Agriculture Reference
In-Depth Information
borers, shipworms are the most rapid destroyers of untreated wood. Adults lay
eggs which hatch into free-swimming larvae. The larvae bore into submerged
wood (marine pilings, wharf timbers, wooden boats) using a pair of boring
shells located on their heads. The tail remains at the entrance, but the body
grows in length and diameter as the animal extends its tunnel up to several
feet in length. Shipworms use the wood for food and shelter. The internal
structure of the wood may be honeycombed with tunnels, but only a tiny
(1/16 to 1/8 inch) entrance hole will be visible on the surface (see
Figure 3.19)
.
Figure 3.17
Land snails soft-bodied and have two pairs of antennae-like
structures. They have a spiralshaped shell which they can use for protection.
Figure 3.18
Soft-bodied slug. Slugs do not have shells.
