Biodiversity benefits pollination, pest control, and crop productivity but suffers from land-use intensification.

Significance: Decades of research have fostered the now-prevalent assumption that noncrop habitat facilitates better pest suppression by providing shelter and food resources to the predators and parasitoids of crop pests. Based on our analysis of the largest pest-control database of its kind, noncrop habitat surrounding farm fields does affect multiple dimensions of pest control, but the actual responses of pests and enemies are highly variable across geographies and cropping systems. Because noncrop habitat often does not enhance biological control, more information about local farming contexts is needed before habitat conservation can be recommended as a viable pest-suppression strategy. Consequently, when pest control does not benefit from noncrop vegetation, farms will need to be carefully comanaged for competing conservation and production objectives.

It is assumed that wild honey bees have become largely extinct across Europe since the 1980s, following the introduction of exotic ectoparasitic mite (Varroa) and the associated spillover of various pathogens. However, several recent studies reported on unmanaged colonies that survived the Varroa mite infestation. Herewith, we present another case of unmanaged, free-living population of honey bees in SE Europe, a rare case of feral bees inhabiting a large and highly populated urban area: Belgrade, the capital of Serbia. We compiled a massive data-set derived from opportunistic citizen science (>1300 records) during the 2011–2017 period and investigated whether these honey bee colonies and the high incidence of swarms could be a result of a stable, self-sustaining feral population (i.e., not of regular inflow of swarms escaping from local managed apiaries), and discussed various explanations for its existence. We also present the possibilities and challenges associated with the detection and effective monitoring of feral/wild honey bees in urban settings, and the role of citizen science in such endeavors. Our results will underpin ongoing initiatives to better understand and support naturally selected resistance mechanisms against the Varroa mite, which should contribute to alleviating current threats and risks to global apiculture and food production security.

This paper presents over 66 tritrophic parasitoid-aphid-plant associations from wetland habitats in western Palaearctic, comprising 24 parasitoid species, 24 aphid hosts and over 30 plant species, based on records from 25 countries. Seven new associations are documented. About half of the established tritrophic associations (34) were recorded rarely, while 6 associations have been documented more than 100 times each, based on 4 common and widespread Aphidiinae species. The majority of recorded parasitoid species (16) are involved in only 1–2 tritrophic associations, 7 species were recorded in 3–5 associations, and one species (Praon necans) is a member of even 16 different associations based on wetland habitats. Generally, the most frequently recorded associations are based on some very common and widespread parasitoids not specific for this class of habitats. On the basis of distribution, host range and habitat specialization we have divided aphid parasitoid associations in wetland habitats into three ecological categories. The most specialized group, containing rarely recorded parasitoid species whose distribution and aphid hosts are strictly associated with wetland habitats, is potentially highly vulnerable to extinction. The role of aphids associated with wetland habitats as reservoirs for economically important parasitoid species is discussed and a key for the identification of aphid parasitoids in wetland habitats is provided.