Should you rake your leaves or leave them be? This ongoing discussion about how to handle the accumulating leaves on your lawn resurfaces every fall, drawing opinions from lawncare aficionados and environmental advocates on the advantages and disadvantages of both choices.

While there are environmental advantages to allowing your lawn to remain natural, like reducing greenhouse gases from decomposing leaves and enriching the soil, there’s a significant concern for those who dislike insects—what could be hiding in those piles.

Still torn on whether to maintain your lawn or clear it of leaves? Here’s what you should know about the creatures that may be living in those leaf piles.

Beetles, spiders, and centipedes, oh my!

Leaves piled up on your lawn make excellent hiding spots for various insects, especially if the leaves are heaped high. Many of these bugs are hibernating for the winter, and the dark, moist, warm, and food-rich conditions provided by leaf piles are ideal for several species.

Common insect inhabitants include ants, beetles, centipedes, millipedes, pillbugs, earwigs, spiders, and ticks, according to Big Lakes Lawncare, Modern Pest Services, and the Department of Entomology at Penn State. While some insects, like centipedes, can be beneficial, others, such as ticks, can pose health risks.

Nonetheless, leaving a few leaves on your yard can foster an environment that supports essential ecological processes, as noted by National Geographic.

Other wildlife, such as rodents and snakes

Leaf piles can also attract wildlife that many might find undesirable, like snakes, salamanders, box turtles, toads, and rodents.

These creatures are drawn to the warmth and shelter that leaf piles offer, as well as the food sources provided by the insects and smaller animals living within. Although they may not be welcome guests for most homeowners, they do play important roles in maintaining ecological balance, according to the Loudon Wildlife Society and the National Wildlife Federation.

If possible, leaving some leaves for species like box turtles and salamanders can be advantageous. However, no one wants rodents, which can carry diseases, entering their homes, so if you opt for minimal raking, try to keep thicker leaf piles a safe distance from your house.

Mold and fungi

Piles of moist leaves that aren’t disturbed often provide the perfect conditions for mold and fungi to thrive.

According to Big Lakes Lawncare, in colder climates, damp leaf piles can attract fungi like Microdochium nivale and Typhula incarnate, which cause snow mold. Snow mold can damage grass by creating unsightly pink or grey patches. Additionally, this condition may trigger allergic reactions and asthma.

Other unwanted fungi that might be hiding in leaf piles include Rhizoctonia leguminicola, which causes grasses to brown, or red thread, a lawn disease caused by Laetisaria fuciformis, as reported by Homes and Gardens.

The best way to avoid these issues? Prevent the build-up of wet leaves on your grass for extended periods.