- ItemOpen AccessLepidoptera of North America 19. Pawnee montane skipper Hesperia leonardus montana Skinner (Lepidoptera: Hesperiidae): habitat requirements, distribution and abundance, population responses to forest thinning and wildfire, and genetic investigations(Colorado State University. Libraries, 2023) Ellis, Scott, author; Sovell, John, author; Painter, Mikele, author; Drummond, Boyce A., editor; C.P. Gillette Museum of Arthropod Diversity, publisherThis Contribution summarizes field studies conducted between 1985 and 2021 on the habitat and biology of the federally listed Pawnee montane skipper butterfly (Hesperia leonardus montana Skinner) and its population responses to forest thinning treatments and large wildfires within the same time frame. Other smaller studies and genetic information are also summarized. H. l. montana (Hlm) occupies a total known range of less than 80 square miles within the South Platte River drainage southwest of Denver, Colorado. Habitat consists of xeric conifer woodland dominated by an overstory of ponderosa pine (Pinus ponderosa), an understory of blue grama grass (Bouteloua gracilis), which is the larval foodplant, and dotted gayfeather (Liatris punctata), the primary adult nectar source. Peak adult Hlm densities during late August to early September generally ranged from 1 to 4 individuals per acre. Based on Hlm densities measured in 1986 belt transects, August abundance estimates ranged from 77,000 to 141,000 individuals within suitable habitat. If the Two Forks Reservoir were built, approximately 21 percent of Hlm suitable habitat would be inundated, and from 23 to 42 percent of the Hlm population would be lost, inferred from the 1986 skipper density measurements. The overall pattern of adult Hlm annual densities at the Trumbull forest thinning transects is interpreted as recovery from the 2001-2002 drought through 2007. Then density varied from year to year in response to both above and below average annual precipitation and temperature, but a general trend of increasing population size through 2021. Forest thinning treatments that were implemented at Trumbull from 2000 through 2004 are compatible with the continued survival of the skipper. A tree thinning pattern that preserves a conifer canopy cover of approximately 30 percent and 100 trees (5 inches or greater in diameter) per acre appears optimum for maintenance of Hlm habitat. Post-Hayman fire Hlm monitoring in moderately to intensively burned areas documents slow population recovery over time. Monitoring indicates that Hlm occurrence is negatively associated with standing dead trees, which may mean that intensively burned areas will remain sparsely inhabited over the long term. This avoidance behavior means that crown fires that kill all mature conifers represent a significant risk to the suitable habitat extent for this species. Genetic samples from Hlm and congeners were analyzed to investigate species and subspecies relationships and determine Hlm population substructure. Analysis of cytochrome c oxidase subunit I (COI) showed H. leonardus haplotypes are distinct from other Hesperia species, but it was not possible to distinguish H. leonardus subspecies from one another based on the observed COI haplotypes. Population structure analysis of Hlm samples using single nucleotide polymorphism (SNP) genotyping revealed gene flow throughout the range of Hlm, but clusters of more related individuals were distinguishable along a geographic gradient from north to south. Two individuals collected 4 miles south of the 1986 study area were noticeably different in the SNP analysis. The area includes remnants of ponderosa pine forest with blue grama and dotted gayfeather that survived the Hayman Fire. More investigation is needed to determine if this finding indicates an isolated subpopulation.
- ItemOpen AccessLepidoptera of North America 18. 2021 butterfly inventories within Boulder County open spaces, Boulder, Colorado(Colorado State University. Libraries, 2022-04-04) Chu, Janet, author; Hirschfeld, Sue, author; Kelly, Venice, author; C.P. Gillette Museum of Arthropod Diversity, publisherThe butterfly inventories continued for the 18th year in a few of the Boulder County Open Space properties. However, because of the Calwood Fire during October 17, 2020, two of the survey areas were inaccessible; Plumely Canyon and the work road through the streamlet near the Lichen Trail. Geer Watershed had been burned, but the meadows above the Resident Ranger's Cabin and associated streamlets were made accessible with our 2021 permit. Cabbage Whites (Pieris rapae), Orange Sulphurs (Colias eurytheme) and Common Wood-nymphs (Cercyonis pegala) were more numerous when compared to 2015-2020 populations before the burn. In 2021 within other Open Spaces, Anne U. White and Caribou, the resident species produced noticeably large populations: Julia Orangetips (Anthocharis julia), Pine Whites (Neophasia menapia), Northern Checkerspots (Chlosyne palla), Common Wood-nymphs, Small Wood-nymphs (C. oetus), Common Checkered-skippers (Burnsius communis). On the other hand, the well adapted non- native Cabbage Whites were again the most common during the long season; Variegated Fritillaries (Euptoieta claudia) and Dainty Sulphurs (Nathalis iole) were numerous flying in from colonies in the eastern plains and low foothills where their host plants were plentiful. 95 species were seen in 2021: 129 species between 2004 and 2021 in the county Open Spaces. 203 species are on the record for Boulder County (Butterflies and Moths of America 2021) website. The average number of species per year observed within the Open Spaces by this team is 88.
- ItemOpen AccessLepidoptera of North America 17. 2019 butterfly inventories within Boulder County open spaces, Boulder, Colorado(Colorado State University. Libraries, 2020-03) Chu, Janet, author; C.P. Gillette Museum of Arthropod Diversity, publisherButterfly Inventories took place for the 16th consecutive year within Boulder County Open Space properties. Over the years 2004-2019, 129 butterfly species have been sighted in eight of the Open Spaces; 76 were counted in this year alone. More photographers than ever before on the team this season captured nearly 93 of the known 202 butterflies in Boulder County. These Butterfly Research Volunteers helped collect data during 340 field hours. Venice Kelly studying on Sherwood Road and in the main Caribou Ranch contributed at least 53 hours on site. Other volunteers did not complete the past transects due to several reasons: trail being moved in the mid-season to a newer, grassier area from Geer Watershed, Heil Valley Ranch; unsafe high-speed bicycle interactions on the Loop Trail, Walker Ranch; personal reasons on Anne U. White Trail. Late wet, cold spring weather slowed butterfly emergences, resulting in some normally typically spring species flying with the early summer species. Certain summer species flew later into the early fall. August and September were mostly hot and dry allowing the continued flight by many brush-foot (Nymphalidae) butterflies.
- ItemOpen AccessLepidoptera of North America 16. Butterflies of the Sierra Nevada(Colorado State University. Libraries, 2020) Davenport, Ken, author; C.P. Gillette Museum of Arthropod Diversity, publisherThis publication covers the butterfly fauna of the Sierra Nevada mountain range in eastern California and a small area of the Carson Spur in western Nevada. At present (2019), 192 species, 104 subspecies and 15 segregates are known to have occurred within the range at least twice. Five additional species have been recorded at least once in the Sierra Nevada. This publication covers distributions of these butterflies within the Sierra Nevada and three National Parks, their habitats, flight periods and taxonomic issues based on current knowledge.
- ItemOpen AccessLepidoptera of North America 12. Butterflies - 2018 inventories in nine Boulder County open spaces(Colorado State University. Libraries, 2018) Chu, Janet, author; C.P. Gillette Museum of Arthropod Diversity, publisherThis was the fifteenth year butterflies were inventoried on nine select properties within Boulder County Parks and Open Space (BCPOS) lands. The trend for all butterfly species was determined for all surveyed Open Spaces and shows a downward trend of approximately -1.3 Individuals per Research Hour per Year. This trend (R2=0.4) explains 40% of the variation for years 2004 through 2018 which is a decrease of almost 3% /year. This leads to the conclusion that the butterfly population will be significantly diminished over time under present conditions. Our results indicate that most butterfly species are not reproducing successfully enough to keep their population numbers stable within Boulder County. Cabbage Whites (Pieris rapae) and Aphrodite Fritillaries (Speyeria aphrodite) were the most numerous of individual butterflies while Field Crescents (Phyciodes pulchella) represented the widest distribution flying in each of the Open Spaces. These resident butterflies are indicator species, as they are primary for determining if the environment is remaining vital. Of course, the BCPOS properties are influenced by state-wide and national environmental changes. Fourteen volunteers were in the field 70 days completing 175 hours of Research Hours (RH) in 2018 recording data and taking photographs. Often team members hiked somewhat near each member to observe, then experienced members input their sightings into the single day's data. The season's cumulative volunteer hours totaled 500. Of course, those following a transect were usually hiking alone, their numbers available separately, but in 2018 these were counted within the seasonal data.