Monitoring Spruce Budworm with Light Traps: The Effect of Trap Position

Table 1

Descriptive parameters related to captures of adult spruce budworms at light traps deployed in tree canopies and forest clearings at seven locations—years (mean ± SE). For each parameter, values with different superscripts are significantly different (paired -tests, < 0.05). Data were subjected to logarithmic (number of moths) and arcsine (proportional data) transformations to reduce heterogeneity of variance.

Independent variable	Position of traps		-test
	Tree canopy	Forest clearing
Abundance of moths (1000)	24.5 ± 5.6^a	1.9 ± 1.1^b	5.02	0.0024
Sex ratio ()	0.193 ± 0.02^a	0.444 ± 0.024^b	7.51	0.0003
Median date of flight	192.4 ± 1.5^a	192.7 ± 1.6^a	0.26	0.8041
Duration of flight (day)	8.7 ± 1.3^a	7.2 ± 1.1^a	1.20	0.2741
Proportion of adults (modal date)	0.251 ± 0.026^a	0.514 ± 0.077^b	3.71	0.0100