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The Insectocalypse (Insect Apocalypse) May Be Closer To Reality Than Anyone Thinks, And It’s Mostly From Humans In The “Anthropocene Age”

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Discussion on the “insect apocalypse” study
 

Perhaps you have not heard of the coming “insect apocalypse.”  If so, it is something you should become familiar with.  Maybe instead you have noticed that, outside of mosquitos and aphids, insect populations have significantly reduced.  By a lot.  In Germany, the insect populations have fallen by 74% in 27 years.  The end of this article contains a helpful “What Can I Do” section, that discusses some of the simple changes you can make in your life to contribute to fixing this problem.

The mosquito population continues to grow despite annual mosquito spraying events across the nation, which may be having the unintended effect of growing their populations.  This is because all pesticide spraying kills the less-resilient non-target predator bugs, such as dragonflies and praying mantises, leaving mosquitos to reproduce without restriction.

The mosquito and agricultural spraying also harms other animals, including birds, frogs, and turtles, with certain types of pesticides being particularly deadly in this way.  ABC Conservancy has been working to get certain pesticides and herbicides, which cause direct harm to birds and small mammals, taken off the market.

Butterfly Sitting on a Leaf. Image Credit: Dmitrii Bardadim

Butterfly Sitting on a Leaf. Image Credit: Dmitrii Bardadim

The insect population reduction is mostly due to humans doing what they do: building houses, parking lots, shopping malls, etc, and also farming using stronger and stronger pesticides without concern to the damage being done to the non-target insects and animal populations.   Such insects would be the ones we want to have around, such as ladybugs, dragonflies, and praying mantises, which eat the “pest” insects, such as fruit flies, aphids, squash borers, and others.   Non-target animals include birds, squirrels, frogs, turtles, etc, which also eat pest insects as a large part of their diets.

These are not the only two human activities that are affecting insect populations, as the graphic below shows, but may be the most important. However, it has led to some scientists calling the present geological age the “Anthropocene Age,” i.e. the age of humans.

In January of 2021, there was a symposium of the National Academy of Sciences, in which 11 research papers were presented. The news that came out of this symposium was not positive. One study stated that due in large part to human interventions and encroachments, there is likely to be a loss of 40% of the world’s bug species.  This study has been debated, and was one of many that prompted the meeting of the National Academy of Sciences.

Death by a thousand cuts: Global threats to insect diversity. Stressors from 10 o’clock to 3 o’clock anchor to climate change. Featured insects: Regal fritillary (Speyeria idalia) (Center), rusty patched bumble bee (Bombus affinis) (Center Right), and Puritan tiger beetle (Cicindela puritana) (Bottom). Each is an imperiled insect that represents a larger lineage that includes many International Union for Conservation of Nature “red list” species (i.e., globally extinct, endangered, and threatened species). Illustration: Virginia R. Wagner (artist). Image Credit - The National Academy Of Sciences

Death by a thousand cuts: Global threats to insect diversity. Stressors from 10 o’clock to 3 o’clock anchor to climate change. Featured insects: Regal fritillary (Speyeria idalia) (Center), rusty patched bumble bee (Bombus affinis) (Center Right), and Puritan tiger beetle (Cicindela puritana) (Bottom). Each is an imperiled insect that represents a larger lineage that includes many International Union for Conservation of Nature “red list” species (i.e., globally extinct, endangered, and threatened species). Illustration: Virginia R. Wagner (artist). Image Credit – The National Academy Of Sciences

In addition, in several other studies, for example a study from Germany that examined the biomass of insects in a large number of protected areas, there was a 74% decrease in insect biomass over the last 27 years. This has been due to a number of factors, among them the destruction and draining of wetlands all over the country.

Wetlands provide crucial habitats for insects, as well as their predator species, keeping the populations of animals higher on the food chain doing well. Staten Island, in other words, is a microcosm of the world around us. As each wetland area is drained and built on, there are fewer and fewer habitats for insects, and for the birds and other animals that need to live as well. There are rodents, frogs, and other small animals that rely on both wetlands and on insects for their survival.

Fragile communities challenged by global change. (A) Cloud forest, Monteverde, Costa Rica: Threatened by rising global temperatures that lead to greater numbers of cloud-free days and extended droughts. Image credit: Janet Ellis (photographer). (B) Silversword (Argyroxiphium sandwicense subsp. macrocephalum) grove, Haleakala National Park, Hawaii: Threatened by diminished water availability and related climate changes. Image credit: Flickr/Forest and Kim Starr, licensed under CC BY 3.0. (C) Tallgrass prairie, Markham, Illinois: Threatened by agriculture and insularization. Image credit: Abbie Schrotenboer (Trinity Christian College, Palos Heights, IL). (D) Community composed of endemic Miconia robinsoniana (sienna-colored shrubs), ferns, and sedges, Santa Cruz Island, Galápagos Islands, Ecuador: Threatened by many exotic plants; the yellow-green shrub is red quinine tree (Cinchona pubescens), an invasive on many Pacific islands. Image credit: Heinke Jäger (Charles Darwin Foundation, Galápagos, Ecuador). Image Credit - The National Academy of Sciences

Fragile communities challenged by global change. (A) Cloud forest, Monteverde, Costa Rica: Threatened by rising global temperatures that lead to greater numbers of cloud-free days and extended droughts. Image credit: Janet Ellis (photographer). (B) Silversword (Argyroxiphium sandwicense subsp. macrocephalum) grove, Haleakala National Park, Hawaii: Threatened by diminished water availability and related climate changes. Image credit: Flickr/Forest and Kim Starr, licensed under CC BY 3.0. (C) Tallgrass prairie, Markham, Illinois: Threatened by agriculture and insularization. Image credit: Abbie Schrotenboer (Trinity Christian College, Palos Heights, IL). (D) Community composed of endemic Miconia robinsoniana (sienna-colored shrubs), ferns, and sedges, Santa Cruz Island, Galápagos Islands, Ecuador: Threatened by many exotic plants; the yellow-green shrub is red quinine tree (Cinchona pubescens), an invasive on many Pacific islands. Image credit: Heinke Jäger (Charles Darwin Foundation, Galápagos, Ecuador). Image Credit – The National Academy of Sciences

Another great threat to insect populations is the invention and widespread use of pesticides and insecticides of all types. All insecticides kill non-target insect populations. It is unavoidable. Thus, the lanternfly is a problem now because the praying mantids and other predatory insects have likely been killed off in large part by the pesticides. Even bees are not immune to the pesticides humans use. Their populations were in peril just a few years ago.

There were other factors that were speculated upon in these proceedings, but the bottom line if that is something is not done, there is a high chance that 40% of the insect species and populations worldwide will be gone in the next decade.  By gone, the meaning is extinct, never to be seen again.

Roundtable Discussion on the possible extinction of insects
This is not a good thing, as the “food chain,” which we all learned about growing up, is very real.  If the insects all die, then the other creatures in a progression up the food chain, will also die, and eventually, everything will be extinct, including humans.  Without insects, food crops will not be pollinated, and waste material will take a lot longer to break down without the bugs that do this work.  See below for things you can do.

Details from the scientific studies are presented below.

From the Proceeding of the National Academy of Sciences paper:

Initial systematic search results from EntoGEM (https://entogem.github.io/): (A) Retrieved studies by order. (B) Locations of retrieved dipteran studies illustrating broad geographic scope, especially in tropical areas, which have been underrepresented in prior syntheses of insect decline. (C) Example dipteran data sets identified in initial screening. (Upper) Mosquitoes, trapped at two sites, Maryland, United States (83); (Lower) black flies, Iceland (53). Image Credit - The National Academy of Sciences

Initial systematic search results from EntoGEM (https://entogem.github.io/): (A) Retrieved studies by order. (B) Locations of retrieved dipteran studies illustrating broad geographic scope, especially in tropical areas, which have been underrepresented in prior syntheses of insect decline. (C) Example dipteran data sets identified in initial screening. (Upper) Mosquitoes, trapped at two sites, Maryland, United States (83); (Lower) black flies, Iceland (53). Image Credit – The National Academy of Sciences

Loss of Abundant Species.


Although conservation efforts have historically focused attention on protecting rare, charismatic, and endangered species, the “insect apocalypse” presents a different challenge. In addition to the loss of rare taxa, many reports mention sweeping declines of formerly abundant insects [e.g., Warren et al. (29)], raising concerns about ecosystem function.

Insects comprise much of the animal biomass linking primary producers and consumers, as well as higher-level consumers in freshwater and terrestrial food webs. Situated at the nexus of many trophic links, many numerically abundant insects provide ecosystem services upon which humans depend: the pollination of fruits, vegetables, and nuts; the biological control of weeds, agricultural pests, disease vectors, and other organisms that compete with humans or threaten their quality of life; and the macrodecomposition of leaves and wood and removal of dung and carrion, which contribute to nutrient cycling, soil formation, and water purification. Clearly, severe insect declines can potentially have global ecological and economic consequences.

While there is much variation—across time, space, and taxonomic lineage—reported rates of annual decline in abundance frequently fall around 1 to 2% (e.g., refs. 12, 13, 17, 18, 30, and 31). Because these rates, based on abundance, are likely reflective of those for insect biomass [see Hallmann et al. (26)], there is ample cause for concern (i.e., that some terrestrial regions are experiencing faunal subtractions of 10% or more of their insects per decade). To what extent such declines translate into shifts or losses of ecosystem function has yet to be assessed.”

Insect diversity. (A) Pennants (Libellulidae): Dragonflies are among the most familiar and popular insects, renowned for their appetite for mosquitoes. (B) Robber flies (Asilidae): These sit-and-wait predators often perch on twigs that allow them to ambush passing prey; accordingly they have enormous eyes. (C) Katydids (Tettigoniidae): This individual is one molt away from having wings long enough to fly (that also will be used to produce its mating song). (D) Bumble bees (Apidae): Important pollinators in temperate, montane, and subpolar regions especially of heaths (including blueberries and cranberries). (E) Wasp moths (Erebidae): Compelling mimics that are hyperdiverse in tropical forests; many are toxic and unpalatable to vertebrates. (F) Leafhoppers (Cicadellidae): A diverse family with 20,000 species, some of which are important plant pests; many communicate with each other by vibrating their messages through a shared substrate. (G) Cuckoo wasps (Chrysididae): Striking armored wasps that enter nests of other bees—virtually impermeable to stings—to lay their eggs in brood cells of a host bee. (H) Tortoise beetles (Chrysomelidae): Mostly tropical plant feeders; this larva is advertising its unpalatability with bold yellow, black, and cream colors. (I) Mantises (Mantidae): These voracious sit-and-wait predators have acute eyesight and rapid predatory strikes; prey are instantly impaled and held in place by the sharp foreleg spines. (J) Emerald moths (Geometridae): Diverse family of primarily forest insects; their caterpillars include the familiar inchworms. (K) Tiger beetles (Cicindelidae): “Tigers” use acute vision and long legs to run down their prey, which are dispatched with their huge jaws. (L) Planthoppers (Fulgoridae): Tropical family of splendid insects, whose snouts are curiously varied and, in a few lineages, account for half the body mass. Images credit: Michael Thomas (photographer).

Insect diversity. (A) Pennants (Libellulidae): Dragonflies are among the most familiar and popular insects, renowned for their appetite for mosquitoes. (B) Robber flies (Asilidae): These sit-and-wait predators often perch on twigs that allow them to ambush passing prey; accordingly they have enormous eyes. (C) Katydids (Tettigoniidae): This individual is one molt away from having wings long enough to fly (that also will be used to produce its mating song). (D) Bumble bees (Apidae): Important pollinators in temperate, montane, and subpolar regions especially of heaths (including blueberries and cranberries). (E) Wasp moths (Erebidae): Compelling mimics that are hyperdiverse in tropical forests; many are toxic and unpalatable to vertebrates. (F) Leafhoppers (Cicadellidae): A diverse family with 20,000 species, some of which are important plant pests; many communicate with each other by vibrating their messages through a shared substrate. (G) Cuckoo wasps (Chrysididae): Striking armored wasps that enter nests of other bees—virtually impermeable to stings—to lay their eggs in brood cells of a host bee. (H) Tortoise beetles (Chrysomelidae): Mostly tropical plant feeders; this larva is advertising its unpalatability with bold yellow, black, and cream colors. (I) Mantises (Mantidae): These voracious sit-and-wait predators have acute eyesight and rapid predatory strikes; prey are instantly impaled and held in place by the sharp foreleg spines. (J) Emerald moths (Geometridae): Diverse family of primarily forest insects; their caterpillars include the familiar inchworms. (K) Tiger beetles (Cicindelidae): “Tigers” use acute vision and long legs to run down their prey, which are dispatched with their huge jaws. (L) Planthoppers (Fulgoridae): Tropical family of splendid insects, whose snouts are curiously varied and, in a few lineages, account for half the body mass. Images credit: Michael Thomas (photographer), The National Academy of Sciences

From the German Paper:

“Global declines in insects have sparked wide interest among scientists, politicians, and the general public. Loss of insect diversity and abundance is expected to provoke cascading effects on food webs and to jeopardize ecosystem services. Our understanding of the extent and underlying causes of this decline is based on the abundance of single species or taxo-nomic groups only, rather than changes in insect biomass which is more relevant for ecological functioning. Here, we used a standardized protocol to measure total insect biomass using Malaise traps, deployed over 27 years in 63 nature protection areas in Germany (96 unique location-year combinations) to infer on the status and trend of local entomofauna. Our analysis estimates a seasonal decline of 76%, and midsummer decline of 82% in flying insect biomass over the 27 years of study. We show that this decline is apparent regardless of habitat type, while changes in weather, land use, and habitat characteristics cannot explain this overall decline. This yet unrecognized loss of insect biomass must be taken into account in evaluating declines in abundance of species depending on insects as a food source, and ecosystem functioning in the European landscape.”

What Can I Do In My Own Life To Help Mitigate The Insectocalypse?

This is a very important question, and if every person started asking this question, the issues we are facing could be solved.  So here are just a few things that you can do, that are mostly very easy to do, that can potentially mitigate this issue.

Backyard Worm Composting. Image Credit: Patricia Maine Degrave

1) Start a home worm composting bin. This is inexpensive and easy to do, and will create in your own backyard an ecosystem of worms, insects, and other creatures. It will have the added benefit of increasing the local insect population. Read Worms Eat My Garbage by Mary Appelhoff (the updated version of a classic from the 1980s) and build or buy your own worm bin. Not only will you divert your household garbage from the landfill, reducing the pollution required to process garbage, but you will help the bugs as well.  It is also easy and fun, especially for kids, to have a worm bin, and it is a great conversation starter if it’s on your patio or porch.  There are some bins that take up about 18″ square of space, with the bins going up in height.  It is not expensive to start, and once you get the system started, there is very little additional cost involved.

2) Cover the plants in your garden, if you have one, when your city performs its aerial spraying for mosquitos. Covering your garden will protect non-target insects from the spray. All of the insecticides used around the country, including in agriculture, damage non-target insect populations.

3) Stop using pesticides on your lawn and in your garden. Adopt organic gardening methods, using predator bugs such as ladybugs and praying mantids to control pest insects. You can also spray your plants with soap and water to make them slippery to aphids, or adopt other natural pest control methods. Stop using beetle traps to trap beetles, as the beetle populations are also declining, and they also provide valuable services to farmers and home gardeners (such as breaking down waste).

4) Grow your own herbs, fruit trees, and wildflowers. This will allow you to contribute less to insecticide intensive agricultural farming.

5) Eat organically. Organic farming methods renew the soil and increase insect populations, by using predatory insects and other safer methods than commercial agriculture uses to control pests.

Perhaps it would be a good idea if humans started taking into account how their actions affect other residents of Earth, so that the Anthropocene (Human Period on Earth) will be a benefit to the planet rather than the reason why the planet goes extinct.

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