1. Coccinellids (Coleoptera: Coccinellidae) provide important ecosystem services as biocontrol agents in contributing to the regulation of key agricultural pests. It is generally accepted that biodiversity of native coccinellid communities has been declining during recent decades. Here, we present the results of a long-term study of coccinellid communities and report an attempt to determine whether recent changes in land use have affected their composition.2. Coccinellids were sampled in cereal crops, on wild herbaceous plants and deciduous trees during two periods (1976-1983 and 2002-2010).3. There are similar species-rich communities of coccinellids on trees and wild herbaceous plants (average numbers of species 3.18 and 3.06, respectively) and a poorer community on cereals (2.63). Only a few species, associated with particular types of vegetation, differed in their absolute abundance in the first and second period. There was no obvious cause of this variation in abundance. Diversity of coccinellid communities was higher in the second than in the first period (Shannon-Wiener index 1.32 and 1.14 respectively), although the number of individuals was lower (average catch per sampling session 10.0 and 18.6 individuals respectively).4. Over the 35 years of this study, the compositions of the communities remained essentially similar with the numbers of particular species more closely correlated in the two periods on cereals (R 2 = 0.97) than on herbaceous plants (R 2 = 0.74) and trees (R 2 = 0.67).

While the use of alien insect species for food and feed can help to alleviate protein shortage and provide for a more sustainable feed production, their invasive potential should be considered since invasive alien species represent one of the five main global threats to biodiversity. In the European Union (EU), eight insect species have already been authorized to be used as feed ingredients for aquaculture organisms, pets, poultry, and pigs. These species were selected based on available national risk assessments, as most of them are non-native to Europe. However, it is not clear how these risk assessments truly consider all EU bioregions, given that the information used was mostly biased towards northern European regions. As a large proportion of invasive alien species already present in the EU were introduced unintentionally, it is therefore crucial to understand and manage the potential pathways of such introductions in a more effective way. Here, we provide a critical overview of the potential risks of rearing alien insect species as feed or as pet food (for both livestock and exotic pets) in the EU. The results showed that some of these insect species have an invasive potential, either due to their reproductive capacity in different climates or due to the fact that they have already established populations in areas where they were introduced, with negative effects on local ecosystems or causing economical losses. For this reason, it is recommended that risk assessments should be performed in other EU bioregions as well as monitoring programs to control the spread of insect species with invasive potential. In addition, other available native insect species with potential to be used as feed ingredients should be considered.

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Highest extinction risk and consequently biodiversity loss are predicted to occur in invertebrates, specifically insects, and these declines are expected to cascade onto ecosystem functioning and human well-being. Although this knowledge is intrinsically present in more traditional communities, in more urban environments, mapping ecosystem services can be an important tool to raise people's awareness on the importance of preserving insect diversity. After an extensive revision of the available literature, we used a rule-based approach to assess the provisioning, regulating and maintenance, and cultural services delivered by insects. We followed the Common International Classification of Ecosystem Services (CICES) and identified several potential indicators that may help underpin the mapping and valuation of the services delivered by insects. From our search, we extracted a total of 73 indicators, divided as 17 Provisional indicators, 27 Regulation and Maintenance indicators, and 29 Cultural indicators. We concluded that insects are providers of services in the three major 'Sections' of ecosystem services defined by CICES. Despite the lack of recognition of provisioning and cultural services, the indicators provided may help to raise awareness on the importance of the little things the run the world, in order to preserve traditional and technological uses of insects and their services.

The ecological effects of introduced species on native organisms can sometimes, but not always be significant. The risks associated with invasive alien pests are difficult to quantify. This paper concentrates on the ecological effects of invasive insect predators that feed on pest insects, because the former may potentially affect the biological control of the latter. The literature indicates that invasive predatory insects generally are resistant to changes in environmental conditions, long-lived and voracious with a high reproductive rate, high dispersal ability, able to spread very rapidly across landscapes and exhibit phenotypic plasticity. Their colonization of patches of prey may induce native predators to leave, but the evidence that invaders negatively affect the abundance of the native species is scarce and not persuasive. Insect predators do not substantially affect the abundance of their prey, if the ratio of generation time of the predator to that of the prey is large (the generation time ratio hypothesis), therefore the effect of an invasion by long-lived alien predators on systems consisting of long-lived native predators and short-lived prey on the abundance of the prey is hard to detect

Abstract. One of the most important services provided by biodiversity is thought to be the biological control of pests in agricultural landscapes, including aphids on cereals. The food webs potentially contributing to biological control of aphids primarily consist of polyphagous predators, parasitoids and pathogens. The problems of aphid pests have increased greatly since the 1970-ies, possibly as an effect of agricultural intensification, which is thought to have reduced diversity and abundance of these predators and parasites and consequently their biocontrol potential. The main objective of this study was to test this by measuring this potential for biological control of aphids, and relate it to agricultural intensification and predator abundance. We selected 30 farms distributed along agricultural intensification gradients, based on the amount of fertilizers applied per hectare. Estimates of ground-living predator density were obtained using pitfall trapping over a one-week period. Traps were placed inside the cereal fields, 10 m from the margin, in 2 replicates per field. Predation risk due to ground-living predators (biocontrol potential) was estimated by monitoring removal of aphids glued to labels. This was done in the same fields, in the immediate vicinity of the traps, over a period of 2 days. The proportion of aphids eaten per unit time was the response variable. We present the correlations between intensity of agricultural exploitation, predator abundance and biocontrol potential. The outcomes are not straightforward in that intensification begets a reduction in predator density and biocontrol potential. We discuss the potential confounding issues that might have affected our results.

Ladybirds (Coleoptera: Coccinellidae) provide services that are critical to food production, and they fulfill an ecological role as a food source for predators. The richness, António O. Soares and Danny Haelewaters contributed equally to this work.

Since typically there are many predators feeding on most herbivores in natural communities, understanding multiple predator effects is critical for both community and applied ecology. Experiments of multiple predator effects on prey populations are extremely demanding, as the number of treatments and the amount of labour associated with these experiments increases exponentially with the number of species in question. Therefore, researchers tend to vary only presence/absence of the species and use only one (supposedly realistic) combination of their numbers in experiments. However, nonlinearities in density dependence, functional responses, interactions between natural enemies etc. are typical for such systems, and nonlinear models of population dynamics generally predict qualitatively different results, if initial absolute densities of the species studied differ, even if their relative densities are maintained. Therefore, testing combinations of natural enemies without varying their densities may not be sufficient. Here we test this prediction experimentally. We show that the population dynamics of a system consisting of 2 natural enemies (aphid predator Adalia bipunctata (L.), and aphid parasitoid, Aphidius colemani Viereck) and their shared prey (peach aphid, Myzus persicae Sulzer) are strongly affected by the absolute initial densities of the species in question. Even if their relative densities are kept constant, the natural enemy species or combination thereof that most effectively suppresses the prey may depend on the absolute initial densities used in the experiment. Future empirical studies of multiple predator – one prey interactions should therefore use a two-dimensional array of initial densities of the studied species. Varying only combinations of natural enemies without varying their densities is not sufficient and can lead to misleading results.