Ambrosia beetle

Image:Xylosandrus crassiusculus galleryR.jpg split open, with pupae and black fungus]]

Until recently ambrosia beetles have been placed in independent families Scolytidae and Platypodidae, however, they are in fact some of the most highly derived weevils, and are now placed in the subfamilies Scolytinae and Platypodinae of Family Curculionidae{{cite journal |last1=Kuschel |first1=Guillermo |last2=Leschen |first2=Richard A. B. |last3=Zimmerman |first3=Elwood C. |title=Platypodidae under scrutiny |journal=Invertebrate Systematics |date=2000 |volume=14 |issue=6 |pages=771–805 |doi=10.1071/IT00024 }}{{cite journal |last1=Marvaldi |first1=Adriana E. |last2=Sequeira |first2=Andrea S. |last3=O'Brien |first3=Charles W. |last4=Farrell |first4=Brian D. |title=Molecular and Morphological Phylogenetics of Weevils (Coleoptera, Curculionoidea): Do Niche Shifts Accompany Diversification? |journal=Systematic Biology |date=September 2002 |volume=51 |issue=5 |pages=761–785 |doi=10.1080/10635150290102465 |pmid=12396590 |doi-access=free }}{{cite journal |last1=McKenna |first1=Duane D. |last2=Sequeira |first2=Andrea S. |last3=Marvaldi |first3=Adriana E. |last4=Farrell |first4=Brian D. |title=Temporal lags and overlap in the diversification of weevils and flowering plants |journal=Proceedings of the National Academy of Sciences |date=28 April 2009 |volume=106 |issue=17 |pages=7083–7088 |doi=10.1073/pnas.0810618106 |pmid=19365072 |pmc=2678426 |bibcode=2009PNAS..106.7083M |doi-access=free }} There are about 3,000 known beetle species employing the ambrosia strategy.{{cite book |doi=10.1016/B978-0-12-417156-5.00002-2 |chapter=Morphology, Taxonomy, and Phylogenetics of Bark Beetles |title=Bark Beetles |year=2015 |last1=Hulcr |first1=Jiri |last2=Atkinson |first2=Thomas H. |last3=Cognato |first3=Anthony I. |last4=Jordal |first4=Bjarte H. |last5=McKenna |first5=Duane D. |pages=41–84 |isbn=978-0-12-417156-5 }}

Ambrosia beetles are an ecological guild, but not a phylogenetic clade. The ambrosia habit is an example of convergent evolution, as several groups evolved the same symbiotic relationship independently.{{cite journal |last1=Farrell |first1=Brian D. |last2=Sequeira |first2=Andrea S. |last3=O'Meara |first3=Brian C. |last4=Normark |first4=Benjamin B. |last5=Chung |first5=Jeffrey H. |last6=Jordal |first6=Bjarte H. |title=The evolution of agriculture in beetles (Curculionidae: Scolytinae and Platypodinae) |journal=Evolution |date=October 2001 |volume=55 |issue=10 |pages=2011–2027 |doi=10.1111/j.0014-3820.2001.tb01318.x |pmid=11761062 |s2cid=26352287 }} The highest diversity of ambrosia beetles is in the tropics. In the Paleotropical region, hundreds of species of Xyleborini and Platypodinae are the main agent initiating dead wood decomposition. In the Neotropics, Platypodinae and Xyleborini are joined by the scolytine tribe Cortylini. Compared to the diversity in the tropics, ambrosia beetle fauna in the temperate zone is rather limited. In the Nearctic region it is dominated by a few species from Cortylini, Xyleborini and Xyloterini. In the Palearctic realm, significant groups are Xyloterini and Xyleborini, joined by Scolytoplatypodini in the Far East.

Image:Dinoplatypus chevrolati.jpg

Beetles and their larvae graze on mycelium exposed on the gallery walls and on bodies called sporodochia, clusters of the fungus' spores. Most ambrosia beetle species don't ingest the wood tissue; instead, the sawdust resulting from the excavation is pushed out of the gallery. Following the larval and pupal stage, adult ambrosia beetles collect masses of fungal spores into their mycangia and leave the gallery to find their own tree.

A few dozen species of ambrosia fungi have been described, currently in the genera Ambrosiella, Meredithiella, and Phialophoropsis (from Microascales), Afroraffaelea and Raffaelea (from Ophiostomatales), Ambrosiozyma (Saccharomycetales), Fusarium and Geosmithia (from Hypocreales), and Flavodon (from Basidiomycota). Many more species remain to be discovered. Little is known about the bionomy or specificity of ambrosia fungi. Ambrosia fungi are thought to be dependent on transport and inoculation provided by their beetle symbionts, as they have not been found in any other habitat. All ambrosia fungi are probably asexual and clonal.{{cite book |last1=Malloch |first1=D |last2=Blackwell |first2=M |chapter=Dispersal biology of ophiostomatoid fungi |pages=195–206 |editor1-last=Wingfield |editor1-first=Michael J. |editor2-last=Seifert |editor2-first=Keith A. |editor3-last=Webber |editor3-first=Joan F. |title=Ceratocystis and Ophiostoma: Taxonomy, Ecology, and Pathogenicity |date=1993 |publisher=American Phytopathological Society |isbn=978-0-89054-156-2 }} Some beetles are known to acquire ("steal") fungal inoculum from fungal gardens of other ambrosia beetle species.{{cite journal |last1=Hulcr |first1=Jiri |last2=Cognato |first2=Anthony I. |title=Repeated evolution of crop theft in fungus‐farming ambrosia beetles |journal=Evolution |date=November 2010 |volume=64 |issue=11 |pages=3205–3212 |doi=10.1111/j.1558-5646.2010.01055.x |pmid=20633043 |s2cid=11844858 |doi-access=free }}

During their evolution, most scolytid and platypodid weevils became progressively more or less dependent on fungi regularly co-habiting dead trees. This evolution had various outcomes in different groups:

• Some phloem-eating bark beetles (phloeophages) are vectors of phytopathogenic fungi, which in some cases contribute to tree death.{{cite journal |last1=Paine |first1=T. D. |last2=Raffa |first2=K. F. |last3=Harrington |first3=T. C. |title=Interactions among scolytid bark beetles, their associated fungi, and live host conifers |journal=Annual Review of Entomology |date=January 1997 |volume=42 |issue=1 |pages=179–206 |doi=10.1146/annurev.ento.42.1.179 |pmid=15012312 }} The extent to which fungal pathogenicity benefits the beetles themselves is not at all trivial and remains disputed.{{cite journal |last1=Six |first1=Diana L. |last2=Wingfield |first2=Michael J. |title=The Role of Phytopathogenicity in Bark Beetle–Fungus Symbioses: A Challenge to the Classic Paradigm |journal=Annual Review of Entomology |date=7 January 2011 |volume=56 |issue=1 |pages=255–272 |doi=10.1146/annurev-ento-120709-144839 |pmid=20822444 |hdl=2263/15796 |hdl-access=free }}
• Many of phloem-feeding bark beetles use phloem-infesting fungi as an addition to their diet. Some phloeophages became dependent on such a mixed diet and evolved mycangia to transport their symbionts from maternal trees to newly infested trees.{{cite journal |last1=Klepzig |first1=Kier D. |last2=Six |first2=D. L. |title=Bark Beetle-Fungal Symbiosis: Context Dependency in Complex Associations |journal=Symbiosis |date=2004 |volume=37 |pages=189–2005 |url=https://www.fs.usda.gov/research/treesearch/7292 }} These beetles are called mycophloeophages.
• Ambrosia beetles and ambrosia fungi are thus only one end of the spectrum of the weevil-fungus association, where both the beetle and the fungus became completely dependent on each other.{{cite book |last1=Beaver |first1=R. A. |chapter=Insect-Fungus Relationship in the Bark and Ambrosia Beetles |pages=121–143 |chapter-url=https://books.google.com/books?id=DwO5_3N7sSAC&pg=PA121 |editor1-last=Meurant |editor1-first=Gerard |title=Insect-Fungus Interactions |date=2012 |publisher=Academic Press |isbn=978-0-08-098453-7 }}

The vast majority of ambrosia beetles colonize dead trees, and have minor or no economic effect. A few species are able to colonize living stressed trees (Xylosandrus).{{cite journal |last1=Ranger |first1=Christopher M. |last2=Reding |first2=Michael E. |last3=Persad |first3=Anand B. |last4=Herms |first4=Daniel A. |title=Ability of stress-related volatiles to attract and induce attacks by Xylosandrus germanus and other ambrosia beetles |journal=Agricultural and Forest Entomology |date=May 2010 |volume=12 |issue=2 |pages=177–185 |doi=10.1111/j.1461-9563.2009.00469.x |s2cid=54556122 |doi-access=free }} A few species are able to attack live and healthy trees, and those can reach epidemic proportions in non-native, invaded regions (Xyleborus glabratus, Euwallacea fornicatus{{cite journal |last1=Hulcr |first1=Jiri |last2=Black |first2=Adam |last3=Prior |first3=Kirsten |last4=Chen |first4=Chi-Yu |last5=Li |first5=Hou-Feng |title=Studies of Ambrosia Beetles (Coleoptera: Curculionidae) in Their Native Ranges Help Predict Invasion Impact |journal=Florida Entomologist |date=June 2017 |volume=100 |issue=2 |pages=257–261 |doi=10.1653/024.100.0219 |s2cid=67808629 |doi-access=free }}).

Beetle species that readily colonize lumber, such as sawlogs, green lumber, and stave-bolts, often cause region-specific economic loss from the pinhole and stained-wood defects caused by their brood galleries. In Northern USA and Canada, conifer logs are attractive to Trypodendron lineatum (Oliv.) during the spring swarming flight (Dyer 1967).{{cite journal |last1=Dyer |first1=E. D. A. |title=Relation of attack by ambrosia beetle (Trypodendron lineatum (Oliv.)) to felling date of spruce in central British Columbia |journal=Bi-monthly Research Notes |date=1967 |volume=23 |issue=2 |pages=11 |url=https://cfs.nrcan.gc.ca/publications?id=27776 }} Previous studies showed that short log sections become attractive more rapidly than corresponding long logs.

• Laurel wilt disease
• Forest pathology

{{reflist}}

{{wikispecies|Platypodinae}}

• [http://www.ambrosiasymbiosis.org Images and information] on the Ambrosia Symbiosis at the University of Florida.
• The [https://web.archive.org/web/20130701003854/http://www.scolytid.msu.edu/ MSU HISL database] contains a worldwide species list of Xyleborini, a major group of ambrosia beetles, from the Catalog of Scolytidae and Platypodidae of S.L. Wood and D.E. Bright (1992)
• A USDA-sponsored [http://itp.lucidcentral.org/id/wbb/xyleborini/ information resource and key] {{Webarchive|url=https://web.archive.org/web/20181208061256/http://itp.lucidcentral.org/id/wbb/xyleborini/ |date=2018-12-08 }} to the world genera of Xyleborini
• [http://www.barkbeetles.info American Bark and Ambrosia Beetles]
• More information on ambrosia beetle social behaviour and fungiculture on [http://behav.zoology.unibe.ch/index.php?pp=55&p=46]
• [https://web.archive.org/web/20120422080021/http://www.dontmovefirewood.org/blog/farewell-taco-topping.html Farewell to taco topping?] The effects of the Redbay ambrosia beetle and laurel wilt disease
• Ambrosia beetles on the UF / IFAS Featured Creatures Web site
• [http://entomology.ifas.ufl.edu/creatures/trees/beetles/platypus.htm Platypus spp., ambrosia beetles]
• [http://entomology.ifas.ufl.edu/creatures/trees/asian_ambrosia_beetle.htm Xylosandrus crassiusculus, Asian (or granulate) ambrosia beetle]
• [http://entomology.ifas.ufl.edu/creatures/trees/black_twig_borer.htm Xylosandrus compactus, black twig borer]

• {{cite journal |last1=van de Peppel |first1=L. J. J. |last2=Aanen |first2=D. K. |last3=Biedermann |first3=P. H. W. |title=Low intraspecific genetic diversity indicates asexuality and vertical transmission in the fungal cultivars of ambrosia beetles |journal=Fungal Ecology |date=April 2018 |volume=32 |pages=57–64 |doi=10.1016/j.funeco.2017.11.010 |hdl=21.11116/0000-0003-BB62-C |hdl-access=free }}

Category:Woodboring beetles

Category:Platypodinae

Category:Scolytinae

Category:Insect common names