Bees, Wasps, and Ants — Order Hymenoptera

Kings, queens, and slaves – the world of Hymenoptera is one of complexity and intrigue. While the hymenopteran groups most familiar to southerners – hornets, honeybees, and ants – are absent from the Arctic, the north has its own assemblage of personalities.

Bumblebees

There are twelve species of bumblebees in the Arctic, at least three of which reach the High Arctic. Bumblebees probably occur in the Arctic where other stinging hymenopterans do not, because they have features that more readily "prepare" them for life in the cold. Their furry bodies help trap warmth, and they nest in the ground, rather than in trees like honeybees. They also have the ability to warm themselves by shivering – a trick that is used to great effect. A bumblebee can generate body temperatures to rival those of humans by shaking the muscles in its body. Arctic bumblebees are large compared to their southern counterparts, partly because size helps to combat the cold, but also because the well developed shivering muscles of northern species add bulk! Arctic bumblebees fly from flower to flower collecting nectar and pollen for food and, in the process, deliver pollen from one plant to another. Bumblebees pollinate many of the prominent wildflowers of Canada’s Arctic, including purple saxifrage.

Sawflies

Sawflies are primitive hymenopterans. They do not have the characteristic thin waist of most members of this insect order, but look like fat wasps with long stingers. The stingers are in fact tubes through which the female injects her eggs. The larvae of sawflies resemble the caterpillars of moths and butterflies. They feed on leaves or stems. Most of the arctic species feed on willow, Salix sp., but others feed on arctic blueberry, sedges, and other plants. The adults also frequent these plants. Some willow plants in the Arctic have galls on their leaves – deformed, fleshy growths of leaf tissue whose formation is caused by the larva of the sawfly, which lives inside. Species in the genus Pontopristia burrow into the catkins of arctic willows and their presence is signalled by dense pockets of fluff. There are over 34 species of sawflies in the Arctic, some of which extend to the northern islands, but little is known about their biology.

Parasitoid Wasps

An ichneumonid wasp.

Parasitoid wasps are by far the largest group of hymenopterans in the Arctic. These wasps have a reproductive strategy that is worthy of any story of intrigue – females seek out tender, helpless larvae, then sneakily pierce their skin to inject one or more eggs into their body cavity. The parasitoid eggs hatch inside the liquid of the caterpillar’s interior, and develop in relative comfort, eating their host from the inside out. When the innards of the host are consumed and the parasitoid larvae are ready to pupate, the host dies, and its carcass provides protection for the wasp pupae. Eventually, adult wasps burst through the wasted caterpillar skin, and take flight into the open air.

One of the major parasitoid wasp families is the Ichneumonidae; there are over 100 species in the Arctic. These wasps vary in appearance, but most are thin and delicate, with long antennae and arched abdomens. Some have long ovipositors – tubes through which their eggs are injected – that look rather intimidating, but are, in fact, harmless to all but their insect host. Besides ichneumonids, there are representatives of over twelve other parasitoid wasp families in the Arctic. Many of these are poorly known, and most are restricted to the southern regions of tundra. However, it is certain that many more species of arctic parasitoid wasps remain undescribed!