Survival of the Insects in the Winter

1. Survival of the Insects in the Winter By Albert Zheng

2. Going Dormant • Some insects go dormant. • Go into a state diapause • Can withstand lower temperature than those who remain active and longer survival time • Some can survive in -42 degrees Celsius.

3. Diapause • Two Class of diapause. • Freeze Susceptible Insects • Avoids freezing temps, depends on antifreeze compounds • Main compound is Glycerol • High viscosity in low temps. • Keeps body fluid and tissue from freezing • Freeze Tolerant Insects • Only the body fluid freezes, freezing the living cells forcing water out of the cell making it more tolerant to freezing cold temp. • Called cryoprotectant

4. Torpor • A temporary state of suspension and sleep, which makes the insect completely immobile. • Example: New Zealand weta, flightless cricket, that likes to live in high altitude. • In the evening, it would freeze solid and in daylight, warms it up and comes out of torpid state and resumes activity

5. Remain Active • The honey bees would cluster together and use their body heat to keep themselves and their brood warm. • Lady bugs lays on top of each other under rocks to share heat. • Grasshoppers lay there eggs deep in the ground to keep warm. • Ants and termites head below the frost line where there they store their food to last all winter.

6. Size Matters • Insects are like bags of water. • So the larger they are, the more water they will contain. • The smaller arthropods, like ants and tiny spiders, can withstand more harsh temps than bigger ones like the grasshopper. • True about the same species too, ex: a smaller house fly will last longer than a larger one.

7. Moisture • A dry environment is more beneficial for some insects to survive in than humid environment. • For example the freezing point of a housefly can be lowered by 50 degrees if it is dehydrated.

8. Nutrition • An insect with an empty gut will last longer than an insect with a full belly. • Food extracts water that can freeze and form ice crystals which will freeze an insect quicker.

9. Temperature • The intensity and duration of the cold temperature is critical to an insects survival. • If exposed to long in these temps, the insects will die, even in moderate cold temps.

10. Migration • Some insects migrates to warmer climates. • Like the Monarch and Painted Lady Butterfly. • Migrate south in late summer and return in the spring. • Will fly up to 2000 miles to spend winter in Mexico • Many other butterflys and moths migrates seasonally too. • black cutworm, fall armyworm, green darners. • Other insects migrate only to nearby habitat • For example fields to woodlands , groves, hedges, or shelterbelts .

11. Growth Stages • Some stages an insect can be in to survive longer than others that are not in these stages. • The non-feeding stage like egg and pupae. • Others build protective structures like cocoons and papae. • Like tomato hornworms who spends their winters in a pupal stage and buries itself several inches deep in soil. • No surface moisture that could cause freezing. • Eggs; Ex: Praying Mantids stay as eggs in the winter • Larvae; Ex: Woolly bear caterpillars curl up in thick layers of leaf litter. • Pupa; Ex: Black swallowtails chrysalides in the winter. • Adults; Ex: Morning cloak butterflies hibernate as an adult for winter, tucking themselves behind loose bark or tree cavity.

12. Environment • In the winter, light fuffy snow can provide an insect insulation more than packed snow.

13. Source • http://www.colostate.edu/Dept/CoopExt/4DMG/Pests/winter.htm • http://insects.about.com/od/adaptations/p/wintersurvival.htm