If you aim to collect 40,000 specimens, it helps to be ‘buggy’ over beetles.
By Sheryl Smith-Rodgers
Dazzling. I can’t think of a better adjective to describe the shimmering colors firmly fastened to my open palm.
Late-morning rays from the sun — welcome warmth on an October day in the Rio Grande Valley — brilliantly illuminate the little dome’s sheath of metallic lime, flecked with gold and bronze. Found treasure? A precious gem? Hardly. No bigger than half a peanut and similar in shape, this beauty’s a beetle.
“You’ve got an anacua tortoise, Coptocycla texana,” proclaims entomologist Ed Riley, squinting over his wire-framed glasses for a closer look. “The species looks like a turtle. Acts like one, too. When it feels threatened, a tortoise beetle hides under its elytra (hard forewings). If you look under anacua leaves, you’ll find its larvae.”
I continue gaping while Riley — who has spent four decades peering at beetles — returns to whacking palm fronds with a beat-up baseball bat. With each shake, a shower of insects falls onto a white sheet he’s holding like a square kite. Few critters escape his scrutiny.
Obviously, few people in Texas know beetles as well as Riley. I’m realizing that as I tag along behind him on a beetle-collecting excursion in the jungly Sabal Palm Audubon Sanctuary near Brownsville. Since 2008, Riley — longtime associate curator of the Texas A&M University Insect Collection — has logged at least 23 other similar trips to gather data for a three-year survey of beetles in Cameron and Hidalgo counties.
When completed, the project — funded through Texas Parks and Wildlife Department, the Department of Entomology at Texas A&M University and Texas AgriLife Research Service — will provide current data on several beetle species of potential conservation interest in the lower Rio Grande Valley. The project’s huge database — recorded by hand, digitally and other means — will also inventory other insects and spiders collected with the beetles.
“We’re capturing and preserving a wealth of scientific specimens,” Riley says. “Basically, we’re documenting what’s here now because habitats change. When this project’s done, we’ll have 30,000 to 40,000 specimens preserved and databased.”
Collecting even a few thousand requires tremendous time and effort, as I see while in Brownsville. But the work doesn’t end in the field. Two weeks later, Riley tours me through A&M’s Insect Collection, where specimens are sorted, mounted, identified, cataloged and archived. Just listening to him describe the process tires me out, but Riley plows ahead, discussing each step with passion and energy.
Simply put, that’s how much he loves beetles.
What’s up with beetles?
Why not focus on butterflies, bees or some other insect? I wondered, too. For perspective, I turned to Richard E. White’s A Field Guide to the Beetles of North America (which Riley recommends for newbies like me). Taxonomically, beetles — characterized as having elytra, chewing mouthparts and complete metamorphosis — are grouped within the insect order Coleoptera. Worldwide, biologists have described some 750,000 insect species. Of those, 300,000 are beetles, the largest order of all living things.
Diverse also describes the habitats where beetles exist. “They’re everywhere, except in marine waters and ice caps,” Riley says. “Their adaptable, highly specialized bodies — and their ability to disperse — allow them to reach and exploit just about every conceivable microhabitat out there. A butterfly or dragonfly can’t do that. So beetles are an expression of an ecosystem’s health.”
They can inflict damage, too. When the boll weevil crossed the Rio Grande in the 1890s and spread northward, infestations greatly damaged the cotton industry. Alarmed, federal officials sent entomologists to live and work in the Brownsville area, and soon a steady stream of beetle collectors followed: Charles Schaeffer, Herbert Barber, Henry Wickham and others. To this day, their century-old, dry-mounted specimens are archived in the Smithsonian’s National Museum of Natural History in Washington, D.C.
In summer 2008, Riley and his research associates spent a week at the museum, gathering historical data on beetle species from the lower Rio Grande Valley. “We also visited private and collegiate collections that include specimens from the region,” he explains. “The historical inventory gives us a glimpse of the past and helps us understand how the area’s beetle fauna has changed over the past 100 years.”
How to hunt beetles
Thick stands of thigh-high grass mixed with mesquite, shrubs and palm fronds hug the narrow road that leads to the Sabal Palm Audubon Sanctuary, a 557-acre preserve that protects what’s left of the Valley’s sabal palm forests. I’m here for the day with Riley and Mike Quinn, an independent entomologist who digitally photographs the insects.
Beetle hunting may sound easy, but experts know better. “There’s no one way to catch beetles because they don’t do just one thing, like butterflies,” Riley explains as he unzips a gray backpack. In go a guppy net, a long-handled net, a baseball bat and lidded plastic containers, large and small. “Each beetle family has its own special habits and life cycle, not only annually but daily,” he continues. “Beetles mate and lay eggs in a particular substrate. Their larvae grow and pupate, then adults emerge and disperse. They’re all a bit different, so you have to know a little something about what each beetle family does for a living. Then you know where and when to look, like in shelf fungus or decaying wood.”
That said, biologists must use many different methods to fully sample a resident beetle population.
First to do this morning: check beetle traps. Lots of them. Pushing through thick understory, Quinn lowers a Lindgren funnel trap that is hanging high from a tree limb, and Riley empties the bottom catch container. This odd trap — an attached series of stacked funnels — captures beetles that fly to tree trunks. Riley replenishes the green propylene glycol, a nontoxic fluid that preserves specimens until the next check.
Onward we go to ground-level and elevated flight-intercept traps, upright nettings that divert flying beetles into a long pan filled with green preservative. At other sites, round pitfall traps — cut from PVC pipe and set flush with the ground — capture ground-dwelling beetles that happen by and tumble in. Carrion traps — plastic milk cartons baited with rancid meat and suspended above the ground — attract carrion-feeding species, while light traps equipped with batteries and on-off timers harvest nocturnally flying beetles.
From each trap, Riley pours out or — using his guppy net — scoops up a sludge of dead insects and leaf debris, all of which go into a labeled container. “I never throw anything out,” he explains. “Everything always gets looked at in the lab.”
Peering over his glasses, Riley swishes the icky stuff around, then pokes an index finger into the mess. “Ah, we’ve got some good stuff!” he announces happily before rattling off a slew of scientific names.
Burritos and peanuts for lunch, then back to beetle hunting. This afternoon, the guys use bats and sweep nets to collect specimens from vegetation. I follow Riley, who’s whacking a very dead tree with his bat.
“I’ve gotten a lot of good beetles off this tepeguaje!” he exclaims while eyeballing what beetles have fallen onto his beat sheet. Some he plucks with tiny tweezers and drops into a tiny bottle; others — along with spiders, ants and praying mantises — he shoos away.
Dry palm fronds, a bushy huisache, more palm fronds — little escapes Riley’s bat. “People ask me how I find such cool beetles, and I tell them by beating on tangles of vines,” he says offhandedly while I wade behind him through thigh-high Guinea grass, a quick-spreading invasive species that threatens the palm grove. (This grass is so thick that when I trip over a hidden log, I fall backward on what feels like a mattress!)
Later, in a nearly dry resaca, Riley pulls out his net and swooshes it through stands of native Panicum grass, wildflowers and other plants. While he plucks beetles from the net, I notice a pile of fresh droppings on the ground. “I wonder what animal left that?” I ask curiously.
“More importantly,” Riley replies over his shoulder, “what kind of beetles could be in it.” Fortunately, we don’t stop to find out.
But we do examine a busy ant bed, where Riley and Quinn — on their hands and knees — search for Blapstinus beetles. “They’re surface scavengers,” Riley says of the elusive species. “They live around the edges of red harvester ant clearings, where they feed on seed castings left by the ants.” Needless to say, Riley finds his quarry and drops some in a bottle.
The day lasts well past dusk. After leaving the Audubon sanctuary at 5 p.m., we head east on Texas Highway 4 so the guys can sweep several sites within the Lower Rio Grande Valley National Wildlife Refuge. OK, confession time: I stay in the car because I’m tired and hate mosquitoes. Not Riley and Quinn! They don’t stop until after the sun goes down.
Early Sunday morning, the duo heads for Santa Ana National Wildlife Refuge to service more traps and beat-sweep for beetles. Not me. I’m homeward bound, still a bit bushed, but loaded with a new appreciation for beetles and the folks who hunt them.
Epilogue: Lab work
Glass canning jars filled with insects collected from a recent Brownsville trip line a counter in an entomology room at Texas A&M University. “There’re good beetles in here!” grins Riley, tapping a metal lid atop one.
For nearly 22 years, Riley has managed the school’s vast collection of insects, which today numbers more than 2.4 million curated specimens. “Our primary mission here is to serve as a research and reference tool,” he explains. “We have 45,000 identified species from all over the world. But our strongest collections come from Texas, the Southwest and Mexico.”
During an afternoon tour, Riley first shows me gray metal cabinets, 6 feet tall and arranged in long rows, library style. Opening the door handle of one, he slides out a wooden drawer from a stack of many. Beneath the glass top, I see column after column of red and black bugs, mounted on individual black pins and neatly labeled with tiny tags.
“Most people don’t understand how diverse insects really are,” Riley muses. “In the insect world, there’s no such a thing as ‘a brown stink bug.’ It’s really half a cabinet of different species of ‘brown stink bugs!’” He opens another cabinet that houses flies and another, butterflies. “We’re not a Noah’s ark collection; we don’t have two of every kind. Instead, we may have a long series representing many different collecting events across time and space.”
Processing one “raw” sample is a lengthy process that’s handled by Riley and a team of undergraduate students. First, specimens from wet trap samples are rinsed and stored in ethyl alcohol (the standard preservative). Using a microscope, students sort insects into target groups, which are later prioritized for dry-mounting. When pinned, specimens are labeled with their collection data (location, date, collector, host, habitat). They’re also assigned a unique number in the form of a bar code, like a retail item. When scanned into a computer, the bar code links to the collecting event data that can be retrieved for later in-house use or exported to the Web.
A hundred years ago, entomologists hand-penned labels that included the approximate location of where a specimen was collected. Today, modern technology allows collectors to pinpoint and record precise coordinates of sampling locations.
“I collected beetles in Brownsville as a college student in the late ’70s, but I couldn’t tell you exactly where because neighborhoods are there now,” Riley says. “Today’s hand-held GPS units and Google Earth have totally changed the way we do business. Everything now can be ‘captured’ digitally into a computer and shared globally on the Web.”
Later at home, I download the Illustrated Beetle Inventory of the Sabal Palm Audubon Sanctuary, a 38-page online document (compiled by Riley and Quinn) that’s linked to beetle images on BugGuide.net. A quick search leads me to photos of a metallic, lime-colored beetle, and, wow, I’m dazzled all over again …