Isabel Valenzuela

Molecular and Morphometric Data Indicate a New Species of the Aphid Genus Rhopalosiphum (Hemiptera: Aphididae)

ABSTRACT Here, we provide evidence for a new aphid species from the genus Rhopalosiphum Koch, based upon an Australian survey of variation in the mitochondrial cytochrome oxidase I gene, and subsequently validated by cytochrome b, nuclear microsatellites, nuclear sequence characterized amplified region locus, and karyotypic analyses. Despite the new species being morphologically very similar to Rhopalosiphum padi (L.), there was significant genetic differentiation, with the new species being closer to the Rhopalosiphum insertum (Walker) group. Karyotypic analyses indicated a putative hybrid origin for the new species, but mitochondrial and nuclear DNA sequence data showed that the available Australian and overseas populations of Rhopalosiphum spp. did not serve as parental lineages. Diagnostic methods were developed that enabled the identification of the new species based on morphometric data and a polymerase chain reaction-restriction fragment length polymorphism based molecular technique.

Strategic national approach for improving the conservation management of insects and allied invertebrates in Australia: Conservation strategy for Australian insects

Despite progress in recent decades, the conservation management of insects and allied invertebrates in Australia is challenging and remains a formidable task against a background of poor taxonomic and biological knowledge, limited resources (funds and scientific expertise) and a relatively low level of community engagement, education and awareness. In this review, we propose a new, strategic national approach for the conservation of insects and allied invertebrates in Australia to complement and build on existing actions and increase awareness with the general public and government. A review of all species listed under relevant State and Territory Acts, national legislation (EPBC Act) and on international lists (IUCN Red List) indicated that of the 285 species currently listed under these conservation schedules, 10 (3%) are considered extinct, 204 (72%) threatened (Critically Endangered, Endangered or Vulnerable) and 71 (25%) are classified as other (Threatened, Near Threatened, Rare or Least Concern). Comparison of the geographic ranges of listed species in relation to bioregions (IBRA regions) shows a striking discordance in spatial representation across the Australian landscape, reflecting an ad hoc approach to threatened species conservation and the concentration of invertebrate biologists in urban centres of temperate coastal Australia. There is a positive relationship between the number of threatened species and extent of protection according to the National Reserve System within each IBRA region, exemplifying the anomaly in spatial representativeness of listed species. To overcome these shortfalls, we propose a novel educational, regional approach based on selecting, for each of the 89 IBRA regions, a relatively small set of ‘flagship taxa’ (threatened species and/or ‘iconic’ species of high scientific/social value), which are then promoted and/or nominated for listing by the scientific community. Such species could be adopted by local community groups whereby a community‐based regional approach would ensure spatial representativeness of insect conservation across the entire Australian continent. This novel approach may ultimately provide a better strategy for the conservation management of habitats and threatened ecological communities, reducing extinction risk of threatened species and addressing key threatening processes. Members of the Australian entomological community are strongly encouraged to nominate candidate taxa as flagship species for wider promotion and/or listing nationally under the EPBC Act.

Patterns of Genetic Variation and Host Adaptation in an Invasive Population of Rhopalosiphum padi (Hemiptera: Aphididae)

ABSTRACT Adaptive changes to local conditions are often thought to be required for successful invasions. However, there are also successful invasive asexual species that may have limited potential for evolutionary change. The bird cherry-oat aphid, Bhopalosiphum padi (L.) (Hemiptera: Aphididae), is thought to have been introduced in Australia 100 yr ago and is now an established pest of cereal crops. Here, we use mitochondrial DNA, cytochrome c oxidase subunit I, and nuclear microsatellites to characterize the genetic diversity in invasive R. padi. Asexual reproduction was detected and clonal diversity was low; with two multilocus genotypes, Rp1 and Rp2, dominating all populations. No geographic or host association was detected between the dominant genotypes on cereals but Rp2 was not found on sweet corn, Zea mays L., crops. The fitness of the predominant multilocus genotypes, Rp1 and Rp2, and an uncommon genotype, Rp26, were investigated on different host types (wheat | Triticum aestivum L. |, barley |Hordeum vulgare L. |, triticale | × Triticosecale Wittm. ex A. Camus. |, and sweet corn | Zea mays L. var. rugosa|) at two temperatures. Rp1 and Rp2 performed similarly on cereals and Rp26 performed poorly on all hosts, patterns that might explain field distributions and abundance of these clones. The results suggest that a high level of clonal diversity is not required for successful invasion and that host associations may develop despite low diversity.

First detection of Russian wheat aphid Diuraphis noxia Kurdjumov (Hemiptera: Aphididae) in Australia: a major threat to cereal production

Invasive pest species pose a major threat to agricultural production around the world. Until recently, the Russian wheat aphid, Diuraphis noxia Kurdjumov, a major pest of wheat and barley crops worldwide, was considered a high‐priority exotic pest threat to the Australian grains industry. Here, we document the initial detection and establishment of D. noxia in Australia in 2016. These are the first records for this genus from South Australia, Victoria and New South Wales. Morphological and molecular information is presented for confirmed diagnosis of the species based on voucher specimens. Known distribution data are provided, along with a list of Poaceae hosts on which D. noxia has been recorded, and a brief description of the typical damage symptoms caused by these aphids. The potential impact of this aphid on Australian cereal production is discussed, and we identify research areas required to underpin future management of this new threat to the Australian cereal industry.

A short work-flow to effectively source faecal pollution in recreational waters – A case study

Microbial pollution of recreational waters poses a significant public health risk which, unless mitigated, will continue to increase with population growth. Water managers must implement strategies to accurately discriminate and source human from animal faecal contamination in complex urbanised environments. Our case-study used a new combination of chemical (i.e. ammonia) and microbial (i.e. Escherichia coli, Bacteroides spp.) faecal monitoring tools in a targeted multi-tiered approach to quickly identify pollution hot-spots and track high-risk subterranean stormwater drains in real-time. We successfully located three point sources of human faecal pollution (both episodic and constant pollution streams) within 11 catchments in a total monitoring time of four months. Alternative approaches for obtaining such fine-scale accuracy are typically labour intensive and require expensive equipment.