Moths complement bumblebee pollination of red clover: a case for day-and-night insect surveillance

Abstract

Recent decades have seen a surge in awareness about insect pollinator declines. Social bees receive the most attention, but most flower-visiting species are lesser known, non-bee insects. Nocturnal flower visitors, e.g. moths, are especially difficult to observe and largely ignored in pollination studies. Clearly, achieving balanced monitoring of all pollinator taxa represents a major scientific challenge. Here, we use time-lapse cameras for season-wide, day-and-night pollinator surveillance of Trifolium pratense (L.; red clover) in an alpine grassland. We reveal the first evidence to suggest that moths, mainly Noctua pronuba (L.; large yellow underwing), pollinate this important wildflower and forage crop, providing 34% of visits (bumblebees: 61%). This is a remarkable finding; moths have received no recognition throughout a century of T. pratense pollinator research. We conclude that despite a non-negligible frequency and duration of nocturnal flower visits, nocturnal pollinators of T. pratense have been systematically overlooked. We further show how the relationship between visitation and seed set may only become clear after accounting for moth visits. As such, population trends in moths, as well as bees, could profoundly affect T. pratense seed yield. Ultimately, camera surveillance gives fair representation to non-bee pollinators and lays a foundation for automated monitoring of species interactions in future.

Towards the fully automated monitoring of ecological communities

“…Such systems, through their standardisation and the high‐resolution multidimensional data they can acquire, have the potential to generate novel ecological insights (Tuia et al, 2022 ; van Klink et al, 2022 ). For example, 24‐hour camera surveillance of Swiss alpine meadows recently revealed moth pollination of Trifolium pratense , a phenomenon overlooked during a century of research into that important wildflower and forage crop species (Alison et al, 2022 ). Furthermore, automation allows ecological interactions to be rigorously quantified at unprecedented spatiotemporal resolutions—ranging from ephemeral interactions between micro‐organisms or insects, to drawn‐out conversations between humpback whales (Cholewiak et al, 2018 ).…”

Quantification of invertebrates on fungal fruit bodies by the use of time‐lapse cameras

“…Further, if the aim is to obtain proper visitation estimates of faster invertebrates such as predators, the cameras should take pictures at shorter time intervals, for example, 1‐min intervals, which are used in pollination studies (e.g. Alison et al, 2022). However, more precise estimates will come at the cost of more image data.…”

“…Camera monitoring has a big potential in supplementing human observations in the field as it is time‐efficient and at the same time accumulates valuable ecological data (Bjerge et al, 2023; Hofmeester et al, 2020). Recently, insects visiting mushrooms on the forest floor have been monitored by the use of time‐lapse cameras (Schmid et al, 2019) and similar techniques have also been used to observe insects visiting flowers (Alison et al, 2022; Bjerge et al, 2023; Suetsugu et al, 2017). In this study, we use time‐lapse cameras to better understand the importance of fungal fruit bodies for forest invertebrates.…”

Characterizing each step of pollination in Phlox drummondii reveals that a single butterfly species predominates in the pollinator assemblage

“…Including multiple populations can identify potential variation in pollinator assemblage across space. If visitation varies across time, observers may miss the relevant window of visitation and/or pollination (Alison et al, 2022). The use of temporal exclusion experiments can be used to identify the relevant period for observations.…”