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Providing safe and qualitative drinking water is becoming increasingly important due to climate change and population growth. Water towers are often used to provide storage and ensure water pressure for drinking water distribution. However, microbial regrowth of water is still a challenge during storage and distribution. Moreover, water towers can be used as an aggregation site by insects, mainly flies (Diptera). In this study, ten water towers in Belgium were monitored for 8 months with sticky traps to evaluate fly species diversity, abundances and activity. The results showed the presence of three fly species: Thaumatomyia notata (yellow swarming fly), Musca autumnalis (face fly) and Pollenia spp. (cluster fly). The flies entered the towers in autumn and took shelter against wintering conditions in cracks and crevices, especially on the highest floors where the water tank is located. In this way, flies can come into contact with the drinking water. Based on the monitoring campaign, a risk assessment matrix was set up to determine risks of possible microbial water contaminations caused by flies in water towers. This was validated by a worst-case experiment in laboratory conditions. Face flies (living and dead) were added to tap water to evaluate their influence on microbial water quality and safety using several techniques such as 16S rRNA amplicon sequencing, flow cytometric cell counts and fingerprinting. Our research showed that flies in drinking water promote bacterial growth and change the phenotypic resident drinking water community. Furthermore, new genera such as Pseudomonas and Acinetobacter as well as the coliforms Serratia fonticola and S. liquefaciens were detected when flies were added to tap water. Hence, prevention and intervention measures are important in water quality management to avoid contact between flies and drinking water in water towers. In this study, several effective prevention methods are discussed, such as sealing ventilation, overflow and weep holes with insect screens with adequate mesh size and covering water tanks.

I here review the potential effects of climate change on aphidophagous ladybirds and their future diversity. Aphidophagous ladybirds face challenges arising directly from climatic change and indirect challenges due to the effect of climate on their aphid prey and other organisms with which they interact. Ladybirds show at least some potential to respond to changes of climate through genetic change or phenotypic plasticity, notably through changes in colour pattern, dormancy and voltinism but also through thermal physiology and microhabitat or habitat plasticity. Phenological changes will likely occur in many aphidophagous species arising from relations with their prey. Changes in aphid abundance may lead to changes in ladybird prey associations over the season. The tendency to prey on multiple aphid species will insulate many ladybird predators from decline resulting from changes in the abundance of particular aphids. Like other insects, the geographic ranges of aphidophagous ladybird species will change as they track the climate. This is evidenced by the fossil record of ladybirds and by recent changes in ladybird biogeography. Such changes may be accompanied by a degree of thermal or phenological adaptation. It is likely that cold-adapted ladybirds and some island species will go extinct. Specialised species may also be threatened. A problem in assessing the threat to the latter is the minimal amount of research carried out on specialised species. In summary, aphidophagous ladybirds exhibit some potential resilience against climate change, but future climatic effects on their overall biodiversity are not fully clear.

I here review the potential effects of climate change on aphidophagous ladybirds and their future diversity. Aphidophagous ladybirds face challenges arising directly from climatic change and indirect challenges due to the effect of climate on their aphid prey and other organisms with which they interact. Ladybirds show at least some potential to respond to changes of climate through genetic change or phenotypic plasticity, notably through changes in colour pattern, dormancy and voltinism but also through thermal physiology and microhabitat or habitat plasticity. Phenological changes will likely occur in many aphidophagous species arising from relations with their prey. Changes in aphid abundance may lead to changes in ladybird prey associations over the season. The tendency to prey on multiple aphid species will insulate many ladybird predators from decline resulting from changes in the abundance of particular aphids. Like other insects, the geographic ranges of aphidophagous ladybird species will change as they track the climate. This is evidenced by the fossil record of ladybirds and by recent changes in ladybird biogeography. Such changes may be accompanied by a degree of thermal or phenological adaptation. It is likely that cold-adapted ladybirds and some island species will go extinct. Specialised species may also be threatened. A problem in assessing the threat to the latter is the minimal amount of research carried out on specialised species. In summary, aphidophagous ladybirds exhibit some potential resilience against climate change, but future climatic effects on their overall biodiversity are not fully clear.

Simple Summary The ladybird Cryptolaemus montrouzieri is a widely commercialized biological control agent of mealybugs. The green lacewing Chrysoperla carnea is mainly released for aphid control, but also attacks mealybugs. Both species have shown potential to control various economically important species of mealybug pests of greenhouse crops. As these predators may be simultaneously present in a crop, the risk of negative interactions between both predators was evaluated in this laboratory study. Individuals of different life stages of either predator were placed together in petri dish arenas and predation was recorded. Attacks between individuals of both species were frequently observed, with lacewing larvae being the dominant predators in most combinations. When mealybug nymphs or lepidopteran eggs were added to the arena, the incidence of attacks between the predators was greatly diminished. The relevance of these observations for the use of the predators in the biological control of greenhouse pests is discussed. The ladybird Cryptolaemus montrouzieri and the green lacewing Chrysoperla carnea have shown potential for use in augmentative biological control of mealybug pests in greenhouse crops. In the context of combining these predators within an integrated pest management system, the risk of negative intraguild interactions between both predators was evaluated in a laboratory setting. Different life stages of either predator were confronted in petri dish arenas containing a Ficus benjamina leaf, and after 24 h the incidence and direction of intraguild predation (IGP) was recorded for each combination. The effect of adding Planococcus citri nymphs or Ephestia kuehniella eggs as extraguild prey on the level of IGP was also studied. IGP was frequently observed between the two predator species and was asymmetrical in favour of C. carnea in most cases. The presence of extraguild prey reduced the number of IGP events between the predators to a similar extent. The relevance of the observed intraguild interactions for the combined use of these predators in protected cultivation is discussed.

International audience; Microorganisms comprise the majority of earth's biodiversity and are integral to biosphere processes. Biological invasions are no exception to this trend. The success of introduced macroorganisms can be deeply influenced by diverse microorganisms (bacteria, virus, fungus and protozoa) occupying the whole range of species interaction outcomes, from parasitism to obligate mutualism. This large range of interactions, often coupled with complex historical and introduction events, can result in a wide variety of ecological dynamics. In this chapter, we review different situations in which microorganisms affect biological invasions. First, we consider outcomes of microorganism loss during the introduction of alien species. Second, we discuss positive effects of microorganisms on the invasiveness of their exotic hosts. Third, we examine the influence of microorganisms hosted by native species on the success of introduced species. Finally, in an applied perspective, we envisage how microorganisms can be used (i) to better decipher invasion processes and (ii) as biological control agents.

A mixed species release of parasitoids is used to suppress outbreaks of tobacco whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae); however, this biocontrol may be inhibited by interspecific interactions. We investigated the effects of mixed releases of natural enemies of B. tabaci on predation rates, parasite performance and adult parasitoid emergence under greenhouse conditions. We tested the polyphagous predatory ladybird Harmonia axyridis (Coleoptera: Coccinellidae) and two whitefly-specific parasitoids, namely Encarsia formosa and Encarsia sophia (both, Hymenoptera: Aphelinidae). Harmonia axyridis exhibited the lowest rates of predation when released with each parasitoid than with both parasitoid species together and showed a significant preference for non-parasitized nymphs as prey. Both E. formosa and E. sophia parasitized more B. tabaci when released with the ladybird than when the wasps were released either alone or mixed with the other parasitoid. We also found that the presence of H. axyridis significantly reduced adult parasitoid emergence; the highest rate of adult emergence was obtained with parasitoids released alone. Our results indicate that different combinations of natural enemies can influence observed rates of predation, parasitism and parasitoid emergence. Therefore, the combination of natural enemies to be used for a particular biological control program should depend on the specific objectives.

Aphids can cause major environmental problems in urban areas. One important problem is the annual outbreaks of lime aphid, Eucallipterus tiliae (L.) (Hemiptera: Aphididae), which spoil the surroundings of lime trees by depositing honeydew. To date no environmentally friendly method has been demonstrated to yield effective control of lime aphids. Attempts are made in some cities to control lime aphids by releasing larvae of the native two-spot ladybird beetle, Adalia bipunctata (L.) (Coleoptera: Coccinellidae). However, it is known that adult ladybird beetles disperse soon after release, and there is little indication they provide control of the aphids. Here, we demonstrate experimentally that releases of a flightless strain of A. bipunctata, obtained from natural variation in wing length, can reduce the impact of honeydew from lime aphid outbreaks on two species of lime in an urban environment. Both larvae and adult beetles were released, and we discuss the contribution of the flightless adults to the decline in honeydew.

The effect of temperature on the functional response of female adults of the two-spot ladybird, Adalia bipunctata L. (Coleoptera: Coccinellidae) was examined in petri dish arenas containing sweet pepper leaves infested with different densities of the green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae). The predator showed a type II functional response at three tested temperatures ranging from 19A degrees C to 27A degrees C. The theoretical maximum number of prey captured by the predator increased with temperature. Based on the random predator equation, the estimated attack rates ranged from 0.13 h(-1) at 19A degrees C to 0.35 h(-1) at 27A degrees C on a leaf area of 20-25 cm(2). There was no significant difference between the attack rates of the predator at 23A degrees C and 27A degrees C. Handling time significantly decreased as temperature increased from 19A degrees C (0.39 h) to 27A degrees C (0.24 h). This study shows that A. bipunctata displays high predation rates on M. persicae for a wide range of temperatures, indicating its potential for augmentative releases against this aphid pest. The limitations of the predictions generated by functional response experiments are discussed.

Intraguild predation among natural enemies is common in food webs with insect herbivores at their base. Though intraguild predation may be reciprocal, typically one species suffers more than the other and frequently exhibits behavioural strategies to lessen these effects. How such short-term behaviours influence population dynamics over several generations has been little studied. We worked with a model insect community consisting of two species of aphid feeding on different host plants (Acyrthosiphon pisum on Vicia and Sitobion avenae on Triticum), a parasitoid (Aphidius ervi) that attacks both species, and a dominant intraguild predator (Coccinella septempunctata) that also feeds on both aphids (whether parasitized or not). As reported previously, we found A. ervi avoided chemical traces of C. septempunctata. In population cages in the laboratory, application of C. septempunctata extracts to Vicia plants reduced parasitism on A. pisum. This did not increase parasitism on the other aphid species, our predicted short-term trait-mediated effect. However, a longer term multigenerational consequence of intraguild predator avoidance was observed. In cages where extracts were applied in the first generation of the study, parasitoid recruitment was reduced leading to higher population densities of both aphid species. S. avenae thus benefits from the presence of a dominant intraguild predator foraging on another species of aphid (A. pisum) on a different food plant, a long-term, trait-mediated example of apparent mutualism. The mechanism underlying this effect is hypothesized to be the reduced searching efficiency of a shared parasitoid in the presence of cues associated with the dominant predator.

We report a case of genetic linkage between the two major loci underlying different wing traits in the two-spot ladybird beetle, Adalia bipunctata (L.) (Coleoptera: Coccinellidae): melanism and winglessness. The loci are estimated to be 38.8 cM apart on one of the nine autosomes. This linkage is likely to facilitate the unravelling of the genetics of these traits. These traits are of interest in the context of the evolution of intraspecific morphological diversity, and for the application of ladybird beetles in biological control programs.

The challenge of using ladybird beetles for biological control of insect pests such as aphids is that the adult beetles tend to fly away from the host plants. Therefore, flightless ladybirds might improve biocontrol. There are several artificial ways to obtain flightless beetles, but it may be preferable to use natural variation in flight ability. We investigated, for the first time, biocontrol by inundative augmentation of natural flightless morphs of the ladybird beetle Adalia bipunctata. Microcosm experiments using single leaves with one of three species of aphid revealed no differences in consumption behavior between flightless and winged beetles. Monitoring for 48 h of single, caged pepper plants infested with aphids of Myzus persicae nicotianae or Aulacorthum solani showed that flightless beetles had a longer residence time on the plants than winged beetles. This only translated into significantly better biocontrol of M. persicae. Despite their difference in residence time, both beetle morphs reduced the population growth of A. solani. This is probably explained by the tendency of A. solani to drop from the plant upon disturbance, and we predict that flightless beetles may outperform winged ones in the long term. Overall, our results provide a proof of principle that natural flightless A. bipunctata can improve biocontrol of aphids by ladybird beetles. However, we recognize that the effect of biocontrol will vary with the species of aphid used and that further examination in long term and large scale experiments is required.