The sudden return to bone-rattling cold temperatures in Manitoba is not gladly received by many people, but it could be worse — if you're a bug.

The mild weather last weekend threw some bugs off their normal routine, bringing them out and setting them up for the possibly fatal cold slap this week.

University of Manitoba entomologist Terry Galloway received rare reports of Winnipeggers collecting wood ticks last Sunday when the temperature soared to 6 C and melted so much snow.

That's a first for February, he said.

"Certainly in the time I've been in Manitoba I've never experienced or even heard anything quite like that," he said.

But the return to frigid temperatures means most of those exposed critters are likely dead.

The daytime high on Friday was a biting –20 C with a windchill factor that made it feel more like –31 C. It was only slightly warmer than that on Thursday.

Mortality rates of culex tarsalis mosquitoes, the ones that carry West Nile Virus, could also be high, Galloway said.

But it's too soon to say how much they will be affected or if any other mosquito populations will also be.

"Unless we get some snow and depending on what the temperatures do, it could be pretty tough on a lot of insects and plants that would normally winter quite comfortably under half a metre of snow," he said.