Scientists have identified a bee species whose population appears to benefit from intensified farming practices, a finding reported by researchers affiliated with the University of Pennsylvania. The species, known scientifically as Eucera pruinosa and commonly referred to as the squash bee, inhabits regions of the United States and Mexico and historically evolved to feed on wild gourds before agriculture became widespread. While pollinator declines concern scientists globally, this particular bee has shown an unexpected growth in numbers, challenging a blanket narrative of universal pollinator loss.
Researchers led by Margarita López-Uribe conducted genomic sequencing and examined patterns of genetic diversity within Eucera pruinosa. The DNA analysis enabled a reconstruction of the species’ evolutionary history. It revealed that roughly one fifth of the bee’s genome carries signals of adaptation to cultivated pumpkins and squash. Interestingly, even as this adaptation occurred, the overall genetic diversity of the species decreased because mutations that did not confer a benefit were removed. A key insight from the study is that adaptation to cultivated plants coincides with shifts in the bee’s chemosensory system, altering how it senses chemicals in the air around it.
Scientists explain that domestic Curcurbita species, including pumpkins, release certain chemicals more readily than their wild counterparts. This chemical landscape likely provided a new sensory environment for the pruinosa population living in agricultural habitats, enabling it to expand its geographic range and drive a noticeable rise in population size. In practical terms, these changes helped the bee establish and persist not only in the Mexican deserts but also across the United States and into southern Canada, where suitable agricultural crops offer abundant resources.
In a separate line of observation from the broader biological literature, researchers have noted that some spiders exhibit a defense strategy wherein females mimic death. This behavior, unrelated to the bee study, illustrates the diversity of evolutionary tactics that researchers observe across different species.