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

Black Vine Weevil (Otiorhynchus sulcatus)

Black Vine Weevil
Credit: Terry Thormin

INTRODUCTION

This weevil is one of a number of weevil species that regularly invade people's homes in the fall. These weevils hibernate as adults and are simply looking for a protected place to spend the winter.

IDENTIFICATION

Weevils tend to be robust beetles with a thick exoskeleton. The head is prolonged into a snout of varying lengths depending on the species, and the antennae are long and elbowed, the first segment fitting into a groove on the snout. The Black Vine Weevil averages about 9 mm long and has a rather short snout. It is black, often with numerous orange or yellow spots on the back, although some individuals have reduced or no spotting.

DISTRIBUTION

This is a European species that was introduced into North America about 150 years ago. It is now widely distributed in North America, being found across southern Canada and northern United States at least as far south as northern California.

TIME OF YEAR

Adults can be found all summer long, becoming active with the first warm weather and often staying active well into the fall.

HABITAT AND HABITS

Larvae are found underground and feed on the roots of a wide variety of plants. Over 100 species of plants have been identified as food sources for the larvae, including many species of berries, rhododendrons and conifers. As a result, the weevil is at times a serious greenhouse and nursery pest. The adults can live up to 3 years and lay hundreds of eggs every spring. This is a parthenogenic beetle; that is, there are no males in the populations and the females lay viable eggs without ever mating. Because the adults live for so long, in the fall they look for a place to spend the winter, and at that time they often make their way into homes.

SIMILAR SPECIES

There are over 2600 species of weevils in the family Curculionidae in North America alone, many of which look rather similar to the Black Vine Weevil. One species that is worth mentioning is the Strawberry Root Weevil, Otiorhynchus ovatus. It is smaller, about 6 mm long, and all shiny black. Like the Black Vine Weevil, it is also a serious pest.

COMMENTS

This article is not designed to provide information on how to control this species, or any other weevil when it is a pest. For information on how to control weevils as pests, we suggest searching for websites that focus on pest control. There are many species of weevils that can find their way into people's houses in the fall, and none of these is likely to become an indoor pest. The best advice we can give is to pick the weevil up and take it back outside. If you are finding large numbers inside, then you need to look for cracks that they are using to get in and consider having the cracks filled in.

Note: We cannot provide advice on controlling insect pests. If you need more information beyond what has been provided here, we suggest you either search further on the web, or talk to a local exterminator.

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Last update: August 6 2004