Wharf borer

The name 'wharf borer' comes from the larval stage of this insect, which often lingers on pilings and timbers of wharves, especially along coastal areas.

The larvae, also creamy white, are equipped with brown mandibles, ready to bore into the timber and feed on the wood.

They are distinct from cockroaches by the black band across the end of both elytra and the three raised longitudinal lines on each wing case – a trait common to all beetles in the family Oedemeridae.

They live anywhere there is moist and decaying wood, such as wharf timbers that are regularly submerged by a tidal flow river.

[1] Pitman et al. (2003) further noted that wharf borers are widespread in the UK and Wales, with a few records in Scotland, but neither adults nor larvae were found in Ireland.

It was said that their populations rose in London following the Second World War when masses of timber became buried under the ground following bomb blasts.

[1] First instar larvae burrow about 1 cm beneath the surface of the wood after hatching, where soft-rot type degradation is evident.

Larvae produce the enzyme cellulase, which enables them to feed on rooting wood, similar to many wood-boring Coleopterans.

[3] The cream-white Pupae are reported to last 6–17 days, the exact amount of time is influenced by temperature and relative humidity.

Lower temperatures increase the time for the larvae to attain the required head capsule size for pupation by a reduced metabolic rate.

Lower relative humidity also decreases longevity due to increased desiccation, especially with non-feeding adults and those without an external water supply.

Damage done to old ships and docks by the wharf borer is a good indication of how old the vessels are as the beetles only attack old timber.

The presence of wharf borers and the simultaneous destruction can be accepted as a safety precaution to repair docks and ships to avoid dangerous accidents.

Oak, poplar, and pine are some of the timbers attacked by the wharf borer, indicating its development in both soft and hardwoods.

[2] In America, Drooz (1953) reported that the insect was responsible for very costly damage to foundations underneath buildings in Milwaukee, Wisconsin.

To protect stored archaeological timbers from the damaging effects of wharf borers, a procedure has been developed to control the attacks.

Wharf borer, Nacerdes melanura
Wharf borer, Nacerdes melanura