Electrostatic detection and electrical signalling in plants

: Are flowers antennas

Abstract

Flying insect pollinators, including bumblebees (Bombus terrestris) and honeybees (Apis mellifera), generally accumulate a positive electrostatic charge during flight. This charge generates an electric field which consists of a positive DC component, modulated by an AC signal driven by their wingbeat frequency. Flowers, being electrically connected to the ground, present a negative charge relative to a foraging bee. When the bee approaches the flower, these charges interact through Coulomb forces, which provide electroreceptive cues to the bee and facilitate pollen transfer between the pollinator and flower. Reciprocally, a change in the electrical state of
the flower can be observed during bee visitation, even before landing. Through a combination of laboratory and field experiments, I investigate two core hypotheses: plants can react to aerial electric fields representative of flying insect pollinators, and plants can transmit a signal induced by an aerial electric field to neighbouring plants. Furthermore, I begin to explore the propagation of anthropogenic electric fields through plants, raising the question of what effect this may have on inter-plant electrical signalling. Using single electrode electrophysiological recordings of the
stem potential in petunias (Petunia grandiflora) and daffodils (Narcissus spp.), I demonstrate that aerial electric fields can be detected in these plant species. Moreover, using potted petunias and native in situ buttercups (Ranunculus repens) and knapweeds (Centaurea nigra), I demonstrate that the changes induced in the stem potential can be rapidly transmitted between plants, provided there is an electrical connection between them. Subterranean propagation of electric signals was also found to extend the range at which anthropogenic electric fields were detected in petunias in the vicinity of a high voltage power line. My results broaden our understanding of the electrical interaction between plants and pollinators and further highlight the possible significance of electric fields in pollination biology.

Date of Award	20 Jan 2026
Original language	English
Awarding Institution	University of Bristol
Supervisor	Daniel Robert (Supervisor)