Search results for "Cultural"

Deimatism: a neglected component of antipredator defence

2017

Deimatic or ‘startle’ displays cause a receiver to recoil reflexively in response to a sudden change in sensory input. Deimatism is sometimes implicitly treated as a form of aposematism (unprofitability associated with a signal). However, the fundamental difference is, in order to provide protection, deimatism does not require a predator to have any learned or innate aversion. Instead, deimatism can confer a survival advantage by exploiting existing neural mechanisms in a way that releases a reflexive response in the predator. We discuss the differences among deimatism, aposematism, and forms of mimicry, and their ecological and evolutionary implications. We highlight outstanding questions …

The evolution of sex roles in mate searching

2016

Searching for mates is a critical stage in the life cycle of most internally, and many externally, fertilizing species. Males usually invest more in this costly activity than females, but the reasons for this are poorly understood. Previous models have shown that female-biased parental investment, including anisogamy, does not by itself select for male-biased mate searching, so it requires additional explanations. Here, we correct and expand upon earlier models, and present two novel hypotheses that might explain the evolution of male-biased mate searching. The "carry-over hypothesis" states that females benefit less from searching if the associated costs affect other stages of the life cyc…

Not all sex ratios are equal : the Fisher condition, parental care and sexual selection

2017

The term ‘sex roles’ encapsulates male–female differences in mate searching, competitive traits that increase mating/fertilization opportunities, choosiness about mates and parental care. Theoretical models suggest that biased sex ratios drive the evolution of sex roles. To model sex role evolution, it is essential to note that in most sexually reproducing species (haplodiploid insects are an exception), each offspring has one father and one mother. Consequently, the total number of offspring produced by each sex is identical, so the mean number of offspring produced by individuals of each sex depends on the sex ratio (Fisher condition). Similarly, the total number of heterosexual matings …

Evolution of bacterial life-history traits is sensitive to community structure

2016

Very few studies have experimentally assessed the evolutionary effects of species interactions within the same trophic level. Here we show that when Serratia marcescens evolve in multispecies communities, their growth rate exceeds the growth rate of the bacteria that evolved alone, whereas the biomass yield gets lower. In addition to the community effects per se, we found that few species in the communities caused strong effects on S. marcescens evolution. The results indicate that evolutionary responses (of a focal species) are different in communities, compared to species evolving alone. Moreover, selection can lead to very different outcomes depending on the community structure. Such con…

Conjugation is necessary for a bacterial plasmid to survive under protozoan predation

2016

Horizontal gene transfer by conjugative plasmids plays a critical role in the evolution of antibiotic resistance. Interactions between bacteria and other organisms can affect the persistence and spread of conjugative plasmids. Here we show that protozoan predation increased the persistence and spread of the antibiotic resistance plasmid RP4 in populations of the opportunist bacterial pathogenSerratia marcescens. A conjugation-defective mutant plasmid was unable to survive under predation, suggesting that conjugative transfer is required for plasmid persistence under the realistic condition of predation. These results indicate that multi-trophic interactions can affect the maintenance of con…

Ant behaviour and brain gene expression of defending hosts depend on the ecological success of the intruding social parasite.

2019

The geographical mosaic theory of coevolution predicts that species interactions vary between locales. Depending on who leads the coevolutionary arms race, the effectivity of parasite attack or host defence strategies will explain parasite prevalence. Here, we compare behaviour and brain transcriptomes of Temnothorax longispinosus ant workers when defending their nest against an invading social parasite, the slavemaking ant Temnothorax americanus . A full-factorial design allowed us to test whether behaviour and gene expression are linked to parasite pressure on host populations or to the ecological success of parasite populations. Albeit host defences had been shown before to covary with …

The influence of slavemaking lifestyle, caste and sex on chemical profiles in Temnothorax ants: insights into the evolution of cuticular hydrocarbons

2017

Chemical communication is central for the formation and maintenance of insect societies. Generally, social insects only allow nest-mates into their colony, which are recognized by their cuticular hydrocarbons (CHCs). Social parasites, which exploit insect societies, are selected to circumvent host recognition. Here, we studied whether chemical strategies to reduce recognition evolved convergently in slavemaking ants, and whether they extend to workers, queens and males alike. We studied CHCs of three social parasites and their related hosts to investigate whether the parasitic lifestyle selects for specific chemical traits that reduce host recognition. Slavemaker profiles were characterize…

EVOLUTIONARY DYNAMICS OF FITNESS RECOVERY FROM THE DEBILITATING EFFECTS OF MULLER'S RATCHET.

1998

The great adaptability shown by RNA viruses is a consequence of their high mutation rates. The evolution of fitness in a severely debilitated, clonal population of the nonsegmented ribovirus vesicular stomatitis virus (VSV) has been compared under five different demographic regimes, ranging from severe serial bottleneck passages (one virion) to large population passages (105 virions or more) under similar environmental conditions (cell culture type and temperature). No matter how small the bottleneck, the fitness of the evolved populations was always higher than the fitness of the starting population; this result is clearly different from that previously reported for viruses with higher fit…

2017

Targeted high-throughput sequencing using hybrid-enrichment offers a promising source of data for inferring multiple, meaningfully resolved, independent gene trees suitable to address challenging phylogenetic problems in species complexes and rapid radiations. The targets in question can either be adopted directly from more or less universal tools, or custom made for particular clades at considerably greater effort. We applied custom made scripts to select sets of homologous sequence markers from transcriptome and WGS data for use in the flowering plant genus Erica (Ericaceae). We compared the resulting targets to those that would be selected both using different available tools (Hyb-Seq; M…

HERITABILITIES OF DOMINANCE-RELATED TRAITS IN MALE BANK VOLES (CLETHRIONOMYS GLAREOLUS)

1998

A number of studies have shown that in several animal species females prefer dominant males as mating partners, but fewer attempts have been made to measure possible indirect benefits of this choice. One reason for this may be that, even though dominance is a widely used concept, the definition of dominance still remains controversial. Furthermore, defining and measuring the heritability of social behaviors is problematic because they are not individual traits but, by definition, involve interactions between at least two individuals. In this study we estimated heritabilities and coefficients of additive genetic variances (CVA) for male traits that are closely associated with dominance and f…