Documenting Diversity at the Katharine Ordway Natural History Study Area
Sphenophorus australis, the Billbug
Common name (of genus Sphenophorus): Billbug
Weevils, or "snout beetles" are small, herbivorous beetles of the
Curculionidae family. Billbugs are the weevils belonging to the
genus Sphenophorus. Billbugs are 1/5'' to 3/4'' long and can be
identified by the long, elephant-like bills that protrude from their
heads which they use to bore into plants2. Sphenophorus australis
has creamy orange-colored stripes on its back that distinguish it from
Weevils are known primarily as pests for their behavior of laying eggs
in the stems of plants and consequently feeding on the stems and later
the crowns and roots of the plants after they hatch. They can do
extensive damage to plants like this and are a big issue for
Weevils have a one-year life cycle. After the larvae hatch from
their eggs in June, they go through three to five growth stages,
molting after each stage, and after a few weeks burrow into the soil,
pupate, and emerge as adults in July3. They overwinter in leaf
litter starting in October and then emerge again in April or May,
laying their eggs in late May.
Billbugs can be found all over the United States and in parts of South
America, Africa, Europe, and Asia. Sphenophorus australis
specifically has been spotted in California, Georgia, Illinois, Iowa,
Maryland, Massachusetts, Michigan, Minnesota, New Jersey, South Dakota,
This specimen was collected in a woodland area at the Katherine Ordway
Natural History Study Area in Inver Grove Heights, Minnesota.
1. BugGuide. 2010. http://bugguide.net/node/view/162468/bgimage
2. North American Insects and Spiders. 2010. http://www.cirrusimage.com/index.htm
3. Penn State College of Agricultural Sciences. 2007.
4. Hay & Forage Grower. 2006. http://hayandforage.com/mag/farming_billbugs_chomp_grass/
Compiled by Amy Osteraas.
Biodiversity & Evolution (BIOL 270) Professr Sarah Boyer. Spring 2010.
Specimen collected at Macalester College’s Katharine Ordway Natural History Study Area on April 15, 2010.