Insect biomass study, first year

Over 25 years of research hints at a stark, harsh truth: worldwide, both the bio-diversity and biomass of insects has declined dramatically, leading to such alarming phrases as “insect Armageddon” and “insect apocalypse.” We suspect this decline is happening in our own backyard, but we don’t have the data to prove it yet. This is changing, however. In a multiyear project sponsored in part by Metchosin Foundation, local Metchosin families have adopted Malaise traps, tent-like devices that allow scientists to figure out the amount (biomass) and distribution of flying insects across the municipality of Metchosin.

          During the pilot project in the summer of 2018, insects caught in the traps were collected at two-week intervals. Over the winter, the University of Victoria scientist Dr. Neville Winchester and his students meticulously sorted each of the collections (145 in total) into major flying insect orders (e.g., flies, bees, wasps and ants). The number of individuals and the biomass for each insect order was recorded.

          The total biomass for each trap varied, based on location. It is clear that some areas are very productive in terms of flying insect biomass, others less so. What attributes do some of these sites have that promote higher insect collection numbers? This, in part, is what will be measured in the summer of 2019, during the second collection season. One result, however, that has already emerged: the amount of flying insects in Metchosin tends to peak in the middle of the growing season (July).

          Dr. Winchester, his students, and the Metchosin Malaise trap adopters are looking forward to a second season of collections.

          Kennedy Nikel assisted Dr. Winchester in collecting and describing the first year’s data. Her honour’s thesis on the study can be viewed here.

The total insect biomass for each of the 15 Metchosin Malaise trap sites from July 22 to October 26, 2018. Each circle size is the relative total biomass, based on 145 collections, and the black dots indicates the location of the trap.

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