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💡🪲 EntoBytes: Scientists’ Warning on Climate Change and Insects

Welcome to the first installment of our ongoing series EntoBytes—a series of blog posts dedicated to unpacking and summarizing current academic papers on insects and the challenges they face in our changing world. In this series, we aim to shed light on the critical research being conducted and make it accessible to everyone who shares our concern for the fate of insect populations.
 

Over the past several decades, there has been mounting evidence of rapid declines in insect populations in both temperate and tropical ecosystems. While finding a single cause for these declines remains challenging, most researchers agree that human-caused climate change plays a significant role. However, it's important to distinguish between gradual warming and short-term extreme weather events, both of which impact insect populations.


Climate change doesn't just affect how insects behave; it disrupts ecosystems by pushing species to their temperature limits. Furthermore, it interacts with other human-related factors such as destroying natural habitats, pollution, use of pesticides, invasive species, and changes in how we use land, all of which contribute to insect declines. Climate change makes these problems even worse, making it harder for insects to adapt or find suitable places to live.


The paper titled "Scientists’ warning on climate change and insects" explores this complex relationship between climate change and insects, highlighting how it affects these small but essential creatures.


Key Takeaways

Before we delve into the specifics of this paper, let's outline some important points:

  • Insects, which are crucial for ecosystems, are declining rapidly, with climate change being a significant contributor to these declines.

  • When insects decline, it disrupts the balance of nature and how ecosystems work.

  • Understanding how climate change affects insects is vital when it comes to informed and targeted conservation efforts.

  • Saving insects from climate change requires action at both a global and individual level.

The Effects of Long-Term Climate Change on Insects

Climate change isn't always easy to notice, especially when it comes to its impact on insects. The gradual warming of our planet affects insects in subtle ways. You begin to see changes in insect populations and their habitats only when specific thresholds are crossed. This warming isn't uniform across the globe, hitting ecosystems at higher latitudes more rapidly.


One significant consequence of this warming is that it speeds up the metabolic rates among insects. While this can be beneficial up to a point, it can reduce their fertility and even cause death. Moreover, climate change can decrease the genetic diversity within insect populations, making them less adaptable. Essentially, climate change disrupts the balance of insect communities, potentially putting their survival at risk unless they can adapt to these changing conditions.


Effects on Where Insects Live

Insects are ectothermic, which means they rely on external temperatures, making climate a key factor in determining where insects make their homes. As temperatures rise due to climate change, some insects face challenges in adapting to these new conditions. To survive, some may try to move to cooler areas. However, the outcomes of these migration efforts can be diverse. Some species might find their habitats shrinking, while others might expand into new regions.


Interestingly, with warming temperatures, some insects may initially thrive. They could face fewer natural enemies and enjoy milder winters. But this advantage may not be sustainable, and it might disrupt ecosystems over time. In essence, climate change can be likened to rearranging the map of where insects live.


It's worth noting that specialist habitat species, which depend on very specific conditions, may find it harder to adapt compared to generalist species, which can tolerate a broader range of environments. This can lead to shifts in species dynamics, potentially causing some generalists to thrive to the point of becoming pests while specialists struggle to find suitable habitats.


For example, mosquitoes, which thrive in warm and humid conditions, may expand their ranges into new areas as temperatures rise due to climate change. This expansion can potentially increase the transmission of diseases like malaria or dengue fever, raising concerns in regions where these diseases are not currently prevalent.


Effects on When Insects Are Active

Climate change alters the timing of insect activities in nature. Here's how it happens:

  • Warmer temperatures can lead to more generations of insects in a year. While this might sound promising, these new generations could be smaller and weaker or have their lifecycle interrupted by the onset of winter.

  • Warmer winters can confuse the internal clocks of insects, causing them to wake up too early or skip hibernation, which can make survival difficult.

  • Heatwaves or warm spells in winter can disrupt insect behavior, potentially causing death.

  • Fewer snowy winters expose insects to harsh conditions and predators, which they would typically be shielded from. Essentially, climate change is not just changing where insects live; it's also changing when they are active.

Effects of Short-Term Climate Extremes

Short-term, unpredictable extreme weather events, such as heatwaves, droughts, heavy rainfall, and fires, have complex effects on insects. The outcome depends on various factors, like the type of insect and the surrounding environment. Here are some essential points:

  • Heatwaves and Extreme Temperatures: High heat can be detrimental to insect survival and reproduction, but its impact varies among different insect types.

  • Drought: Different types of droughts can disrupt the food supply for insects and increase competition among other creatures higher up in the food chain.

  • Heavy Rain and Floods: Insects may face displacement and even drowning during floods, which can indirectly affect soil conditions and plant growth.

  • Fire: Changes in the frequency and location of fires can disrupt insect communities and their interactions, sometimes leading to more insect pests.

These extreme events don't occur in isolation; they often interact with other environmental challenges, making the situation more complicated.


Insect Conservation under Climate Change

Insects are facing challenges, and it's not just because of climate change; there are other issues like losing their habitats, pollution, invasive species, and more. However, climate change exacerbates these problems, making it even harder to save insects. Here's why:

  • Combining Problems: Climate change makes other problems worse. If insects can move to safer areas due to climate change but cannot find suitable habitats due to human activities, they're in trouble.

  • Ecosystem Effects: When insects decline, it disrupts the entire ecosystem, potentially leading to declines in species that rely on them.

  • What We Can Do: To help insects, we need to ensure their habitats are safe from climate change. We also need to create routes for them to move to cooler areas.

Conserving insects isn't just about saving bugs; it's about making sure our world keeps working well.


Unanswered Questions

While this paper provides valuable insights into how climate change affects insects, there are still things we don't know. The paper talks about making habitats safe from climate change and helping insects move, but it doesn't detail how we should do this or who will cover the costs. These are important questions that require further exploration.


What You Can Do Right Now

Despite the challenges being substantial and not having all the answers, there are actions you can take to help insects:

  1. Citizen Science: You can join projects where regular people like you help scientists keep an eye on insect populations in your area. Your observations can provide valuable data.

  2. Create Insect-Friendly Habitats: You can make spaces in your garden or yard that are attractive to insects. Plant native flowers, provide water sources, and avoid using chemicals that harm them.

  3. Raise Awareness: Talk to your friends and family about why insects are essential and the threats they face. Sharing articles and supporting organizations dedicated to insect conservation can make a significant difference.

Conclusion

Insects play a vital role in our ecosystems, and their declining numbers due to climate change are cause for concern. As we've explained in this blog post, when insects struggle, it affects everything in nature. To help them, we need to work together on big things like global policies and small things like what we do in our own yards. Saving insects isn't just something for scientists; it's something we all need to care about. Keep an eye out for more posts where we talk about insects and what we can do to help them thrive.


Note: The original paper provides a deeper dive into each of these topics and offers further insights into this critical issue.


Source: Harvey, J.A., Tougeron, K., Gols, R., Heinen, R., Abarca, M., Abram, P.K., Basset, Y., Berg, M., Boggs, C., Brodeur, J., Cardoso, P., de Boer, J.G., De Snoo, G.R., Deacon, C., Dell, J.E., Desneux, N., Dillon, M.E., Duffy, G.A., Dyer, L.A. and Ellers, J. (2022). Scientists’ warning on climate change and insects. Ecological Monographs, 93(1). doi:https://doi.org/10.1002/ecm.1553.


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