Continued Insect Decline Could Be Harmful To Earth
July 13, 2018 at 11:39 a.m.
By Max [email protected]
Not too many years back, smeared tiny wings, legs and antennas made vision difficult during midsummer drives. Nowadays, a drive through northern New York, for example, yielded barely a blemish.
Many scientists pondered over the sudden change. Just recently a study conducted last fall by dozens of amateur entomologists documented a 76 percent decline in the seasonal biomass of flying insects trapped in a number of locations in Germany from 1989 through 2016. Losses in midsummer, when insects are most numerous, exceeded an alarming 80 percent. The method employed was to gather the samples and then weigh them (biomass). (The research captured all flying insects, including wasps and flies, which are rarely studied, making it a much stronger indicator of decline.)
Measuring the weight of the insects saved the scientists from the laborious process of identifying individual species but still allowed the scientists to assess changes in insect abundance over time. The researchers concluded that all flying insects — not just vulnerable species — had rapidly deteriorated in the span of just three decades.
Losing such a large amount of biomass negatively affects a significant portion up the food chain: birds, bats and amphibians. Through their feeding activities, plant-feeding insects (about 25 percent of the species on the planet) convert plant biomass to animal biomass. In turn, these creatures serve as the primary source of food for other insects and for many birds, fish and mammals that are, in turn, food for yet still more animals. In addition to their value in providing a food source, insects provide a number of other benefits.
According to Whitney Cranshaw and Richard Redak in their book “Bugs Rule,” insects perform the following:
• They are essential to the pollination of most flowering plants, and many of the flowering plants are the result of co-evolution with their insect pollinators. The tremendous variety of flower types reflects different ways that plants have evolved to more efficiently attract pollinators. In response, new species of insects have arisen to better exploit these sources of nectar and pollen. In addition to native plants, essentially all fruits, vegetables and many of the forage crops (e.g., clover, alfalfa) are dependent on insects to produce seed.
• Insects also help to recycle plant and animal matter. Many insects develop by feeding on dead plant matter, dead animal matter or animal dung. In this role, they function as macrodecomposers that are in the first line “clean-up crew” essential to the recovery and recycling of nutrients. Through insect feeding, these substances are broken down into much smaller particles and partially digested, which greatly accelerates the process of decay that frees the nutrients to nourish later generations of plants. In the absence of insects, nutrient-recycling systems break down and organic matter accumulates.
• Insects are of major value in soil formation and mixing. The great majority of terrestrial arthropods live within the soil. These animals help to turn the soil and incorporate organic matter and nutrients. The impacts of these activities can be very dramatic, with some of the social insects (e.g., the ants and termites) moving and mixing tremendous amounts of soil as they tunnel. These processes are critical to soil formation and the maintenance of soil fertility. Without these insects, plant growth would be reduced and restricted.
Certainly we can ill afford to lose insects. They are integral part of life on Earth and, according to a recent article in The Guardian, without them the world is "on course for ecological Armageddon." The cause of the decline is still unclear, although the destruction of wild areas and the widespread use of pesticides are the most likely factors, and climate change may play a role. One thing is certain: We need new crops of professionals trained in field biology and ecology to focus on monitoring the changing values and migration habits of insects.
We do know that current data suggest an overall pattern of decline in insect varieties and numbers. For example, populations of European grassland butterflies are estimated to have declined by 50 percent between 1990 and 2011. Data for other species like bees and moths suggest the same trend.
In the United States the ecosystem services provided by wild insects have been estimated at $57 billion annually. Clearly, preserving insect abundance and diversity should constitute a prime conservation priority. According to the eminent biologist Edward O. Wilson, "If all mankind were to disappear, the world would regenerate back to the rich state of equilibrium that existed ten thousand years ago. If insects were to vanish, the environment would collapse into chaos."
Max Sherman is a medical writer and pharmacist retired from the medical device industry. He has taught college courses on regulatory and compliance issues at Ivy Tech, Grace College and Butler University. Sherman has an unquenchable thirst for knowledge on all levels. Eclectic Science, the title of his column, will touch on famed doctors and scientists, human senses, aging, various diseases, and little-known facts about many species, including their contributions to scientific research. He can be reached by email at [email protected].
Not too many years back, smeared tiny wings, legs and antennas made vision difficult during midsummer drives. Nowadays, a drive through northern New York, for example, yielded barely a blemish.
Many scientists pondered over the sudden change. Just recently a study conducted last fall by dozens of amateur entomologists documented a 76 percent decline in the seasonal biomass of flying insects trapped in a number of locations in Germany from 1989 through 2016. Losses in midsummer, when insects are most numerous, exceeded an alarming 80 percent. The method employed was to gather the samples and then weigh them (biomass). (The research captured all flying insects, including wasps and flies, which are rarely studied, making it a much stronger indicator of decline.)
Measuring the weight of the insects saved the scientists from the laborious process of identifying individual species but still allowed the scientists to assess changes in insect abundance over time. The researchers concluded that all flying insects — not just vulnerable species — had rapidly deteriorated in the span of just three decades.
Losing such a large amount of biomass negatively affects a significant portion up the food chain: birds, bats and amphibians. Through their feeding activities, plant-feeding insects (about 25 percent of the species on the planet) convert plant biomass to animal biomass. In turn, these creatures serve as the primary source of food for other insects and for many birds, fish and mammals that are, in turn, food for yet still more animals. In addition to their value in providing a food source, insects provide a number of other benefits.
According to Whitney Cranshaw and Richard Redak in their book “Bugs Rule,” insects perform the following:
• They are essential to the pollination of most flowering plants, and many of the flowering plants are the result of co-evolution with their insect pollinators. The tremendous variety of flower types reflects different ways that plants have evolved to more efficiently attract pollinators. In response, new species of insects have arisen to better exploit these sources of nectar and pollen. In addition to native plants, essentially all fruits, vegetables and many of the forage crops (e.g., clover, alfalfa) are dependent on insects to produce seed.
• Insects also help to recycle plant and animal matter. Many insects develop by feeding on dead plant matter, dead animal matter or animal dung. In this role, they function as macrodecomposers that are in the first line “clean-up crew” essential to the recovery and recycling of nutrients. Through insect feeding, these substances are broken down into much smaller particles and partially digested, which greatly accelerates the process of decay that frees the nutrients to nourish later generations of plants. In the absence of insects, nutrient-recycling systems break down and organic matter accumulates.
• Insects are of major value in soil formation and mixing. The great majority of terrestrial arthropods live within the soil. These animals help to turn the soil and incorporate organic matter and nutrients. The impacts of these activities can be very dramatic, with some of the social insects (e.g., the ants and termites) moving and mixing tremendous amounts of soil as they tunnel. These processes are critical to soil formation and the maintenance of soil fertility. Without these insects, plant growth would be reduced and restricted.
Certainly we can ill afford to lose insects. They are integral part of life on Earth and, according to a recent article in The Guardian, without them the world is "on course for ecological Armageddon." The cause of the decline is still unclear, although the destruction of wild areas and the widespread use of pesticides are the most likely factors, and climate change may play a role. One thing is certain: We need new crops of professionals trained in field biology and ecology to focus on monitoring the changing values and migration habits of insects.
We do know that current data suggest an overall pattern of decline in insect varieties and numbers. For example, populations of European grassland butterflies are estimated to have declined by 50 percent between 1990 and 2011. Data for other species like bees and moths suggest the same trend.
In the United States the ecosystem services provided by wild insects have been estimated at $57 billion annually. Clearly, preserving insect abundance and diversity should constitute a prime conservation priority. According to the eminent biologist Edward O. Wilson, "If all mankind were to disappear, the world would regenerate back to the rich state of equilibrium that existed ten thousand years ago. If insects were to vanish, the environment would collapse into chaos."
Max Sherman is a medical writer and pharmacist retired from the medical device industry. He has taught college courses on regulatory and compliance issues at Ivy Tech, Grace College and Butler University. Sherman has an unquenchable thirst for knowledge on all levels. Eclectic Science, the title of his column, will touch on famed doctors and scientists, human senses, aging, various diseases, and little-known facts about many species, including their contributions to scientific research. He can be reached by email at [email protected].
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