Which characteristic identifies the saw-tooth grain beetle?

Which characteristic identifies the saw-tooth grain beetle?

• A. They are bright blue
• B. They have a metallic sheen
• C. Eggs hatch in a week and adults can live up to 3 years
• D. They are aquatic in larval stage

Answer: (C)

This item tests life-history traits of stored-product beetles, focusing on how quickly they develop and how long adults live. The saw-tooth grain beetle is a common pest in grain and pantry products, and its eggs hatch in about a week. At the same time, adults can persist for a long time under favorable conditions, up to months or even years. This combination—rapid egg development and long adult lifespan—fits the statement that eggs hatch in a week and adults can live up to three years, making it the best identifying characteristic among the options. The other options don’t fit: the beetle is not bright blue or metallic in color, and its larvae are not aquatic but develop within stored plant material.

This item tests life-history traits of stored-product beetles, focusing on how quickly they develop and how long adults live. The saw-tooth grain beetle is a common pest in grain and pantry products, and its eggs hatch in about a week. At the same time, adults can persist for a long time under favorable conditions, up to months or even years. This combination—rapid egg development and long adult lifespan—fits the statement that eggs hatch in a week and adults can live up to three years, making it the best identifying characteristic among the options. The other options don’t fit: the beetle is not bright blue or metallic in color, and its larvae are not aquatic but develop within stored plant material.