Biocontrol Science and Technology (2015) 25, 1467-1482

Melissa J. Fischer, Carlyle C. Brewster, Nathan P. Havill, Scott M. Salom and Loke T. Kok (2015)
Assessment of the potential for hybridisation between Laricobius nigrinus (Coleoptera: Derodontidae) and Laricobius osakensis, predators of the hemlock woolly adelgid (Hemiptera: Adelgidae)
Biocontrol Science and Technology 25 (12), 1467-1482
Abstract: In 2003, Laricobius nigrinus Fender was introduced into the eastern United States as a biological control agent of the hemlock woolly adelgid (Adelges tsugae Annand). Following its release, it was discovered that L. nigrinus was hybridising and producing viable progeny with Laricobius rubidus LeConte, a species native to eastern North America. Recently, Laricobius osakensis Montgomery and Shiyake was imported from Japan into the USA as a potential biological control agent of hemlock woolly adelgid. Hybridisation between L. nigrinus and L. rubidus led to interest in the outcome of interactions between L. osakensis and the other two Laricobius spp. The purpose of this study was to determine if L. osakensis could mate with L. nigrinus, if they could produce hybrid progeny, and whether mating interferes with reproductive output. Laricobius spp. were observed mating directly following emergence and found to be capable of producing sterile eggs in the absence of a mating event. Laboratory and confined field studies found no evidence that L. osakensis and L. nigrinus could produce hybrid progeny and the interaction between the two species did not result in a lower reproduction associated with interspecific mating attempts. Interbreeding should therefore not have an impact on biological control using these species. Fecundity experiments showed that L. osakensis produced eggs earlier in the season and at a higher rate than L. nigrinus, suggesting that L. osakensis may have the potential to be an even more successful biological control agent than L. nigrinus.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Nathan P. Havill, Scott M. Salom, Loke T. Kok

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Adelges tsugae
Laricobius nigrinus (predator)	Adelges tsugae
Laricobius osakensis (predator)	Adelges tsugae