부산대학교 도서관

As evidence of global insect declines continues to mount, insect conservationists are becoming increasingly interested in modeling the demographic history of at-risk species from long-term survey data. However, certain entomological survey methods may be susceptible to temporal biases that will complicate these efforts. Entomological light traps, in particular, may catch fewer insects today than they once did due solely to increases in anthropogenic light pollution. Here we investigate this possibility by comparing the demographic histories of corn earworm moths (Helicoverpa zea) estimated from pairs of blacklight and pheromone traps monitored at the same farms. We find a stark decline in blacklight trap efficacy over 25 years of monitoring in Delaware, USA, mirrored over 10 years of monitoring in New Jersey, USA. While the precise causes of this decline remain a subject for discussion, the practical consequences are clear: insect conservationists cannot fully rely on long-term trends from entomological light traps.
Implications for insect conservation: H. zea populations appear to have remained largely stable over the past 25 years when assessed using pheromone trap data; when assessed using blacklight trap data, however, they appear to have declined precipitously. This disparity is consistent with a gradual loss in light trap efficacy due to concomitant increases in anthropogenic light pollution. Unfortunately, many nocturnal insects of conservation concern have historically been monitored via light traps alone. Going forward, insect conservationists should seek out alternative sources of monitoring data against which to calibrate estimates of demographic history obtained from light traps.