When pollinators arrive after sunset

A look at the night shift

Animals visit flowers at night too. Moths can pick up pollen in the process and transfer it to other flowers. These activities are less noticeable to people than daytime buzzing, but they form part of many pollination networks. A University of Sussex study presented by Butterfly Conservation examined bramble flowers at ten sites in south-east England. The researchers compared flower visits and pollen deposition during the day and at night. This did not directly measure fruit or seed production. Although there were considerably more visits during the day, moths made an important contribution during the shorter night-time period. Such findings broaden our view of pollinators. They also show why a study should not merely count how many animals visit a flower, but must also examine what those visits actually achieve in terms of pollen transfer.

Why a headline does not apply everywhere

The study does not establish that all moths are inherently more efficient than all bees. It measured a particular relationship with a plant in particular locations and during a limited part of the year. Other flowers have different shapes, opening times and groups of visitors. The term efficiency also needs a clear frame of reference: does it mean pollen transfer per visit, per period of time, or the total contribution to reproduction? These measures can produce different rankings. A factual account therefore specifies the particular finding without inventing a general competition between groups of animals. Pollination networks benefit precisely from having different species active under changing conditions. Daytime and night-time visitors do not have to replace one another; they can use different time windows and plant resources, contributing to reproduction together.

Darkness as part of the habitat

For nocturnal insects, suitable light conditions and refuges matter as well as flowers. Artificial lighting can alter behaviour and draw animals to places outside their normal routes. A bright lamp may therefore make many moths visible, but does not give an undistorted picture of how they would use an area without lighting. Anyone wishing to observe them should avoid unnecessary light and document natural flower visits with as little disturbance as possible. Caterpillar food plants and sheltered development sites also belong in efforts to support them. A single nectar-rich corner cannot fully compensate for missing habitats. Attention to moths thus broadens a familiar conservation principle: what matters is not just the adults at a conspicuous moment, but the entire life cycle and the environmental conditions in which it can actually take place.

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