Concentrated in New Jersey, the Carolinas and Florida, Hesperia attalus slossonae is declining within its coastal barrens and sand hills range. Within The Nature Conservancy's Manumuskin River Preserve in southern New Jersey, a persistent population occurs on sand mine remains, where larvae utilize at least three genera of native grasses and the adults nectar virtually exclusively on the exotic spotted knapweed (Centaurea maculosa). To determine this population's size, distribution and habitat requirements, Mark-Release-Recapture [MRR] studies were conducted. A novel anaesthetic method using cyanide was developed to provide safe handling and reduce traumatic escape response. Analysis of the MRR data by Jolly-Seber methodology indicate that this population contained ca. 100 adults in 2000 and 450 adults in 2001. The flight season was about 10-15 days longer in 2001 than in 2000, although it started July 8-11 both years. In 2000 only a few adults were still present on July 31 whereas in 2001 males were just beginning to decline and females had not yet peaked on August 4. In 2000 peak daily numbers were about 55% of the total for that brood (50% for males only) but in 2001 the peak daily numbers were only about 16% of the total (21% for males only). Since the observed eclosion pattern varied so greatly between 2000 and 2001, census methods based on daily numbers will not give a reliable index of annual population changes. For now, the only reliable way of monitoring annual changes in this population is by MRR.
Species 1: Lepidoptera Hesperiidae Hesperia attalus (dotted skipper)
Keywords: conservation, mark-release-recapture
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