Winter temperature predicts prolonged diapause in pine processionary moth species across their geographic range

Prolonged diapause occurs in a number of insects and is interpreted as a way to evade adverse conditions. The winter pine processionary moths (Thaumetopoea pityocampa and Th. wilkinsoni) are important pests of pines and cedars in the Mediterranean region. They are typically univoltine, with larvae feeding across the winter, pupating in spring in the soil and emerging as adults in summer. Pupae may, however, enter a prolonged diapause with adults emerging one or more years later. We tested the effect of variation in winter temperature on the incidence of prolonged diapause, using a total of 64 individual datasets related to insect cohorts over the period 1964-2015 for 36 sites in seven countries, covering most of the geographic range of both species. We found high variation in prolonged diapause incidence over their ranges. At both lower and upper ends of the thermal range in winter, prolonged diapause tended to be higher than at intermediate temperatures. Prolonged diapause may represent a risk-spreading strategy to mitigate climate uncertainty, although it may increase individual mortality because of a longer exposure to mortality factors such as predation, parasitism, diseases or energy depletion. Climate change, and in particular the increase of winter temperature, may reduce the incidence of prolonged diapause in colder regions whereas it may increase it in warmer ones, with consequences for population dynamics

Do Torymus sinensis (Hymenoptera: Torymidae) and agroforestry system affect native parasitoids associated with the Asian chestnut gall wasp?

The Asian chestnut gall wasp, Dryocosmus kuriphilus Yasumatsu, is one of the most serious pests of Castanea spp. worldwide. Since local parasitoids did not effectively control this exotic pest, the Chinese parasitoid Torymus sinensis Kamijo was released into Japan and Europe resulting in a successful control of the invader. A survey of native parasitoids usually infesting oak gall wasps but associated with D. kuriphilus was carried out, sampling chestnut galls in Italy in 2013. The effect of predictive variables (years since T. sinensis release, oak occurrence, type of chestnut formation, latitude) on composition and density of native parasitoid populations was modelled with Generalized Linear Models. In total, 4410 chalcid parasitoids were recorded, and the most abundant species were T. flavipes Walker, Eupelmus spp., and Bootanomyia (= Megastigmus) dorsalis (F.). Introduction of T. sinensis and oak occurrence influenced native parasitoid richness, conversely to the latitude of the study area. In particular, every additional year of presence of T. sinensis was proved to determine the loss of about 14% of native species, and 32% of their population density. A positive correlation between the oak density occurring in the infested chestnut forests and the richness and abundance of native parasitoid species was recorded as well, highlighting how generalist parasitoids may switch hosts easily. A positive effect of increasing densities of oak trees was recorded on most of the taxa, except for T. geranii (Walker), Eupelmus spp., and Eurytoma pistaciae Rondani. Our results provide insight that both T. sinensis and oak trees affect native parasitoids, shedding light on the possible implications related to the release of exotic biological control agents on the recruitment and accumulation of native natural enemies

New mutations in TK2 gene associated with mitochondrial DNA depletion

Mitochondrial deoxyribonucleic acid depletion syndromes are autosomal recessive disorders characterized by a reduction of the amount of mitochondrial deoxyribonucleic acid, which impairs the synthesis of respiratory chain complexes. Mutations in the deoxyguanosine kinase and polymerase gamma genes have been identified in hepatocerebral forms, whereas thymidine kinase 2 gene mutations have been found in patients with isolated myopathy, encephalomyopathy, or spinal muscular atrophy. Mutations in the gene encoding the beta subunit of the adenosine diphosphate-forming succinyl-coenzyme A synthetase have also been reported in a family. In this report, the clinical, molecular, morphologic, and biochemical features of five children from two independent families with an infantile encephalomyopathy are characterized. The affected children manifested muscle mitochondrial deoxyribonucleic acid depletion and three novel thymidine kinase 2 gene mutations. They consist of a homozygous substitution resulting in Ala to Val change at the highly conserved position 181 of thymidine kinase in the first family, and two heterozygous substitutions in the second family: a Cys to Trp change at residue 108 and a Leu to Pro change at residue 257 of the enzyme. Common clinical features associated with these TK2 mutations are a normal early developmental phase followed by psychomotor regression, encephalopathy often with epileptic seizures, and myopathy with features of a progressive dystrophic process

Influences of Botanical Pesticides and Biological Agents on Orius Laevigatus - Frankliniella Occidentalis Dynamics Under Greenhouse Conditions

Influences of Botanical Pesticides and Biological Agents onOrius Laevigatus - Frankliniella OccidentalisDynamics Under Greenhouse ConditionsWe assessed the influence of nine biopesticides on adults and larvae of western flower thrips (WFT),Frankliniella occidentalis(Pergande) and its predator, the anthocoridOrius laevigatus(Fieber) under Mediterranean greenhouse conditions. Trials were carried out in a strawberry crop where both species had naturally established. Foliar sprays were applied weekly for one month. Treatments did not provide sufficient control of larval and adultF. occidentalis. The negative effects on the dynamics of the predator were evident only with the use of some specific products. The botanical insecticides rotenone and neem, and the nematodeSteinernema feltiae(Filipjev) reducedO. laevigatusnumbers, and these effect are evident in the adult stage ofO. laevigatus. Such products have determined a reduction of the population of the predator from the first treatments even if the incidence was not very high. We conclude that the use of some botanical pesticides and nematodes against WFT is uneconomical and possibly disadvantageous where there is an established predator-prey population

Potential impact of climate change on whiteflies and implications for the spread of vectored viruses

Published online: 31 Oct 2018Whiteflies (Hemiptera: Aleyrodidae) are important insect pests causing serious damage to plants and transmitting hundreds of plant viruses. Climate change is expected to influence life history and trophic interactions among plants, whiteflies and their natural enemies. Here, we review the potential impacts of climate change on whiteflies and the likely consequences for agricultural systems. This review concludes that while climatic stress tends to negatively affect life history traits, the effects differ with the tolerance of the whiteflies and the amount of stress experienced. Whiteflies also differ in their adaptability. Better adapted species will likely experience increased distribution and abundance provided their tolerance limits are not exceeded, while species with lower tolerance and adaptation limits will suffer reduced fitness, which will have overall effects on their distribution and abundance in space and time. The majority of methods used to control whiteflies will still be useful especially if complementary methods are combined for maximum efficacy. Parasitism and predation rates of whitefly natural enemies could increase with temperature within the optimum ranges of the natural enemies, although life history traits and population growth potential are generally maximised below 30 °C. Changes in climatic suitability modifying the distribution and abundance of whiteflies, and environmental suitability for plant viruses, will likely affect epidemics of viral diseases. Greater efforts are required to improve understanding of the complex effects of climate change on multi-species and multi-trophic interactions in the agro-ecological systems inhabited by whiteflies, and to use this new knowledge to develop robust and climate-smart management strategies