Fears of grasshoppers that have locust, or swarming, tendencies are
nothing more than worried imaginings.
Late last summer grasshoppers that looked like locusts were discovered
in the region between Edmonton and the Saskatchewan border.
Dan Johnson, an entomologist at Agriculture Canada’s research centre in
Lethbridge, Alta., said there are no locusts in Western Canada, so the
fear of clouds of the hungry pests winging their way across prairie
crops on the wind can be dispensed with.
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“It is not evolutionary. The change is interesting but it doesn’t spell
disaster for prairie farmers …. there are genes in these grasshoppers
that are being triggered by we don’t what. This grasshopper has a big
genetic repertoire, but it is not the start of a mighty plague,” said
Johnson.
The lesser migratory grasshopper is growing longer wings and donning a
darker pigment on its head, reminiscent of locusts.
But the modification likely is a response to environmental stress.
Johnson said he can replicate the change in the laboratory, making the
grasshoppers take on the physical characteristics of the locusts, but
they do not swarm or act like their larger cousins.
He said the term locust applies to a type of grasshopper that will
change its wing, body size and pigmentation along with its behaviour
patterns when faced with overcrowding or loss of food sources.
Locusts transform from solitary creatures to swarming ones, either as
non-flying adolescents or as mature airborne insects. They inhabit
Australia, Africa and portions of Asia. One type of locust is found in
the southern United States and Central America, but does not exist at
northern latitudes.
The last time this behaviour was identified in prairie grasshoppers was
1947 when crops suffered through a summer drought similar to the one in
2001.
