Sibling rivalry gone mad! Can a parasitoid alter competition between aphid embryos?

Prior experiments have shown that soybean aphids (Aphis glycines Matsumura) stung by the aphidiine braconid Lysiphlebus orientalis Starý can lay nymphs before dying that develop to be more fecund than aphids born of not-stung mothers.  Also, L. orientalis shows a preference for 4^th instar and adult aphid hosts, which are able to reproduce before succumbing to a developing parasitoid.  These two factors may be at least partially responsible for L. orientalis being unable to control soybean aphid in long-term cage studies despite high parasitoid numbers.  One proposed mechanism for this phenomenon is that parasitoid venom and teratocytes kill most aphid embryos, but not all, freeing the survivors from “competition” with their siblings within the mother aphid.  These embryos then develop in a more nutrient-rich maternal environment before birth, and are therefore expected to be larger and less numerous.  I will discuss results from a series of soybean aphid dissections characterizing aphid embryo and parasitoid teratocyte development.  Implications for our understanding of compensatory dynamics in consumer-resource systems will also be addressed.