Insects are currently enjoying a moment of mostly positive media attention, thanks to the remarkable mass emergence of periodical cicadas in parts of the Eastern United States. As a bug-lover, I’m delighted to see news stories and public reaction focusing on the remarkable life histories and adaptations of these insects, instead of on the “Ick!” factor, as usual.
Regrettably, Martha’s Vineyard is missing the party. As far as I know, the Island has no firm records for any of the seven species of periodical cicadas. Brood X, which involves members of three species and is so famously plentiful this year, does not occur in Eastern Massachusetts (though some off-cycle members of Brood XIV, which is mainly expected to emerge in 2025, have been reported from Cape Cod and Plymouth County). Meanwhile, the emergence of our several species of annual cicadas, which announce their presence with prolonged, incredibly loud buzzing calls mostly from tree canopies, is still weeks away.
If you’re feeling cicada-deprived, though, don’t despair. Other Hemiptera, related to cicadas and resembling them in many ways, are entering their summertime season of peak abundance and are growing increasingly easy to find.
I’m thinking mainly of the leafhoppers, which is an informal name for the family Cicadellidae. It’s a large family, with some 3,000 described species in North America and an estimated global diversity in excess of 100,000 species. Generally about a centimeter long, leafhoppers are far smaller and less impressive than cicadas, though they also have sound-producing organs (which, sadly, don’t usually make enough sound for clumsy human ears to listen in on).
Leafhoppers are shaped a lot like their larger cousins (that is, they’re built roughly like doorstops). Also like cicadas, they feed exclusively on the sap or juices of plants and are harmless to humans. (Leafhoppers, I’ve noticed, will occasionally give an exploratory chomp to your arm, just to see whether you’re edible. These bites sting momentarily but don’t itch and don’t leave a mark.)
In evolutionary terms, leafhoppers seem to be one of those cases in which a very effective basic design undergoes an explosion of subtle differentiation, resulting in a wealth of similar and closely related species occupying slightly different ecological niches. In many cases, it seems to be associated with particular plants that set leafhoppers apart from each other: It is possible to find nearly indistinguishable members of the same genus living in the same place at the same time but associating with different plant species. As you might expect, a lot remains to be learned about the elaborate ecology of this group.
I’ve spent very little time working on leafhoppers, but so far my impression is that while these insects can be abundant on Martha’s Vineyard, we may not have very much actual diversity. A few species, that is, make up the vast bulk of the leafhoppers you encounter. I’m open to the idea, though, that what’s really deficient is my expertise not the diversity of these insects; as I learn more, I may find a lot more species.
One leafhopper currently plentiful in my Oak Bluffs yard proves to be an introduced species. Pagaronia minor (it has no common name) originated in Japan. In 2005, according to the species account on Bugguide.net, it was first detected in North American, specifically New York, presumably the result of unintentional transportation on plant material of some kind. By 2018, the species had made it to the Vineyard (that’s the year for the first Island record for the species in iNaturalist.org), and over the last two seasons, it has emerged as one of the most common leafhoppers in my yard. It seems safe to assume that, like its jump from Japan to New York, its progress from New York to the Vineyard occurred via human transport of plant material.
A pale green leafhopper marked by three tiny black dots on its snout, Pagaronia may well settle in as a generally well-behaved member of our insect fauna. I haven’t noticed any decline in the numbers or diversity of other leafhoppers in our yard since Pagaronia showed up (though I haven’t been rigorous in keeping track of numbers). And I have yet to find Pagaronia in natural areas of the Island (again, though, I could easily be missing something).
Part of the picture may be that Pagaronia may have found a nemesis here in the form of a little robber fly, Dioctria hyalinipennis. Dioctria seems to prey heavily on leafhoppers. And Pagaronia, which is a slow and seemingly not very alert aerialist, makes a dandy target. The periods of adult activity of these species roughly coincide, and already this spring I’ve seen a couple of Pagaronia individuals in the clutches of this robber fly. It’s possible that this one predator alone makes a significant dent in the population of this introduced leafhopper.
In any case, it’s too bad we won’t see swarms of Brood X cicadas. But there are plenty of their relatives around to keep us entertained.