On Planthoppers…or…Some of the Coolest Bugs EVER!
A few years back, I was planning a fieldwork expedition to collect insect specimens at a well-known biological station (La Selva) in the rainforests of Costa Rica. A colleague of mine, a more ‘senior’ researcher (OK, read…”old”), had been to La Selva more than 10 years earlier and told me that when I visit the station I should locate a specific rainforest path and walk to a specific mile-marker on that path where I would find a specific tree on which I would find specimens of a particularly charismatic planthopper species (the “dragon-headed bug”, Phrictus quinquepartitus). Faced with this directive, I’ll admit that I harbored a healthy amount of skepticism. This colleague hadn’t actually been to La Selva in more than a decade, and I thought the likelihood of finding one specific tree in the middle of a jungle was low…and even if I did, the probability of finding a particular insect on that tree was pretty darned remote.
So, fast forward to my Costa Rica expedition and here’s what happened: I walked along the specified rainforest path until I arrived at the specified mile-marker where THE tree was supposed to be. Guess what….no tree. I was vindicated….I KNEW that my *senile* colleague was crazy to suggest I’d find the tree and the insect. I’m always right, right? Wrong. It turned out that I was on the wrong path, both literally and figuratively. Upon realizing that the mistake was mine, I located the correct jungle trail and, sure enough, found the correct tree – just where it was supposed to be. And guess what? The dragon-headed bug was right there, as my *wise and knowledgeable* colleague had assured me….!!
The dragon-headed bug is but one example of a planthopper….a vastly diverse group of insects related to the subjects of my previous blog posts — spittlebugs and treehoppers. Like the spittlebugs and treehoppers, planthoppers are exclusively herbivores (plant-eaters), using their straw-like mouthparts to suck phloem sap out of their host plants. Like the dragon-headed bug, many planthoppers are rather conservative with their food preference, eating only certain plant species; and sometimes (for unknown reasons) planthoppers will feed on specific individual plants for generations and generations. That’s why my *Yoda-like* colleague knew that I’d find the dragon-headed bug on that tree after more than ten years. Cool, huh?
Worldwide, there are more than 9,000 described species of planthoppers, taxonomically distributed among about 20 families; included in this group are some of the most important pests of human agriculture….insects causing millions of dollars of damage annually to crops like rice, corn, wheat, and barley.
To an evolutionary biologist like me, what’s most fascinating about planthoppers is the astonishing diversity in terms of their anatomy. Planthoppers have all kinds of bizarre horns, spines, spikes, colors, and patterns, making them a tremendously exciting insect group to observe and study. It’s hard to become bored with a group when, every time you collect a bunch, you see something new. What are these things for? How did these curious structures evolve?
Arguably the most remarkable and charismatic of the planthopper families is Fulgoridae…more commonly known as the lanternflies. Worldwide, this family includes approximately 500 described species; of these, perhaps 2 or 3 species occur in North Carolina. Certain lanternflies (like the aforementioned dragon-headed bug, and the entomologically famous peanut-headed bug) are commonly used as examples of tropical biodiversity, presumably because of their outlandish appearance.
My colleague (Dr. Julie Urban, Assistant Director of the NC Museum’s Genomics Lab), and I have published research articles on the evolution of planthoppers in general, and also of specific planthopper families, including the lanternflies (family Fulgoridae) and (with Dr. Charles Bartlett of the University of Delaware) another planthopper family called Delphacidae, which includes the most important of those agricultural pests mentioned above. Our latest research publication examines the evolution of certain bacteria that live inside planthoppers; these bacteria are thought to produce nutrients that the planthoppers need, and vice versa, in an ‘obligate’ symbiotic relationship (meaning that the insects can’t survive without the bacteria, and the bacteria can’t survive without the insects). These are truly fascinating animals, and so much about their biology and evolution remains unknown. You can check out some pictures of planthoppers and related insects on my Flickr photostream at: http://www.flickr.com/photos/jasoncryan/