DEPARTMENT OF INTERIOR
NATIONAL PARK SERVICE
CRATER LAKE NATIONAL PARK
OREGON

This is one of a series of bulletins issued monthly during the summer season, by the staff of the Educational Division to give information on subjects of interest concerning the Natural History of Crater Lake. It is supplemental to the lectures and field trips conducted by the staff.

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The bumblebees of any section present a very interesting study as one watches the workers going from flower to flower in their efforts to provide the necessary nectar and pollen for the colony needs at home in some deserted mouse nest.

If the individual bumblebees are watched more closely, it will be observed that there are apparently several different kinds, as in fact, there are. Some have conspicuous bands of red or brown on the abdomen, some are black and yellow, while others are marked with a white tip on the end of the abdomen.

There are in fact no less than five or six species of bumblebees found frequenting our alpine and subalpine flora. The two most common forms seen are the Occidental (Bremus occidentalis) and the near-artic bumblebees (Bremus biforius nearticus). The former is more often seen on the Lewis Mimulus, while the latter has been more often taken on rabbit brush in the Canadian Zone.

It may be recalled here that the bumblebee colony maintains itself only through the short summer months. In later summer all of the individuals of the colony die except the young queens, which retire to some protected spot, and hibernate during the winter months. When the snow melts and spring flowers appear, the young queens come out, and start feeding on such early plants as the willow and maple. After a brief period of aimless wondering, they start to look for a suitable nesting place. In the early stages of brooding, the young queen does all the work of wax secreting, food gathering, brooding, and so on, until the first batch of young workers appears. These are also females, but of small size. The queen from then on remains in the nest. Additional small female workers are produced, and these assume the field duties of the queen, and assist in caring for the brood. By late July as a rule, males or "drones" appear. Soon young queens are produced which resemble the workers in all respect except size, they being much larger. After mating, the young queens retire for the winter, and the yearly cycle is complete.

It might be of interest to know that a colony of yellow jackets passes through the same yearly cycle. The outstanding difference being that yellow-jackets feed their young on animal matter while they young bumblebees are fed on nectar and pollen from flowers.

Hunting Wasps are so called because they go about capturing other insects which they use for food for their young.

There are many different species adapted to different habitats, and each, as a rule, has his own idea about the best food for baby wasps. Some use only flies, some refuse everything but beetles, while others take only spiders or caterpillers.

There are many different species of these hunting or solitary wasps, as they are also called, in Crater Lake National Park.

Probably the most interesting species of hunting wasp is the Ammophila, which can be recognized by its long, slender abdomen, mostly red, but with a black posterior end. The adult may often be seen on flowers where it feeds on pollen. As a rule, however, she can be seen lying about among the leaves looking for caterpillers. When one is found which meets her requirements she grabs it about the neck with her strong jaws, and inserts her stinger into the underside at several points. This paralyzes the worm, but as a rule, does not kill it. The supply of fresh meat is then carried to a little hole in the ground, which the mother wasp has previously made. An egg is then laid on the paralyzed worm, the hole covered, and forgotten about. In due time the egg hatches, the young wasp feeds on the living, but not active flesh, but does not emerge as an adult until the next year.

All of our solitary, or hunting wasps, have similar habits. They differ only in the kind of food they use, and the place they build their nests. Some use the small holes made by various wood-boring insects. Some build small mud nests in protected places. In fact the kind of nest and its location differs among the species as much as does the food they use.