Study questions the universal rise in pests with warming

A study led by entomologist Mia Lippey of the University of California, Davis, challenges the hypothesis of a widespread increase in agricultural pests under climate warming. The research indicates distinct responses among species, crops, and regions.

Scientists analyzed numerous field observations per year. The survey included 43 arthropod populations. The group gathered 30 pest populations and 13 natural enemy populations. The data involved 28 pest species and 11 natural enemy species in rice, cotton, grapes, citrus, and olive trees. The areas evaluated are located in Andalusia, Spain, and California, in the United States.

Pest proliferation

The results do not confirm a universal proliferation of pests. Some populations increased under higher temperatures. Others decreased or showed no response. The same pattern occurred among natural enemies. The study found partial support for greater vulnerability of these enemies to warming, compared to pests.

According to the researchers, models based on laboratory experiments predicted an increase in pest density and a reduction in natural enemies with rising temperatures. Field data challenge this prediction. The team also could not explain the variation in responses through thermal performance measured in the laboratory or through life history characteristics.

Lippey stated that species, culture, and location contributed to the diversity of the results. She also said that isolated characteristics do not allow for reliable predictions of the effects of climate change on agricultural arthropods.

Further information at doi.org/10.1073/pnas.2606726123