What are the motifs in Numbers: Book 1 by Rachel Ward?

THe need for companionship is a recurring idea. Jem has distanced herself from others most of her life but she still needs companionship and love. This need is evidenced by the fact that she responds to Spider's offer of friendship even though she knows he's going to die in a short time. Spider also seems to need Jem's friendship. Though he is more outgoing, he seems to have a shortage of real friends. Jem says at one point that others see him as a young black boy filled with aggression.