself in any way as it goes through the difficult transformation into butterfly. For this reason, it is immensely difficult to locate monarch chrysalises in the wild. They are often not placed on milkweed plants, and also camouflage well with their surroundings.

 

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Over the course of approximately two to three weeks, a monarch caterpillar will increase its total mass 2000 times. Seen clearly in comparison between a 5th instar and a newly hatched 1st instar.
Photo credit: Stephanie Rathsack

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A 5th instar puts on a lot of weight in order to pupate—and their body segments will become especially pronounced. Photo credit: Stephanie Rathsack

 

Once they have found the perfect spot, the caterpillar must do several things in order to pupate. First, it must start laying down a mat of silk. It would have done this every time it molted as well, as this mat of silk provides a surface on which to grip and adds extra stability. This time the mat is noticeably larger and thicker. The caterpillar will also create a small wad of silk that is much thicker—this will be the point at which it attaches itself during pupation. Caterpillars produce silk similarly to spiders—through an organ known as a “spinneret”. On monarchs it is located beneath the mouth. Silk begins as a liquid produced in the salivary glands after which it is excreted through the spinneret. Upon coming into contact with air, the liquid silk will turn into solid strands which the caterpillar may then place down. Throughout its life as a caterpillar they retain this ability, and it is most often used as a mat when molting, or as a “life line” if the caterpillar were ever to fall off its host plant. After pupating they lose the spinneret, and also the ability to create silk as it will not be needed in the adult stage.

 

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The silver-white strands of silk are clearly seen crisscrossing underneath the caterpillar. Once finished laying down this mat, it will then begin work on a silk pad, visible here as a small white ball located beneath the caterpillar’s head. Photo credit: Stephanie Rathsack

 

 

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Once the silk pad is completed, the caterpillar will turn around and grip the pad with its back prolegs. Photo credit: Stephanie Rathsack

 

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As of the afternoon of June 11th, both larger caterpillars were in the distinctive “J” of pre-pupation, while the third, smaller caterpillar, was still feeding.
Photo credit: Stephanie Rathsack

Upon completion of its silk pad, the caterpillar will use this as a gripping point as it moves into the next stage of pupation. In order to form a chrysalis, the caterpillar will drop its head so that it will be hanging upside down by its back prolegs.  They will remain like this for anywhere between 10 and 24 hours, completely unmoving and unchanged—at least on the outside. It couldn’t be further from the case inside. As the hours tick by, the caterpillar will start to move again, appearing to almost be doing sit ups as it will move its head up and down repeatedly. Next, it will appear to grow tired of this movement and hang more loosely, looking less like a J and more like an I. At this point, if you look at its front tentacles carefully, you may notice that they appear shriveled—this is a sign that pupation will soon occur, as there is no longer any “caterpillar” inside that part of its body any longer, and it is ready to molt for the last time. The last sign will be a small tear along the caterpillar’s back, right behind the head. This tear will reveal the bright green of the chrysalis underneath and will grow larger and larger as the skin is worked upwards. This entire process once the skin splits takes just about a minute to complete, so viewing this phenomenon takes not just patience, but also luck and good timing. As the skin continues to come off, more of the chrysalis will be revealed, and many butterfly features will be clearly visible—such as the wings and antennae. When the skin has reached the rear legs, the chrysalis will start twisting around in circles—this serves a duo purpose: one, to remove the old skin completely, and two, to firmly attach itself to the pad of silk. This transition needs to occur quickly, as the caterpillar no longer has back legs to hold onto the silk with. Instead, it must use the cremaster (the black peg on the chrysalis) by hooking it onto the silk. The twisting motion increases the number of strands that hook on, similar to how Velcro works.

By the evening of the 11th both larger caterpillars had pupated and the smallest of the had begun work on its silk pad. Overnight, the smallest caterpillar pupated as well.

 

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The two first chrysalises were carefully removed from where they had originally pupated in order to be relocated. If you raise your own monarchs, do NOT attempt this without prior experience. Photo credit: Stephanie Rathsack

 

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The morning of Monday the 12th both chrysalises were safely transferred to a new location for easier observation. The 3rd chrysalis had pupated overnight and was still too soft to move. Photo credit: Stephanie Rathsack

 

Want to learn more?

Stop by our interpretive center this week to talk to a naturalist and see the monarchs for yourself! The monarchs will be available to view:

Mon-Fri     8:00-4:30
Sat              9:00-4:00
Sun             9:00-2:00

 

Interested in getting more involved?

River Bend will be offering MLMP trainings to teach interested members of the community to become certified MLMP volunteers! Monitor at home or at River Bend, and help save this amazing insect from extinction.

Register online to attend the training scheduled for July 29th 100-4:00pm.

For more information, see our website at: http://www.rbnc.org/

Growing up Monarch – 2

“Growing up Monarch” is an on-going segment in the River Bend blog that follows the lives of several monarch butterflies as they grow from egg, to caterpillar, to chrysalis, to adult. We’ll be updating with photos and fun facts and observations throughout the summer!

 

It’s been a week since we last looked at the monarchs that River Bend is raising, and a lot has happened in those seven days! In the life of a caterpillar, change happens quickly, and with just about a month to go from a tiny egg to a full-fledged butterfly, there’s no time to waste in putting on those growth spurts, and our resident royalty has been doing just that.

1The smallest of the three caterpillars remains a “1st instar”, though its larger cage mates have already molted. Photo credit: Stephanie Rathsack

Ever since day one, these larvae have been professional eating machines—spending most of their day chowing down on the provided milkweed leaves. You’ll recall from our last post that monarch larva feed exclusively on milkweed—refusing any other offered vegetation. They do, however, start their lives off with a slightly different meal: their own eggshell. And unfortunately, in some cases, the eggshells of other caterpillars. Such was the case for our River Bend monarchs.

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Skin clings to the back of a newly molted 2nd instar caterpillar.
Photo credit: Stephanie Rathsack

Last week we had a total of three caterpillars and one ready-to-hatch egg, but since then we’ve dropped by one, as one of the caterpillars made a meal out of the last egg before it could hatch. This cannibalistic behavior may be another reason for why female monarchs lay only one egg per plant, as the larvae appear to have no qualms about siblicide. With that being said, we now have a grand total of three healthy caterpillars, and all danger of competition between them has passed. Since then, they have continued to feed voraciously. They no longer eat in the characteristic circle pattern of newly hatched caterpillars, instead they now chew all the way through the leaves, creating small holes as they do so.

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While nearly the same size, the caterpillar on the left is a recently molted 2nd instar, while the caterpillar on the right is still a 1st instar, preparing to molt—indicated by the dropped head capsule and the white silk holding it in place. Photo credit: Stephanie Rathsack

With all that eating, it’s no surprise that they’ve already increased in size. As of Tuesday May 30th, one caterpillar had already molted into its 2nd instar stage, with another preparing to do so as well.

4Rearing its head may help this 3rd instar navigate its surroundings. Photo credit: Stephanie Rathsack

The third caterpillar is slightly smaller, and took longer to be ready to molt its skin. This molting, or “ecdysis” as it’s referred to by scientists, will occur several times during the caterpillar stage and can be predicted by several behaviors as well as physical changes—the most obvious being a lack of appetite. Our caterpillars would stop eating and stop moving completely as they prepared to shed their skin. Prior to molting, the caterpillars will lay down a layer of silk that helps hold them in place.

5Upon completing its molt, the caterpillar’s new skin is soft and light colored—obvious in this photo as seen by its yellow head and legs. These parts will darken over the next few hours, but until then the larva is at its most vulnerable, similar to a crab without its shell. Photo credit: Stephanie Rathsack

By Saturday, June 3rd, all three caterpillars had shed twice, and were officially “3rd instars”—the largest even preparing to molt again to become a 4th instar.

The smallest of the three caterpillars was once again the last to prepare to molt, though on Saturday it was in search of a location to do so as it roamed its habitat, occasionally rearing its head up—which may assist sensing its environment, as well as start loosening the older skin and head capsule.

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Two third instar caterpillars, with the individual in the foreground preparing to molt. Note the dropped head capsule, with the newer, lighter colored skin above it. Photo credit: Stephanie Rathsack

It takes caterpillars roughly two weeks to go from 1st instar to chrysalis, and our three caterpillars, having hatched on Friday, May 26th should be preparing to pupate late this upcoming weekend. They still have some growing to do however, and will continue feeding every day in order to do so.

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“Frass happens”
This 3rd instar expelled some of its waste during observation. Caterpillar poop is known as “frass” in the scientific world, and this caterpillar displayed an odd behavior as it promptly turned around, and picked the frass up, moving it around several times before leaving it behind.
Photo credit: Stephanie Rathsack

Today, Monday the 5th, all three caterpillars have shed their skin and are officially 4th instars. They have bold stripes along their bodies, large banded heads, and front antennae that droop down past their head capsules—all key characteristics of 4th instar caterpillars. Within the next few days they’ll shed again to become 5th instars, and then finally, they will shed their skin a final time in order to transform into a chrysalis.

 

unnamedA view of all three caterpillars as viewed on Monday, June 5th. All three are considered “4th instars” at this stage, despite the differences in size. Photo credit: Stephanie Rathsack

 

Want to learn more?

Stop by our interpretive center this weekend to talk to a naturalist and see the monarchs for yourself! The monarchs will be viewable  as follows:
Fri 8:00-4:30
Sat 9:00-4:30
Sun 9:00-2:00

Interested in getting more involved?

River Bend will be offering MLMP trainings to teach interested members of the community to become certified MLMP volunteers! Monitor at home or at River Bend, and help save this amazing insect from extinction.
Register online to attend the training scheduled for June 10th from 1:00-4:00pm.

For more information, see our website at: http://www.rbnc.org/

Growing Up Monarch – 1

In 2014, monarch butterfly populations reached an all-time low—having declined approximately 90% in the last twenty two years. This sparked a Nation-wide effort to help preserve and protect the once common insect and its incredible 2000 mile migration. Now, studies have shown a potential rise in numbers, ending with the 2015-2016 annual overwintering count which reported the highest population since 2009. This increase in population was predicted by experts due to ideal weather conditions during the breeding months, as populations are widely effected by changing weather. For example, in 2002, a single storm killed an estimated 500 million monarchs. Statistics like this solidify the fact that monarchs need a very large population size in order to be resilient to threats. In other words, there must be a surplus of individuals in order for the species to endure.

monarch-population-figure-monarchwatch-2016

In addition to weather, monarch butterflies face numerous threats to their overall survival, many of which involve humans. The true difficulty in protecting this species also lies with the fact that it spans across three countries and two distinct “sites”. Monarch butterflies require a breeding and feeding site as well as an overwintering site. In search of these sites, a monarch butterfly may travel from Canada through the United States to Mexico. This large expanse of land covered makes it difficult to protect the entire range. These two specific sites also present their own unique threats; for example, loss of milkweed due to new agricultural practices. Monarch butterflies go through a 3-5 generation cycle during the breeding season, and the caterpillars feed exclusively on milkweed. It has been shown that nearly half of the migrating monarchs are produced in the U.S. “corn belt”, and yet with new agricultural practices, the milkweed found in this region is being eradicated, particularly due to modified crops that are herbicide-tolerant, allowing for wide-spread use of chemicals that eliminate all other vegetation.

Even after surviving through the summer months, monarchs face a whole new set of challenges, including the actual act of migrating up to 2,000 miles (a daunting task, even when you’re not an insect that weights half a gram). Once at the wintering grounds, the butterflies rely entirely on the microclimate provided by the forests of central Mexico. Due to this unique need, monarch butterflies are at special risk throughout the winter. One of the largest threats is deforestation (both legal and illegal logging practices) which removes roosts, as well as threatens the delicate microclimate. However, the nature of how the monarchs overwinter is a risk in and of itself. The butterflies are concentrated into one small region which makes the entire population vulnerable to a single storm or any other disaster such as fire and disease. Ecotourism also poses a threat to the integrity of the winter refuge, along with many other pressures. In short, people compete with monarch butterflies, not only for space, but also for food and water, and the needs of the people who live in this region must be balanced with the needs of the butterflies. And while many of these difficulties may seem far away and difficult to manage, especially for those living in the Midwest, there are many ways that anyone can make a difference in protecting monarch butterflies. The first and potentially most impactful way you can make a difference is through education. Many people are still unaware of the plight of the monarch butterfly, and even more don’t fully understand the effects of their actions, such as removing milkweed or spraying herbicides/insecticides. For this reason, it is important to not only remain up to date on developing research, but also to educate others as well. This can be as simple as planting a native plant garden in your yard, participating in citizen science, or attending one of many monarch butterfly events throughout the nation. River Bend Nature Center will be hosting one such event on June 10th—a program offering community members a chance to become certified citizen scientists for the Monarch Larva Monitoring Program. During the course of the program, participants will learn details on monarch life history, including their migration, before heading outside to get hands-on experience in searching for monarchs and collecting data.

River Bend will also be playing host to several monarchs in the Interpretive Building as we watch them go through their incredible life cycle. Stop in to see them transform from egg, to larva, to pupa, to adult, and finally, if you’re lucky, help us release them back into the wild!

Our current monarchs were laid on Tuesday, May 23rd. Adult female monarchs in Minnesota in late spring are most often “2nd generation” butterflies, meaning that they are the children of those individuals who overwintered in Mexico. They were hatched in the southern states and flew the remainder of the migration to the northern states and Canada where they breed, lay eggs, and die. This would make the eggs we have “3rd generation”, or the grandchildren of the butterflies in Mexico.

1 egg layingWhen laying their eggs, a female will cling to a leaf and bend her abdomen underneath so that the egg will be on the bottom side. This placement would potentially help moderate heat and moisture, and also reduce predation rates. The female will generally only lay one egg per plant in order to decrease competition between larva, but multiple eggs per plant are not unheard of if multiple females visit the same plant.
Photo credit: Stephanie Rathsack

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Monarch egg on the underside of a milkweed leaf. When the eggs are first laid, they’re often a creamy white, and will become more yellow in appearance as they age.
Photo credit: Stephanie Rathsack

The eggs are minuscule in size, and it takes a trained eye in order to spot them. However, they can be easily identified as monarchs by their pointed top and the distinct ridges that run vertically all around the egg.

It will take about four days for the eggs to be ready to hatch, though the process may be sped up or slowed down by temperatures. Colder temperatures will slow down the hatch rate, while warmer temperatures will speed it up.

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This photo, taken several days after the egg was laid, clearly shows the ridges that run up and down the outside of the shell, distinguishing it from other insect eggs as well as milkweed sap.
Photo credit: Stephanie Rathsack

Three of our four eggs hatched on Friday, May 26th and the fourth is scheduled to hatch some time today.

4 eggs
These two eggs side by side allow a clear distinction in age to be seen. The egg on the right is several days old, but is not yet ready to hatch, while the egg on the left has become translucent and allows the viewer to see the black head capsule of the caterpillar inside. This change in appearance indicates that the caterpillar could be emerging anywhere between hours and minutes.
Photo credit: Stephanie Rathsack

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Another view of the egg preparing to hatch.
Photo credit: Stephanie Rathsack
River Bend’s last monarch egg shows signs of being ready to hatch today, and we are eagerly waiting for it to emerge. Meanwhile, the other three caterpillars have already completed their first meal (their own eggshells) and have moved on to feeding on the provided milkweed leaves. As a species, monarch larva feed EXCLUSIVELY on plants in the milkweed family. Pictured here is the plant “common milkweed” which can often be found growing along roadsides and in prairies.

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When monarchs first hatch, they are roughly the size of the egg they were in, and their coloration is vastly different than their older counterparts. While older larva will have the distinct black, yellow, and white banding, these younger caterpillars are light gray with minimal banding, and have a large, black head.
Photo credit: Stephanie Rathsack

After feeding on its eggshell, monarch caterpillars will immediately begin to feed on the milkweed plant they were laid on. These youngest larva are known as “1st instars”, indicating that they have not yet molted their skin. After feeding almost nonstop, they’ll be ready to molt in several days. River Bend’s caterpillars are all currently 1st instars.

7 circleFirst instar caterpillars will feed in a circle around themselves until they’re large enough to not be at risk of drowning in milkweed sap.
Photo credit: Stephanie Rathsack

As our caterpillars start eating for the first time, they feed in a very distinctive circular pattern. Many scientists believe that this is to decrease sap flow in the leaf. While the sap is toxic to almost every other animal species except the monarch, these tiny caterpillars could easily drown if sap were to start flowing out of the cuts they make as they feed. To prevent this, the caterpillars feed shallowly, and create a safe “island” for themselves.

Want to learn more?

Stop by our interpretive center any day during the week to talk to a naturalist and see the monarchs for yourself! The building hours are as follows:
Mon-Fri 8:00-4:30
Sat 9:00-4:30
Sun 9:00-2:00

Interested in getting more involved?

River Bend will be offering MLMP trainings to teach interested members of the community to become certified MLMP volunteers! Monitor at home or at River Bend, and help save this amazing insect from extinction.
Register online to attend the training scheduled for June 10th from 1:00-4:00pm.

For more information, see our website at: http://www.rbnc.org/

‘Til Death Do Us Part — Nature’s Five Most Romantic Couples

Sarah Shimek

By Sarah Shimek, Education Coordinator

5. Bald Eagles

Bald Eagle Pair - adults   Photo by Len Blumin

Bald Eagle Pair – adults
Creative Commons Attribution-Noncommercial-No Derivative Works 2.0 Generic License   ByLen Blumin

While bald eagles are known for their fantastically acrobatic aerial mating rituals, it is actually the nest-building that cements the bond between mates, building on the same nest season after season. Bald eagles are among the estimated 95% of birds that are socially monogamous – meaning they cooperatively raise their young over the course of a mating season and in most cases, will return to the same nest and mate year after year. One nest, used by an eagle pair for over 3 decades, measured 9 feet across, almost 12 feet high, and was estimated to weigh over 2 tons.  While genetic testing shows that they may engage in a little fling on the side now & then, known as “extra-pair copulation,” only several years of unsuccessful clutches or the death of one eagle will break up these super-couples.

Sandhill Crane Parents with baby By Matthew Paulson

Sandhill Crane Parents with baby
Creative Commons Attribution-Noncommercial-No Derivative Works 2.0 Generic License  By Photomatt28

4. Sandhill Cranes

Another bird renowned for their elaborate mating dances, the sandhill crane is also known as a symbol of long-term fidelity.  Bonded pairs call in unison, spreading the word that they are in a committed relationship.  During the massive breeding-ground migrations in the spring, their synchronized “kar-roo” is thought to be a bonding activity, kind of like Ginger Rogers and Fred Astaire dancing and singing their way across the stage. Unlike Fred & Ginger, crane pairs will stay together until one of them dies, even if they have a couple nests that flop.  Philandering among crane pairs is so rare that when a single extra-pair copulation event was witnessed in 2006 it was big news; in fact it was the first one ever documented.

3. Black Vultures

Black Vulture - Coragyps atratus   By Martha de Jong-Lantink

Black Vulture – Coragyps atratus
Creative Commons Attribution-Noncommercial-No Derivative Works 2.0 Generic License  By Martha de Jong-Lantink

For black vultures, enforcing monogamy is a community affair. These ominous birds seem to be deeply serious about their commitment to a chosen partner. The pair will hang out together year-round and share parenting duties.  Individuals caught engaging in extra-pair copulation will not only be attacked by their mate but by neighboring vultures as well. Genetic study of 17 different vulture families found no evidence of extra-pair fooling around, giving new meaning to the phrase “It takes a village…”

Prairie Vole

Prairie Vole

2. Prairie Voles

Mammals – rodents in particular, are not necessarily known for their fidelity.  But the little prairie vole is a notable exception. Once they have lost their virginity, males will prefer to mate exclusively with that female, even going so far as to attack other females.  Scientists have traced this behavior to a hormone in the brain, which triggers lasting bond formations and aggression towards potential home-wreckers.  Once mated, these “high school sweethearts” share parental duties, groom one another, and appear quite affectionate. When presented with “unfamiliar, virgin females” in the wild, less than 10% of male voles succumbed to the temptation. Even more unusual, less than 20% of committed voles sought out a new mate if their partner died.

1. Diplozoon paradoxum (parasitic worm)

As unattractive as it sounds, this worm takes the prize for most committed among Nature’s couples. I’ve spared you pictures of this particularly homely couple. This fish parasite practices an extreme form of monogamy. Individuals meet as virgin adolescent larvae and literally fuse together at their midsections. Sexual maturity is not reached until the worm fuses with a mate. Once fused, they remain together until they die sometimes several years later, when even then they are not parted.  As Dr. Barash, a professor of psychology at the University of Washington in Seattle noted in an article in the New York Times, “That’s the only species I know of in which there seems to be 100 percent monogamy.” The only heartache here is in the unfortunate fish that hosts this epic romance.

Sarah Shimek is the education coordinator for the River Bend Nature Center, a 501(c)3 non-profit organization in Faribault, Minnesota that specializes in nature and environmental education.  The Nature Center property includes 743 acres of original and restored natural lands with over ten miles of trails that are open to the public 365 days per year. River Bend Nature Center relies on donations and memberships to fund its operations, please join and give today. Contact us at rbncinfo@rbnc.org or 507-332-7151.

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