Status of the regal fritillary (Speyeria idalia) and effects of fire management on its abundance in northeastern Kansas, USA

  • Published source details Powell A., Busby W.H. & Kindscher K. (2007) Status of the regal fritillary (Speyeria idalia) and effects of fire management on its abundance in northeastern Kansas, USA. Journal of Insect Conservation, 11, 299-308.


The regal fritillary Speyeria idalia has disappeared from much of its former range in North America and is restricted to remnants of native tallgrass prairie in the Great Plains. Native prairies are often burned in March or April to prevent scrub growth, which kills regal fritillary larvae. This study monitored the abundance of regal fritillaries on prairie remnants burned within the past year or not, in Douglas, Leavenworth and Miami County, northeastern Kansas, USA.

Eighty-seven prairie remnants were surveyed (618 ha in total) in mid June 2005. Twenty-one of the sites had been burned in the last year, having charred stems, recently killed juniper bushes and no litter. Sixty-six sites did not show signs of recent burning. Burned and unburned sites were of a similar average size (6.7 and 7.2 ha respectively).

Adult regal fritillary butterflies were counted up to 30 m each side of a transect walked at 4 km/h on dry, warm, sunny days (25-34° C) with wind speed less than 20 km/h, between 08:30 h and 17:00 h. Transects ran the length of each site (range 130-1300 m long), parallel to and more than 30 m from the edge of the site. Butterfly counts were converted to the number of individuals/100 m of transect. If no regal fritillaries were recorded on the transect count, the entire site was searched with binoculars for 10 minutes, to record presence or absence.

Regal fritillaries were significantly more abundant on unburned than on recently burned sites. On average unburned sites had 3.2 butterflies/100 m, recently burned sites had 0.9 butterflies/100 m.

The presence or absence of these butterflies was unrelated to whether the sites were burned or not. Regal fritillaries were recorded at 70 of the 87 prairie remnants, with 1,112 butterflies counted in total.

The authors conclude that burning reduces abundance of regal fritillaries and recommend that prescribed burning is restricted to only a portion of a site in a given year.

Note: If using or referring to this published study, please read and quote the original paper, the abstract of which can be viewed at:

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