Beetles with a view

Ladybugs are not 'bugs' but actually beetles in the order Coleoptera and swarm on or around mountain peaks. Common species in the Blackfoot Watershed include the convergent lady beetle, Hippodamia convergens.

This lady beetle gathering can be a regular occurrence. For many years this phenomenon has been seen worldwide as well as in Montana.

Called 'summit ladybugs', the different lady beetle species can be found in different alpine locations by the hundreds, thousands or even ten thousands.

Lady beetles have a hard shell or wing case called elytra which protects their wings. This wing case is reddish and symmetrical with bright colors and dots to ward off predators. They also secrete smelly fluid when disturbed.

Lady beetles are a bivoltine species which means they produce two generations a year in the spring and fall. Females lay clusters of 15-20 eggs on plants, which hatch and go through five phases until full maturity in 21 days. A female may produce 200-500 eggs in her lifetime. Most lady beetles live up to a year but some species can live two to three years.

Times are tough on lady beetles during winter so they aggregate, hunker down and enter into reproductive diapause. Diapause is animal dormancy used as a means to survive predictable, unfavorable environmental conditions, such as temperature extremes, drought or reduced food availability.

Locally in the Blackfoot watershed and in the Mission Mountains the convergent lady beetles cluster and swarm in the fall at high elevations around 8,000 feet and higher to prepare for overwintering within rocks and logs. The heavy snow pack insulates them from the cold temperatures.

Missoula County Extension said the lady beetles may also breed at the high elevations before migrating to their aphid eating areas in lower elevations in the spring and summer.

When the lady beetles cluster in their feeding and wintering areas they sometimes attract a certain bug-eating predator. Both black and grizzly bears have been known to eat the gathering lady beetles and trails in the Mission Mountains and in Glacier National Park have been closed due to increased bear activity where lady beetles swarm.

In 1952, J. Gordon Edwards witnessed summit lady beetles gathering at 9,365 feet in Glacier Park during his ranger naturalist work. In 1932, Montanan John Romer saw 12 grizzly bears digging and nosing around rocks feeding on the clustered lady beetles at an elevation of 10,000 feet in the Mission Mountains.

Whether the beetles are swarming high for winter or low for feeding, their numbers are a sight to see.