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Existing assessments of the ecosystem service of pollination have been largely restricted to diurnal insects, with a particular focus on generalist foragers such as wild and honey bees. As knowledge of how these plant-pollinator systems function, their relevance to food security and biodiversity, and the fragility of these mutually beneficial interactions increases, attention is diverting to other, less well-studied pollinator groups. One such group are those that forage at night. In this review, we document evidence that nocturnal species are providers of pollination services (including pollination of economically valuable and culturally important crops, as well as wild plants of conservation concern), but highlight how little is known about the scale of such services. We discuss the primary mechanisms involved in night-time communication between plants and insect pollen-vectors, including floral scent, visual cues (and associated specialized visual systems), and thermogenic sensitivity (associated with thermogenic flowers). We highlight that these mechanisms are vulnerable to direct and indirect disruption by a range of anthropogenic drivers of environmental change, including air and soil pollution, artificial light at night, and climate change. Lastly, we highlight a number of directions for future research that will be important if nocturnal pollination services are to be fully understood and ultimately conserved., (© 2020 The Author(s).)

Climate change is a key driver of increased wildfire activity globally. Whilst the recovery of plant communities after fire is generally understood, the impacts on ecological processes, such as pollen transport by insects, have received little attention. We investigated the effects of wildfire on diurnal insects and pollen transport over 2 years following a large fire in Southern Portugal. By comparing samples collected at burned and adjacent unburned sites, we examined wildfire effects on (a) abundance and species richness of insects across seasons, (b) pollen being transported, (c) three of the most abundant species: Oxythyrea funesta, Heliothaurus ruficolis (both Coleoptera), and Apis mellifera (Hymenoptera). Wildfire and season had significant, interacting effects on the abundance of insects but not species richness. Abundance and species richness increased over time at both burned and unburned sites, most notably each spring. Pollen loads, and species richness, found on individual insects were significantly higher in burned sites in the first spring only, but generally increased with time after the wildfire. The abundance of O. funesta was similar between burned and unburned sites in the spring, but in the winter was significantly higher in burned sites; there were no significant differences in summer and autumn. H. ruficolis abundance was higher in burned sites. A. mellifera abundance was unaffected. Overall, across almost all the community metrics, our results suggest that wildfire affects pollen transport by diurnal insects, at least in the short term, but with time, these become similar to unburned habitats. [ABSTRACT FROM AUTHOR]

Wildfires drive global biodiversity patterns and affect plant–pollinator interactions, and are expected to become more frequent and severe under climate change. Post‐fire plant communities often have increased floral abundance and diversity, but the effects of wildfires on the ecological process of pollination are poorly understood. Nocturnal moths are globally important pollinators, but no previous study has examined the effects of wildfire on nocturnal pollination interactions.We investigated the effects of wildfire on nocturnal pollen‐transport networks. We analysed the abundance and species richness of moths and flowers, and the structure of these networks, at three burned and three unburned sites in Portugal for two years, starting eight months after a large fire.Nocturnal pollen‐transport networks had lower complexity and robustness following the fire than at nearby unburned sites. Overall, 70% of individual moths carried pollen, and moths were found to be transporting pollen from 83% of the flower species present. Burned sites had significantly more abundant flowers, but less abundant and species‐rich moths. Individual moths transported more pollen in summer at burned sites, but less in winter; however, total pollen transport by the moth assemblage at burned sites was just 20% of that at unburned sites. Interaction turnover between burned and unburned networks was high.Negative effects of fire upon moths will likely permeate to other taxa through loss of mutualisms. Therefore, if wildfires become more frequent under climate change, community resilience may be eroded. Understanding the responses of ecological networks to wildfire can inform management that promotes resilience and facilitates whole‐ecosystem conservation. [ABSTRACT FROM AUTHOR]

1. Moths are globally relevant as pollinators but nocturnal pollination remains poorly understood. Plant–pollinator interaction networks are traditionally constructed using either flower‐visitor observations or pollen‐transport detection using microscopy. Recent studies have shown the potential of DNA metabarcoding for detecting and identifying pollen‐transport interactions. However, no study has directly compared the realised observations of pollen‐transport networks between DNA metabarcoding and conventional light microscopy. 2. Using matched samples of nocturnal moths, we constructed pollen‐transport networks using two methods: light microscopy and DNA metabarcoding. Focussing on the feeding mouthparts of moths, we developed and provide reproducible methods for merging DNA metabarcoding and ecological network analysis to better understand species interactions. 3. DNA metabarcoding detected pollen on more individual moths, and detected multiple pollen types on more individuals than microscopy, although the average number of pollen types per individual was unchanged. However, after aggregating individuals of each species, metabarcoding detected more interactions per moth species. Pollen‐transport network metrics differed between methods because of variation in the ability of each to detect multiple pollen types per moth and to separate morphologically similar or related pollen. We detected unexpected but plausible moth–plant interactions with metabarcoding, revealing new detail about nocturnal pollination systems. 4. The nocturnal pollination networks observed using metabarcoding and microscopy were similar yet distinct, with implications for network ecologists. Comparisons between networks constructed using metabarcoding and traditional methods should therefore be treated with caution. Nevertheless, the potential applications of metabarcoding for studying plant–pollinator interaction networks are encouraging, especially when investigating understudied pollinators such as moths. We constructed nocturnal pollination networks for matched samples of moths from a U.K. agro‐ecosystem, using a conventional light microscopy approach and a DNA metabarcoding approach.DNA metabarcoding detected more pollen‐transport interactions per moth species than microscopy, and had a greater ability to separate morphologically similar or related pollen types.We detected previously unknown moth–plant pollen‐transport interactions, including pollen of several insect‐pollinated crop species, highlighting a need for research into the possible role of moths as ecosystem service providers. [ABSTRACT FROM AUTHOR]

Artificial light at night (ALAN) is an increasingly important driver of global change. Lighting directly affects plants, but few studies have investigated indirect effects mediated by interacting organisms. Nocturnal Lepidoptera are globally important pollinators, and pollen transport by moths is disrupted by lighting. Many street lighting systems are being replaced with novel, energy-efficient lighting, with unknown ecological consequences. Using the wildflower Silene latifolia, we compared pollination success and quality at experimentally lit and unlit plots, testing two major changes to street lighting technology: in lamp type, from high-pressure sodium lamps to light-emitting diodes, and in lighting regime, from fullnight (FN) to part-night (PN) lighting. We predicted that lighting would reduce pollination. S. latifolia was pollinated both diurnally and nocturnally. Contrary to our predictions, flowers under FN lighting had higher pollination success than flowers under either PN lighting or unlit controls, which did not signifi- cantly differ from each other. Lamp type, lighting regime, and distance from the light all significantly affected aspects of pollination quality. These results confirm that street lighting could affect plant reproduction through indirect effects mediated by nocturnal insects, and further highlight the possibility for novel lighting technologies to mitigate the effects of ALAN on ecosystems. [ABSTRACT FROM AUTHOR]