ORIGINAL RESEARCH ARTICLE Intraguild interactions of a generalist predator, Orius albidipennis, with two Bemisia tabaci parasitoids Sahar Pirzadfard 1 & Nooshin Zandi-Sohani 1 & Fariba Sohrabi 2 & Ali Rajabpour 1 Received: 2 July 2019 /Accepted: 12 November 2019 # African Association of Insect Scientists 2020 Abstract The influence of intraguild predation between Orius albidipennis Reuter and two parasitoids, Eretmocerus mundus Mercet or Eretmocerus eremicus Rose and Zolnerowich, on the suppression of Bemisia tabaci Gennadius was investigated under laboratory conditions. Through a non-choice test, the 2nd and 3rd instar nymphs of B. tabaci and larval and pupal stages of both parasitoids were offered separately to both 5th instar nymphs and adults of O. albidipennis. In the choice test, various combinations of parasitized and unparasitized preys were provided for two stages of O. albidipennis, and their preference was recorded. Both predator stages readily preyed upon unparasitized and parasitized nymphs of B. tabaci. The most predation of O. albidipennis adults occurred on E. eremicus larvae, while for the 5th instar nymphs, it was recorded on E. eremicus larvae and pupae. The least predation of both stages was recorded on unparasitized nymphs of B. tabaci and E. mundus pupae. None of the prey combinations showed any obvious preference of adults and the 5th instars of O. albidipennis toward parasitized or unparasitized prey. Keywords Anthocoridae . Aphelinidae . Parasitoid . Predator . Preference Introduction Intraguild predation (IGP) is one of the possible interspecific interactions that occur when different natural enemies are re- leased to control the same pest in a system (Polis et al. 1989). IGP commonly occurs in food webs, both in natural and man- aged systems, where species compete for a common pest prey/host. IGP may occur between predators, parasitoids, and predators and parasitoids (Polis et al. 1989; Rosenheim et al. 1995; Rosenheim 1998). Predator–parasitoid interaction occurs in two different modes. In addition, predators may prey directly on parasitoids or indirectly by consuming the parasitized host and the associated immature parasitoid (Rosenheim et al. 1995). Insects represent different interactions with IGP. IGP may disrupt biological control and thus lead to an increase in the pest population (Erbilgin et al. 2004; Rosenheim et al. 1993; Sohrabi et al. 2013). However, the effect of IGP on biological control is not always negative (Herrick et al. 2008). Positive effects have also been shown when an increase occurs in the efficacy of natural enemies (Gardiner and Landis 2007; Schausberger and Walzer 2001; Snyder et al. 2004). Bemisia tabaci Gennadius is a very harmful pest world- wide for many crops, especially greenhouse crops such as ornamentals, tomato, pepper, bean, eggplant, and cucumber. More than 600 species of different plants are the hosts of B. tabaci (Oliveira et al. 2001). Biological control of B. tabaci mostly relies on parasitoids from family Aphelinidae such as the genus Eretmocerus and Encarsia (Hymenoptera: Aphelinidae) (Gerling et al. 2001; Naranjo and Ellsworth 2005; Zandi-Sohani et al. 2009). Eretmocerus mundus Mercet is a parasitoid that is able to efficiently control B. tabaci (Gabarra et al. 2006 ; Stansly et al. 2005). Eretmocerus eremicus Rose and Zolnerowich are native to the Americas (Rose and Zolnerowich 1997). In Iran, this par- asitoid has been reported from Gilan Province (Shahbazvar et al. 2010). In greenhouse crops, polyphagous predatory in- sects of the genus Orius (Heteroptera: Anthocoridae) are also used to control B. tabaci (Sohrabi et al. 2013). Orius albidipennis Reuter, a common predator in several regions of Iran, has been reported as a promising generalist biocontrol agent in greenhouses and fields (Salehi et al. 2016). Therefore, * Nooshin Zandi-Sohani zandi@asnrukh.ac.ir 1 Department of Plant Protection, Faculty of Agriculture, Agricultural Sciences and Natural Resources University of Khuzestan, Mollasani, Ahvaz, Iran 2 Department of Plant Protection, Faculty of Agriculture and Natural Resources, Persian Gulf University, Bushehr, Iran International Journal of Tropical Insect Science https://doi.org/10.1007/s42690-019-00075-w