|The regal fritillary butterfly has been sighted at Fort
Tim Wilder, endangered species biologist for Fort McCoy’s Natural
Resources Branch (NRB), said that at first glance the butterfly
resembles a monarch butterfly but is slightly smaller.
A male regal fritillary butterfly
is among the butterflies being surveyed by the Fort McCoy
Natural Resources Branch Endangered Species program.
(Photo by John Polk)
NRB personnel are about halfway through a survey for the regal
fritillary butterfly. The butterfly is listed as a state of Wisconsin
endangered species and a federally listed species of concern, he said.
Regal fritillaries were first documented on Fort McCoy in 2010, when
five were observed. To determine if this was just a fluke, surveys for
regal fritillaries are being conducted in 2011.
“To date, more than 70 observations of the butterfly have been
documented in numerous locations on the installation,” Wilder said.
Wilder said it isn’t clear how long the butterfly has been at Fort McCoy
— if it recently found its way to Fort McCoy or has been here for a
The regal fritillary is part of a genus, which includes the Aphrodite
fritillary and the great spangled fritillary. Both of those butterflies
also are found at Fort McCoy, which can make it challenging to
positively identify the regal fritillary.
Regal fritillary males tend to be slightly smaller than females and
spend a considerable amount of time flying throughout their habitat area
searching for females. Wilder said the females are more secretive,
making them more difficult to observe.
The butterflies generally are found in an area of tall grass or prairie
vegetation. Adults will nectar on a wide variety of plants to include
bergamot, various thistles, common milkweed, and butterfly weed. Larvae
feed on the violet plant family.
Adult butterflies emerge in late June or early July with the flight
lasting until late August or early September.
The butterfly also is found at Fort Indiantown Gap, Pa., and has been
co-existing with training there, he said.
“I don’t think the butterfly will have that much impact on ground
training here,” Wilder said. “It may have some impact on activities that
permanently remove habitat, like building construction.”
Fort McCoy NRB personnel will help manage the installation’s land to
support the butterfly. Controlling brush through mechanical means,
herbicides, and prescribed fire all will all be considered.
The frequency of prescribed burns will be monitored to ensure the regal
fritillary butterfly is not negatively affected.
(See related story.)