author(s)
Ines Ksentini, Taieb Jardak and Najiba Zeghal

abstract
Trichogramma species are known to prefer young host eggs, However, they could found themselves in environments populated in majority with old host eggs, or could become increasingly aged as they could spend days searching fruitlessly for hosts. As anticipation of their behaviours in such circumstances, One, two and three-day old Trichogramma oleae and Trichogramma cacoeciae females, were examined in order to determine the impact of alternating two different Ephestia kuehniella egg qualities (fresh and four-days old), on their fecundity and their offspring’s survivorship. Results showed that T. oleae females significantly accepted more fresh eggs than older eggs, whatever was the presentation order of these eggs during both tests 1 and 2. However, T. cacoeciae significantly parasitized more, the eggs presented during the first half of tests 1 and 2, whatever was their quality. Also, female age effect on parasitization preferences was more visible on T. oleae adults, which tended to accept more deteriorated eggs when females’ age increased. These results showed that both species behaved differently when put under the same circumstances.