The Effects of Climate Change on PlantPollinator Communication BY KATE SINGER '24 Cover Image: European honeybee extracts nectar. Image Source: Wikimedia Commons
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Introduction It is common knowledge that the global climate is changing due to anthropogenic influences. Increased CO2 levels in the atmosphere will lead to an increase in the global average temperature (Ekwurzel et al., 2017) which will have many negative impacts on the environment and its inhabitants. The timing of the biological cycles of many species is often correlated with environmental cues that are being affected by climate change. However, when the cycles of two interacting species are correlated with different cues, there can be a misalliance of interconnected biological processes. This phenomenon of timing discrepancies of biological cycles is known as phenological mismatch. This process is largely driven by climate change and affects species across taxa (Visser & Gienapp, 2019). Mismatched phenological processes can also impede interspecies communication, particularly communication between plants and pollinators. Plants normally communicate with their pollinators through modalities such as olfactory, visual, or electric signaling. These signals allow pollinators to locate the flower and its pollen stores (Sun et al., 2018), as well as determine whether that flower has previously been visited
by another pollinator and has consequently been depleted of its resources (Clarke et al., 2013). The changing climate is also altering the visual and olfactory signals produced by the flowers. While it is clear that these changes are occurring, the broader implications are still unknown.
Phenological Mismatch The timing of many organisms’ life history activities, or phenology, is dependent on environmental cues such as temperature or day length. Should these cues cease to be reliable due to changes in the climate, these processes will not occur at the optimal time and the overall fitness of the organism will decrease (McNamara et al., 2011). Hutchings et al. (2018) illustrate the phenomenon of decreased plant and pollinator fitness due to phenological mismatch through observation of the spider orchid, Ophrys sphegodes, and the solitary mining bee, Andrena nigroaenea. Optimal pollination relies on male bees emerging from hibernation right before the orchids bloom, and females emerging after the bloom. This is because these orchids create a scent bouquet which mimics the mating pheromones of a female bee. Since the orchid blooms before the female bees emerge and DARTMOUTH UNDERGRADUATE JOURNAL OF SCIENCE
