I have a question concerning cold weather and insects. I have always
assumed that once the temperature drops below 45 or 50 degrees all insects
went dormant. However, during the last cold snap I saw insects flying
past my outdoor camera at night with the temperature at 26 degrees.
The low for the night was 14 degrees in my yard. As I type this, my
camera is on and the temp is 28 degrees, and I see insects flying around.
My question is what insects are active at such cold temperatures?
The question is intriguing in two ways, the first being, what are the
insects? But a second aspect that I find equally interesting is, why
dont more people inquire about these nighttime, cold-weather flying
insects? In fact, I have never before been asked this question. The
answer to the second question is that most people out in the cold at
night are not really paying attention to flying bugs, or if they do
see one flitting by, they mark the observation up to an exception and
move on. The wildlife camera provided an opportunity to observe the
the most likely insects you have seen flying on cold winter nights belong
to the family of owlet moths. Certain members are known to be active
at subfreezing temperatures. Rather than spending the cold months in
an egg or larval stage underground or shielded from the elements inside
of a log, these small moths remain active as adults in winter. Two mechanisms
keep them from freezing. They are able to shiver to create body heat.
Although we associate shivering with exposure to cold, such behavior
is uncommon in insects, the most notable exception being honeybees that
cluster together to warm up the hive. A second trait of winter moths
is their ability to store heat in their body by reducing blood flow
to the more exposed head and abdomen and retaining warmer blood in the
Recently, you wrote about the Arctic fox in Iceland. I am curious about
something: What do the foxes eat? And what did they eat before people
inhabited the island?
As I noted in that earlier column, Arctic foxes are native land mammals
in Iceland. And many natural food sources are available including seabirds,
fish and invertebrates along the shorelines. They will readily scavenge
the carcasses of marine mammals that wash ashore and have been documented
to attack and kill seal pups. Once Iceland was colonized by people,
invasive species including rats, rabbits and mink ultimately became
established and are now fair game for foxes.
intentionally brought along some other additions to the Icelandic buffet
for foxessheep and chickens. Foxes are universally viewed by farmers
as predators on livestock. According to a reliable reference, Walkers
Mammals of the World, In Iceland the Arctic fox is persecuted
because of its reputed depredations on sheep and lambs. Legislation
there has promoted its destruction since at least as early as A. D.
1295. Thats a lot of centuries to try to get rid of a perceived
pest that probably does not eat nearly as many lambs or chickens as
to a wide array of natural and human-introduced food sources, Arctic
foxes have a variety of adaptations that allow them to weather harsh
winters when food may be scarce. From summer to winter they have an
increase in fur depth of nearly 200 percent and have a short
muzzle, ears, and legs and a short, rounded body, all of which
serve to reduce heat loss. They can even reduce their metabolism up
to 50 percent to wait out extended periods of limited food. Another
cold weather adaptation is a circulatory system mechanism that sends
warm blood to the pads of their feet in winter. My guess is that the
little foxes of Iceland will be around for a long time to come.
you have an environmental question or comment, email