This species
is found widely across eastern North America and is common at
Ojibway in mid summer. It is often seen over lawns, meadows and
other grassy habitats. Big Dipper Fireflies flash a distinctive
pattern shortly after sunset for an half hour or so and usually fly
less than 2 metres off the ground. The males suddenly rise in the
air during their flashing producing a yellow "J" stroke. The flash
lasts about a half second, the male pauses and then flies a short
ways before repeating its performance. Flashes are produced every 5
to 8 seconds. Females remain perched in the grass and respond after
2 or 3 seconds with a half-second flash.
The larvae
of this species are subterranean and likely feed on earthworms.
Larvae of the genus Photuris are surface dwellers, feeding on
snails and other invertebrates. These are the most commonly seen
"glowworms".
All
Fireflies belong to a family a beetles called the Lampyridae. About
180 species are found in Canada and the US. Some species do not
produce any light as an adult beetle and some adult females cannot
fly. The luminous segments of the abdomen can easily be
distinguished by their pale yellow colour (as seen the above
photo). All species have luminous larvae.
A firefly's
light is turned on or off by controlling the air supply to the
luminescent organs. The chemical luciferin is instantly converted
to light in the presence of a specific enzyme and oxygen. Fireflies
produce green, yellow or orange light depending on the particular
species.
While some
species of fireflies have declined in population the Big Dipper
Firefly has probably benefited from the clearing of forests in
eastern North America and is more widespread now than in historical
times.
