Crouching on a lane of soft silt surrounded by pickleweed, with ants scurrying around our shoes, Wes Maffei and I squinted ahead across the cracked mud.

“There he is,” Maffei said, pointing, “just past that reddish pebble—he’s coming right toward us. See how he holds himself high off the ground?”

“He” was a tiger beetle (Cicindela senilis senilis), the first one we’d spotted. He had jumped ahead of us in looping arcs as we walked, always landing so that he could keep an eye on us. Now we’d been still for a while, so he seemed bolder, feinting from time to time at a passing ant.

“He won’t eat ants, but he’s very sensitive to movement,” said Maffei. Indeed, as I raised my camera, he leaped toward the weeds. “Tiger beetles need clear spaces for hunting, to take advantage of their speed.”

Eventually others appeared, and danced warily around each other, or zipped across a swath of salt crust to nab brineflies (Ephydra cinerea) that swarmed in brackish brown puddles. A mating pair appeared, one carrying the other on its back.

We were in Mezzetta Marsh, a degraded tidal marsh about five acres in size, near the Napa River and the city of American Canyon. We were looking at tiger beetles because Maffei sees them as indicators of marsh health. Their presence or absence can signal disturbance in the marsh habitat.

Later, in his home laboratory, he showed me specimens of tiger beetle species he’s collected, their backs marked with white glyphs like musical eighth notes. One large species has a bright red belly, another iridescent blue, a third is tinged with purple. In the marsh we couldn’t get close enough to the skittish beetles to make out these details, but as we focused on them, we began to notice an array of other insects. Red or bright blue damselflies hovered, darted, or perched on swaying plant stalks. Little black spiders joined in the brinefly hunt. ”They can run right across the water,” Maffei said. Firebrats—primitive relatives of silverfish, with wiggly tapered bodies—slithered through clumps of bright yellow brass buttons.

Insect study is Maffei’s passion; keeping peace between insects and people is his job. He has been manager of the Napa County Mosquito Abatement District (NCMAD) since 1997, and before that worked at mosquito control for nine years in Alameda County. A man of apparently boundless energy, he also teaches general biology at a community college; consults for numerous boards, panels, and committees; and maintains an impressive entomology library, lab, and collection (including “voucher specimens” of Bay Area insects that may be used for teaching or photographing). In his “spare time” he studies the insect biology of the Bay shoreline.

I met Maffei at his office, a low metal building next to county sanitation department headquarters. A couple of pickup trucks, a small boat, and a little “creeper” ATV, all equipped with sprayers, were parked outside. Four full-time (and one half-time) employees serve the entire county, on an annual budget of $450,000.

Mosquito abatement may not sound very glamorous, but the Napa County staff—most of them have been there for many years—are enthusiastic about their work. They are aware of its importance, and enjoy an easy camaraderie.

Because mosquitoes need standing water to develop, agents monitor wetlands, riparian areas, drainage ditches and other likely sources of mosquitoes. Agents also respond to complaint calls, trap and identify mosquitoes and other insects, and inform the public about insects and their roles in local ecology.

They try to control mosquito infestations by using methods that cause the least possible damage to the environment and other species, even when more toxic methods cost less in dollars. Sometimes it’s enough to improve water flows or supply mosquitofish (Gambusia affinis), which feed on mosquito larvae. When something more is needed, they prefer to use target-specific methods that cause no known damage to other life forms: either bacterial spores of Bacillus thuringiensis var. israelensis (Bti), which cause internal tissue breakdown when ingested by mosquito or blackfly larvae, or Methoprene (Altosid), an insect growth regulator that prevents mosquito larvae from maturing. The District however, will spray with pyrethrins, made from chrysanthemum flowers, at ultra-low volume (one ounce per acre) when large populations of adult mosquitoes are present, especially when they pose a threat of disease. As a last resort, a petroleum-based pesticide, Golden Bear 1111, may be used to prevent adult mosquitoes from emerging. Both this pesticide and pyrethrins break down quickly in the environment, but they do affect other insects.

I followed Maffei to a corner of the District’s workshop, where he keeps county maps with colored pins that indicate locations of complaint calls answered each year and what species of insect was found at each site. A dense cluster of tan pins on the 1998 map showed many calls from near a wetland where a dike had been breached. “The disturbed conditions caused by the breaching led to huge hatchings of opportunistic midges,” Maffei explained. “Whole walls of nearby buildings turned brown with midges. We told the callers that the midges were harmless, and that they would provide lots of food for birds.” The 1999 map had no tan pins in that area. As conditions in the marsh stabilized, the midge population had diminished.

Larger pushpins showed sites where mosquitofish had been released, where light traps had been placed to attract and capture adult mosquitoes (especiallyto check for carriers of encephalitis), and where flocks of “sentinel chickens” are checked periodically: some disease-carrying mosquitoes feed on chickens—blood drawn from the birds’ combs is tested.

I learned that a mosquito is not “just a mosquito.” Napa County has ten common mosquito species, and at least ten others. Among them are several that can spread malaria, encephalitis, or dog heartworm. These diseases occur only rarely, thanks to modern abatement procedures. However, as more and more Californians travel abroad, the risk grows that exotic strains of malaria could be transmitted to endemic malaria mosquitoes, which could then spread the disease. Bcause local medical practitioners tend to be unfamiliar with malarial symptoms, mosquito control agents are concerned and extra careful.

What most fascinates Maffei is insect life in the context of larger biosystems. Very little has been published about the role of insects in Bay Area ecology, he says. Protection and restoration efforts have focused on mammals, birds, and fish; yet “how can we say we’ve restored clapper rail or salt marsh harvest mouse habitat if one of their main food supplies is gone?” he pointed out. “And how many presentations about insects have there been in all the State of the Estuary conferences we’ve had? None.”

To illustrate his point, he told me about the burrowing owls that live near Oakland Municipal Airport. In a 1971 study, examination of owl droppings showed that their most common prey was the finger-sized Jerusalem cricket (Stenopelmatus fuscus)—also called potato bug, old bald-headed man, and niña de la tierra. Tests in the late 1990s, however, found remains of only one cricket in the droppings, along with many fragments of earwigs. No one seems to have noticed the disappearance of the crickets, though we can guess that much of their habitat was lost to airport expansion and other development. “The owls still have food,” Maffei said, “but it takes a lot more time and energy for them to get adequate protein from earwigs.”

In 1989, Maffei was asked to survey insects in inactive salt ponds in Hayward. Since then he has continued, on his own time, collecting and observing insects and arachnids in wetlands and adjacent uplands from Alameda to Alviso, and now in the North Bay, gradually piecing together patterns that can reveal intricate and unsuspected relationships.

Maffei says his family and friends roll their eyes when he wanders off to watch insects by the hour. But crouching near him in Mezzetta Marsh, I was able to share some of his enthusiasm and fascination. That ability to sit quietly observing in fields and marshes, day and night, year after year, enables him to find and assemble myriad puzzle pieces into stories and pictures that show us how these habitats work.