Augmentative biological control in greenhouses in Japan.

In Japan, augmentative biological control is mainly implemented in greenhouses using arthropod natural enemies. Two imported natural enemy species, Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) against spider mites and Encarsia formosa Gahan (Hymenoptera: Aphelinidae) against the greenhouse whitefly, Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae), were first commercialised in greenhouses in 1995, followed by the commercialisation of other exotic species. Exotic arthropod natural enemies are used to control both exotic and indigenous pests in greenhouses. Currently, the most popular exotic natural enemy species are predatory mites such as P. persimilis and Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae). Recently, there has been a shift from using exotic to using indigenous natural enemies in greenhouses. Currently, the importation of generalist predators for augmentative biological control is very difficult in Japan. Several collaborative studies have been conducted in Japan to develop biological control using indigenous natural enemies. These studies developed innovative technologies, such as new banker plant systems based on combinations of two natural enemies or flightless Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae). Indigenous natural enemies have been commercialised following the registration of Orius strigicollis (Poppius) (Hemiptera: Anthocoridae). Biological control can be achieved using an indigenous strain of Nesidiocoris tenuis (Reuter) (Hemiptera: Miridae) with a banker plant system, on which the bug can reproduce without alternative prey. Research and development of biological control using indigenous natural enemies should be continued in Japan.

HARMONIA AXYRIDIS (PALLAS, 1773) (COLEOPTERA: COCCINELLIDAE) IN MOSCOW CITY AND YALTA CITY: ITS COMPETITION WITH NATIVE SPECIES OF COCCINELLIDS AND THE INFLUENCE OF PARASITOIDS ON ITS NUMBER

The Asian ladybird Harmonia axyridis is an invasive species that is rapidly spreading around the world. Occupying new territories, H. axyridis often causes a decrease in the biodiversity of native species of coccinellids, competing with them for food resources. A comparison of H. axyridis with six species of ladybirds was made in terms of the ratio of the number of individuals and the degree of infestation with parasitoids. In Moscow city, the most widespread species of ladybirds was Adalia bipunctata (67.1%), H. axyridis ranks second (16.5%). The total infestation of H. axyridis pupae with parasitoids is 1.8% in Moscow city and 12.2% in Yalta city. Infestation with parasitoids of other ladybird species in Moscow city is much higher: from 11.0% to 36.4%. Thus, parasitoids effectively regulate the number of native ladybird species, but have an insignificant effect on the number of the invasive species H. axyridis .

Predatory Ability of Harmonia axyridis (Coleoptera: Coccinellidae) and Orius sauteri (Hemiptera: Anthocoridae) for Suppression of Fall Armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae)

The lepidopteran pest, Spodoptera frugiperda (JE Smith), spread rapidly after its first detection in China and has caused significant yield loss to maize production in the southwestern part of the country. Although natural enemies of S. frugiperda are present in the field, biological control using naturally distributed predators is ineffective because their underlying populations are too low. To enhance our understanding of the potential role of natural enemies in regulating this invasive pest, functional response experiments were conducted to quantify the response of two predators, Orius sauteri (Poppius) (Hemiptera: Anthocoridae) and Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), in terms of consumption of S. frugiperda. Experimental results revealed that the predatory effects of nymphs of O. sauteri and H. axyridis on the eggs and larvae of S. frugiperda fitted Holling’s Type II functional response model. Importantly, the theoretical maximum number of prey consumed per day (Na-max), the instantaneous attack rate (a′) and the handling time (Th) of O. sauteri nymphs on S. frugiperda eggs were 15.19, 0.7444 and 0.049 d, respectively; and the parameters on first instar larvae of S. frugiperda were 700.24, 0.5602 and 0.0008 d, respectively. These data contrast to those of H. axyridis, where the Na-max, a′ and Th of adults on eggs of S. frugiperda were 130.73, 1.1112 and 0.085 d, respectively, and on the first instar larvae of S. frugiperda were 1401.1, 0.8407 and 0.0006 d, respectively. These results revealed that H. axyridis is a highly voracious predator of the eggs and young larvae of S. frugiperda and O. sauteri could also be used as biocontrol agent of this pest. Our work provides a theoretical framework for the application of natural enemies to control S. frugiperda in the field. Further research is required to strategize conservation biological control approaches in the field to increase populations of these predators and enhance the suppression of S. frugiperda.

Exotic predators are not better biocontrol agents: the harlequin ladybird is not the most voracious in Mexico

The use of exotic species for pest biocontrol has been a common pathway for introduction and dispersal of invasive species that may have undesired outcomes. Biocontrol agents are believed to be a less damaging alternative than pesticides, but some species may also prey on or parasitize native species or outcompete them for resources. The harlequin ladybird (Harmonia axyridis) is a well-known biocontrol agent originally from Asia that has established invasive populations in 59 countries around the globe. Harlequin ladybirds are generalist predators that in addition to pests prey on an array of different species including other coccinelids’ eggs and larvae. In Mexico, native ladybirds that share ecological requirements with harlequin ladybirds are at risk of being outcompeted and predated upon. The aim of our study was to compare the foraging efficiency of harlequin ladybirds against three species of native coccinelids when preying on aphids. We investigated the foraging behaviour of ladybirds alone and in pairs with a conspecific, a native heterospecific or an exotic heterospecific. We found that the native Cycloneda sanguinea was the species that consumed the most aphids, while Hippodamia convergens was the fastest to find and consume each aphid. Harlequin ladybirds and H. convergens consumed the same number of aphids while P. vittigera consumed less. Conspecific competition was stronger than heterospecific competition. We discuss the suitability of using the exotic invasive harlequin ladybird for aphid biocontrol in comparison with native coccinelids.

Jack, Master or Both? The Invasive Ladybird Harmonia Axyridis Outperforms Its Native Counterpart Despite Similar Levels of Plasticity

The plasticity of performance traits is expected to promote the successful invasion of species. Therefore, the comparison of reaction norms of invasive species with native competitors should enhance predictions of alien species establishment. Yet, most studies focus on a reduced set of traits, rarely in combination, or do not include trait variability to make predictions of establishment success. Here, we acclimated individuals to a cold, medium or warm temperature regime and measured critical thermal limits, life-history traits, and starvation resistance of the globally invasive Harmonia axyridis and its native counterpart Cheilomenes lunata. The native C. lunata had higher thermal plasticity of starvation resistance and higher upper thermal tolerance than H. axyridis. By contrast, H. axyridis outperformed C. lunata in most life-history traits. We combined trait responses, transport duration and propagule pressure to simulate the final number of beetles established in the introduced site in cold, medium and warm scenarios, where beetles also experienced a heatwave once established. Although C. lunata initially outcompeted the invasive species during transport, more H. axyridis survived in all environments because of higher life-history trait responses, in particular, higher fecundity. Despite increased starvation mortality in the warm scenario, H. axyridis established successfully given sufficient propagule size. By contrast, in the event of a heatwave, H. axyridis numbers plummeted and higher numbers of the native species established in the cold scenario. This study underscores the importance of considering a combination of traits and respective cascading effects when estimating the establishment potential of species and responses to climate warming.

Qualitative lysine crotonylome analysis in the ovarian tissue of Harmonia axyridis (Pallas)

Lysine crotonylation (Kcr) is a newly discovered posttranslational modification (PTM), which has been studied at the proteomics level in a few species, with the study of Kcr in female fertility and in insect species is still lacking. Harmonia axyridis (Pallas) is a well-known beneficial insect used as a natural biological control agent against aphids in agriculture. Here, global Kcr identification in ovarian tissue of H. axyridis at diapause stage was performed to reveal potential roles for Kcr in H. axyridis ovarian cellular processes, female fertility and diapause regulation. In total, 3084 Kcr sites in 920 proteins were identified. Bioinformatic analyses revealed the distribution of these proteins in multiple subcellular localization categories and their involvement in diverse biological processes and metabolism pathways. Carbohydrate and energy metabolism related cellular processes including citric acid cycle, glycolysis and oxidative phosphorylation appeared be affected by Kcr modification. In addition, regulation of translation and protein biosynthesis may reflect Kcr involvement in diapause in H. axyridis, with Kcr affecting ribosome activities and amino acid metabolism. Moreover, Kcr modulation H. axyridis ovary development regulation may share some common mechanism with Kcr participation in some disease progression. These processes and pathways were uncovered under diapause stage, but possibly not enriched/specific for diapause stage due to limitations of qualitative proteomics experimental design. Our results informs on the potential for Kcr modifications to regulate female fertility and insect physiology.