Modern agriculture has numerous consequences, such as soil degradation, toxicants
accumulation and toxicity for non-target organisms. For this reason, researchers refer to the
discovery of harmless pest control tools as an alternative to synthetic insecticides. A solution
might be a natural origin compounds such as plant-derived substances. Among them are
plants secondary metabolites, which may be bioinsecticides, due to their biological activity
like inhibition of food intake or insect growth and development.

Insects can produce many eggs, so oogenesis and oviposition could be the worthwhile aim
of pest control. This study aimed to evaluate the influence of four plant metabolites: (E)-2-
decenal, furfural, 2-undecanone and (E,E)-2-4-decadienal on ovarian development, taking into
account the morphology of final oocytes, the number of eggs and larvae hatching the Tenebrio
molitor beetle, a common storage pest. We used compounds in 2 concentrations: 10^-5
and 10^-7M injected into an adult females insect.

We showed a significant decrease in the volume of terminal oocytes after application of 2-
undecanone at concentration 10^-5 M and an increase for (E,E)-2-4-decadienal and furfural
treatment. In the lower concentration of chemicals, we noted a gentle drop in the volume of
terminal oocytes only after (E)-2-decenal. In each case, follicle epithelium was well
developed. We observed a significant decrease in the number of laid eggs only for the 2-
undecanone in the lower concentration 10^-7 M. In any other case, there were no significant
changes. Moreover, the number of hatching larvae after application tested compounds in 10^-5
and 10^-7 M dose was lower as an effect of lying unfertilized eggs by females.

Obtained results suggest a disturbing effect of tested compounds on pests reproduction