New research, driven in part by citizen scientists, has uncovered some astonishing facts about the meadow spittlebug (Philaenus spumarius), also known as froghoppers. These insects are famous for the foamy, spit-like secretion produced by their nymphs. The study, published in the journal PLOS ONE, highlights that these bugs can feed on an astonishing 1,300 different species of host plants, more than double the number of any other insect.
This discovery has significant implications for efforts to combat the spread of a pathogenic bacterium associated with the meadow spittlebug. This bacterium has caused crop losses globally, affecting olive trees in Italy, grapevines in California, citrus trees in South America, and almond trees in Spain.
The bugs, which use straw-like mouthparts to suck sap from plants, can pick up harmful bacteria and act as vectors for plant diseases. Recently, they’ve been found to transmit the devastating Xylella fastidiosa bacterium, which has decimated olive groves in Italy.
To assess the risk to other plant species and ecosystems, researchers needed to understand the full extent of the meadow spittlebug’s host range. The study’s lead author, Vinton Thompson, collaborated with scientists in the UK and compiled data from various sources, including museum specimens and a citizen science project called BRIGIT.
Meadow spittlebugs are highly adaptable, thriving in diverse climates from Hawaii to the Arctic Circle. While suspicions existed about their wide host range, the actual number is staggering: these bugs feed on over 1,300 plant species across 117 families, setting a world record among insects. These host plants encompass ferns, herbs, shrubs, vines, trees, annuals, perennials, grasses, and more, spanning various climates and environments.
Surprisingly, the second-highest number of plant hosts is found in the fall webworm, a moth known to feed on 636 plant species.
One intriguing aspect that requires further investigation is why meadow spittlebugs have such a vast array of host plants. Researchers suspect it’s related to their preference for sap from the xylem, the plant’s water-carrying structure, which remains relatively consistent across different host plants. Unlike other sap-feeding insects that target the phloem, which transmits sugars and metabolic compounds, the meadow spittlebug’s adaptability allows it to exploit a wide range of plant species.
Claire Harkin, a study author from the University of Sussex, aptly describes the meadow spittlebug as the “ultimate herbivore champion” with an incredible ability to feed on nearly any vascular plant type, except those submerged in aquatic environments.
This extensive host range poses a significant concern regarding the potential spread of X. fastidiosa in natural ecosystems if introduced. The study serves as a starting point for devising strategies to control this bug and the diseases it carries.
Apart from their remarkable dietary flexibility, meadow spittlebugs hold other superlatives, such as being the highest jumpers relative to body size and having the most potent sucking power among insects. In fact, they can extract water from a cup placed at the Statue of Liberty’s base while perched on its crown. Additionally, their urination prowess is exceptional, equivalent to excreting 2,500 gallons of urine daily in human terms.