Ačkoli jsou elektrické signály typičtější pro neurony živočichů, také rostliny jsou schopné vytvářet tento druh signálů. Rozeznáváme u nich dva základní typy - variační a akční potenciály. Ty se od sebe odlišují určitými vlastnostmi, ale oba typy mají významný dopad na fyziologické procesy v rostlinách, např. na pohyb listů, fotosyntézu, dýchání, opylování, zavírání průduchů, syntézu hormonů nebo trávení hmyzu u masožravých rostlin., Although electrical signals are more typical for animal neurons, plants also have the ability to generate these signals. Two different types are recognized: action and variation potentials. They differ in certain characteristics, however both have significant impact on physiological processes in plants; e.g. on leaf movement, photosynthesis, respiration, pollination, stomata closure, hormone synthesis and insect digestion in carnivorous plants., Andrej Pavlovič., and Obsahuje seznam literatury
V článku je popsán původ, domestikace a současný význam kapra obecného (Cyprinus carpio) jako nejdůležitějšího druhu rybničních chovů v Evropě. Stručně je vysvětlena technologie chovu kapra a její vlivy na ekosystémy rybníků., The origin, domestication process and present value of Common Carp (Cyprinus carpio) as the most important species in pond aquaculture in Europe is described. The technology of carp production and the impact of carp culture on the ecosystems of fishponds are briefly explained., Josef Matěna, Martin Flajšhans., and Obsahuj seznam literatury
Herbivorous insects are often highly specialised, likely due to trade-offs in fitness on alternative host species. However, some pest insects are extremely adaptable and readily adopt novel hosts, sometimes causing rapid expansion of their host range as they spread from their original host and geographic origin. The genetic basis of this phenomenon is poorly understood, limiting our ability to predict or mitigate global insect pest outbreaks. We investigated the trajectory of early adaptation to novel hosts in a regionally-specialised global crop pest species (the cowpea seed beetle Callosobruchus maculatus). After experimentally-enforced dietary specialisation for nearly 300 generations, we measured changes in fitness over the first 5 generations of adaptation to 6 novel hosts. Of these, C. maculatus reproduced successfully on all but one, with reduced fitness observed on three hosts in the first generation. Loss of fitness was followed by very rapid, decelerating increases in fitness over the first 1-5 generations, resulting in comparable levels of population fitness to that observed on the original host after 5 generations. Heritability of fitness on novel hosts was high. Adaptation occurred primarily via changes in behavioural and phenological traits, and never via changes in offspring survival to adulthood, despite high heritability for this trait. These results suggest that C. maculatus possesses ample additive genetic variation for very rapid host shifts, despite a prolonged period of enforced specialization, and also suggest that some previously-inferred environmental maternal effects on host use may in part actually represent (rapidly) evolved changes. We highlight the need to examine in more detail the genetic architecture facilitating retention of high additive genetic variation for host shifts in extremely adaptable global crop pests., Thomas N. Price, Aoife Leonard, Lesley T. Lancaster., and Obsahuje bibliografii
Many insects masquerade as parts of plants, such as bark or leaves, or mimic poisonous organisms in order to defend themselves against predators. However, recent studies indicate that plants may mimic insects and other arthropods to deter herbivores. Here, I report visually similar white structures of plants and arthropods in Japan and suggest they are part of a mimicry complex. Young shoots covered with white trichomes or waxy substances may mimic wax-producing insects, such as woolly aphids, coccids and caterpillars, potentially resulting in reduced herbivory. Since wax-producing insects would reduce plant quality and quantity, be distasteful and attract natural enemies, herbivorous insects and mammals may avoid such white shoots. Furthermore, fungus-infected insects, gregarious braconid cocoons, spider egg sacs and froth made by froghopper nymphs or blasticotomid sawfly larvae are also conspicuously white and impose risks for herbivorous insects. Thus, these white structures may be mimicry models for white shoots and are likely to be part of a defensive mimicry complex. Although this study focuses on defence against herbivores, there are simultaneous physiological roles for white colouration that will not be discussed in depth here., Kazuo Yamazaki., and Obsahuje bibliografii
Boj o záchranu jednoho z nejvzácnějších a nejunikátnějších ptačích druhů - Kakapa sovího (Strigops habroptilus) - trvá už několik desítek let. Veškeré snahy dlouhou dobu selhávaly, než vědci odhalili, jak úzce záhadné rozmnožování tohoto druhu souvisí s jeho výživou. Od roku 2000 se tak podařilo populaci více než zdvojnásobit. Za zachráněný však druh bude považován až ve chvíli, kdy dokáže přežít a rozmnožovat se bez pomoci člověka. Záchrana kakapa sovího je běh na dlouhou trať, čím víc ale o jeho biologii víme, tím větší máme naději, že se to podaří., The endeavour to save one of the rarest and most unique species of birds - Kakapo (Strigops habroptilus) - has been going on for decades. All efforts were unsuccessful until the scientists discovered how closely is the reproduction of this species related to its diet. Since the year of 2000 the population has doubled its original. However, the recovery of Kakapo populations is a long process, the species can only be considered salvaged when it is able to reproduce without human assistance., and Petra Tumová.