Assessment of genetic structuring in the Lygodium fern moths Austromusotima camptozonale and Neomusotima conspurcatalis in their native range: implications for biological control

Assessing the genetic diversity and structuring of potential biological control agents in their native range can be a vital step in developing efficient biological control programs. These assessments, however, are not routinely conducted prior to release of agents. Assessments of these variables after releases have been made may also provide valuable insights into why some agents fail to establish in the introduced range. We therefore examined, within their native distribution, the phylogeographic structuring of two biological control agents previously released for the control of Lygodium microphyllum in Florida, USA: Neomusotima conspurcatalis (which has successfully established) and Austromusotima camptozonale (which has failed to establish). Strong regional genetic structuring was detected within N. conspurcatalis, with three distinct geographical clades identified. The Australian populations were, surprisingly, not recovered as monophyletic. In A. camptozonale, by contrast, regional genetic structuring was far less clear. Seven distinct haplotypes were identified from Cape York Peninsula of northern Queensland, Australia (the putative geographic origin of the Florida L. microphyllum). The moths released in Florida were from southern Queensland, with material from this region having a unique haplotype not present in any of the Cape York Peninsula material. Further testing is required to confirm the species status of the distinct mitochondrial lineages in both A. camptozonale and N. conspurcatalis, and to assess whether any of these lineages are better adapted and more damaging to the Florida L. microphyllum genotype than the lineages previously released

Contrasting patterns of phylogeographic structuring in two key beetle pests of stored grain in India and Australia

Rhyzopertha dominica and Tribolium castaneum are key pests of stored grains globally. Fumigation with phosphine gas is the primary control method for these beetles, so the development of phosphine resistant populations threatens the continued use of this fumigant. Developing effective strategies to manage the spread of phosphine resistance requires an understanding of the genetic diversity and structuring in these pests. We therefore assessed the phylogeographic structuring of these beetles in Australia and India, two significant grain producing countries. Genetic diversity was high in T. castaneum, with 40 discrete haplotypes identified from the 268 specimens sequenced. Four haplotypes, including the three most common haplotypes, were found in both India and Australia. Genetic diversity was notably lower in India, potentially driven by the higher frequency of phosphine fumigations in India. No genetic structuring was identified in Australia T. castaneum, but a small amount was detected in India. Genetic diversity was much lower in R. dominica, with only three discrete COI haplotypes identified from 215 specimens. The low level of genetic diversity in R. dominica suggests selection may be occurring on the mitochondrial genome, potentially driven by an endosymbiont such as Wolbachia. The contrasting phylogeographic patterns, across species and countries, emphasise the importance of developing insecticide resistance management practices that are both species specific (even if pests share a similar environment), as well as region specific. For instance, the limited genetic structuring identified in T. castaneum suggests phosphine resistance could potentially spread rapidly across Australia, meaning broad-scale resistance management strategies are essential

Scrutinizing biological control survey data from the native range – the phylogeny and Lygodium fern host associations of Musotiminae moths

Lygodium microphyllum is considered one of the most damaging environmental weeds in Florida. Despite substantial efforts to control this fern, it continues to spread rapidly through the Greater Everglades ecosystem and other regions of Florida. Biological control is considered a critical component of the management strategy to control this weed, and foreign exploration for natural enemies is ongoing. A number of crambid moths from the subfamily Musotiminae are considered the most promising of the potential biological control agents found to date, because they are relatively abundant on Lygodium and apparently host-specific. We amplified three genes (COI, 18S rRNA and 28S rRNA) to assess the phylogenetic relationships among these moths in relation to geography. Limited genetic structuring was typical within each moth species, and no obvious signals of unrecognised host-specific cryptic species were detected, though further investigation is required, particularly for Eugauria albidentata. Our results emphasize the value of complementing initial field surveys with molecular screening, as such an approach provides valuable information on the biogeographic distribution, genetic structuring, and field host range of potential biological control agents

Am. J. Hum. Genet.

families with nonsyndromic X-linked mental retardation (NS-XLMR), >30% of mutations seem to cluster on proximal Xp and in the pericentric region. In a systematic screen of brain-expressed genes from this region in 210 families with XLMR, we identified seven different mutations in JARID1C, including one frameshift mutation and two nonsense mutations that introduce premature stop codons, as well as four missense mutations that alter evolutionarily conserved amino acids. In two of these families, expression studies revealed the almost complete absence of the mutated JARID1C transcript, suggesting that the phenotype in these families results from functional loss of the JARID1C protein. JARID1C (Jumonji AT-rich interactive domain 1C), formerly known as "SMCX," is highly similar to the Y-chromosomal gene JARID1D/SMCY, which encodes the H-Y antigen. The JARID1C protein belongs to the highly conserved ARID protein family. It contains several DNA-binding motifs that link it to transcriptional regulation and chromatin remodeling, processes that are defective in various other forms of mental retardation. Our results suggest that JARID1C mutations are a relatively common cause of XLMR and that this gene might play an important role in human brain function

Am. J. Hum. Genet.

families with nonsyndromic X-linked mental retardation (NS-XLMR), >30% of mutations seem to cluster on proximal Xp and in the pericentric region. In a systematic screen of brain-expressed genes from this region in 210 families with XLMR, we identified seven different mutations in JARID1C, including one frameshift mutation and two nonsense mutations that introduce premature stop codons, as well as four missense mutations that alter evolutionarily conserved amino acids. In two of these families, expression studies revealed the almost complete absence of the mutated JARID1C transcript, suggesting that the phenotype in these families results from functional loss of the JARID1C protein. JARID1C (Jumonji AT-rich interactive domain 1C), formerly known as "SMCX," is highly similar to the Y-chromosomal gene JARID1D/SMCY, which encodes the H-Y antigen. The JARID1C protein belongs to the highly conserved ARID protein family. It contains several DNA-binding motifs that link it to transcriptional regulation and chromatin remodeling, processes that are defective in various other forms of mental retardation. Our results suggest that JARID1C mutations are a relatively common cause of XLMR and that this gene might play an important role in human brain function

How Predictable Are the Behavioral Responses of Insects to Herbivore Induced Changes in Plants? Responses of Two Congeneric Thrips to Induced Cotton Plants

Changes in plants following insect attack are referred to as induced responses. These responses are widely viewed as a form of defence against further insect attack. In the current study we explore whether it is possible to make generalizations about induced plant responses given the unpredictability and variability observed in insect-plant interactions. Experiments were conducted to test for consistency in the responses of two congeneric thrips, Frankliniella schultzei Trybom and Frankliniella occidentalis Pergrande (Thysanoptera: Thripidae) to cotton seedlings (Gossypium hirsutum Linneaus (Malvales: Malvaceae)) damaged by various insect herbivores. In dual-choice experiments that compared intact and damaged cotton seedlings, F. schultzei was attracted to seedlings damaged by Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae), Tetranychus urticae (Koch) (Trombidiforms: Tetranychidae), Tenebrio molitor Linnaeus (Coleoptera: Tenebrionidae), F. schultzei and F. occidentalis but not to mechanically damaged seedlings. In similar tests, F. occidentalis was attracted to undamaged cotton seedlings when simultaneously exposed to seedlings damaged by H. armigera, T. molitor or F. occidentalis. However, when exposed to F. schultzei or T. urticae damaged plants, F. occidentalis was more attracted towards damaged plants. A quantitative relationship was also apparent, F. schultzei showed increased attraction to damaged seedlings as the density of T. urticae or F. schultzei increased. In contrast, although F. occidentalis demonstrated increased attraction to plants damaged by higher densities of T. urticae, there was a negative relationship between attraction and the density of damaging conspecifics. Both species showed greater attraction to T. urticae damaged seedlings than to seedlings damaged by conspecifics. Results demonstrate that the responses of both species of thrips were context dependent, making generalizations difficult to formulate