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Do bugs bug humans more than humans bug bugs?

For most humans on our planet, bugs are often overlooked and sometimes swatted away. However, we need to learn to coexist, because insects and spiders, or arthropods, are pivotal to the ecosystems humans depend on.

These creatures, characterized by their hard exoskeletons and jointed legs, constitute a staggering 84% of known animal species. Their role in our urban landscapes is more critical than many realize.

How humans and bugs interact

Recent research has shed light on how human activities influence insect biodiversity. The study, a collaboration between USC Dornsife College and the Natural History Museum of Los Angeles County’s BioSCAN project, focuses on nonbiological factors like temperature fluctuations and proximity to the ocean and their impact on arthropods in urban settings.

The BioSCAN project, bolstered by around 80 volunteers, involved setting up Malaise traps across Los Angeles to collect various flying arthropods, including bees, flies, and moths.

Spiders were also hand-collected in these areas. This community science initiative played a vital role in understanding the arthropod diversity in the bustling metropolis.

Insects have diverse responses to humans

Melissa Guzman, the study’s lead researcher and Assistant Professor of Biological Sciences and Quantitative and Computational Biology at USC Dornsife, highlighted the unexpected diversity in bug responses to humans in urban environmental factors.

These included land covered by asphalt or concrete, and daily temperature changes. Contrary to initial thoughts, these factors had varied impacts across different arthropod groups.

For instance, the prevalence of concrete and asphalt surfaces increased the diversity of fruit flies but decreased that of crane flies.

“In general, we thought most arthropods would be similarly affected by environmental factors such as land covered by asphalt or concrete and temperature fluctuations over a 24-hour cycle,” said Guzman.

“Instead, we found an unexpectedly large range of responses to factors such as these, both within closely related groups and across different groups.”

Spiders, interestingly, thrived in these hard-covered areas. Temperature variations also significantly influenced the diversity of specific insect families.

The researchers theorize that summertime’s higher temperatures cause the drying up of plants that aphids feed on, thus depleting a primary food source for many hover flies.

Additionally, they observe that non-native honeybees increase their foraging in warmer temperatures, directly competing for the same food resources as some hover flies.

Urban planning and biodiversity

These insights are crucial for urban planners and developers. Understanding the link between species diversity and factors like land value and temperature can guide adjustments in urban projects to enhance biodiversity.

This, in turn, brings numerous benefits, including improved air quality, flood risk reduction, and better mental health for city dwellers.

Brian Brown, entomology curator at the Natural History Museum, revealed an exciting outcome. They discovered many arthropod species previously unknown in the L.A. area, including about 50 new to science.

“Based on that, we have a new understanding of what the biodiversity of Los Angeles is like in terms of insects,” he said. “So instead of the 3,500 or 4,000 species that we previously thought, now we’re thinking there are close to 20,000 species living here in the ‘city of insects.’”

In a heartwarming tribute, each newly discovered species was named after a family participating in the BioSCAN project, emphasizing the crucial role of community involvement in conservation efforts.

The path forward for humans and bugs

Despite some limitations, like not accounting for seasonal variations in weather, the study offers practical ways for Los Angeles residents to enhance arthropod biodiversity.

Guzman suggests prioritizing green areas, reducing pesticide use, and designing microhabitats in urban developments to support diverse species.

“Prioritizing green areas and reducing the use of pesticides would go a long way,” Guzman says. “And urban planners and builders could include microhabitats designed to allow a greater variety of species to thrive.”

While focused on Los Angeles, the study’s findings have broader implications for urban environments across western North America.

By understanding and applying these insights, land developers and homeowners can play a significant role in nurturing and preserving the delicate balance of urban ecosystems.

In summary, the study emphasizes the often-unseen diversity of urban wildlife and provides a roadmap for fostering healthy, resilient urban ecosystems.

Through community involvement and informed urban planning, we can ensure that our cities remain vibrant havens for diverse life forms.

The full study was published in the journal Scientific Reports.


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