Experts fear troublesome insect might spread to entire reindeer herding area

Experiments being conducted on deer fly Lipoptena cervi's ability to withstand harsh winter

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The deer fly or deer ked (Lipoptena cervi),* has been found to have spread to reindeer in the Puolanka region.
      The insect, which generally feeds on blood that it sucks from elk, spread to Finland from areas southeast of the country in the 1960s.
      The deer ked has also spread further north with each successive year, and its present habitat extends to the southern edges of Finland's reindeer husbandry area.
      Professor Arja Kaitala of the University of Oulu is currently leading a study to investigate how the pupa of the deer ked can survive the harsh northern winter, and if it might spread to the whole reindeer-herding area. Also taking part in the project are researchers from the universities of Helsinki and Joensuu.
     
For the purposes of the study, pupae of the insects have been placed in jars that have been left in the wilds in Kuusamo, Rovaniemi, Utsjoki, and Konnevesi.
      "The ked is expected to emerge from the cocoon in August. This will probably happen first in Konnevesi, which is further to the south", says Markku Rontti of the University of Oulu. He is investigating the condition of jars placed in a pine forest in the spring. Between the jars there are sensors which record the temperature and humidity.
      There are about 200 jars in each open cage. Each of the numbered jars has one pupa under a screen. The jar contains moss, because in nature, cocoons of the deer ked can be found in areas where elk lie down to rest.
      "We are also studying the effect that the insects have on reindeer, beacuse a single insect can spend several months in the animal's fur. We also do not know much about the effect that they have on elk. The deer ked has also spread to Sweden and Norway. In Sweden, furless elk have been found, but there is probably some other reason for this."
     
In the early spring 10,000 deer ked pupae were collected around Finland.
      Once they emerge from the cocoons, the mature insects in the jars will be taken to the University of Oulu, where their behaviour will be observed under laboratory conditions.
      "We will also study how the deer ked chooses a host - if it flies to a dark, or to a light figure, and drops its wings", Kaitala says.
      The first cold exposure test showed that the deer ked pupa will not survive if the temperature drops down to -39° Celsius.
      The insect is a nuisance to humans, though not particularly dangerous. Bites can cause an allergic reaction. In any event, humans are not the prime target - the insect is a parasite feeding on elk. As many as 16,000 specimens have been found from a single animal.
      From the human perspective, one bit of bad news is that normal mosquito repellents do not deter the deer ked. Naturally reindeer herders are concerned that their animals, hitherto relatively free from such parasites, would now become susceptible to their attacks.
     
*Thanks go to a sharp-eyed reader who pointed out that it is Lipoptena and not Lipoptema


Links:
  Deer fly or deer ked (Wikipedia)

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