An unprecedented third brood of Karner Blue butterflies this year will delight people who want a glimpse of the endangered insects.
But whether it’s good or bad for the species remains to be seen.
Workers at the Albany Pine Bush Preserve Commission began noticing Karner Blues flying around Thursday and confirmed that they are the third generation of this season, said Neil Gifford, conservation director at the preserve.
It’s the first time staffers at the Pine Bush have been sure they have a third generation in a single year, and they don’t know what implications it might have on the long-term health of the fragile species.
In 2010, they suspected there was a third hatching but didn’t have enough information to be sure.
“This year we’ve gone out and documented that butterflies were absent from these sites for a couple of weeks,” Gifford said. When butterflies appeared again late last week and early this week, it was obvious from their light blue color and pristine wings that they were newly out of the cocoon.
Karner Blue butterflies typically produce two generations a year — adult butterflies hatch around May 21 and lay eggs that develop into a second generation that emerges from cocoons shortly after July 4, Gifford said.
That second generation lays eggs that usually wait to hatch until the next spring.
But this year, a warm winter and early spring triggered an earlier development for the spring butterflies. The first batch emerged from cocoons May 4, the second June 20.
The eggs that the second generation laid are now adults flying around the Pine Bush Preserve.
Gifford wonders whether this third generation will have time to mate and lay eggs to produce a healthy brood next spring. He hopes so.
“We do have some photos of them mating,” he said. And the wild blue lupine plants where the butterflies lay their eggs are still green, which is a good sign.
“No one knows exactly what triggers eggs to hatch versus overwinter,” Gifford said.
Scientists believe it might be the summer solstice and day length, rather than temperature, that causes the eggs to overwinter, he added. So eggs laid after the solstice, June 21, may wait until spring as the days get shorter, while eggs laid before or near the solstice will develop quickly into butterflies.
Adult Karner Blues live only three to five days, mating and laying eggs on the wild blue lupine plant soon after they emerge from their cocoons. The eggs hatch into caterpillars, which munch on the plant.
With all of the unanswered questions, there’s only one thing to do — wait. Staffers will know better in the spring how the third hatching affected the Karner Blue population.
They’ll know sooner than that what the population is this year. In 2011, the preserve estimated that it had 2,000 Karner Blues.
And who knows? The extra hatching may actually boost the population, Gifford said.
“We want to try to better understand how the biology of the butterfly may be adapting to or changing in the face of a changing climate,” he said. “We just don’t know that yet.”
In the meantime, people who want to catch a glimpse of the little butterflies can visit the Albany Pine Bush. A trail behind the Discovery Center, at 195 New Karner Road in Albany, offers good possibilities for seeing the insects, Gifford said.
The Karner Blue butterfly is endangered because its food source grows in a very specific habitat — the sandy pine barrens at the 3,200-acre Pine Bush and at the 2,000-acre Wilton Wildlife Preserve and Park, plus various smaller undeveloped properties around the Capital Region.
Margo Olson, director of the Wilton Wildlife Preserve and Park, doesn’t know whether there will be three generations of the butterflies in Wilton.
“We will be on the lookout for that,” she said, noting that the northern preserve’s hatchings are usually a few days behind Albany’s.