Whilst most insects are slumbering at this time of year, some cold-loving creatures are just emerging. Amongst them are the aptly named Winter Moth and December Moth. Discover how these moths are adapted to deal with the winter weather.
The December Moth is, as the name suggests, a moth that tends to be seen flying most often in December; although, some eager individuals can be seen emerging in November or as early as October.
This fluffy-looking moth is fully kitted up for the winter weather with its thick body and a coat of long hair-like scales which help keep it warm when the temperatures drop.
The adult moths aren’t able to feed and instead spend their time searching for a mate and laying eggs, which they do so under the bark of Oaks, Birches and Hawthorns. The eggs won’t hatch until the following spring.
The Winter Moth takes a different approach to the December Moth - no fluffy coats, no thick body, and overall, it’s rather delicate. However, the Winter Moth still braves the elements to fly between October and January.
Unlike other moths which need to warm their bodies to over 30 degrees Celsius to fly, the Winter Moth seems to be able to use its unusually low body weight compared to the size of its wings to its advantage and fly even when its body temperature is close to the temperature outside. Research suggests that because their large wings don’t need to beat as fast as some other moths to keep their relatively light body in the air, their muscles don’t need to be warmed up to work efficiently. They can even fly when it’s close to freezing.
However, this wing trick only applies to male Winter Moths as the females don’t fly at all! Female Winter Moth wings are little more than short nubs, so rather than fly about in search of a mate, they wait for the males to come to them. To help the process along a bit, the females produce pheromones which they release into the air to lure the males to them. This strategy is one used by a number of cold-weather species, like the Mottled Umber, Pale Brindled Beauty and Early Moths.
But why fly or, in the case of some female moths, wait for a mate in the cold at all? Scientists think this is a strategy to avoid predators like bats who don’t tend to fly or feed as often in the winter months. However, climate change and unusual weather patterns are having an impact on bat hibernation cycles, which could mean that the UK’s winter-loving moths might be on the menu in future.