A nymph meadow spittlebug (Philaenus spumarius) surrounded by spittle mass. Credit: © Claire Harkin
Key points:
- The meadow spittlebug can feed on at least 1,300 species of host plants across 117 families.
- Meadow spittlebugs suck sap from xylem, which likely allows them to feed on more plant species than bugs that feed on the phloem.
- Meadow spittlebugs act as a vector for diseases and bacteria that can decimate plant species across a wide geographic range.
A new study, published in PLOS ONE, reveals that the meadow spittlebug feeds on at least 1,300 species of host plants—more than twice the number of any other insect.
Meadow spittlebugs, or Philaenus spumarius, use their straw like mouthparts to suck sap from plants. They pick up bacteria and become vectors for plant diseases including the bacterium Xylella fastidiosa, which has devastated olive groves in the Apulia region of Italy. By spreading this bacterium, meadow spittlebugs have contributed to the death of other crops worldwide, including grapevines in California, citrus trees in South America, and almond trees in Spain.
Now, scientists are preparing for meadow spittlebugs to introduce X. fastidiosa to the UK. Using data from published literature, host records associated with museum specimens, observations, and data from a citizen science effort, scientists have determined that meadow spittlebugs can thrive in many different geographical climates ranging from Hawaii to just south of the Artic Circle.
The research team calculated the number of hosts and discovered that the spittlebug feeds on more than 1,300 species of plants across 117 families. This number of plant hosts is a world record for insects. The fall webworm, which only feeds on 636 different plant species, has the second-highest number of hosts.
“The spittlebug is the ultimate herbivore champion,” said study author Claire Harkin of the University of Sussex. “It will feed on just about every imaginable kind of vascular plant except those submerged in aquatic environments.”
The researchers suspect that the meadow spittlebug has so many host plants because it prefers sap from the xylem or the water-carrying structure of plants. Most other sap-eating bugs feed from the phloem, which is the tissue that transmits sugar and other metabolic compounds. The sap from phloem differs between plant species, while the liquid in the xylem is similar across plants. As a result, feeding on xylem may underlie the spittlebug’s capacity to spread incurable plant diseases to crops.
“There is tremendous potential for the spread of X. fastidiosa in natural ecosystems if it’s introduced,” explained the study’s lead author Vinton Thompson. “This review Is just the first step in thinking about how to control this bug and the diseases it spreads.”