  Sex determination in the order Hymenoptera is based on arrhenotoky,
hymenopteran males are usually haploid and females diploid. Males of the
Ichneumonidae Diadromus pulchellus, solitary endoparasitoid of A. assectella
pupae are normally haploid, but diploid males are present in a natural
population and can be obtained in a experimental population. The future of an
ovocyte laid by mated females of the solitary endoparasitoid Diadromus
pulchellus was characterised by 6 probabilities related to the sex and the
development of the ovocyte. The probabilities of fertilisation of female
ovocyte (k1) or non-fertilisation (k3) showed that an inseminated female
functioned as a unmated female for half of the time (since k1= 0.492 and k3 =
0.455) with the probability of fertilisation of male ovocyte (k2 = 0.053).The
survival probabilities of each type of ovocyte showed that an ovocyte had a
high probability of developing up to the adult stage, although the difference
between the calculated sex ratios at laying (males / females = 1.032) and at
emergence (0.90) revealed a slight reduction in the number of haploid sons. The
probabilities of fertilisation and of viability of all the ovocytes laid by
each of the 33 mated females were analysed by an ascending hierarchical
classification of Euclidean distances and by an analysis of their principal
components. The 33 mothers were distributed into 4 distinct sub-groups
characterised by a sex ratio varying from an exclusive presence of females to
an exclusive presence of males. Our hypothesis was that this distribution in 4
sub-sets could not simply result from the random nature of the sample.
