Inferring Biological Control Potential of Adult Predatory Coccinellids Using Life History Traits and Putative Habitat Preference

Aspects of the nutritional ecology and life histories of five predatory coccinellids (Coleoptera: Coccinellidae)-two arboreal predator species, Oenopia conglobata contaminata (Menetries) and Adalia bipunctata (Linnaeus), and three herbaceous dwelling predator species, Coccinella undecimpunctata aegyptica (Reiche), Exochomus nigripennis (Erichson), and Hippodamia variegata (Goeze) (Coleoptera: Coccinellidae)-were compared when fed either Agonoscena pistaciae Burckhardt and Lauterer (Hemiptera: Aphalaridae), the key psylla pest of pistachio trees, or Aphis gossypii Glover (Hemiptera: Aphididae), a common aphid on herbaceous plants in pistachio orchards. The putative habitat preferences of four of the five coccinellids studied were consistent with their performance on the major herbivore present in those two habitats in terms of net reproductive rate. Oenopia conglobata contaminata and Ad. bipunctata showed higher net reproductive rates when fed on pistachio psylla prey, whereas C. undecimpunctata aegyptiaca and E. nigripennis had better reproductive output on aphid prey. Moreover, E. nigripennis was the most specialized of these generalist predators, eating more and reproducing better when fed aphids. Hippodamia variegata was relatively unaffected by the diet offered, suggesting greater ability to switch among herbivore prey and perhaps better potential as a biocontrol agent with abilities to exploit Ag. pistaciae without large life history tradeoffs.

Food Utilization, Development, and Reproductive Performance of Coccinella septempunctata (Coleoptera: Coccinellidae) Feeding on an Aphid or Psylla Prey Species

Laboratory studies were conducted to determine the effect of two prey species, Agonoscena pistaciae Burckhardt and Lauterer (Hemiptera: Aphalaridae) and Aphis gossypii Glover (Hemiptera: Aphididae) on the biology, reproduction, and food consumption indices of Coccinella septempunctata L. (Coleoptera: Coccinellidae). Both species of prey were readily consumed by C. septempunctata larvae and adults. The predator was able to successfully utilize the psylla prey for larval development, but failed to lay eggs when fed this prey. However, A. gossypii fully supported both development and reproduction of C. septempunctata. Dry mass of ingested food was similar on both diets for each larval instar. However, the dry mass gained during each stadium for C. septempunctata was significantly greater with A. gossypii prey. The aphid diet was superior to the psylla diet in terms of food conversion efficiency as larvae consumed aphids more efficiently than psyllas, regardless of the higher consumption index on the psylla prey. Our results confirm that the study of prey suitability for larvae and adult stages of predatory lady beetles should be studied separately.

Predator performance: inferring predator switching behaviors based on nutritional indices in a coccinellid-psylla-aphid system

BACKGROUND

Knowledge of the nutritional ecology of predatory coccinellids is important for the selection of efficient biocontrol agents. We examined five species common in pistachio orchards and determined their nutritional indices when fed on the key psylla pest of the system, Agonoscena pistaciae, in contrast to an alternative prey common on herbaceous plants in orchards, Aphis gossypii.

RESULTS

Feeding experiments revealed that Oenopia conglobata contaminata and Adalia bipunctata may be more efficient as biocontrol agents for A. pistaciae than for A. gossypii, as A. bipunctata had a high efficiency of conversion of ingested food and a high relative growth rate and O. conglobata contaminata had a high consumption index on psylla prey. In contrast, the nutritional indices of Coccinella undecimpunctata aegyptica, Hippodamia variegata and Exochomus nigripennis suggest that A. gossypii was a more suitable host food.

CONCLUSION

Where both the psyllids and the aphids occur in pistachio orchards, especially under conditions of unlimited access to A. gossypii, C. undecimpunctata aegyptica, H. variegata and E. nigripennis may prefer to move from psylla-infested leaves of pistachio trees and travel to and stay on weeds to feed on A. gossypii. The value of using nutritional ecology as a means of understanding and predicting biocontrol outcomes and selecting better candidates for mass rearing is discussed. © 2018 Society of Chemical Industry.

Ooencyrtus (Hymenoptera: Encyrtidae), egg parasitoids of the pistachio green stink bugs (Hemiptera: Pentatomidae) in Iran

This paper deals with three species of Ooencyrtus Ashmead (Hymenoptera: Encyrtidae) obtained from eggs of the green stink bug, Brachynema germarii (Kolenati) (Hemiptera: Pentatomidae) infesting pistachio plants in Iran. Two new species, Ooencyrtus iranicus Hayat & Mehrnejad, sp. nov. and O. pistaciae Hayat & Mehrnejad, sp. nov., are described, and O. telenomicida (Vassiliev) is newly recorded from Iran, redescribed and illustrated. A key to some species considered similar to the species treated here is also given.