Envisaging a Warmer World by Fusing Theoretical Concepts with Real-Life Observations

Climate changes conjure up a whirlwind journey that seems to present some creatures with opportunities to thrive. Scientists writing supercharged scenarios warn that the difference between seasonal acclimatization and long-term adaptation is significant — and difficult to predict.

MSU biologists have studied damselflies—dragonfly-like flies that are abundant as predator and prey in wetlands—to understand what happens throughout their life cycle from nymph to winged insect, along with what they eat as summers get warmer and for longer.

their work this week Proceedings of the Royal Society b It has an evolution – combining seasons of observational and experimental work in the field and laboratory with input from a theoretical ecologist and mathematician through training with massive modeling stocks.

The results: a more realistic look at what a hot summer can bring to a nearby pond, and a newfound respect for the dizzying speed that global warming brings.

“We’re seeing that the pace of climate change is much faster than what organisms experienced in their evolutionary experience,” said co-author Phoebe Zarnitsky, associate professor of integrative biology.

Principal Investigator in the Spatial and Community Environment (SpaCE) Laboratory and Director of IBEEM. “This fast pace is going to be a bigger problem with the increase in extreme events like heatwaves.”

Work in “Life-history responses to temperature and seasonality mediating consumer and external resource dynamics under climate warming” found that incorporating the right level of data from field experiments, specifically the effects of seasonal temperature changes on consumer life cycles, creates a more robust model for predator simulation and prey.

The work differs from results from similar models with the less biological realism that predicted that warming trends would kill off predators. They see Michigan flies survive a warming climate by switching to a life cycle similar to their southern relatives—causing two life cycles in one season instead of one.

The work was developed from the work of first author Laura Twardochleb as Ph.D. student in Zarnitsky’s lab. She spent time observing the life cycle of damselflies for one year in Michigan. They emerge as adults from the ponds in the spring. They mate and reproduce, and the juveniles grow over a year in the pond by eating zooplankton. She said they make good study materials because they thrive both outside and in the lab.

Twardochleb, now with the California Water Resources Control Board, was part of MSU’s Ecology, Evolution, and Behavior Program and as part of that took a class from Chris Klausmaier, professor of plant biology and integrative biology at MSU.

She reasoned that the early models that predicted how climatic temperatures would affect ectothermic predators were much simpler than the nature she was observing. For one thing, the models didn’t allow for a change of seasons in the North. The models also weren’t tracking predator size, growth rate, and changes in its life cycle with global warming.

Meanwhile, Klausmeyer, a theoretical ecologist, was aware of the special sauce the empiricist brings when creating mathematical models that make assumptions about how organisms behave, grow, are born, and die.

“I can make any model I want unconstrained by reality,” Klausmeier said. “But this is a little dangerous because of course you want something that is relevant to the real world. When you join an experimenter, you can bring not only experimental results and parameters, but also a deep natural history and knowledge into the system to know the key variables and limitations.”

The work, which takes into account a warmer, but still seasonal climate, shows how damselflies can grow and reproduce more quickly. When creating a model that would only allow hypothetical damselflies to live a one-year life cycle in a warmer world, they burned and died. Extinction was on the horizon.

But allowing insects the option of bringing in two generations in one season, and flourishing was a possibility. “A lot of the models said that (the predators) would starve,” Twardoukhleb said. “That’s what’s exciting – that we can make the models more realistic.”

Twardochleb said the work is a good basis for understanding how other species might respond to a warmer world, particularly species like mosquitoes that cause nuisance and possibly carry disease.

Zarnitsk added that the ongoing challenge will be beyond the idea that different species will adapt to a new world. Climate change is outpacing this kind of evolution in an unprecedented way. And extreme weather events—heat waves, droughts, and floods—are all variables.

“This is our next step,” Zarnitsky said. Unpredictability is hard.