Xyleborus bispinatus

Eichhoff, 1868

Xyleborus bispinatus is a tropical ambrosia beetle in the tribe Xyleborini. Native to the Americas, it has established in Florida and been introduced to the Iberian Peninsula. The maintains nutritional mutualisms with ambrosia fungi and has demonstrated unusual flexibility in acquiring from beetle , including plant . It is a potential for laurel wilt and has been associated with avocado decline in multiple regions.

Xyleborus (10.3897-zookeys.768.24697) Figure 15 by Gomez DF, Rabaglia RJ, Fairbanks KEO, Hulcr J (2018) North American Xyleborini north of Mexico: a review and key to genera and species (Coleoptera, Curculionidae, Scolytinae). ZooKeys 768: 19-68. https://doi.org/10.3897/zookeys.768.24697. Used under a CC BY 4.0 license.

Pronunciation

How to pronounce Xyleborus bispinatus: /zaɪˈliːbɔrəs baɪˌspɪˈneɪtəs/

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Habitat

Native to tropical regions of the Americas; established in Florida avocado orchards. In Spain, detected in baited traps in Murcia, Alicante, and Valencia provinces; stable confirmed in central Valencian province. Laboratory rearing successful on artificial sawdust media at 25°C and 70% relative humidity.

Distribution

Native range: Middle America, North America, South America (present in Brazil: Mato Grosso, Santa Catarina). Introduced range: Iberian Peninsula (Spain, first detected 2009), India. Florida established in avocado production areas.

Diet

Obligate nutritional mutualism with ambrosia fungi. Native include Raffaelea subfusca and Raffaelea arxii. Capable of acquiring and sustaining on non-native fungal symbionts including Harringtonia lauricola (laurel wilt from Xyleborus glabratus) and Fusarium sp. nov. (Fusarium dieback pathogen from Euwallacea perbrevis). Fungi serve as sole food source; no wood consumption.

Host Associations

Persea americana - treeavocado; used for gallery establishment and larval development in Florida orchards
Persea humilis - treesilkbay; used in artificial rearing media
Raffaelea subfusca - native nutritional primary ambrosia fungus
Raffaelea arxii - native nutritional primary ambrosia fungus
Harringtonia lauricola - acquired laurel wilt ; acquired from Xyleborus glabratus, can transmit to healthy avocado trees
Fusarium sp. nov. - acquired Fusarium dieback ; acquired from Euwallacea perbrevis, significantly increased in laboratory
Fusarium proliferatum - associated associated with avocado decline in India

Life Cycle

Complete : , larva, pupa, . time approximately 16-20 days at optimal temperatures (26-29°C), extending to 36 days at lower temperatures. Optimal thermal range 26.2°C with maximum intrinsic growth rate of 0.13 individuals/individuals/day. Larvae feed on symbiotic fungi in gallery tunnels. Gut contents emptied during pupal stage; naïve adults acquire via feeding after . Pre-oral mycangia present for fungal transport and inoculation of new galleries.

Behavior

In- at dusk, attracted to ethanol lures. Single female foundress establishes galleries; males few in number, produced parthenogenetically. Gallery boring into trees and artificial media. Capable of lateral transfer of fungal from ambrosia beetle . Surface-disinfested pupae can be rendered and re-established with novel fungal partners under laboratory conditions.

Ecological Role

Native ambrosia beetle that functions as a bridge between native and ambrosia beetle-fungus . Potential for economically significant plant including laurel wilt (Harringtonia lauricola) and Fusarium dieback. In invaded ranges, may contribute to disease in avocado production systems and native Lauraceae forests. influenced by identity and thermal conditions.

Human Relevance

Economic pest of avocado production in Florida and potential threat to avocado industries in invaded regions. Associated with avocado decline in India through Fusarium proliferatum transmission. capability for laurel wilt raises concerns for commercial avocado production and native forest conservation. Subject of biosecurity surveillance in Spain due to established without known plant attacks.

Similar Taxa

Xyleborus glabratusBoth are Xyleborus ambrosia beetles; X. glabratus is the primary of Harringtonia lauricola, while X. bispinatus has demonstrated ability to acquire and transmit this secondarily
Euwallacea perbrevisBoth share Fusarium sp. nov. as a ; X. bispinatus acquired this from Euwallacea through lateral transfer

More Details

Symbiont flexibility significance

Xyleborus bispinatus demonstrates exceptional flexibility in fungal , surviving and reproducing on fungi from phylogenetically distant lineages including plant . This trait enables lateral transfer of virulent pathogens between and native , with implications for in agricultural and forest systems.

Thermal biology

Laboratory studies demonstrate narrow optimal thermal range (26-29°C) with sharp declines outside this range. This thermal sensitivity may limit establishment in temperate regions but facilitate modeling for invaded ranges.

Iberian Peninsula invasion status

First detected in Spain in 2009 with stable confirmed by 2021. Unlike Florida populations, no plant attacks have been detected and the host plant remains unknown, suggesting possible alternative or incomplete establishment.