TL;DR: Investigation of intraguild predation (IGP) between H. axyridis and eleven native non-target European coccinellids, including less common species which have not been studied so far within this context of non- target effects suggests that H.Axyridis may become a threat to a wide range of native aphidophagous coccINEllids sharing similar ecological niches except species showing high potential for chemical or physical protection.
Abstract: The coccinellid Harmonia axyridis (Pallas) has been used for augmentative and classical biological control in many environments. More recently it has invaded large parts of Europe and negative effects for native populations of aphidophagous coccinellids are beginning to emerge. Here we investigate intraguild predation (IGP) between H. axyridis and eleven native non-target European coccinellids, including less common species which have not been studied so far within this context of non-target effects. When first-instars of H. axyridis were paired with the native species, only Anatis ocellata (Linnaeus) and Calvia quatuordecimguttata (L.) were significantly superior to the former whereas H. axyridis was superior in three cases, i.e. against Aphidecta obliterata (L.), Coccinella septempunctata L. and Hippodamia variegata (Goeze). Non-significant results were obtained for all other pairings. Similar tests with the fourth larval instar revealed stronger IGP rates and H. axyridis was found to be superior in the interactions with Adalia bipunctata (L.), Adalia decempunctata (L.), A. obliterata, Calvia decemguttata (L.), C. quatuordecimguttata, C. septempunctata, H. variegata, Oenopia conglobata (L.) and Propylea quatuordecimpunctata (L.) whereas non-significant results were obtained for interactions with two other native species. Another experiment revealed that H. axyridis was able to prey more successfully upon egg of most native coccinellid species than vice versa. However, C. quatuordecimguttata eggs seem to be more protected against predation than those of the other species. Survival of first-instar H. axyridis was higher on conspecific eggs compared to eggs of any other species tested. Our results suggest that H. axyridis may become a threat to a wide range of native aphidophagous coccinellids sharing similar ecological niches except species showing high potential for chemical or physical protection.
TL;DR: In a laboratory choice experiment, the adult ladybirds showed a strong preference for A. pistaciae compared to A. gossypii, in agreement with field observation that O. conglobata contaminata is almost always found on psyllid colonies, even when aphids were plentiful on weeds in the pistachio orchards.
Abstract: The predatory beetle, Oenopia conglobata contaminata, is associated with the common pistachio psylla, Agonoscena pistaciae, the major pistachio pest in Iran. Successful development and reproduction on both A. pistaciae and Aphis gossypii (the major weed aphid in the pistachio orchards) indicated they were suitable prey for O. conglobata contaminata. Under ample prey supply, larval development on A. pistaciae was shorter and mortality was lower compared to those reared on A. gossypii. Furthermore, this ladybird attacks and destroys a large number of psyllid nymphs during the whole of its larval period (620±17 fourth stage nymphs) and also in its adult stage (191±7.5 4th stage nymphs daily). The optimum temperature for development was 30°C, the theoretical threshold for development was 13°C and thermal requirements from egg to adult was estimated as 196 degree-days (°D). Fecundity for the first 21 days of adult life was 387 and 355 eggs when females fed on A. pistaciae and A. gossypii nymphs, respectively. ...
TL;DR: This study yielded 33 coccinellid species feeding upon 59 aphid species, which were determined in cultivated and uncultivated fields in Kahramanmaras by collecting adults and immature stages by suction tube.
Abstract: Aphidophagus coccinellid (Coccinellidae: Coleoptera) species were determined in cultivated and uncultivated fields in Kahramanmaras. Furthermore, aphid species preyed upon by each coccinellid species were also specified. Adult coccinellids observed feeding on the aphid species were collected by suction tube while immature stages were collected with their preys and cultivated in order to obtain adults. This study yielded 33 coccinellid species feeding upon 59 aphid species. The most encountered coccinellid species that fed on many aphid species were Coccinella septempunctata (L.) 41, Hippodamia variegata (Goeze) 19, Scymnus subvillosus (Goeze) 15, Adalia fasciatopunctata revelieri Muls. 10 and Oenopia conglobata (L.) 9. On the other hand, the coccinellid species that fed on only 1 aphid species were Chilocorus bipustulatus (L.), Exochomus quadripustulatus (L.), Harmonia quadripunctata Puntop, Hyperaspis repensis (Herbst), Nephus nigricans Weise, Scymnus levaillanti Muls. and Stethorus gilvifrons (Muls.).
TL;DR: Although eight psyllophagous coccinellid species were collected in colonies of the CPP on pistachio trees, they did not regulate psyllid numbers below damaging levels, and conservation should assume a central role in biological control strategies for this pest.
Abstract: The abundance of coccinellids on pistachio trees was monitored at both a cultivated pistachio plantation and a wild pistachio growing area in Rafsanjan, Iran. Eleven ladybird species were identified from planted pistachio trees with Adalia bipunctata (Linnaeus) and Oenopia conglobata contaminata (Menetries) the most abundant ladybirds. At the wild pistachio plantation site, 17 coccinellid species were collected, with Brumus undulatus Weise the most abundant ladybird, followed by A. bipunctata and O. conglobata contaminata. Three species of Coccinellidae were evaluated for their potential for biological control of the common pistachio psylla (CPP), Agonoscena pistaciae Burckhardt and Lauterer. Coccinella undecimpunctata aegyptica (Reiche), Exochomus nigripennis (Erichson) and Hippodamia variegata (Goeze) developed successfully on A. pistaciae nymphs and reproduced successfully. Development and reproduction of these ladybirds were also examined on an alternative prey, the cotton aphid Aphis gossypii Glover, the most abundant aphid species on herbal weeds in pistachio orchards. The highest intrinsic rate of natural increase (rm value) was observed in C. undecimpunctata aegyptica, 0.22 and 0.23 when it was fed on A. pistaciae and A. gossypii Glover, respectively. In comparison, the lowest rm values (0.12 and 0.13) were found in E. nigripennis on the CPP and cotton aphid diets, respectively. Exochomus nigripennis consumed the largest number of psyllid nymphs during larval period, while the adults consumed the lowest number of psyllid nymphs daily. Although eight psyllophagous coccinellid species were collected in colonies of the CPP on pistachio trees, they did not regulate psyllid numbers below damaging levels. At present, conservation should assume a central role in biological control strategies for this pest.
TL;DR: The hypothesis that the invasive Harmonia axyridis makes better use of information from a plant-prey (Vicia faba - Aphis fabae) system compared to the native Oenopia conglobata is tested and support the hypothesis that H.Axyridis is more reactive to olfactory cues from the plant- prey system.
Abstract: Understanding the traits that might be linked with biological invasions represents a great challenge for preventing non-target effects on local biodiversity. In predatory insects, the ability to exploit habitats for oviposition and the physiological response to prey availability differs between species. Those species that respond more readily to environmental changes may confer to their offspring a competitive advantage over other species. Here, we tested the hypothesis that the invasive Harmonia axyridis (Coleoptera: Coccinellidae) makes better use of information from a plant-prey (Vicia faba - Aphis fabae) system compared to the native Oenopia conglobata. Y-tube olfactometer bioassays revealed that both species used olfactory cues from the system, but H. axyridis exhibited a more complete response. This species was also attracted by plants previously infested by aphids, indicating the capacity to exploit volatile synomones induced in plants by aphid attack. Oocyte resorption was investigated when different olfactory stimuli were provided under prey shortage and the readiness of new oogenesis was measured when prey was available again. H. axyridis exhibited higher plasticity in oogenesis related to the presence/absence of plant-aphid volatiles. Our results support the hypothesis that H. axyridis is more reactive than O. conglobata to olfactory cues from the plant-prey system.