Nosebot maggots make appearance in Baffin caribou

LYNN PEPLINSKI

Pauloosie Kilabuk, a renewable resources officer in Iqaluit, had an unpleasant surprise recently while butchering a caribou.

“I was removing the tongue when I saw them there” said Kilabuk, who dropped the beast’s head and backed away in mild horror at the sight of the caribou’s throat.

What Pauloosie had discovered was the nosebot fly larvae.

The nosebot, also known as the nasal warble fly, is common among caribou in northern Quebec, in the western Northwest Territories, and throughout the circumpolar North. Now, it seems, the nosebot has made its way to Baffin Island.

Kilabuk isn’t alone in his reaction to the parasites. “At least five caribou heads have been brought into the district office in the last year” he said. “Many people around here haven’t seen these before.”

The nose and throat areas of a single animal can sustain between 30 to 300 nosebot larvae at a time.

Baffin hunters are familiar with the skin warble fly larvae commonly found under the skin along the backs of caribou. The nosebots are similar in appearance, though they may be smaller and narrower.

Both kinds of warble fly larvae are parasites, a special type of predator that uses its prey as a place to live and breed. Though they can be repulsive to look at, they do not affect the quality of the meat. The fly larvae are simply uninvited guests in the caribou’s body, obtaining free food and a roof over their heads while they grow toward adulthood.

Heavily infested caribou may be tormented by the irritating presence of the parasites and be thinner than other caribou, but the caribou meat is still OK to eat.

The big difference between both kinds of warble fly is in how they lay their eggs and where the larvae end up. The skin warble fly lays its eggs directly onto the new coat of the caribou. The eggs hatch within a few days and the larvae then burrow their way into the skin. There they will molt into the familiar yellow, roundish, segmented capsules we find along the back under the caribou’s skin in the spring.

The nosebot fly’s eggs hatch while they’re still in the fly’s body. The female fly then hovers around the nose of the caribou waiting for the right moment to spray her larvae into the caribou’s nostrils. From there the larvae migrate further into the nasal area and into the back of the throat.

Because the nosebots are relatively new to the Baffin, some people are wary of them. However, the meat is not affected by the presence of either of these parasites. Just as we’re accustomed to the skin warble fly, we’ll now have to learn to live with the nosebot fly.

Lynn Peplinski is manager of the Iqaluit Research Centre