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/

Fall Programs Recap & Wrap-up — From the Rookie’s Point of View

By Dahna Kreger, Intern Naturalist

For the River Bend naturalist staff, early November can bring either a much welcome break from long hours of wall-to-wall programming; or it can signal the beginning of a lengthy period of down-time that for some may elicit an uprising of pending doom from the gut.  I feel that this primarily applies to me, because of my complete and total inability to sit still for any length of time.  Nonetheless, I am excited to see what projects we will create to keep occupied when not entrenched in the few programs that we’ll be working on during the winter months…

In light of the recent change in our office atmosphere, moving from cyclical chaos and relative calm to one of more consistent calm and placidity, I have luckily been able to complete a blog post during the latter period.  And perhaps because I mourn the end of fall programming, that is the subject to which it is dedicated.

Recap – here is a run-down of the programs we have completed in the last two months:

  • Kindergarten:  Seasons and Senses
  • First Grade:  Homes and Habitats
  • Second Grade:  Seeds of Life
  • Third Grade:  Nature Pyramid
  • Fourth Grade:  Prairie Biome
  • Fifth Grade (Owatonna):  Soils and Erosion
  • Fifth Grade (Faribault):  Aquatic and Ecosystem Research
  • Sixth Grade:  Decomposition

Each brought its own set of challenges, and more frequently, rewards!  As a total greenhorn, I found myself plunged face-first into the fast-paced flow of fall programming at River Bend.  Nervous and stressed at the onset, I quickly built my confidence as a public speaker and group manager.  At least, I think I successfully managed to grow in these areas… my greatest joy of all however- other than the breadth of content and material I learned, in addition to having a fantastic opportunity to work with some wonderfully knowledgeable and exceptionally bright people- was being able to hang out with kids every day, and once again be able to see life through the fresh and curious eyes of a child.  Although I don’t think I had much of a problem doing that anyway, some might argue.

I like to start with favorites, so I’ll begin with my favorite of the fall programs.  I found that I had the most fun with younger kids, and I had a blast working with the kindergarteners during their “Seasons and Senses” program.  For this one, the kids come to River Bend with their class during the fall, winter, and spring; each time visiting their special “kinderspots” which are small areas of either forest or prairie that the groups will track changes with over time using their senses of sight, sound, touch, hearing, and even taste (within reason!).  Each group had an opportunity to visit Turtle Pond.  The clever names always got the kids extremely excited, and it was so fun to see their reactions during the introduction.  The spots were called:  Fuzzy Bunny Boulevard, Raccoon Hollow, Spiderweb Square, and Butterfly AlleyI can’t wait for them to come back in late January!

Another program I found very enjoyable was the Fifth Grade Aquatic and Ecosystem Research.  For this program, students learned how to identify and analyze the different factors that impact the health of an aquatic ecosystem and how to test for them.  The students got to perform some very legitimate tests – including dissolved oxygen, turbidity, pH, and even building filters that might help clean up dirtied water.  A collective favorite though was critter catching, where the students would use dip nets to capture insects and other small animals inhabiting each of the ponds where we conducted the testing.  It was always a highlight to find exceptionally large water beetles in Turtle Pond, or tiny fish swimming around in the hidden ponds tucked away in Owl Valley.   That one really shocked us, since no one really thought that fish could grow in such a small space with very few resources.  We naturalists did encounter a rather intimidating water beetle with one of the groups – it must have had a length of about 3.5 inches, including its pincers.  We kept it in a small container to show the classes coming later that afternoon, but it had escaped into the building at Trailside while we were away at lunch!  I still wonder where it might be lurking…

At this point it becomes very difficult for me to choose favorites, so perhaps continuing in chronological order might be best…

Fourth grade marked the beginning of our fall programming in early September with their study of the prairie biome.  The students were split up into pairs within small groups, and each pair was assigned to a square-shaped plot out in our prairie to conduct some basic scientific tests; such as temperature of soil and plant mass (both in the actual prairie and in the mowed trails), identifying plants and determining how common they are at River Bend, and finally catching insects in nets and jars to see what kinds of critters thrive in our mixed-grass prairie.  Again the students tended to most enjoy the critter-catching.  Sometimes, though, complete and total pandemonium would ensue whenever a bee was found and even caught in a jar… it would often become difficult to restore order after this happened, but we always managed to get everyone back on track.  To achieve this, one of the naturalist staff would “dispose” of the offending bee far off into the woods, or just release it back into the air when no one was looking.

Prairie

The River Bend prairie that the fourth graders surveyed.

Nature Pyramid

The nature pyramid helps us organize the different levels of the food chain. In this program students learned how to categorize the animals they found.

Third graders came next with their study of the Nature Pyramid.  This one was very enjoyable for the children, since it too involved a lot of log and rock rolling to search for insects.  The goal of this unit was to help students better understand each living thing’s place in nature, how abundant they are, and comprehension of the idea that nature is sustained through food chains such as the Nature Pyramid.  My personal favorite was looking for insects in the forest – since we frequently found very large millipedes that children interpreted as freaky and cool.  While they are completely safe to handle, some children opted out of that since it does feel a little funny to have a thing crawling on you that has a hundred tiny little legs, and will likely poo on your hand since it’s scared.  Overall the children did very well at categorizing where each animal belonged on the pyramid, and they especially got a kick when they realized that they too belonged on there – we’re the top dog at the highest tier!

Second graders came to us next for their Seeds of Life Program.  This one was always enjoyable to do – especially early on when we had lots of “poppers” and “hitchhikers” for the kids!  In this unit, we introduce the kids to the idea of adaptations.  That is, things that help a plant or animal survive in its habitat.  We use seeds as examples of different adaptations.  There are four different types of seeds:  hitch-hikers stick to fur, feathers, or clothing to later fall off at a new place; droppers simply fall to the ground, however animals usually carry them to other places; poppers burst from their seed container to spread away from the plant; and flyers are carried through the air by the wind by their wings or feathery parachutes.  Pretty much across the board everyone loved milkweed pods the best – finding the downy fluff scattered across the ground or still encased within the pod.  Of course, there were always those few children who would pluck a whole pod right off the plant and pocket it, and maybe one of the group leaders would discover it later on, or parents much later on at home… but I never really minded this because they loved it so much; how soft and feathery they felt, and how easily they blew away in the wind!  I remember loving that as a child, and even still today it brings me irrational amounts of joy.

Milkweed

Milkweed – flyer
*This is a tricky one; many believe that it is a popper, and while the pod does pop open, the seeds themselves fly out of the pod to distribute themselves.

This brings us to the concluding weeks of our fall programs, in which we had sixth graders and first graders coming to visit us!  The two programs did end up overlapping just a bit, however I always appreciate a little variety in the workweek, so I didn’t mind this at all and I am sure that none of the other naturalists did either.   At this point though I think we were all beginning to get a little tired, and were more or less looking forward to having a break coming up…

Beginning with sixth grade — this unit was all about decomposition, and introducing/reinforcing the concept behind and importance of using the scientific method.  In this unit, the goal was to have students be able to distinguish between producers, consumers, and decomposers; identify the non-living parts of cycles in natures (air, water, sunlight, rocks), and to review a food chain/web — either theoretical or observed that incorporates all the components of a nutrient cycle.  I had a total blast with this program!  I had been anticipating grumpy cantankerous pre-adolescent children giving me attitude and spewing out negativity about whatever I’d try to say to them.  And, I ended up with slightly cantankerous pre-adolescent children who got surprisingly excited about things like moss, lichen, and fungi.  For the program, the students were split up into pairs and groups — of which we had a total of four.  These included fungi, moss, lichen, middens and arthropods.  Of course being the leader of the midden/arthropod group often proved to be a significant advantage when it came to keeping everyone engaged and interested in what you were doing, I found.  On the first day of this unit, my group found a wolf spider and a unique species of millipede that still had a predominantly black body, but yellow and orange legs!

Nerstrand First Graders

Nerstrand first graders – showing off their pretend “squirrel” food caches of hickory nuts and basswood seeds!

Finally this leaves the first graders and their homes and habitats unit.  I know that I’ve said this about pretty much every program so far, but this one was really a lot of fun!  For this unit, the goal was to get the children to understand that a habitat is more than just where an animal can build its home. It is also a certain area where an animal prefers to live, and can find everything that it needs to survive.  An integral part of this program was reinforcing the four things that animals need to survive in their habitats – food, water, shelter, and space.  We went out in groups to investigate “evidence” of an animal’s presence – we asked them, “What would the animals have left behind in their homes or habitats?”  We were looking for things like tracks, scat, fur, feathers, scratch marks from claws, hollows in trees, and even bones.  We did have a couple of places where  we had intentionally hid animal bones – everyone really got a kick out of that!  And just because the kids are so adorable, I am including a few snapshots of some of the groups who came for this program.

Caitlin & first graders

Naturalist Caitlin Savage leading a group of first graders from Lincoln through our prairie!

As I finish this write-up, I have to say that thinking about all these programs that have passed us by has made me a little sentimental… but at least the naturalist staff gets to see everyone again in the spring!  And, after already halfway through the first week of no programming, I am doing well with the decreased activity levels of hectic-ness, and I have to say I think everyone else is too.

Dahna Kreger is an intern naturalist for the River Bend Nature Center, a member supported non-profit dedicated to helping people discover, enjoy, understand and preserve the incredible natural world that surrounds us. Contact us at rbncinfo@rbnc.org or 507-332-7151.

The Top 5 Scary Animals (That Aren’t Really That Scary)

By Garrett Genereux, Intern Naturalist

Assassin Bug

An assassin bug having a bee for lunch! Photo credit Dave Wilson Photography.

During this spooky time of year it is popular to post lists of scary things. Often times these lists feature animals such as the Great White shark or the Grizzly bear – animals that are actually quite frightening when encountered in nature. The five animals I am going to write about are “scary” but they will not get your instinctual-adrenaline pumping. These animals either appear scary or have some type of behavior that is scary, but in reality they pose little threat to us humans.

5. Assassin Bugs

These small (less than 40 mm) insects from the order Hemiptera (true bugs) are real-life vampires. Like their name suggests, they are highly-skilled predators. Assassin bugs employ camouflage coloring, dust, and sometimes even the exoskeletons of previous victims to hide and wait for their prey. They have also been known attack while flying. Once they have caught their prey, they use their straw-like mouth, called a rostrum, to inject saliva into their victim’s body. This isn’t just ordinary saliva; this saliva dissolves the inner tissues of their prey into liquid which the assassin bug then sucks out through the rostrum. There are 7,000 species worldwide. The Assassin bugs that can commonly be found in the prairie here at River Bend are quite benign. However, there are several species that inhabit parts of Central and South America that do feed on the blood of humans while they are sleeping. A few specific species of these blood-sucking Assassin bugs carry Chagas disease which can be fatal.

Wrinkle Faced Bat

It is hard to forget a face like that! Photo credit Evets Lembek.

4. Wrinkle-faced Bat

This fruit-eating bat truly has a face that only a mother could love. Wrinkle-faced bats can be found in several Central and South American countries. The face of the male bat typically has more wrinkles than the female. These skin growths are thought to help direct sound waves to their ears. Also quite strange is that the male bats have a flap of skin on their neck that they can tuck their whole head into. Very interesting to note is that the wrinkle-faced bat’s head is wider than it is tall. This adaptation allows the bat to increase the strength of its bite. Some scientists have conjectured that this allows the Wrinkle-faced bat to eat tough-skinned fruit when soft fruit is not available.

Tailless Whip Scorpion

Just remember it can’t hurt you! Photo credit Brujo.

3. Tailless Whip Scorpion

Although not a scorpion, this arachnid is perhaps more visually startling than its relative. Besides its six walking legs and two pedipalps (the two claw/pincer type legs near the animal’s mouth) it has a long appendage on each side of its body which is the “whip”. These appendages are not actually used as whips, but they do help catch prey. Typically the Tailless Whip scorpion walks sideways with its whips probing in front and behind as it walks feeling around for prey. Once it finds its prey it catches it with the pedipalps which have thornish spikes to ensure the prey does not get away. These arachnids do not have spinnerets or venom. There are 155 species that live in tropical and sub-tropical areas (so nothing to fear here in Minnesota). These animals prefer a humid environment.

Pistol Shrimp

For being so small it sure packs a punch! Photo credit Debby Ng.

2. Pistol Shrimp

Yes, a diminutive, plain-looking shrimp is at number two on this list. So if it doesn’t look frightening, then why is it on this list? Because it can do something quite spectacular that makes me thankful that it is fairly small and lives on the ocean floor far away from here.  The Pistol shrimp, also known as the Snapping shrimp, is a predatory shrimp and has a very unique way of catching its prey. The shrimp has asymmetrical claws, with one of the claws being able to produce very loud (190 decibels) snapping noise that it uses to catch prey and communicate. When there are great populations of these shrimp they can actually disrupt sonar and cause noise pollution in the ocean due to their incredibly loud snapping. Now to the interesting part, how they catch their prey. Typically they feed on small fish and other shrimp. They lay in wait until they sense movement with their antennae. Then they cock back their snapping claw and aim it at their prey. Next it releases the claw (hence the pistol name) and it creates a cavitation bubble (the loud snapping noise creates a pressure difference in the water) which travels towards the prey at upwards of 100 km/hr and at a temperature of 9000 ⁰C. Yes you read that correctly. Nine. Thousand. Degrees. Celsius. And yes, that is hotter than the surface of the sun. This cavitation bubble eventually implodes, effectively and severely stunning the prey which allows the Pistol shrimp to grab it and bring it back to its burrow to feed. This shrimp lives in oceans worldwide.

House Centipede

So terrifying!!! Photo credit AussieBotanist.

1. House Centipede

This centipede is only five centimeters long, which is dramatically smaller than its largest cousin, the Amazonian Giant centipede, which can be up to 35 centimeters long.  However, this centipede can be commonly found in your house, it moves uncommonly fast, and is not pleasant to look at. It may be of consolation that if this centipede is found in your house, it means that it is getting rid of other pests including ants, silverfish, small spiders, and even bed bugs. To catch this prey it moves very fast- up to .5 meters per second. Like many other centipedes, the house centipede uses venom to kill its prey. This species has specialized legs near its mouth that inject the venom instead of using mouthparts. House centipedes have been observed jumping onto their prey, lassoing them with their legs, and even bludgeoning their prey with their legs. Another adaptation that makes this centipede a great hunter is that it has highly developed eyes which are unusual among centipedes, although it still uses its antennae quite a bit. If you are quick enough to squash this arthropod, you better be accurate. House centipedes are notorious for being able to drop appendages that are trapped. However, if you squash too hard the centipede may drop all of its legs and essentially explodes. Originally from the Mediterranean, the House centipede is found almost worldwide. Just hope that the next time you move a piece of furniture you don’t see this creepy crawler speed away to its next hiding spot.

I hope that these animals did not scare you too much. Just remember that most of them don’t live here in Minnesota and that you as a human are much larger than they are so in reality they are probably more scared of you than you are of them. Enjoy Halloween!

Garrett Genereux is an intern naturalist for the River Bend Nature Center, a member supported non-profit dedicated to helping people discover, enjoy, understand and preserve the incredible natural world that surrounds us. Contact us at rbncinfo@rbnc.org or 507-332-7151.