Starvation During Larval Stage Driving Population Decline in the Butterfly Specialist Luehdorfia chinensis Leech 1893 (Lepidoptera: Papilionidae)

Host plant limitation poses a major threat to the endangered specialist butterfly Luehdorfia chinensis, whose larvae are strictly monophagous on Asarum spp. (A. sieboldii or A. forbesii). To simulate natural starvation caused by host plant scarcity, third- to fifth-instar larvae were subjected to a three-day deprivation treatment, and the effects on individual fitness traits—including larval development, pupal duration, and adult fecundity—together with population dynamics were assessed. Starvation significantly prolonged larval development, shortened the pupal stage, reduced female fecundity, and markedly decreased key population parameters, such as the intrinsic rate of increase (rₘ) and the net reproductive rate (R₀). Population projections further indicated that repeated starvation stress could reduce population size by more than 83% within two years, potentially intensifying genetic drift, inbreeding depression, and demographic instability, and ultimately increasing extinction risk. These findings provide direct evidence that host plant limitation drives population decline in L. chinensis, contribute to the broader understanding of global butterfly declines, and underscore the critical importance of conserving and restoring essential habitat resources. Moreover, they highlight the relevance of the resource-based habitat concept for the effective protection of specialist species.