Insecticide Resistance Associated with kdr Mutations in Aedes albopictus: An Update on Worldwide Evidences

Insecticide resistance is an increasing problem worldwide that limits the efficacy of control methods against several pests of health interest. Among them, Aedes albopictus mosquitoes are efficient vectors of relevant pathogens causing animal and human diseases worldwide, including yellow fever, chikungunya, dengue, and Zika. Different mechanisms are associated in conferring resistance to chemical insecticides. One of the most widespread and analysed mechanisms is the knockdown resistance (kdr) causing resistance to DDT and pyrethroids. The mechanism is associated with mutations in the voltage sensitive sodium channel, which is involved in beginning and propagation of action potentials in nervous cells. The mechanism was originally discovered in the housefly and then it was found in a large number of arthropods. In 2011, a kdr associated mutation was evidenced for the first time in A. albopictus and afterward several evidences were reported in the different areas of the world, including China, USA, Brazil, India, and Mediterranean Countries. This review aims to update and summarize current evidences on kdr in A. albopictus, in order to stimulate further researches to analyse in depth A. albopictus resistance status across the world, especially in countries where the presence of this vector is still an emerging issue. Such information is currently needed given the well-known vector role of A. albopictus in the transmission of severe infectious diseases. Furthermore, the widespread use of chemical insecticides for control strategies against A. albopictus progressively lead to pressure selection inducing the rise of insecticide resistance-related mutations in the species. Such event is especially evident in some countries as China, often related to a history of uncontrolled use of chemical insecticides. Thus, a careful picture on the diffusion of kdr mutations worldwide represents a milestone for the implementation of control plans and the triggering of novel research on alternative strategies for mosquito-borne infections.

Somaclonal variations for crop improvement: Selection for disease resistant variants in vitro

Somaclonal variations (SV) are genetic or epigenetic changes induced in plant cell and tissue culture. Induction of somaclonal variation, is an alternate approach to conventional breeding and transgenic approaches to introduce desirable genetic variability in the gene pool. SVs that occur spontaneously in culture induce changes in a range of plant characters. However, the probability of improving a key agronomic trait such as disease resistance can be cumbersome when left to chance alone. The efficiency of developing disease resistant SVs is better with the imposition of an appropriate in vitro selection pressure. Selection agents that have been applied include pathogen elicitors, pathogen culture filtrate and purified pathotoxins. This method of SV selection has been successful in enhancing disease resistance in several crops and it is an accepted biotechnological approach with tremendous potential for crop improvement.

Effect of the Landscape Types on Hunting Selection in Roe Deer (Capreolus Capreolus, Linnaeus 1758) Trophies in Czech Republic

Czech Republic has a long tradition of hunting, and trophy hunting is important to manage game populations. In this study data was analysed from the five last trophy exhibitions in Czech Republic. Namely, hunter selection, compensatory selection, management selection, hunting pressure selection and depletion selection was tested in different landscape types. In compensatory hunting there is a difference between the landscape types; apparent differences exist between the landscape type with respect to hunting pressure. There was no hunter selection, or depletion selection, and no differences in management between landscape types. This study suggests that the landscape composition has an effect on selective hunting in Czech Republic.