dc.description.abstract | The number of insects caught in pitfall traps in two
habitats in Wyoming, a mixed woods and a sagebrush flat, may
be considered a direct measurement of the insect activity in
each of the two habitats. The trap catches showed that greater overall activity occurred in the habitat with diversified
vegetation, the mixed woods, than in the habitat with uniform
vegetation, the sagebrush flat. Both habitats displayed greater
activity by day than by night, but slightly more activity
occurred at night in the mixed woods than in the sagebrush flat,
although the ratios of day to night activity in the Woods and
in the Sage did not differ significantly. Daily fluctuations
in activity were due mainly to fluctuations in the weather, as
shown by the significant correlations of some air and soil temperature
and relative humidity measurements with the day or night
catches of insects in the two habitats. The observed changes in
activity due to weather also affected the ratio of day to night
activity in both habitats. The insects sampled in this study
were caught in one-gallon jars 1/4 filled with dilute alcohol,
and sunken into the ground to their rims. 16 jars were systematically
placed in each habitat within an area of 25 m., and
checked morning and evening on 3 consecutive days of each week,
during the 4 weeks of July, 1973. 1,247 mature insects were collected and removed from the two habitats altogether. The
results obtained by statistically evaluating the trap catches
in the two habitats indicate that pitfall trapping is valuable
in directly comparing the activity of insect communities. | en_US |