You know, we talk a lot about insect pests and how to control them on the Bug Lessons blog. However, insects play a very important role in various ecosystems around the world. In this blog, we want to focus on the traits that make insects unique, valuable, and critical to a happy, healthy earth! Read on to find out why bugs are not just foes—in fact, most of them are friends.
A Few Fun Facts
Insects are all over the place. We mean that literally; insects are the most abundant animals on the planet. Over 1.5 million species of insects are currently described, and there are probably many more that we haven’t even found yet! There are insects in almost every habitat within every biome and they come in all sorts of colors, shapes, sizes, and exhibit many amazing and unique behaviors. Although we tend to focus on ways to get rid of insects that cause damage, today we are going to go over five reasons why we actually need insects to help sustain us and our planet.
1. Insects form the base of the food web. Insects are the largest food source for animals that eat meat—both on land and in freshwater. Because there are an estimated one quintillion (1,000,000,000,000,000,000) insects on earth at any one time, they outweigh and outnumber all other animals combined. This means that insects are the biggest link between plants and animals in food webs.
2. Insects are predators, too, and they keep many harmful organisms in check. Although not technically insects, spiders eat anywhere from 400-800 million tons of insect pests annually. Wasps are voracious predators that can consume up to two pounds of pest insects within a 2,000 square foot garden. Called “biological control”, many insects serve as natural enemies of pest insects and we use these insects to control pests in an array of settings (e.g., releasing lady beetles to control aphids in greenhouse settings).
Insects are, on occasion, their own worst enemies. A lady beetle can eat as many as 50 aphids in a day. Many insect predators play an important role as natural enemies (organisms that reduce the population sizes of other organisms) that control pest insects (insects that can cause damage within ecosystems). (Image Credit: John Flannery, Image Source: Wikimedia Commons)
3. You’ve probably already heard the buzz (no pun intended) associated with insect pollinators such as honey bees. Insects play a nearly incalculable role in the pollination of plants. Approximately 75% of plants require an animal pollinator. There are over 200,000 animal pollinators, and the majority of these are insects. Various agency efforts to protect insect pollinators are crucial, because it is estimated that insects provide more than 24 billion dollars to the US economy through their pollination services.
4. Insects also provide waste services. Many insects are scavengers or decomposers that break down dead or dying materials to form new life. They clean up dung, dead plants, dead animals, and recycle wood—and they turn these waste materials into nutrient rich sources of organic matter for other organisms. Humans may be struggling to understand recycling, but insects have it down pat!
5. Did you know that some insects and/or insect byproducts can serve as medicine? Bee venom is a powerful compound used to treat rheumatoid arthritis (RA), gout, osteoarthritis, chronic fatigue system, and a number of other ailments. As weird as it may sound, maggots are helpful in cleaning up infected wounds. Maggots eat the infected tissue, leaving healthy tissue behind. This is a strategy that has been utilized since the Mayans. Scientists are still researching other uses for insects as medicine, too, so stay tuned!
Insects have been around since well before the dinosaurs. They were the first flying creatures on earth and have managed to survive multiple mass extinctions. Insects do not need humans, but humans certainly need insects to survive and thrive. Nonetheless, insect diversity and abundance are declining. It is up to all of us to be aware of threats to beneficial insects, such as monoculture, forestry practices, loss of habitat, pesticide use, climate change, and invasive species. In addition to awareness, we need to take action against these threats, too. A loss of insects could, quite literally, threaten our existence. There will always be a need to control damaging pest arthropods, but in our haste to kill or hate insects, let’s be sure to take a moment to appreciate just how much these little critters do for us. For a bit more information, check out this article and helpful video from The Florida Museum.
Who knew that a species of fungi that consumes insects (mainly ants) would be such a hot topic in 2023? Unexpectedly, “The Last of Us”, a post-apocalyptic zombie show based on a popular video game, had everyone talking about Ophiocordyceps unilateralis—zombie-ant fungus. This week, we want to get the facts straight while season two continues development and we reminisce about a brilliant season one! What is an entomopathogenic fungus? Why can’t a species of Ophiocordyceps, or something similar, become a zombie-human fungus? Finally, how does this species manipulate its host in such a frightening way? Read on to find out the less dramatic, but equally fascinating, story about these mind mushing monsters.
Could We Be Infected?
First things first—quite a few news outlets have written about the feasibility of a Cordyceps outbreak in humans. Vox, Futurism, Sky News, The Washington Post, Vulture, and many more. We’re not here to reinvent the wheel, so if you want to read about the video game-inspired story, the likelihood of Cordyceps species infecting humans, or zombie-themed content… give one of those links a try. It is probably already obvious that the spread of fungal species in a way that HBO or a video game portrays is incredibly improbable. That does not mean that we should not be prepared for pandemics, however (COVID-19 was a great example of that fact). But as fun as it is to think about the feasibility of the zombie apocalypse, we are a bug blog, so we’re going to focus on Ophiocordyceps and the extremely creepy way they manipulate insects to do their bidding.
What Are Entomopathogenic Fungi?
Simply put, entomopathogenic fungi are fungi that kill or seriously impair insects. They span the entire fungal kingdom and there are multiple ways that these organisms attack and kill insects. Many of the strategies are nightmare-inducing. For instance, one species that attacks cicadas plugs their butts, and scatters spores from the sky as they fly around. “The Last of Us” chronicles the zombie-ant fungus, which controls an ant’s muscles until the ant dies and a fruiting body explodes from its’ head. Some of these pathogens can attack a wide array of insects, and some are very host specific. Some broad-spectrum insect killers, like Beauvaria bassiana have been turned into pesticides. Ophiocordyceps, the pathogen we’re talking about in this blog, is host-specific. Each species of Ophiocordyceps attacks a specific insect species.
Ophiocordyceps, the group of fungi that inspired the latest zombie phenomenon, contain over 100 species that attack insects like moths, butterflies, and beetles. At least 35 species within the group are capable of performing some sort of “mind control” on the host. According to experts, there may be as many as 600 species in this group waiting to be described. Each species is matched to its specific insect host. For example, Ophiocordyceps odonatae attacks dragonflies (Order: Odonata).
How Do They Work?
Let’s focus on Ophiocordyceps unilateralis for this part, the zombie-ant fungus. The life cycle of this fungal species can be described in four parts: infection, death grip, stalk growth, and dispersal. Spores (the infectious part) of this species targets a type of carpenter ant (Camponotus leonardi). Spores attach to the cuticle (skin) of a passing ant and begin to secrete digestive enzymes that start eating away at the ant’s body so that they can enter the host. Then, yeast-like growth begins inside. This eventually causes the ant to fall from the tree canopy to a lower height that is more optimal for fungal growth. To control movement, the fungus controls ant muscles (so, not technically the ant’s mind like a true ‘zombie’) and prompts the ant to crawl up to a leaf. Then, the ant bites the leaf with a death-grip that keeps it from falling. Once the ant dies, a stalk grows from the base of the neck and exits the head. Spores release, a new ant is infected, and the cycle begins again. Interestingly, healthy ants in a colony can tell when a fellow worker is infected and they will carry the diseased far away to protect the whole.
Mycologists (folks that study fungi) agree that the chance of an Ophiocordyceps species transition from insects to humans is non-existent. These scary little pathogens are extremely host-specific—they simply don’t have the machinery to survive in people and the leaps that would need to occur for them to adapt to us are just too great. These pathogens, although frightening to watch, keep insect numbers in check and contribute to ecosystem balance. Unfortunately, their only function, maintain natural order, is much less ‘sexy’ than the chaos zombie thrillers want you to think that they can cause. So, for now, rest easy. Bug-killing fungi should only haunt the dreams of insects!
Last month on the Bug Lessons blog, we introduced the concept of integrated pest management (IPM)—a science-based strategy used to control pests in all sorts of environments. This month in our IPM series, we’re taking a closer look at the components of a successful IPM plan. Read on to learn more about the most important steps you can take to control pests in a responsible yet effective way no matter where you are!
Important Components to an IPM Plan
Pest Identification: Prior to engaging in any sort of pest management strategy, it is crucial that the pest in question is properly identified. If you cannot identify the organism causing problems, employ a local extension agent or specialist for assistance. This is arguably the most important step in any IPM program. Treating for the wrong pest can lead to program failure because IPM hinges on understanding pest biology and behavior.
Setting Guidelines to Determine When to Use What Action: Before action is taken, an idea of how much damage or how many pests can be tolerated should be established. This prevents unnecessary labor and pesticide application. For instance, even one rodent in a commercial kitchen is probably unacceptable whereas a homeowner might be willing to deal with one or more rodents in and around their home. Again, the threshold for action should be established prior to engaging in pest control
Getting the correct insect identification is crucial for effective pest management. Diagnostic entomologists and taxonomists specialize in the identification and classification of insects. If you need assistance identifying a specimen, contact a local extension entomologist. (Image Credit: Chris Martin, Image Source: Getty Images)
Monitoring and Assessing Pest Numbers and/or Damage: Monitoring for pests is the only way to assess whether or not the established damage/pest threshold has been reached. Monitoring allows for the qualitative assessment of what pests are present and the damage they are causing. This step will also help you decide what management methods to employ, as many management strategies are based on pest density (e.g., how much bait to apply for a cockroach infestation). The specific tools used for monitoring are pest-dependent, but devices such as sticky traps are often used. Record-keeping is an important part of monitoring so that you can understand when pests are most active and, thus, the most critical time for action.
Preventing Future Pest Problems: Many pest problems are more effectively solved with preventative versus reactive strategies. Sanitation, pest-proofing, reducing hospitable pest environments, etc. should be considered so that the problem does not return. Prevention should really be the first tool in pest management, because it is usually environmentally-friendly, low cost, and effective.
Using All Control Tactics Available and Reasonable: Ideally, a successful IPM program will utilize a combination of control strategies that synergize one another (i.e., they work better together than separately). It is a common misconception that chemical (pesticide) use is not permitted in an IPM program. Pesticides can absolutely be used in an IPM program, but alternatives should be considered in addition. When pesticides are used, they should be used with consideration for the environment. Some strategies outside of chemical pest control include:
Assessing and Adapting the IPM Program: Once action has been taken and all control strategies have been given ample time to work—progress should be evaluated. Were the established thresholds and guidelines from step two met? Are pests still causing excessive damage? If the IPM plan has failed, troubleshooting and additional control measures should be employed.
Integrated pest management is a great way to control pests while being conscious about environmental impact and preserving the efficacy of chemical pesticides. It is important to remember that your first IPM plan may not go…to plan! These steps can be rearranged as necessary depending on where you are in the pest control process. Steps may also be done in tandem (e.g., preventing pest entry while monitoring pest activity). This roadmap is just a guide. If you need more help designing an IPM plan, feel free to contact us at Bug Lessons, or, contact your local extension specialist.
It was a rare moment for bug lovers, where media outlets all over the US were talking about insects. In case you missed it, what was with all the metaphorical buzz? Well, TL;DR: a rare Jurassic-era insect was quietly discovered at a Wal-mart in Fayetteville, Arkansas over ten years ago. This went unnoticed until 2020, and, even stranger, no one really talked about it until 2023. So, if you STILL somehow haven’t heard the news, read on to read the bizarre story of a diagnostician’s rare and exciting discovery that truly is one for the history books!
Jurassic Park…. ish
Even experienced diagnosticians and entomologists are known to make an oversight or two! Dr. Michael Skvarla, who is the director of Penn State University’s Insect ID Lab, snagged an (unbeknownst to him) incredibly rare specimen back in 2012 while doing routine shopping at his local Walmart. He recounted to many news outlets that he was walking into the store to simply grab some milk when on the way inside, he saw a huge insect that caught his eye.
As entomologists are apt to do, he performed a quick collection on the spot and gently plucked the sizeable bug from its resting place. He described spending the rest of his shopping trip with the specimen in hand. After getting it home, he mounted it, and told reporters that he forgot to do anything with it until 2020. Thinking it was an antlion, he was describing the Jurassic-era specimen to students in his online course when, in real time, he realized he had misidentified the insect. Even more notably, he and his students all got to come to the same conclusion together while they watched the situation unfold online during a lab course.
A Specimen From Another Era
Rather than an antlion, according to molecular tests, the specimen was actually a giant lacewing species that predates the dinosaurs. These insects were once common here in the US (even after the extinction of dinosaurs), but they basically disappeared by 1950. No one really knows why, but some cite light pollution and urbanization as probable causes. The discovery is a very rare find given that these insects have been absent from the US for decades. In addition, this recent sighting was the first report of this species in the state of Arkansas, ever. The next closest sighting of another one of these creatures is reported to be over 1,200 miles away. That makes this finding this lacewing in Arkansas rare enough, but even more spectacular—it is the first sighting from the whole of Eastern North America in over 50 years.
How did this rare find end up on the side of a Walmart? Perhaps it was attracted to the lights and flew from a more wooded area, “like a moth to a flame”, if we’re being cliché? Or, maybe it hitchhiked in from a western Walmart truck? Either way, researchers are emphasizing this moment as a time to reflect on and further study the biodiversity found in the Ozarks, an area (clearly) teeming with life, but understudied compared to the Southern Appalachian Mountain region.
The specimen can now be found in the Frost Entomological Museum at Penn State University. A publication also resulted from the find and can be accessed using this link. Insects rarely make headlines, but this is a great example of the wonderment that can ensue when insects are given a just a bit of the limelight!
This week’s post was developed from a press release sent out by Penn State that can be found here: https://www.psu.edu/news/research/story/rare-insect-found-arkansas-walmart-sets-historic-record-prompts-mystery/
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