Development of captive rearing and translocation methods for Taylor’s checkerspot in south Puget Sound: 2009-2010 and an update for 2010-2011. 2010 ACUB Project Progress Report.

The goal of this project is to establish new populations Taylor’s checkerspot in south Puget Sound to stem their declining status and move toward recovery. Funding was awarded to support ongoing captive rearing and associated release and monitoring of Taylor’s checkerspot in South Puget Sound in 2009-2010 and 2010-2011. This report summarizes results to date. In both 2009 and 2010, we observed differences in development time, growth rate, and activity levels of captive postdiapause checkerspot larvae between indoor and outdoor rearing treatments that appear to result from lower night time temperatures, although differences in light intensity may also play a role. Differences in pupation rate and rate of return to diapause between rearing treatments in 2009 did not appear to hold in 2010; these data have yet to be statistically tested. There was little difference in average weights and sizes of individuals reared outdoors vs. indoors, regardless of year, and all measures increased in 2010 compared to 2009, suggesting a learning curve effect. There is some suggestion that genetics may play a role in rate of return to diapause; this is worthy of additional study. Observations of Taylor’s checkerspot mating, oviposition and hatching success in 2008-2010 suggest that sunlight is a key factor affecting success. A more detailed look at these relationships may suggest strategies for increasing captive success. Survival rates from hatching to postdiapause and to adult continue to be high in captivity, with survival rates in nearly all developmental stages consistently above 90 percent.


Translocation success has been generally favorable, although with mixed results between years. Most postdiapause larvae released in 2009 appear to have perished as a result of a lengthy cold and wet spring. While this loss of larvae was tragic, the presence of a fairly sizeable flight season at SCS that year (releases occurred in previous years) in contrast to two and one checkerspots observed at the new sites (SCN and PCM), is evidence for on-site reproduction at SCS, and is the most encouraging news yet. Four sites (two new sites – SCN, PCM – from 2009 and two release sites – SCS, R50 – for 2010) were monitored during the 2010 flight season; four to six distance sampling surveys were conducted at each. No adults were observed at SCN or PCM. Flight season lengths at SCS, R50 and r76 (source site) were almost twice as long as typically seen in Puget Sound and ranged from a minimum of 34 to 40 days. The peak single day count at SCS was 46 (range 1-46) and at R50 was 67 (range 4-67); in total, 154 (SCS) and 211 (R50) Taylor’s checkerspot observations were collected during surveys of these sites. The first release of 259 adult checkerspots occurred in 2010; this appears to be a viable strategy for release and/or captive population management. Net survey data have not been summarized or analyzed, but initial results suggest the number of naturally-eclosing adult butterflies is quite high. Searches for prediapause larvae at SCS and R50 revealed that reproduction occurred at both sites; both Plantago lanceolata (introduced host) and Castilleja hispida (native host) were used for oviposition.