Pine Beetle uses infrared to find next meal

Scientists discovered that the White pine cone beetle dines on pine cone seeds,  It uses a special ability to find its next meal. It senses the pine cones temperature. As part of being alive, all living things give off heat and infrared light energy. While this wave length of light cannot be seen by humans, scientists have found that the white pine cone seed-eating beetle is able to detect infrared energy.

Image one (at the right) shows two pine cones, the large one is healthy and normal size, but look at the smaller one. That one has become dinner for this beetle.cone-beetle-damage

Scientists decided to find out how they found the cone amongst the needles and why the beetle chose one cone over the other to eat.

They observed the beetles in the wild on the trees and in the lab and measured the heat given off by the needles and the cones to see if there were any differences in temperature. The researchers decided to use a special camera that can make infrared light visible. On the camera screen, heat given off by living things showed up in shades of yellow and orange. It can make infrared light, this heat  visible.

When the scientists looked at the western white pine tree with this thermographic camera, the beetles’ food, the pine cones lit up like holiday lights. The trees looked as if they were covered in candles. The camera’s lens showed that the pine cones actually are hotter than the needles. The cones run 15 degrees Celsius warmer than the surrounding needles all year around.  So was this insect prefering a hot meal?

How did the beetles sense this heat difference from the needles to cones?

Back in the lab the scientists wanted to find out how these beetles sense heat. The scientists tested this theory by painting over the external body sensors with silica paint. This kind of paint blocked the pine beetles’ sensors from detecting the heat. The painted beetles no longer could find the heated cones. On the beetle’s’ body, researchers found sensors that seemed to be used to find the warm cones.a1790_22061

Inside the insects’ nervous system, which responds to input from the senses. The researchers found a clear pathway from the sensors to the brain. This connection might be used to tell the beetle’s brain that hot food is directly ahead or, maybe, a little to the right.

Why do scientists care how this beetle finds its food?display_hotcomesahotcommodityforseedbugs

This beetle is eating young pine cone seed so they cannot become trees. Inside the pine seed when the beetle finishes eating it looks like wet sawdust. It is quite troublesome. The Western White Pine (Pinus monticola) on which the beetles dine is endangered. It occurs almost exclusively in the Northern Rockies Eco-region. Until about 50 years ago, it was the most abundant forest type in that region. 
Replacement fires occurred at a given location every 150 to 250 years on the average. Mixed severity fires that killed only part of the stand occurred at about 60 to 85 year intervals.

Today, the number of western white pine is 93 percent less than 40 years ago.

Scientists are trying to find out how to protect these trees from a combination of blister rust, mountain pine beetle and harvesting has nearly eliminated mature western white pine stands.  The trees are dehydrated from warming temperatures and this lowers the plant’s resistance to pests and diseases,

Excerpts from    Hungry bug seeks hot meal Science News November 19, 2008

Image (1)

Image (2) The cones heat.Photograph Hannah Bottomley; Thermography: Stephen Takács

NFRARED TREE Seed-eating bugs armed with infrared detectors zero in on the glow of cones. Photography Lisak Andreller; Thermography: Stephen Takács

Heat detecting camera using Thermography show the cones’ heat. Photography: Hannah Bottomley; Thermography: Stephen Takács

image (3)

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