An improved integrated pest management model under 2-control parameters (sterile male and pesticide)

The object of the present paper is to study an integrated pest management (IPM) problem in an agroecosystem (paddy-fish culture) through mathematical modeling and analysis, where release of sterile males and spraying of pesticide have been used as control measures for pest population. Using optimal analysis of the model, we have shown that restricted and proper use of control measures might enhance the crop production of the system in an economically viable way. The paper also considers the vulnerability of the underlined ecosystem due to the effect of temperature on the pest growth. Using Liapunov-like function, we have found out a suitable range of temperature, where this IPM strategy remains effective. Some important remarks have finally been made on the basis of numerical simulation.     

Spatial and host related genomic variation in partially sympatric cactophagous moth species

Surveys of patterns of genetic variation in natural sympatric and allopatric populations of recently diverged species are necessary to understand the processes driving intra- and interspecific diversification. The South American moths Cactoblastis cactorum, Cactoblastis doddi and Cactoblastis bucyrus are specialized in the use of cacti as host plants. These species have partially different geographic ranges and differ in patterns of host plant use. However, there are areas that overlap, particularly, in northwestern Argentina, where they are sympatric. Using a combination of genome-wide SNPs and mitochondrial data we assessed intra and interspecific genetic variation and investigated the relative roles of geography and host plants on genetic divergence. We also searched for genetic footprints of hybridization between species. We identified three well delimited species and detected signs of hybridization in the area of sympatry. Our results supported a hypothetical scenario of allopatric speciation in the generalist C. cactorum and genetic interchange during secondary geographic contact with the pair of specialists C. bucyrus and C. doddi that probably speciated sympatrically. In both cases, adaptation to new host plants probably played an important role in speciation. The results also suggested the interplay of geography and host plant use as drivers of divergence and limiting gene flow at intra and interspecific levels.     

Non‐destructive observation of the mycangia of Euwallacea interjectus (Blandford) (Coleoptera: Curculionidae: Scolytinae) using X‐ray computed tomography

X‐ray microtomography has been applied successfully to obtain reliable microstructural information of many insect species. Nonetheless, the technique has not been widely applied to ambrosia beetles. The ambrosia beetle Euwallacea interjectus (Blandford) was first recorded as a vector of plant pathogenic fungus Ceratocystis ficicola Kajitani & Masuya, which has caused serious wilt disease in many fig orchards in Japan since 1999. Previous studies of E. interjectus have not described the mycangia (fungus‐storing organ) in detail. In this study, we non‐destructively examined the internal structure of an adult female of E. interjectus through computed microtomography scans. Paired mycangia were observed on typical computed tomography cross‐sections of the head. Each mycangium, ovoid in shape, was located in tissues just posterior to emarginated notch of eyes, adjacent to pharynx. Three dimensions (length × width × depth) of the mycangia were measured on stereography. We confirmed the absence of mycangia in the other body parts, such as elytra, prothorax and coxa of legs.     

Occurrence of natural lectin with bacterial agglutination property in the serum of lepidopteran pest,Parasa lepida

Insects depend on lectins for non‐self recognition and clearance of invading pathogens. Naturally occurring lectin showing specificity for galactose was purified from the serum of lepidopteran pest Parasa lepida by affinity chromatography using Sepharose 6B coupled with galactose as a gel matrix. Preliminary studies on crude serum agglutinin revealed that the agglutinin molecule showed varying degrees of specificity to avian and mammalian red blood cells tested. Among them, the highest titer of 128 was recorded against rabbit red blood cell type. The agglutinin molecule in the crude serum was stable up to 60°C and at pH between 6 and 9. Also, the hemagglutinating activity was neither dependent on divalent cations nor sensitive to ethylenediaminetetraacetic acid treatment. Galactose inhibited the hemagglutinating activity at minimum inhibitory concentration of 12.5 mM and hence it was used as a ligand for affinity chromatography. Native polyacrylamide gel electrophoresis analysis revealed a single band and the molecular weight of the lectin was found to be approximately 90 kDa. Bacterial agglutination activity of the purified lectin with two significant toxin bacteria, namely Salmonella typhi and Bacillus thuringiensis, was observed.     

Removal and eradication of introduced species in a fenced reserve: Quantifying effort,costs and results

Given the difficulty of effective landscape‐scale control of introduced predators, fenced areas that exclude them (i.e. ‘mainland islands') can play an important role in conserving threatened mammal species in Australia. Despite this, the effort required to eradicate or remove introduced species from within fenced areas remains poorly quantified. This study was conducted at Mt Gibson Wildlife Sanctuary in semi‐arid Western Australia, where a 43 km predator‐exclusion fence surrounding 7832 ha was completed in June 2014. The subsequent effort expended in eradicating feral Cat (Felis catus) and removing European Rabbit (Oryctolagus cuniculus) populations was logged daily during 11 months of active population removal and 3.5 months of monitoring. The total effort expended on cat eradication, rabbit removal and monitoring included over 4800 person‐hours of work and nearly 67,000 km of driving (of which 6700 km was for spotlighting), and the conduct of over 15,000 trap nights, 2300 km of sand tracking transects, and over 7800 camera‐trap nights. Total costs (in 2015 figures) were estimated at just over AUD $390,000, which equates to approximately $50 per hectare. Cage trapping was most efficacious for catching cats, although it took nine months to capture the last individual, which was detected independently by both sand tracking transects and camera traps. This research provides baseline data on the resources required for future eradication and removal projects, particularly those within fenced reserves.     

Witnessing four decades of change in coastal park management: Interview with Mike Dodkin

Mike Dodkin’s career as an officer with the NSW National Park and Wildlife Service spanned four decades. His work involved ecological surveys of potential new conservation reserves, overseeing rehabilitation works after mineral sand mining, supporting innovative restoration projects in rainforest and coastal dunes, and pioneering work in marine mammal rescue. In this interview, Mike reflects on those activities and the changes he has witnessed over time.     

From low to high gear: there has been a paradigm shift in our understanding of evolution

Experimental studies of evolution performed in nature and the associated demonstration of rapid evolution, observable on a time scale of months to years, were an acclaimed novelty in the 1980–1990s. Contemporary evolution is now considered ordinary and is an integrated feature of many areas of research. This shift from extraordinary to ordinary reflects a change in the perception of evolution. It was formerly thought of as a historical process, perceived through the footprints left in the fossil record or living organisms. It is now seen as a contemporary process that acts in real time. Here we review how this shift occurred and its consequences for fields as diverse as wildlife management, conservation biology, and ecosystems ecology. Incorporating contemporary evolution in these fields has caused old questions to be recast, changed the answers, caused new and previously inconceivable questions to be addressed, and inspired the development of new subdisciplines. We argue further that the potential of contemporary evolution has yet to be fulfilled. Incorporating evolutionary dynamics in any research program can provide a better assessment of how and why organisms and communities came to be as they are than is attainable without an explicit treatment of these dynamics.     

Effects of grafting on host plant resistance in ash (Fraxinus spp.) to emerald ash borer (Agrilus planipennis Fairmaire)

相似文献   

Spotted wing drosophila (Drosophila suzukii) utilization and dispersal from the wild host Asian bush honeysuckle (Lonicera spp.)

相似文献