\u201cWhen we look at pollinator communities along altitude and latitudinal gradients, flies become more dominant pollinators in colder areas of the planet,\u201d L\u00f3pez-Uribe said.<\/p>\n
Flies\u2019 preference for cooler conditions may help explain their greater sensitivity to heat compared to bees. Bees evolved in arid environments and can generate and have ways to regulate their own body heat, while flies appear to be more strictly dependent on outside temperatures.<\/p>\n
This study emerged as a response to COVID-19 lockdowns, with students conducting experiments in their backyards across three locations: a high-altitude site in Colombia and two subtropical sites in Texas and California. Using a water bath setup, researchers tested over 400 insects to determine their critical thermal maximum, the temperature at which they lose motor control.<\/p>\n
While the study provides insights, L\u00f3pez-Uribe notes some limitations. \u201cThe sampling was limited to urban and suburban areas, which implies there may be a bias for species that are already somewhat tolerant to higher temperatures due to urban heat island effects. Even with this bias, flies were still more heat-susceptible than bees.\u201d<\/p>\n
This sensitivity becomes particularly concerning, given the pace of global warming. The planet has already warmed by about 1.1\u00b0C since pre-industrial times. Scientists warn we could exceed 1.5\u00b0C of warming within the next decade \u2013 a rate of change that may be too rapid for many species to adapt to. At current trajectories, experts say we could see temperature increases of 2.4-3.5\u00b0C by 2100 without more aggressive climate action, which could push many heat-sensitive insects beyond their thermal limits.<\/p>\n
These implications could be concerning for crops like cacao, used to make chocolate, which relies heavily on tiny flies called midges for pollination.<\/p>\n
\u201cThe cacao pollination system is incredibly delicate,\u201d said L\u00f3pez-Uribe. \u201cThe flowers are very small and the pollen is viable for very few hours during the day. Changes of even a couple of Celsius degrees could actually impact the ability of pollinators to forage and potentially impact pollination of these crops.\u201d<\/p>\n The findings suggest that conservation efforts need to consider flies alongside more celebrated pollinators like bees and butterflies. L\u00f3pez-Uribe emphasizes the importance of creating diverse microhabitats within human-modified landscapes that can serve as refuges for heat-sensitive insects.<\/p>\n \u201cUnderstanding these differences in tolerance and susceptibility to heat may lead to stronger arguments for why we should be designing spaces and landscapes where these diversity microhabitats are thought and planned in design,\u201d she says.<\/p>\n The study comes amid growing global concern about insect declines. Research shows insect populations are declining by about 1% annually, amounting to 24% fewer insects in 30 years and 50% fewer in 75 years if current trends continue.<\/p>\n According to a 2021 meta-analysis, insect populations are suffering from \u201cdeath by a thousand cuts\u201d or a combination of multiple stressors. Climate change, habitat degradation, and agricultural practices (and use of pesticides) are identified as the three most significant factors driving insect declines globally.<\/p>\n However, there are ways that individuals can help protect both flies and other important pollinators in their own yards and communities. Conservation experts recommend creating pollinator-friendly habitats by planting a variety of native flowering plants that bloom throughout the growing season to provide consistent food sources. Leaving some areas of bare ground and hollow plant stems provides nesting habitat for many species while reducing lawn mowing frequency allows flowering \u201cweeds\u201d like clover and dandelions to provide additional forage.<\/p>\n Simple actions like installing \u201cinsect hotels\u201d made from bundled hollow stems or blocks of wood with holes drilled in them and leaving dead wood and leaf litter in place create microhabitats that many insects need for nesting and overwintering.<\/p>\n Equally important is avoiding pesticides, herbicides, and other harmful chemicals that can directly kill beneficial insects or persist in the environment<\/p>\n Finally, supporting conservation organizations working to protect insects through donations or volunteer time helps advance broader efforts to study and conserve these essential creatures.<\/p>\n As biologist Edward O. Wilson once observed, \u201cIf human beings were to disappear tomorrow, the world would go on with little change\u2026 But if invertebrates were to disappear, I doubt the human species could last more than a few months.\u201d<\/p>\n L\u00f3pez-Uribe, M. M., Appert, M. K., Delgado, A. X., Herrera-Motta, A. F., Jimenez, A., Mart\u00edn-Rojas, R. D., \u2026 & Gonzalez, V. H. (2024). Critical thermal maxima differ between groups of insect pollinators and their foraging times: Implications for their responses to climate change. Journal of Melittology, (122).<\/p>\nCitation:<\/h2>\n