What are the motifs in The Silence of the Lambs by Thomas Harris?

Ambition is a recurring idea in the story. Ambition is Clarice Starling's driving motivation. Starling is proud of her father and mother, and so she never speaks ill of her indigent upbringing. However, the reader learns, through Starling's reactions to the poverty of Frederica Bimmel, just how much Starling hated growing up poor in the country. As Starling looks at the ancient, dusty rubbish piled up in Frederica's home, she wonders if Frederica had a friend good enough to take through that mess.