| Insect Antifreeze |
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 A Little Bit MoreLiving organisms are just as linked to the laws of physics as are non-living things. When water freezes, it expands whether on a lake surface, in a rocky crack, or in the cells of a living organism. In water’s liquid form, the molecules are randomly mixed but when they freeze, the molecules line up in a specific arrangement that takes up more space than when liquid. As a result, frozen water takes up more space whether in the crack of a rock or in the cells of a wasp. This expansion in living organisms can rupture cells and cause damage or death to that organism.  According to the sources I was able to access, the way the glycerol proteins function to prevent ice crystals from forming within an insect’s cells is not understood, but it clearly works. Not all insects living in cold climates need this chemical in winter – those living in lakes and streams can function quite nicely as long as the waters they’re in are not frozen. But for those insects living on land where they’re easily frozen in winter, glycerol makes life possible. Different species of insects have different means of overwintering – they may pass this time of year as eggs, as larvae, as pupae, or as adults. Insects are ectotherms (cold-blooded animals) so are unable to generate heat to keep their bodies from freezing like birds and mammals. As winter approaches, insects begin to produce glycerol in their cells and at the same time expel waste products and foreign material from their cells that might give ice crystals something to form around. This process then allows an insect to retain water within its cells that doesn’t freeze. Of course, if temperatures become too cold, freezing will occur anyway and the insect will suffer the consequences. ActivitiesScience – Hidden InsectsObjectives: Observe an insect as it warms from its winter “home” Materials: (winter activity) Local adult Insect(s), and container Almost all of North America gets pretty cold during the winter months. Even Florida and southern California can get pretty cold during some periods. At these times, there will be insects spending these cold periods under bark, beneath logs, under the leaves, in the soil and in cracks and crevices in houses and outbuildings. With a little sleuthing, students should be able to come up with one or two adult insects. Have the students place any insects they find into a plastic container (small holes in top for air) and bring them in to class. Insects shouldn’t be handled but can be coaxed into their containers without touching. If you live in colder areas of North America, have them keep their insect cold (refrigerator works well) until they can bring in to class. Otherwise, they can keep their containers outside IN THE SHADE until they bring them in to class. Once you have the insect(s) in the classroom, you can remove the lid and allow the students to monitor the insect. At this point, the insect should be immobile or quite slow in any/all of its movement. As time passes and the insect warms, it should begin to move more and more quickly as it reaches room temperature. You may want to observe the insect for a day or two and then it should be returned to its original location. BEFORE returning it, however, it should be once again cooled (refrigerator again) and then placed outside where you found it where the temp will be about the same or even colder. Related WebsitesDownload this Poster |