Royal Alberta Museum: Invertebrate Zoology - Bug Facts

[Caterpillars and Other Immature Insects]

Fact Sheets: Commonly Observed and Asked About Insects and Spiders Found in Alberta

Harvestmen, Daddy-long-legs (Phalangium opilio)

Harvestman
Photo CD 0023 3291 1601, Image #22 - Credit: Terry Thormin

INTRODUCTION

Daddy-long-legs with their long slender legs are easily recognized. What most people do not seem to know is that they are not spiders, but members of a different group that is closely related to spiders, and they should correctly be called Harvestmen.

IDENTIFICATION

There are at least eight species of harvestmen in Alberta, but Phalangium opilio is by far the most likely to be seen. They look rather spider-like, but the legs are much longer and thinner than those of most spiders and they have only one body part as opposed to the two that spiders have. They also lack the poison glands and the silk-producing glands that spiders have.

DISTRIBUTION

Found throughout Alberta. Harvestmen are found throughout the world, but Phalangium opilio is restricted to North America, Europe and temperate Asia.

TIME OF YEAR

Throughout the summer. Large adults are most likely to be seen in late summer and fall. Eggs are laid in the soil in the fall where they overwinter and hatch the following spring.

HABITAT AND HABITS

Harvestmen feed on a wide variety of things, including small insects and other invertebrates, dead animals and plants, They can be found in a wide variety of habitats, including forests, brushy areas, open grasslands and even disturbed areas. I have often seen them sitting on a flower head or leaf in full sunlight. Occasionally they get into peoples basements.

SIMILAR SPECIES

Trying to identify the species of harvestmen that occur in Alberta is beyond the scope of this article. It is worth, however, mentioning two types of spiders that may cause some confusion. The Daddy-long-legs spiders (family Pholcidae) have very long legs and the name adds more to the confusion. The House Spiders (Tegenaria ssp.) also have quite long legs and can be confused with Harvestmen. The most obvious difference is the two body parts of the spiders.

COMMENTS

The biggest myth concerning Harvestmen concerns how poisonous they are. They are not poisonous, and completely lack the toxin producing glands that spiders have. They do have scent glands that produce a peculiar smelling fluid when the animal is disturbed. This probably acts as a repellant to some predators.

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Last update: August 29 2008