Trade-offs between reproductive traits and the influence of food intake during pregnancy in the garter snake, Thamnophis elegans. | Mendeley

I don't have access to the full paper, but the introduction states that gravid females ate 43% as much as non-gravid females; this suggests that pre-copulatory condition and nutrition are very important. I'll try to find the whole paper and see how the feeding rates of gravid females affected litter size and scrub size. My guess would be that condition at copulation determines litter size while food intake after copulation determines scrub size.