Feeding preference and intraguild interactions between the parasitoidTrichogramma achaeaeand the predatorMacrolophus pygmaeus, two biological agents ofTuta absoluta

Abstract

BACKGROUNDTuta absoluta is an exotic species and a major pest of tomato crops in Europe. Macrolophus pygmaeus and Trichogramma achaeae are two biocontrol agents widely used in integrated pest management programs of the South American tomato pinworm Tuta absoluta. In this study, we evaluated under laboratory conditions the (i) voracity of M. pygmaeus females fed on single diets of Tuta absoluta eggs parasitized or unparasitized by Trichogramma achaeae, (ii) voracity and feeding preference of M. pygmaeus females provided with mixed diets of Tuta absoluta eggs unparasitized and parasitized by Trichogramma achaeae and (iii) effect of competitive and intraguild interactions between M. pygmaeus and Trichogramma achaeae on the number of Tuta absoluta eggs consumed and/or parasitized. Lastly, we assessed under field conditions the effect of interspecific and intraspecific interactions between natural enemies on the number of Tuta absoluta eggs consumed and/or parasitized.RESULTSMacrolophus pygmaeus consumed more unparasitized than parasitized eggs of Tuta absoluta. Under mixed diet regimes, Manly indices revealed a feeding preference for unparasitized eggs, and a decrease in the total number of eggs consumed, as the proportion of available parasitized eggs increased, whereas the unparasitized eggs were consumed in direct proportion to their availability. Conspecific interactions between M. pygmaeus, in contrast to Trichogramma achaeae, revealed the possible occurrence of intraspecific competition. For intraguild heterospecific interactions, the number of Tuta absoluta eggs consumed by M. pygmaeus and parasitized by Trichogramma achaeae was lower than that predicted for additive and non‐interactive scenarios. Under field conditions, a significant difference between the conspecific treatment and heterospecific treatments revealed a slightly higher success rate in controlling Tuta absoluta when both M. pygmaeus and Trichogramma achaeae were used simultaneously.CONCLUSIONMacrolophus pygmaeus prefers unparasitized eggs of Tuta absoluta but inflicts intraguild predation on Trichogramma achaeae. In conspecific experiments, mutual interference between M. pygmaeus predators intensifies as the number of individuals increases, but for Trichogramma achaeae, it occurs in an unpredictable manner. Adding Trichogramma achaeae could significantly increase the level of control of Tuta absoluta compared to what could be achieved when only M. pygmaeus is present in glasshouse tomatoes. © 2023 Society of Chemical Industry.

Ephestia kuehniella eggs as a surrogate host to test feeding preference and intraguild interactions between and Macrolophus pygmaeus and Trichogramma achaeae

“…The results obtained in the current experiments, namely prey consumption on single diets and feeding preference under mixed diets displayed by females of M. pygmaeus, were contrasted with the one published in Borges et al (2023b), in which T. absoluta was used as food resource. For such, we contrasted the independent factors i) host species (eggs of T. absoluta or E. kuehniella) and ii) host quality (parasitized or unparasitized eggs), by using a Generalized Linear Model 9 (GZLM) was used and a Pairwise multi comparisons were performed with P values corrected using Bonferroni test.…”

“…The effect of intraguild interactions between M. pygmaeus and/or T. achaeae on the number of eggs consumed and/or parasitized, was also contrasted with the results by Borges et al (2023b).…”

“…For such, we i) assessed prey consumption of M. pygmaeus fed on single diets of E. kuehniella eggs unparasitized or parasitized by T. achaeae, ii) compared prey consumption and feeding preference of M. pygmaeus when provided with mixed diets of E. kuehniella eggs both unparasitized and parasitized, (iii) assessed the effect of the density of either M. pygmaeus or T. achaeae on the number of E. kuehniella eggs consumed and/or parasitized (conspecific experiments and. heterospecific experiments) and iv) discuss the results obtained with the ones published in a recent paper by Borges et al (2023b) in which T. absoluta eggs were used as prey.…”

“…In the Mediterranean area two native natural enemies are currently being used in augmentative biological control programs: Macrolophus pygmaeus (Rambur 1839) (Hemiptera: Miridae) and Trichogramma achaeae Nagaraja and Nagarkatti (Hymenoptera: 6 Trichogrammatidae) (Desneux et al 2022). Laboratory and field studies using these native natural enemies, either separately or simultaneously, have shown promising results in controlling T. absoluta in protected cultures (Oliveira et al 2017;Oliveira et al 2023;Borges et al 2023a;2023b;in press).…”

“…Very recently we undertook a study aiming to assess prey preference and intraguild interactions between M. pygmaeus and T. achaeae viewing their use in biological control programs. A limitation to the speed and fluidity of the experiments was the amount of labor and multi-tasks needed to have all the biological material for the experiments (see methodological details in Borges et al 2023a;2023b). Producing large quantities of T. absoluta eggs is an extremely laborious task requiring large investment of time, equipment and man hour work.…”