Male giraffes fight each other by 'necking'! They push their long necks against each other, bending and twisting them in order to win the fight by a show of strength. Many animals fight this way, including snakes, insects and crabs. Competing in this way allows animals to find out who's boss while protecting themselves from injury. The strongest wins and the loser just has to go away.
When good bugs turn bad
When good bugs turn bad Biocontrol is a method of controlling insect or
plant pests by breeding and releasing their predators and
parasites. This technique has proven popular but researchers now
question the wisdom of releasing non-native creatures into an
ecosystem. It has been suggested that we are merely substituting
one kind of plague for another in the fight against pests.
Biocontrol may be turning good bugs bad.
Non-native species are now establishing themselves well beyond the
areas in which they are released and are threatening the natural
diversity of the ecosystems in which they find themselves. Of
greatest concern is the fact that, as interlopers, these non-native
species have no natural predators in the area. This has led, in
many cases, to a population explosion and the degredation of many
acres of land.
Critics of biocontrol are now calling for rules. The number of
insects released should be limited, biocontrol of insect pests must
be regulated at least as well as those aimed at plants, and
pre-release tests should consider the indirect as well as the
direct ecological impacts. 15 JANUARY 2000, P. 31-33
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