Climate change alters nectar production

Extreme weather events caused by climate change are altering nectar production in plants and could jeopardize global food security, according to recent research conducted by Brazilian and Argentine scientists.

The study investigated the effects of severe rainfall variations on the availability of nectar for bees in plants of the species Cucurbita pepo, popularly known as Italian zucchini. The researchers simulated four scenarios: control (regular rainfall), heavy rainfall, moderate reduction in rainfall and extreme drought.

The results demonstrated significant changes in nectar production and composition under extreme conditions. In extreme drought conditions, there was a sharp drop in nectar quantity, both in volume and sugar concentration. Female flowers had up to 98% less sugar, while male flowers had a reduction of up to 95%.

On the other hand, scenarios with heavy rainfall caused an increase in sugar production per flower, reaching 79% more than in the control. This increase, however, was not accompanied by changes in nectar concentration, which remained stable.

Impacts at the plant and agricultural scale

Climate variations also directly impacted the number of flowers produced by plants. Plants exposed to heavy rainfall produced more female flowers, while those subjected to severe droughts had a significant reduction in both female and male flowers.

On an agricultural scale, the scenario with heavy rainfall resulted in a 74% increase in the caloric supply of nectar available to pollinators per cultivated hectare. The extreme drought led to a drastic reduction of up to 95% in this supply, putting the survival of bees at risk and compromising pollination.

Ecological and economic consequences

The research highlights that the observed changes could seriously compromise the relationship between plants and their pollinators. The drastic reduction in the supply of nectar could lead bees and other pollinating insects to seek other resources, reducing visits and, consequently, fruit production.

This scenario of reduced pollination has direct implications for agricultural production. Zucchini is just one example of many agricultural crops that depend on animal pollination. In Brazil, this crop is among the ten most economically valuable, especially for small farmers, who are more vulnerable to the impacts of these changes.

Predictions until 2075

Using projections from the most recent report by the Intergovernmental Panel on Climate Change (IPCC), the study predicts that by 2075, regions could face reductions of up to 23% in nectar production under severe drought scenarios. On the other hand, areas subject to heavy rainfall could experience increases of up to 79% in the availability of this resource.

However, researchers warn that the increase in rainfall is not entirely positive, as frequent and intense rains can generate soil erosion, nutrient leaching and a reduction in pollinator activity, due to the difficulty of flying under adverse conditions.

Further information at doi.org/10.1038/s41598-025-94565-2