Spittlebugs use a saliva-like excretion to protect themselves from the sun and predators. Photo by Mikaela Huntzinger/UC-Davis
Aug. 16 (UPI) -- Once abundant along the California coast, the meadow spittlebug is on the decline, according to new research by ecologists at the University of California, Davis.
"I've been surveying seaside daisies for spittlebugs at Bodega Bay every spring for the past 35 years and found that the number of these highly visible and previously widespread insects was related to temperature," researcher Richard Karban said in a news release.
Spittlebugs are named for their saliva-like excretion. The bubbly deposits make the insect's presence known. But since 2006, spittle masses have gone missing from Bodega Bay Reserve's coastal prairie.
Meadow spittlebugs, sometimes called meadow froghoppers, prefer cool, wet conditions. The insects suck a plant's juice, xylem fluid, from its leaves. Regurgitated plant juice forms the spittle mass, which forms a protective layer, keeping the spittlebugs hydrated and hidden from predators.
The latest survey of California's spittlebug population confirmed the insect's sensitivity to environmental changes. Scientists believe California's warm temperatures over the last decade have forced meadow spittlebugs to relocate, and more recently, disappear entirely.
Researchers detailed their survey this week in the journal Ecology.
"In 1988 and again in 2001, we surveyed various populations of seaside daisies up and down the coast and found that the distribution of spittlebugs appeared to be shifting north, or toward the pole, a pattern that other people have found for many species in response to climate change," scientists wrote. "However, we resurveyed these populations in 2017 and 2018 and found instead that they were becoming rare or missing throughout much of this former range."
California has experienced several especially hot and dry years over the last decades. Scientists suggest more species are likely to suffer the fate of the spittlebug as warming trends continue along the California coast.
Researchers had previously mistaken the spittlebug's widespread abundance for a level of resilience and an ability to adapt.
"What we have found is that even this species has not been able to adjust physiologically or ecologically," researchers wrote. "If the pattern they show is common, we may also see surprising changes in the abundance or distribution of other insects as well."