Dinocampus coccinellae females which eclose in mid-summer have the opportunity to oviposit in overwintered or in newly eclosed coccinellid hosts. Given the short further longevity of overwintered hosts, offspring fitness would be increased by ovipositing preferentially in young hosts. Laboratory choice tests show that female D. coccinellae do exhibit such a preference.
The parasitoid wasp Dinocampus coccinellae has been reported to parasitise adult, pupal and larval coccinellids. Field samples of larvae and pupae of Coccinella septempunctata, collected over 13 years in Britain, have failed to reveal any infected pre-imaginal individuals. The parasitisation rates of D. coccinellae into pre-imaginal and adult C. septempunctata were assessed in both choice and no-choice tests. Observations and test results revealed that British D. coccinellae have a strong preference to oviposit in adult coccinellids rather than larvae or pupae. This preference decreases as wasps age if denied oviposition opportunities.
A range of nuclear magnetic resonance (NMR) techniques, 1H liquid spectroscopy and T1 and T2 relaxation measurements, and microimaging, have been used to observe changes taking place within the bodies of live samples of Coccinella septempunctata, under a variety of conditions. NMR measurements showed that various organs could be seen and identified. It also showed that by changing the diet of the ladybird from aphids [Acyrthosiphon pisum (Harris)] to a standard artificial diet, major changes took place in the insects' tissues. By using a combination of all three techniques it was concluded that on changing the diet of C. septempunctata a mass of nutrient was built up within the insect's abdomen possibly in the same manner as happens before diapause. Changes in the response to NMR measurements were also seen after infection of C. septempunctata by the parasitoid wasp (Dinocampus coccinellae). Most significantly an image of the parasitoid larva could be seen within the body mass of the ladybird. It was concluded that NMR could become a major tool in the non-destructive study of insects not just as a means of studying anatomy but also to observe changes in the nature of body tissue.