An abundance-occupancy time-lag during the decline of an arctiid tiger moth

The positive interspecific abundance-occupancy relationship is one of the m ost general patterns in ecology. Positive intraspecific relationships shoul d also exist within species over time, and so a species should occupy more sites in years when it is more abundant. However, positive intraspecific re lationships are not as ubiquitous as their interspecific counterparts. It h as been hypothesized that low levels of temporal variation and time-lags be tween changes of abundance and occupancy within species make positive intra specific relationships difficult to detect. We analyse 31 years of U.K.-wid e data on the decline of an arctiid moth, Arctia caja, which provides the f irst empirical demonstration of an abundance-occupancy time-lag for any spe cies. Such time-lags are probably common and we discuss their impact on the intraspecific abundance-occupancy relationship and their implications for conservation management. In A. caja, the time-lag indicates that the declin e of the species is probably not driven by habitat loss.