Biological abilities of storage pests required for the successful penetration of food packages or seeds

Storage pests cause enormous damage to stored seed commodities and packaged food. Most of the work published on pest risk assessment concentrates mainly on the effects of “pest –package” or “pest-seed” interactions: i.e. if some species is able (or not able) to penetrate in a sound kernel or package. Based on such “YES-NO outcomes”, the particular stored product pest species is then categorized to either as a “primary” or “secondary” seed feeder; or “penetrator” or “invader” of packages. However, less research attention is paid to the functional explanations of the observed interaction-outcomes. This work therefore deals with comparison of morphological adaptation in various species storage insects with regards to their penetration abilities. For this analysis our original data as well as data from literature were used. As the most important morphological (pre-) adaptations, modulating penetrative/invasive success of storage insect pests, have been recognized: (i) shape and hardness of mandibles, (ii) size and strength of mandibular muscles, (iii) morphology of tarsi enabling climbing and/or firm stance on smooth surfaces. In addition to the morphological adaptations the specific genetically pre-programmed behavioural patterns and abilities may also play a significant role. It will be demonstrated that the above morphological abilities must be taken into account while establishing standard methods of testing of various packages in terms of their sensitivity to penetration/invasion by various species s of storage pests.