Scientists discover link between climate change and invasive wasp numbers
New Zealand scientists have discovered a new consequence of global warming higher numbers of invasive wasps. The research also suggests that the cool, wet spring in the Nelson region last year may have helped to stunt wasp populations this summer. Research from Wellington's Victoria University, published today in the Journal of Animal Ecology , found that climate change has a significant effect on common wasp populations. The study examined 23 years of data on wasp numbers from New Zealand, largely in the top of the South Island, and 39 years from the United Kingdom. READ MORE: * Paper wasps: What they are and how to get rid of them * Monarch butterflies disappearing from Nelson as paper wasps take hold * Special feature: Time to wipe out wasps * Project overview: How you can join the battle * Meet our wasp invaders: Gunter and Carrie Victoria University insect ecologist Professor Phil Lester said the data showed that wasps thrived in warm, dry spring weather. "The average global temperature is rising each year. We are therefore likely to see more wasp abundance in the future as our weather gets warmer." This increase in wasp numbers was observed in Rothamsted in the United Kingdom, Lester said. "The area experienced a change in climate in the 1990s, and its warmer spring weather has resulted in considerably higher numbers of wasps." Conversely, wet and cold weather particularly in spring has a negative impact on wasp numbers, according to the study. "The patterns typically show lower numbers of wasps after cold, wet springs, and higher numbers after warm, dry springs," Lester said. "This year we've had a really wet spring in many areas across New Zealand. These places that have seen a lot of spring rainfall could expect lower numbers of wasps than average this summer." Lester said it was not known exactly why the success of common wasps was heavily weather dependent. He said it may be because the queens have to build the nest and forage for food alone during spring. "That early stage wasp nest, when it's just developing, seems to be susceptible to rain and low temperatures. If they don't get off the ground then you just don't see the same wasp numbers." It was also possible that high rainfall caused nests in the ground to be flooded, inhibiting its early development. Lester said fluctuating wasp populations had implications for New Zealand's native biodiversity, particularly bird and insect populations. "In terms of our biodiversity, a high density of wasps means high predation rates. These things are huge predators, they harvest just about anything and everything."