BETHLEHEM (TNS) — It was another warm, humid evening and a Bethlehem backyard was filled with eye-catching streaks of yellow-green.

Lightning bugs, or fireflies, were silently moving about, using bioluminescence from organs in their lower abdomen to signal their species within the family Lampyridae and find a mate.

This summertime spectacle is threatened as firefly populations decline across the country.

A study published a year ago in Science of the Total Environment points to various environmental factors that could doom populations of the lightning bug, Penn State University reports.

“Subtle changes in climate patterns, especially related to temperature, are significantly impacting firefly breeding cycles and habitat quality,” said Darin McNeil, a principal investigator in the study, according to a Penn State summary of the research.

The U.S. Fish and Wildlife Service says “fireflies are not as common today” as in the past for reasons that include:

• “Light pollution interferes with their mating rituals, lowering reproductive success.
• “Habitat loss, mainly of leaf litter and tall grasses, reduces the food and space available — halting and reversing population growth.
• “Pesticide exposure can disrupt their metabolism and development while in egg and larval life stages.
• “Climate change adds stress by exacerbating all of these threats, particularly through drought and sea level rise.”

What can we do to protect these and other backyard and streetside insects? Fish and Wildlife Service officials suggest:

• “Turn off outdoor lights in the evening. If you have inside lights on, close the blinds.
• “Plant native plants.
• “Mow grass less frequently and raise the length of the cut to 4 inches.
• “When leaves drop in the fall, rake them if you want, but keep them in your yard.
• “Use non-pesticide solutions for insect control.
• “Know how much salt is necessary to de-ice sidewalks, and don’t over-do it.
• “Contact your city about reducing or finding alternatives to salt usage.
• “Watch insects closely, enjoy their presence as you learn about their bodies and behaviors.
• “Show others, particularly kids, how insects are interesting not intimidating.”

Keeping some leaf litter around is especially important. The Facebook account Chasing Bugs with Danae Wolfe posted photos, including of a firefly larva on the underside of a fallen leaf with its telltale glow — a true glow worm.

“Fireflies spend most of their lives — one to two years — as larvae living in the soil and leaf litter, hunting snails, slugs, and worms in the dark,” the account posted. “They pupate underground before emerging as adults for just a few short weeks to find a mate and start the cycle again.”

As adults, “their only task is to reproduce,” according to the federal Fish and Wildlife Service: “Some don’t even eat! Their flashes, through pattern and color, signal what species and sex they are. If a female recognizes her specie’s pattern from a male, she will light up her own lantern and beckon him over.”

In Pennsylvania, lightning bugs are at their peak through about the second week of July. The best viewing conditions are warm, humid evenings with little wind and low light pollution.