Search results for " evolution"
showing 10 items of 9699 documents
Parasite avoidance behaviours in aquatic environments
2018
Parasites, including macroparasites, protists, fungi, bacteria and viruses, can impose a heavy burden upon host animals. However, hosts are not without defences. One aspect of host defence, behavioural avoidance, has been studied in the terrestrial realm for over 50 years, but was first reported from the aquatic environment approximately 20 years ago. Evidence has mounted on the importance of parasite avoidance behaviours and it is increasingly apparent that there are core similarities in the function and benefit of this defence mechanism between terrestrial and aquatic systems. However, there are also stark differences driven by the unique biotic and abiotic characteristics of terrestrial …
Not just the sum of its parts : Geographic variation and nonadditive effects of pyrazines in the chemical defence of an aposematic moth
2022
Chemical defences often vary within and between populations both in quantity and quality, which is puzzling if prey survival is dependent on the strength of the defence. We investigated the within- and between-population variability in chemical defence of the wood tiger moth (Arctia plantaginis). The major components of its defences, SBMP (2-sec-butyl-3-methoxypyrazine) and IBMP (2-isobutyl-3-methoxypyrazine), are volatiles that deter bird attacks. We hypothesized that (1) variation in the chemical defences of male wood tiger moths reflects the local predation pressure; (2) observed differences in quantity and quality of defence among populations have a genetic basis; and (3) increasing con…
Comparative transcriptomics of albino and warningly‐coloured caterpillars
2021
Abstract Coloration is perhaps one of the most prominent adaptations for survival and reproduction of many taxa. Coloration is of particular importance for aposematic species, which rely on their coloring and patterning acting as a warning signal to deter predators. Most research has focused on the evolution of warning coloration by natural selection. However, little information is available for color mutants of aposematic species, particularly at the genomic level. Here, I compare the transcriptomes of albino mutant caterpillars of the aposematic wood tiger moth (Arctia plantaginis) to those of their full sibs having their distinctive orange‐black warning coloration. The results showed >29…
The giant panda is cryptic
2021
The giant panda (Ailuropoda melanoleuca) is an iconic mammal, but the function of its black-and-white coloration is mysterious. Using photographs of giant pandas taken in the wild and state-of-the-art image analysis, we confirm the counterintuitive hypothesis that their coloration provides camouflage in their natural environment. The black fur blends into dark shades and tree trunks, whereas white fur matches foliage and snow when present, and intermediate pelage tones match rocks and ground. At longer viewing distances giant pandas show high edge disruption that breaks up their outline, and up close they rely more on background matching. The results are consistent across acuity-corrected c…
Size-related mortality during overwintering in cavity-nesting ant colonies (Hymenoptera: Formicidae)
2016
The ongoing process of climate change will result in higher temperatures during winter and therefore might increase the survival of overwintering invertebrates. However, the process may also lead to a reduction in snow cover and expose overwintering invertebrates to lower temperatures, which could result in higher mortality. During a field experiment, I investigated the effects of a reduction in snow cover on the survival of the ant Temnothorax crassispinus, which overwinters in nests located on the ground. Ant colonies differed in the survival rate of the workers in the experimental (from which snow cover was removed) and control group. In the control group, the survival rate was unrelated…
Inheritance in the water frog Rana ridibunda Pallas, 1771 - Is it Mendelian or hemiclonal?
2008
The genome of Rana ridibunda has been detected in all known hybridogenetic water frog systems. This raises the question whether R. ridibunda is pre-adapted to reproduce hemiclonally by hybridogenesis. We allozymatically compared genotypes of primary oocytes and somatic cells of R. ridibunda females from several sites in southern France. In case of hemiclonal reproduction only one allele per locus is expected to be detectable in oocytes. However, patterns detected from oocytes of analysed females were not different from those of sexually reproducing water frogs. We therefore conclude that R. ridibunda in southern France reproduces sexually and is not pre-adapted to hemiclonal reproduction.
Chromosome Painting in Cercopithecus petaurista (Schreber, 1774) Compared to Other Monkeys of the Cercopithecini Tribe (Catarrhini, Primates)
2023
The Cercopithecini tribe includes terrestrial and arboreal clades whose relationships are controversial, with a high level of chromosome rearrangements. In order to provide new insights on the tribe’s phylogeny, chromosome painting, using the complete set of human syntenic probes, was performed in Cercopithecus petaurista, a representative species of the Cercopithecini tribe. The results show C. petaurista with a highly rearranged karyotype characterized by the fission of human chromosomes 1, 2, 3, 5, 6, 8, 11, and 12. These results compared with the literature data permit us to confirm the monophyly of the Cercopithecini tribe (fissions of chromosomes 5 and 6), as previously proposed by ch…
Interactive Multiple Criteria Decision Making based on preference driven Evolutionary Multiobjective Optimization with controllable accuracy
2012
Abstract We present an approach to interactive Multiple Criteria Decision Making based on preference driven Evolutionary Multiobjective Optimization with controllable accuracy. The approach relies on formulae for lower and upper bounds on coordinates of the outcome of an arbitrary efficient variant corresponding to preference information expressed by the Decision Maker. In contrast to earlier works on that subject, here lower and upper bounds can be calculated and their accuracy controlled entirely within evolutionary computation framework. This is made possible by exploration of not only the region of feasible variants – a standard within evolutionary optimization, but also the region of i…
Ensemble strategies in Compact Differential Evolution
2011
Differential Evolution is a population based stochastic algorithm with less number of parameters to tune. However, the performance of DE is sensitive to the mutation and crossover strategies and their associated parameters. To obtain optimal performance, DE requires time consuming trial and error parameter tuning. To overcome the computationally expensive parameter tuning different adaptive/self-adaptive techniques have been proposed. Recently the idea of ensemble strategies in DE has been proposed and favorably compared with some of the state-of-the-art self-adaptive techniques. Compact Differential Evolution (cDE) is modified version of DE algorithm which can be effectively used to solve …
Super-fit and population size reduction in compact Differential Evolution
2011
Although Differential Evolution is an efficient and versatile optimizer, it has a wide margin of improvement. During the latest years much effort of computer scientists studying Differential Evolution has been oriented towards the improvement of the algorithmic paradigm by adding and modifying components. In particular, two modifications lead to important improvements to the original algorithmic performance. The first is the super-fit mechanism, that is the injection at the beginning of the optimization process of a solution previously improved by another algorithm. The second is the progressive reduction of the population size during the evolution of the population. Recently, the algorithm…