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閱讀理解
We bet that on cold wintry days, many of you love to stay in your warm home and, every now and then, come out into the kitchen for a snack．Unfortunately, plenty of creepy-crawly critters(爬行生物)like to do the same thing!
Winter is the time when bugs(蟲(chóng)子)invade your house without an invitation．The season can be tough for such creatures．In winter the air is cold, the ground is hard and many trees have no leaves．So bugs do what they have to do to survive．
Monarch butterflies head south to warmer climates．Ants crowd in deep underground colonies and eat food they have been storing all year．Many insects go into a deep sleep called diapause．There’re different kinds of diapause, but all are similar to hibernation, a time when bigger animals become inactive in the cold．Insects go into an inactive period, too, but it often isn’t when the temperature drops．
They rely on more dependable signals in the environment．For example, many insects can tell how much sunlight there’s each day．They use that to tell themselves when to shut down．Bugs are cold-blood-ed, meaning that their inside temperature is the same as the outside．They can’t move much when it gets below 40 degrees Fahrenheit．So they search for any warm place．
They’re looking for protection．These guys have been doing this for 300 million years, so they don’t really know they’re coming into your house．The home is a recent event in terms of their evolutionary behav-ior．They enter through tiny cracks or come in unnoticed on your clothes or shoes．Remember that they may be invading your homes for warmth and food, but they don’t care about humans．
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