Applying Satellite-based Habitat Models to Inform Riparian Habitat Restoration and Management Actions for Two Listed Riparian Species, the Southwestern Willow Flycatcher and the Yellow-billed Cuckoo
James Hatten1, Jennifer Holmes2, and Matthew Johnson3*
Stahlke et al. developed a reference genome for tamarisk beetles (Diorhabda spp.) and reference panel of all four introduced parental species to monitor range expansion and hybridization across North America. They found a substantial genetic bottleneck among D. carinulata in N. America, although populations continue to establish and spread, possibly due to aggregation behavior. Among hybrids, they found that D. carinata, D. elongata, and D.
Clark et al. evaluated theoretical predictions for evolution of reproductive life-history and dispersal traits in the range expansion of the tamarisk biological control agent, Diorhabda carinulata, or northern tamarisk beetle. With experiments run on field-collected populations, they found that females at the expansion front had increased fecundity and body mass, and reduced age at first reproduction; and that dispersal increased at the expansion front in males, especially when unmated and reared at low density.
Does hybridization among tamarisk beetles change the risk of non-target attack in the field? Clark et al. study the consequences of hybridization in tamarisk beetles (Diorhabda). They paired laboratory phenotyping with genomics to assess changes in risk of non-target attack and body size and fecundity. Body size and early fecundity were similar in pure and hybrid females, indicating that hybridization is not detrimental to insect fitness or the biocontrol program and may provide variation that allows populations to become locally adapted.
The leaf beetle Diorhabda elongata Brullé subspecies deserticola Chen, collected in northwestern China, has been released in the western United States to control tamarisk (Tamarix spp.). While beetle establishment and saltcedar defoliation have been noted at northern study sites, this species has not established at latitudes south of the 38th parallel.
A presentation by Dan Bean at the 2020 RiversEdge West Conference about new knowledge on aggregation phermones, phenology, and genomics.
This document is an update to the previous risk analysis that was produced on August 9, 2017, to help inform decision makers of the spread potential of Diorhabda beetles and the potential control options available within the authority of APHIS to limit impacts to the SWFL and designated critical habitat. APHIS updated the analysis in response to a remedial order from the United States District Court for the District of Nevada on June 19, 2018.