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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Invasive Species and Pollinator Health » Research » Publications at this Location » Publication #363490

Research Project: Management of Invasive Weeds in Rangeland, Forest and Riparian Ecosystems in the Far Western U.S. Using Biological Control

Location: Invasive Species and Pollinator Health

Title: Three prospective agents instead of one? Cryptic diversity of the biological control agent Psylliodes chalcomera

Author
item DE BIASE, ALESSIO - University Of Rome Sapienza
item Smith, Lincoln - Link
item BRUNETTI, MATTEO - University Of Rome Sapienza
item BELVEDERE, SILVIA - University Of Rome Sapienza
item PRIMERANO, SIMONA - University Of Rome Sapienza
item ANTONINI, GLORIA - University Of Rome Sapienza
item LA MARCA, ALESSANDRA - Bbca-Onlus, Italy
item AUDISIO, PAOLO - University Of Rome Sapienza
item BIONDI, MAURIZIO - University Of L’Aquila
item CRISTOFARO, MASSIMO - Enea Casaccia Research Center

Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/28/2019
Publication Date: 5/30/2019
Citation: De Biase, A., Smith, L., Brunetti, M., Belvedere, S., Primerano, S., Antonini, G., La Marca, A., Audisio, P., Biondi, M., Cristofaro, M. 2019. Three prospective agents instead of one? Cryptic diversity of the biological control agent Psylliodes chalcomera. Biological Control. 136:103998. https://doi.org/10.1016/j.biocontrol.2019.103998.
DOI: https://doi.org/10.1016/j.biocontrol.2019.103998

Interpretive Summary: Classical biological control of invasive plants depends on the use of host specific insects that attack only one or a few species of plant. The flea beetle, Psylliodes chalcomera, was thought to be specific to musk thistle. However, we discovered this species on two other host plants in Europe: yellow starthistle and Scotch thistle. This suggested that either the flea beetle is one species that is capable of attacking multiple species of plants, or that there are races or cryptic species of the beetle that are each specific to a different host plant. We analyzed the DNA of adults and larvae from the three species of plant in Italy, Bulgaria, Turkey and Russia. The results indicate that there are at least 3 genetically distinct groups: one associated with yellow starthistle, one with Scotch thistle and one associated with multiple species: musk thistle, Scotch thistle and possibly yellow starthistle. This suggests that this "species" is comprised of at least 3 host plant races, each of which could be used as a biological control agent for musk thistle. Scotch thistle and yellow starthistle.

Technical Abstract: The flea beetle, Psylliodes chalcomera, was previously permitted as a biological control agent of Carduus nutans (musk thistle) in the USA. However, during subsequent exploration for prospective biological control agents of Centaurea solstitialis (yellow starthistle), we observed individuals attacking this plant in southern Russia. We also observed this insect on Onopordum spp. (Scotch thistle), which raised the question whether this beetle is polyphagous, or whether it is comprised of host races or cryptic species that are specialized on different host plants. We analyzed the DNA of adult and larval specimens collected from these three plants in Bulgaria, Italy, Russia and Turkey to study the population structure of this beetle. The results indicate at least three different groups: 1) associated with C. solstitialis in Bulgaria, Russia and Turkey, 2) associated with Onopordum spp. in Bulgaria, Russia and Turkey, and 3) associated with Carduus spp., Onopordum spp., and possibly C. solstitialis, in Bulgaria, Italy, Russia and Turkey. Adult specimens indicated a fourth group associated with Onopordum spp. and C. solstitialis in Turkey, but we did not have any larval specimens to confirm the host plant of this group. Our results suggest that three of the host races may be interesting to evaluate as prospective candidates for classical biological control of these three weed targets.