Ambrosia Beetles
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common ambrosia beetle, Platypus parallelus, dorsal view; Photo by Simon Hinkley and Ken Walker, Museum Victoria, Pests and Diseases Image Library |
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common ambrosia beetle, Platypus parallelus, lateral view; Photo by Simon Hinkley and Ken Walker, Museum Victoria, Pests and Diseases Image Library |
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seed borer, Coccotrypes advena, dorsal view; Photo by Ken Walker, Museum Victoria, Pests and Diseases Image Library |
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seed borer, Coccotrypes advena, lateral view; Photo by Ken Walker, Museum Victoria, Pests and Diseases Image Library |
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palm seed borer, Coccotrypes dactyliperda, dorsal view; Photo by Simon Hinkley and Ken Walker, Museum Victoria, Pests and Diseases Image Library |
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palm seed borer, Coccotrypes dactyliperda, lateral view; Photo by Simon Hinkley and Ken Walker, Museum Victoria, Pests and Diseases Image Library |
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Platypus sp., larvae and pupae; Photo by Jiri Hulcr, University of North Carolina |
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granulate ambrosia beetle, Xylosandrus crassiusculus, larvae; Photo by Jiri Hulcr, University of North Carolina (Note: This species does not occur on palms, but Scolytinae larvae all share the same general appearance.) |
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sawdust plug from ambrosia beetle on Carpentaria acuminata trunk; Photo by T.K. Broschat, University of Florida, IFAS/FLREC |
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gum and sawdust from ambrosia beetle damage on Carpentaria acuminata trunk; Photo by T.K. Broschat, University of Florida, IFAS/FLREC |
Rank & taxon
Ambrosia beetles are an ecological guild rather than a phylogeneticphylogenetic:
relating to or based on evolutionary history
group, and include members of the family Curculionidae in the subfamilies Scolytinae and Platypodinae.
Description
Ambrosia beetles are highly derived weevils that employ a unique habit. They bore galleries in the trunks of trees, but rather than feeding on the wood, they cultivate ambrosia fungi in the galleries and feed on the fungus instead. The adults are small, less than 5 mm long, and they look superficially like powder-post beetles; that is, they are elongate and mostly cylindrical in shape, and sometimes the head is pointed downward and invisible from above, particularly in the Scolytinae. They may be yellowish to reddish-brown in color. Adults can be differentiated from powder post beetles by their elbowed, clubbed antennae, and four visible tarsomerestarsomeres:
the segments of the tarsi
. The larvae are similar in appearance to other weevils, being grublike, footless, and white to cream-colored. Scolytinae larvae are generally C-shaped while Platypodinae larvae are rectilinear.
Distribution
Worldwide, most diverse in the tropics; about 3,000 species
Biology/life cycle
The adult beetle bores into the stem of the palm, forming brood chambers where they overwinter. In spring, some adult females mate with apterousapterous:
lacking wings
males and emerge from the tree at night to find a new suitable host. Unmated females may produce haploidhaploid:
a cell or organism having half the number of a typical somatic cell's chromosomes
males with whom they mate, producing only female progeny. Gallery formation may be initiated by either sex, depending on the species. Colonies of the symbiotic fungus are cultivated in the galleries, and the adults and their brood feed upon these colonies. Females lay eggs, which hatch in 6-10 days. The larvae will often form their own pupal chamber, emerging as adults usually within 2-4 weeks of hatching.
Hosts
Palms: a wide variety of palms
Other: a wide variety of trees
Representative taxa on palms
Platypus parallelus (subfamily Platypodinae) is a tropical species that is one of the most commonly collected beetles from dead or weakened palms in Florida.
Xyleborus ferrugineus (subfamily Scolytinae) is one of the most common, widely distributed, and economically important ambrosia beetles in the world. It is an alleged pest of coconut palm but primarily attacks recently killed or dying trees.
Additional comments
Ambrosia beetles are almost always considered secondary pests, feeding almost exclusively on dead or dying trees.
