Megaplatypus mutatus

Preferred Scientific Name

• Megaplatypus mutatus (Chapius, 1865)

Other Scientific Names

• Platypus mutatus Chapuis, 1865
• Platypus plicatus Brèthes
• Platypus sulcatus Chapuis

International Common Names

• English: ambrosia beetles
• Spanish: barreno de los forestales y frutales; taladrillo grande de los forestales

EPPO code

• PLTPMU (Platypus mutatus)

• Domain: Eukaryota
•     Kingdom: Metazoa
•         Phylum: Arthropoda
•             Subphylum: Uniramia
•                 Class: Insecta
•                     Order: Coleoptera
•                         Family: Platypodidae
•                             Genus: Megaplatypus
•                                 Species: Megaplatypus mutatus

Megaplatypus mutatus is often referred to as Platypus sulcatus or Platypus mutatus in the literature (Alfaro et al., 2007). The first revision of the genera of Platypodidae was provided by Wood (1993), who designated nine new genera and Platypus mutatus was assigned the genus Megaplatypus. Bright and Skidmore (2002) adopted this generic transfer in their world catalogue of Scolytidae and Platypodidae, second supplement.

Eggs

Toscani (1990) described the eggs as elliptical, whitish and translucent. They are 1 mm long and 0.6 mm wide.

Larvae

First instar larvae are bright white and elliptical. Fifth instars are cylindrical. Mature larvae measure approximately 7.2 mm long and become yellowish (Santoro, 1965).

Pupae

Pupae are 8 to 9 mm long and whitish (Santoro, 1965).

Adults

The adults are cylindrical with sulcate elytral striae. The head is as long as the pronotum. The male is dark-brown above and clearer below, measuring approximately 7.5 mm long. The female is brown above and reddish-yellow below, measuring approximately 8-9 mm long. The tarsi and antennae are reddish. The male elytrae have truncate tips, with characteristic spiniform processes on the declivity. The female elytrae have round tips, without processes. The anterior tibiae of both males and females are rasp-like, which assist in the movement of the adults through the galleries (OEPP/EPPO, 2009).

Also refer to Allegro and Griffo (2008) for adult and larval morphology, and development. Liguori et al. (2007) describe a multi-chamber trap that can be used to collect adults for behavioural studies. Traps used to capture adults of M. mutatus previously have resulted in injury because adults are trapped in the same chamber and are antagonistic, resulting in injured adults incapable of reproduction. The trap developed by Liguori et al. traps the adults in separate chambers, ensuring isolation until collection.

M. mutatus is native to South America and was first recorded in the Caserta province of Italy in 2000 (Tremblay et al., 2000) and is thought to have been introduced with a single consignment of roundwood of poplar with bark imported from Argentina (OEPP/EPPO, 2009). It was found in five communities in 2000 and is now present in 14 communities; however, still confined to the Caserta province (Allegro and Griffo, 2008). In 2003 in Campania, monitoring of the pest was established and by 2007 spread of the infestation was confirmed. From 2000 to 2007, the area of distribution of M. mutatus increased from 130 km² to 587 km², respectively (Allegro and Griffo, 2008).

M. mutatus only attacks standing live trees and does not mass attack host trees (Alfaro et al., 2007). Attacks generally occur in late spring (September to November in the southern hemisphere), usually initiated by the males (Alfaro et al., 2007). Tree trunks over 15 cm in diameter are the preferred hosts and the main symptom of attack is the presence of 3 mm diameter holes in the early summer that exude frass and sap. Internal galleries bored by the adults are stained by mycelia of the associated symbiotic fungus (OEPP/EPPO, 2009).

Natural Dispersal (Non-Biotic)

M. mutatus is an important pest of timber trees especially poplar and only attacks live standing trees (Allegro, 1990). Declining trees or cut wood are not attacked and if found are an indication of earlier attack (OEPP/EPPO, 2009). Trees that have been drilled and bored into by the pest, constructing internal galleries, can break in the wind. Highly stressed trees can die. Boring causes a reduction in wood volume, and the presence of larval galleries and the dark staining produced by the ambrosial mycelia growing on the tunnel walls reduces wood quality and prevents the wood from meeting the plywood industry standards (Alfaro et al., 2007; OEPP/EPPO, 2009).

Apart from damage to trees planted as windbreaks, no environmental impacts have been reported (OEPP/EPPO, 2009).

OEPP/EPPO (2009) state that some poplar producers in South America have been forced to diversify to maintain their income after their high quality wood market was lost; alternatively they sell reduced quality wood. It is thought that this could also happen in Italy, due to the high quality standards required by the wood industry.

• Has a broad native range
• Abundant in its native range
• Is a habitat generalist
• Capable of securing and ingesting a wide range of food

• Damaged ecosystem services
• Ecosystem change/ habitat alteration
• Host damage
• Negatively impacts forestry
• Negatively impacts livelihoods
• Reduced amenity values
• Threat to/ loss of endangered species
• Negatively impacts trade/international relations

• Highly likely to be transported internationally accidentally