How do proteins play an important role in the mating of japanese beetles?
a. by storing lipids for future use by the reproductive cells
b. by sending and detecting chemical messages
c. by making hormones tha increase the drive to mate
d. by breaking down proteins for energy used in reproduction

The answer is B.

The female beetle releases proteins as pheromones and these are detected  by protein receptors on the male beetles. The proteins play the role of guiding the male to the female for mating purposes.

Pheromones are a type of hormone, but unlike most other hormones, they are ectohormones, that is they act outside the body of the organism that is secreting them and impact the behavior of another individual. Hormones usually only affect the organism or individual that is secreting them.