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The Russian wheat aphid, Diuraphis noxia (Mordvilko ex Kurdjumov), is one of the world's most economically important pests of grain crops and has been recorded from at least 140 grass species within Poaceae. It has rapidly dispersed from its native origin of Central Asia into most major grain-producing regions of the world including Africa, Asia, Europe, the Middle East, North America and South America. Diuraphis noxia was first found in Australia in a wheat crop in the mid-north of South Australia in May 2016. Since then, D. noxia has been recorded throughout grain-growing regions of South Australia, Victoria, New South Wales and Tasmania. The distribution will continue to expand, with climatic suitability modelling suggesting D. noxia can persist in all key grain regions, including large parts of Western Australia and Queensland. Australian populations of D. noxia appear to be anholocyclic, with no sexual stages being observed. The aphids can reproduce year round as long as host plants are available. Australian farmers have generally adopted prophylactic insecticide seed treatments and/or foliar sprays to manage D. noxia. Research is required to fully understand yield impacts, host preferences and host plant resistance associated with D. noxia. Cultural control through managing alternate host plants over summer, agronomic crop management, biological control and developments in host plant resistance should provide considerable future benefits.

The maternally inherited endosymbiont, Wolbachia pipientis, plays an important role in the ecology and evolution of many of its hosts by affecting host reproduction and fitness. Here, we investigated 13 dipteran leaf-mining species to characterize Wolbachia infections and the potential for this endosymbiont in biocontrol. Wolbachia infections were present in 12 species, including 10 species where the Wolbachia infection was at or near fixation. A comparison of Wolbachia relatedness based on the wsp/MLST gene set showed that unrelated leaf-mining species often shared similar Wolbachia, suggesting common horizontal transfer. We established a colony of Liriomyza brassicae and found adult Wolbachia density was stable, although Wolbachia density differed between the sexes, with females having a 20-fold higher density than males. Wolbachia density increased during L. brassicae development, with higher densities in pupae than larvae. We removed Wolbachia using tetracycline and performed reciprocal crosses between Wolbachia-infected and uninfected individuals. Cured females crossed with infected males failed to produce offspring, indicating that Wolbachia induced complete cytoplasmic incompatibility in L. brassicae. The results highlight the potential of Wolbachia to suppress Liriomyza pests based on approaches such as the incompatible insect technique, where infected males are released into populations lacking Wolbachia or with a different incompatible infection.

Organisms vary widely in size, from microbes weighing 0.1 pg to trees weighing thousands of megagrams — a 1021-fold range similar to the difference in mass between an elephant and the Earth. Mass has a pervasive influence on biological processes, but the effect is usually non-proportional; for example, a tenfold increase in mass is typically accompanied by just a four- to sevenfold increase in metabolic rate. Understanding the cause of allometric scaling has been a long-standing problem in biology. Here, we examine the evolution of metabolic allometry in animals by linking microevolutionary processes to macroevolutionary patterns. We show that the genetic correlation between mass and metabolic rate is strong and positive in insects, birds and mammals. We then use these data to simulate the macroevolution of mass and metabolic rate, and show that the interspecific relationship between these traits in animals is consistent with evolution under persistent multivariate selection on mass and metabolic rate over long periods of time. The authors identify a strong positive relationship between mass and metabolic rate among insects, fish, amphibians, reptiles, birds and mammals, and show that the genetic and interspecific correlations between these traits are consistent with a pattern of multivariate selection.

1. Understanding how invasive species respond to novel environments is limited by a lack of sensitivity and throughput in conventional biomonitoring methods. Arthropods in particular are often difficult to monitor due to small size, rapid lifecycles, and/or visual similarities with co-occurring species. This is true for the agromyzid leafminer, Liriomyza sativae, a global pest of vegetable and nursery industries that has recently established in Australia. 2. A highly robust method based on environmental DNA (eDNA) was developed exploiting traces of DNA left inside ‘empty’ leaf mines, which are easier to collect and persist longer in the environment than the insect. This extended the window of possible diagnosis to at least 28 days since a leaf mine became empty. The test allowed for visually indistinguishable leafmining damage caused by L. sativae to be genetically differentiated from that of other flies. 3. Field application resulted in the identification of new local plant hosts for L. sativae, including widely distributed weeds and common garden crops, with important implications for the pest’s ability to spread. Moreover, the test allowed for the confirmation of L. sativae on an island with a previously unconfirmed population. 4. The developed eDNA method is likely to become an important tool for L. sativae and other leafmining species of biosecurity significance, which, historically, have been difficult to detect, diagnose and monitor. More generally, eDNA is emerging as a highly sensitive and labour-efficient surveillance tool for difficult to survey species to improve outcomes for agricultural industries, global health, and the environment.

Aphids are economically important pests of cereal crops globally. They feed on the sap of plants, which can directly reduce yield and grain quality. Many species are also proficient at transmitting important plant viruses. Two of the world’s most damaging cereal aphids are the Russian wheat aphid (Diuraphis noxia) and bird cherry oat aphid (Rhopalosiphum padi). These species are present in all major grain-growing regions worldwide, with D. noxia recently invading Australia. In many countries, including Australia, chemicals are an important control option. Insecticide seed-dressings, in particular, are widely used to combat early-season infestations of aphids in establishing cereal crops. In this study we examined the length of protection provided by several insecticide seed-dressings against D. noxia in wheat, and compared this with R. padi. All seed-dressings examined were efficacious for up to 5 weeks after wheat emergence; however, notable differences were evident between aphid species. In most instances, R. padi was able to persist and reproduce on wheat at an earlier growth stage than D. noxia. These findings suggest that R. padi is more tolerant to certain insecticides and may therefore re-infest insecticide-treated wheat fields earlier than D. noxia.

Quantifying detectability of exotic pests in local contexts is crucial for designing efficient and regionally relevant surveillance guidelines. Ironically, for areas most in need of preparedness advice, the study of detectability is hampered by the pest's absence. Here, we present a mock surveillance method whereby pest symptoms are simulated on plants, and the detection probability of visual inspection by practitioners is measured across a range of high priority regions at risk of incursions. Detectability of simulated leaf mining damage was found to be no different to real damage in surveillance trials conducted on the vegetable leafminer, Liriomyza sativae, a recently established pest in Australia. Additional trials confirmed that reducing the natural search speed of survey participants by half increased the odds of detecting a leaf mine by an estimated 3.0 times. However, as movement speed mediates a trade-off between the total area covered (the number of pest encounters) and sensitivity (detection probability for each encounter), we found that a survey effort of 10 s per transect meter enhanced field-level detection of L. sativae at a variety of abundances and available times for surveillance. This study demonstrates that mock surveillance trials, through their use of visual effects to mimic plant pest symptoms, can produce locally tested recommendations to enhance preparedness for exotic pests.

Summary Body size scaling relationships allow biologists to study ecological phenomena in terms of individual level metabolic processes. Recently, dynamic energy budget (DEB) theory has been shown to offer novel insights on the effect of body size on biological rates. We test whether DEB theory and its unique partitioning of biomass into reserve and structural components can explain the effect of egg size on hatch time and the time course of respiration in insect embryos. We find that without any parameterization (calibration), DEB theory is able to predict hatch time for eggs sizes spanning four orders of magnitude from fundamental biological processes. We find, however, that the standard DEB model poorly predicts the time course of respiration, particularly in early embryonic development where a strong effect of egg size is observed. Further, we show that other theoretical models also poorly predict early embryonic respiration. By modifying the assumption that a fresh egg is entirely reserve, we show that embryonic respiration and hatch time can be better predicted by the DEB model. Useful theories in metabolic ecology, such as DEB theory, can help explain universal scaling patterns in development times. However, simple theoretical models must be expanded if they are to capture the scaling of metabolic rate in insect eggs. A Lay Summary is available for this article.

Trisomy 5p and Miller-Dieker syndromes frequently are the result of unbalanced segregations of reciprocal translocations of chromosomes 5 and 17 with other autosomes. The critical regions for the expression of the mentioned syndromes have been mapped to 5p13-->pter, and 17p13.3-->pter. In this report, we describe an 8-year-old girl with mental retardation, postnatal growth deficiency, generalized muscular hypotonia, seizures, microcephaly, cortical atrophy, partial agenesis of corpus callosum, cerebral ventriculomegaly, facial anomalies, patent ductus arteriosus, pectus excavatum, long fingers, and bilateral talipes equinovarus caused by the presence of a 46,XX,der(17)t(5;17)(p13.1;p13.3)mat chromosome complement. Cytogenetic studies of the family confirmed a balanced reciprocal translocation (5;17)(p13.1;p13.3) in her mother, maternal grandfather, maternal aunt, and a female first cousin. Fluorescence in situ hybridization studies on the mother and the proposita using three probes, which map to distal 17p, confirmed the reciprocal translocation in the mother and a terminal deletion in the patient, which resulted in the retention of LIS1 and D17S379 loci and deletion of the 17p telomere. These findings and the phenotype of the proposita, strongly suggest that genes telomeric to LIS1 and locus D17S379 are involved in many clinical findings, including the minor facial anomalies of the Miller-Dieker syndrome.