I would use grams.
Millimeter
kilograms
A kilogram.
Grasshopper generally grow up to 2 inches long. The average mass is around 17 grams. Some species may weigh more or less.
The metric standard unit of mass is the kilogram (Kg).
Grams.
The kilogram.
Kilogram
The gram.
The SI (metric) unit for mass is the kilogram.
Pounds.
The SI unit for mass in the metric system is the kilogram.