Welcome to an exciting journey into the world of insects, where we meet Crystal, the Collection Manager of Insects at the Field Museum of Natural History. Crystal is an entomologist, which means she studies insects, and her particular focus is on a group of water beetles known as Riffle Beetles. These beetles are not just any ordinary insects; they have some remarkable adaptations that make them truly fascinating.
Riffle Beetles are aquatic insects that spend their entire lives underwater. What makes them extraordinary is their ability to carry a bubble of air with them, which they use to breathe. This air bubble can last them up to five years! The beetles are so small that they can utilize the natural properties of water to breathe. As they consume oxygen from the bubble, the pressure decreases, allowing more oxygen from the surrounding water to diffuse into the bubble. Simultaneously, carbon dioxide produced by the beetles diffuses out into the water. This efficient system allows them to thrive underwater.
Why have Riffle Beetles adapted to live underwater? Crystal explains that it was an empty niche with no other beetles and a plentiful food source in the form of periphyton. This opportunity led them to evolve and occupy this unique habitat. Interestingly, there are related beetle groups that venture into water but do not stay submerged permanently. This evolutionary journey is similar to that of whales, which returned to the ocean after their ancestors had once left it.
Crystal recently embarked on a collecting trip to New Zealand, exploring various streams on the South Island to study different populations of water beetles. Each stream hosts distinct populations, and by examining their morphology and DNA, researchers can trace their evolutionary history and link it to geological events. This research is crucial for understanding the health of ecosystems, as water beetles serve as bioindicators. In North America, many Riffle Beetle species are sensitive to pollution and changes in pH, making them valuable tools for assessing water quality.
During her trip, Crystal encountered another intriguing insect, the Blephariceridae, a type of fly with larvae that live in the cleanest, coldest streams. These larvae have suction cups on their bodies, allowing them to cling to rocks in fast-flowing streams. When disturbed, they detach and sometimes stick to researchers’ legs, earning them the endearing nickname “The Adorable Maggots.”
Crystal’s passion for studying water beetles and other insects highlights the importance of understanding these creatures and their ecosystems. Through research and conservation efforts, we can learn more about the intricate relationships within nature and work towards preserving these vital environments. Whether you’re an aspiring entomologist or simply curious about the natural world, the study of insects like Riffle Beetles offers endless opportunities for discovery and wonder.
Visit a local stream or water body and observe the aquatic insect life. Try to identify Riffle Beetles and other aquatic insects using a field guide. Document your findings with sketches or photographs, noting any unique adaptations you observe. This hands-on experience will deepen your understanding of their ecological niche and adaptations.
Prepare a presentation on the evolutionary adaptations of Riffle Beetles. Focus on their respiratory adaptations and compare them with other aquatic insects. Use diagrams and animations to illustrate how their air bubble system works. Present your findings to your peers to enhance your communication skills and deepen your understanding of evolutionary biology.
Participate in a workshop where you can learn about DNA extraction and analysis techniques. Use sample data from Riffle Beetles to understand how genetic information can trace evolutionary history and population differences. This activity will provide practical insights into molecular biology and its applications in entomology.
Engage in a debate on the importance of conserving aquatic ecosystems, focusing on the role of Riffle Beetles as bioindicators. Research the impact of pollution and climate change on these beetles and argue for or against specific conservation strategies. This will help you develop critical thinking and public speaking skills.
Write a short story or essay from the perspective of a Riffle Beetle. Describe its daily life, challenges, and interactions within its ecosystem. Use this creative exercise to explore the beetle’s adaptations and ecological role in a narrative format, enhancing your understanding through storytelling.
**Sanitized Transcript:**
[Emily] Hey! We’re here with Crystal, back at the Field Museum. Crystal, what is it that you do here?
[Crystal] I am the Collection Manager of Insects at the Field Museum of Natural History.
[Emily] You’re an entomologist?
[Crystal] I am!
[Emily] You study insects?
[Crystal] Yeah!
[Emily] What is your area of focus?
[Crystal] So, I study water beetles, specifically a group called the Riffle Beetles. And the Riffle Beetles are the greatest beetles on Earth.
[Emily] You don’t think that might be a bit of a biased statement?
[Crystal] I don’t.
[Emily] What’s so great about Riffle Beetles? Also, whenever I hear the word “Riffle Beetles,” I feel like there should be a guitar riff, like a (imitates guitar riff).
[Crystal] Riffle Beetles live underwater and they carry a bubble of air with them, and they hold that air bubble for the rest of their life.
[Emily] Really!?
[Crystal] And that can be up to five years or so.
[Emily] You put me underwater with one bubble, I’ll probably die.
[Crystal] Part of it is that they’re so tiny that they’re actually able to use some of the natural properties of water in order to breathe. There’s lots of different kinds of air in the air bubble. There’s oxygen, carbon dioxide, and nitrogen. As they use the oxygen in the air bubble, the pressure of the oxygen goes down and it’s less than in the surrounding water, so oxygen passively diffuses back into that air bubble.
[Emily] Whaaaaaat?
[Crystal] So, as they use oxygen and give off carbon dioxide in the air bubble, the concentration of carbon dioxide in the air bubble increases compared to the surrounding water. The carbon dioxide then diffuses back out into the water.
[Emily] What would be the evolutionary imperative for an organism to undergo so many adaptations that allow this to happen? Like, what’s so great about living in the water? Why do the beetles want to—
[Crystal] This is why I work on water beetles! It was just an empty niche. There were no beetles living there and nothing eating the periphyton, so these beetles saw that as an opportunity and they went underwater. What’s actually cool is that there are closely related groups that will go into the water but they won’t stay underwater.
[Emily] Oh!
[Crystal] So, you can kind of almost see that gradient from life entirely out of water to a life entirely underwater where they never leave.
[Emily] Yeah. It reminds me of whales, you know, ancient relatives of whales came out of the ocean and then at some point they were like, “you know, it wasn’t so bad in there.”
[Crystal] Right!
[Emily] And then they evolved to go back to the ocean.
[Crystal] Exactly! And what’s really cool is that you can see this happen over and over again in the Riffle Beetles.
[Emily] You were just on a collecting trip to New Zealand?
[Crystal] I was! We collected all around the South Island, traveling from stream to stream, sampling each stream looking for different populations of water beetles.
[Emily] Why is it so important to go to so many different streams? Why don’t you just go to one New Zealand stream and say, “oh, that’s good”?
[Crystal] Because every stream has a different population. You can imagine a watershed as a hand, with lots of little fingers that come out. Each of those little fingers is a stream, and they all come together into one larger stream. You might have another watershed over here, maybe there’s a mountain in the middle, and those two are separate. They might have separate evolutionary paths. So, we can study all those populations, their morphology, and use their DNA to figure out how they’re related and how far into the past they separated. You might be able to match that up with different geological events.
[Emily] You mentioned how important water beetles are for learning about the health of New Zealand streams, but they also live all over the world.
[Crystal] Actually, we know a lot more about the water beetles in the US than we do about the water beetles in New Zealand. In fact, we had a curator here named Harry Nelson who worked on the same group of water beetles that I do. He geo-referenced every place he collected on a map. This is just an example of one of the maps that Harry Nelson put together. He outlined all of the watersheds in Illinois on this map in different colors. Now, we can actually use Geographic Information System, or GIS. You can use Google Earth. In fact, you can go on Google Earth right now and put all of your collecting localities on Google Earth.
[Emily] Oh!
[Crystal] If you really wanted to.
[Emily] That time I found a dead raccoon on the side of the road and brought it in?
[Crystal] Put it on the map!
[Emily] Yeah! Streams are super important environments, and when I think of conservation, a lot of times streams are kind of neglected. You can put a border around a national park or a protected area, but the stream goes in and out, and there are opportunities for invasive species and pollution to enter. Are water beetles another one of those bioindicator species?
[Crystal] They are! They actually make a pretty good bioindicator because many species of Riffle Beetles, at least in North America, are sensitive to things like pollution and changes in pH. It’s nice to conserve them for their inherent value, like, “Oh, this is a species of water beetle that only lives in this stream or watershed.” But we can also use them as a tool to determine water quality.
[Emily] You were obviously excited about seeing all these water beetles in New Zealand. Was there anything else that you saw that was also really exciting?
[Crystal] Yeah! One of my favorite insects that I saw in New Zealand is called the Blephariceridae.
[Emily] What?
[Crystal, slowly] Blephariceridae.
[Emily] Sounds like someone sneezed, like (imitates sneezing).
[Crystal] These Blepharicerids are a type of fly and they’re unlike any fly you’ve ever seen before. Their larvae actually live in the coldest, cleanest, most riffly streams, right where you find Riffle Beetles.
[Emily] Oh!
[Crystal] What they do is they have little suction cups on their bodies and they suction cup to rocks in streams. When you’re collecting in the stream, you’re disturbing all the critters, and what happens is they get disturbed too, and then they float off and stick to your legs.
[Emily] The little suctions!
[Crystal] Yes, and you have little suction cups sticking to your legs. It’s really cute.
[Emily] It sounds like an adorable maggot.
[Crystal] It’s an adorable maggot.
[Emily] ‘Cause that’s what they are! They’re fly larvae.
[Crystal] That’s their new common name: The Adorable Maggots.
[Emily] The Adorable Maggots, I like that.
[Crystal] If I had to work on a fly, I would work on Blepharicerids.
[Emily] Yeah, I think I would too. I probably… There’s probably no chance I’ll do that, but I’ll just look at pictures of them.
[Crystal] Okay.
[Emily] Little videos.
Insects – Insects are a class of invertebrates within the arthropod phylum that have a chitinous exoskeleton, a three-part body, three pairs of jointed legs, compound eyes, and one pair of antennae. – Insects play a crucial role in pollination and are vital to maintaining the balance of ecosystems.
Riffle – A riffle is a shallow section of a stream or river with rapid current and surface agitation, often found between pools. – The presence of riffles in a river can increase oxygenation, which benefits aquatic life forms.
Beetles – Beetles are a group of insects that form the order Coleoptera, characterized by their hard forewings and diverse habitats. – Beetles are often used as bioindicators to assess the health of an ecosystem due to their sensitivity to environmental changes.
Aquatic – Aquatic refers to organisms or environments that are related to water, whether freshwater or marine. – Aquatic plants are essential for providing oxygen and habitat in freshwater ecosystems.
Adaptations – Adaptations are the changes in physical or behavioral traits that improve an organism’s ability to survive and reproduce in its environment. – The thick fur of polar bears is an adaptation that allows them to survive in cold Arctic climates.
Ecosystems – Ecosystems are communities of living organisms interacting with their physical environment, functioning as a unit. – Tropical rainforests are complex ecosystems that support a vast array of biodiversity.
Research – Research is the systematic investigation into and study of materials and sources to establish facts and reach new conclusions. – Recent research in marine biology has led to the discovery of new species in the deep ocean.
Conservation – Conservation is the protection and preservation of natural resources and environments to prevent exploitation, degradation, and destruction. – Conservation efforts are critical for protecting endangered species and maintaining biodiversity.
Populations – Populations refer to groups of individuals of the same species living in a particular geographic area, capable of interbreeding. – Studying the genetic diversity within populations can provide insights into their resilience to environmental changes.
Biodiversity – Biodiversity is the variety and variability of life forms within a given ecosystem, biome, or the entire Earth, encompassing diversity within species, between species, and of ecosystems. – High biodiversity in an ecosystem can enhance its productivity and stability.
