Do Insects Hibernate in Winter?
Many insects hibernate as
adults; they each have their own method for surviving the conditions of the
winter season. Lady birds for example, congregate in large numbers in the fall
at high levels above ground. Tree holes, leaf litter, and under logs and rocks
are all places insects hibernate in winter. In some insect larvae, the water content
of its body is reduced and it builds up glycerol which acts as an antifreeze.
Generally, it is easier for insects to survive cold temperatures when the
temperatures are stable rather than fluctuating.
A ‘sleep time’ which is
different to hibernation is known as diapause. This is usually done by insects
and is a delay in the insect’s development where they do not grow. There are
two types of diapause. One type is called obligatory. This is where the insect
must go through diapause at some stage in its development. The second type is
called facultative. This is where the insect ‘sleeps’ because of adverse
weather conditions. However, unlike hibernation, the insect ‘sleeps’ before the
adverse weather.
Before the insects leave diapause
and begin developing again, they receive warning signs, such as; the days get
longer (which the insects can sense) and/or the outside temperature increases. In
conclusion, diapause is simply the way ‘animals adapt to the world around
them’.
References: (All Accessed 27th
February 2012 )
By Emma Barkley, 27th
February 2012
Interesting stuff Emma. A supplementary Q for you (and everyone)... If the climate is changing, what impacts will this have on the diapause/hibernation of animals and in particular on the times they enter and leave hibernation? If eggs hatch earlier than previously because of higher spring temperatures, could that cause problems if the first leaf growth on their food plants is cued by something different that is not affected by global warming (eg day length)??? Help!!!
ReplyDeleteThere is certainly evidence to show that climate change is effecting the hibernation of animals; there have been cases of animals emerging earlier than usual. This means that global warming could cause many challenges to animal and insect species, because the length of the summer or winter season could change, and/or the cues to their hibernation could change. For example, if the air is warmer earlier, insects or animals could emerge from hibernation to find hard ground and little nutrients, meaning survival rates could potentially be lowered. Over time, this could create adaptations in species so that those able to cope with a gradual climate change will survive and pass on their genes; the species will have evolved.
DeleteI have managed to find an extremely interesting, yet easy to access, research article on how climate change affects migration and hibernation:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC26486/
Very interesting. Could you could give some example as I was wondering which insects use diapause and do they use obligatory or facultative diapause? Or do most insects just use this as their main type of hibernation?
ReplyDeleteLauren
The majority of insects use facultative diapause, where the environment is used by an insect to determine whether to enter diapause or not. This means that the insect can track seasonal changes, thus controlling its development.
DeleteLess insects use obligatory diapause, but an example of an insect that does is the Gypsy Moth. With this insect, temperature determines when diapause ends, yet it does not affect when it starts. Instead, diapause is a stage which the Gypsy Moth has to pass through and this happens when the embryo has completed its development.
Emma, 16th April
Research:
Resh V., and Carde, R. (2009) Encyclopedia of Insects. London: Academic Press.