Rule-breaking mimics: palatability of the butterflies Hypolimnas bolina and Hypolimnas misippus,a sister species pair

Sibling species are, by definition, closely related and Hypolimnas bolina and Hypolimnas misippus are good examples. It has been known for some years that H. misippus often breaks the rules of mimicry, being polymorphic in the female and retaining the mimetic patterns even where no models are present. Hypolimnas bolina is here shown to follow a similar course, with no models present in Madagascar. The toxicity of both butterflies seems usually to be largely dependent on the foodplant but this is irrelevant to mimicry in the absence of models. The evidence suggests that in both species mimicry at the present time is of little or no importance to the survival of these butterflies.     

Evidence for the Interaction of Nucleotides with Immobilized Amino-acids and its Significance for the Origin of the Genetic Code

ONE of the essential relationships between nucleic acids and amino-acids in present biological systems and perhaps in evolutionary precursors to these systems is expressed in binding and recognition interactions. Such interactions depend on the size, composition and conformation of the interacting species^1–8. When the two reacting species are simple (that is, when neither is polymeric) one cannot expect to observe “specificity” of the sort implied in the biological use of the term. Working with monomeric species in aqueous media permits the effects of individual factors to be assessed so that more complex interactions between these molecules can be understood and their evolutionary potential evaluated.     

Geostatistical genetic analysis for inferring the dispersal pattern of a partially clonal species: example of the chestnut blight fungus

Spatial genetic analyses can be used to infer dispersal processes in natural populations. For partially clonal species with alternating sexual and asexual reproduction, the repetition of genotypes must be taken into account in analyses. The methods currently employed to evaluate the relevance of the spatial scale used for the estimation of gene flow are not suitable for these species. We investigated recently developed methods for taking into account repeated genotypes and for determining whether the sampling scale is large enough to capture all the spatial genetic structure existing within a population. We applied these methods to a fungal plant pathogen species, Cryphonectria parasitica, which has caused the death of many American and European chestnut trees since its introduction from Asia at the beginning of the 20th century. These methods were found to be useful for unravelling the effects of clonality and historical gene flow on the spatial genetic structure, and indicated that dispersal processes have probably occurred over a larger spatial scale than previously assumed.     

Gene frequency in an artificial colony of the Scarlet Tiger Moth Panaxia dominula (L.) after 28 years

An artificial colony of Panaxia dominula was started in Wirral in 1961 by P. M. Sheppard to study the selection acting on the medionigra gene. Previous evidence from Oxford indicated a lowered fitness which, balanced by a mating advantage, led to an equilibrium at about three per cent. The Wirral colony was rediscovered in 1989 and now has a medionigra gene frequency of 27 per cent compared with an initial one of 25 per cent, i.e. the Hardy-Weinberg equilibrium has been virtually unchanged. The selective balance in the colony is therefore very different from that elsewhere, and the suggestion is made that the original gene frequencies have remained unchanged because there has been no human interference, unlike Oxford where mark-release-recapture has been the standard procedure, but there are some caveats to this view.     

Detecting phenology change in the mayfly Ephemera danica: responses to spatial and temporal water temperature variations

1. Rising water temperatures under climate change are expected to affect the phenology of aquatic insects, including the mayfly Ephemera danica Müller which is widespread throughout Europe. 2. To assess temporal and spatial variability in mayfly emergence, E. danica were monitored at two thermally contrasting reaches in the River Dove, English Peak District over the period 2007–2013. Inter‐annual variations in growing degree days (GDDs) were modelled for an upstream site with intermittent spring flow supplementing main channel flow (Beresford Dale) and downstream site dominated by near constant discharges of cool groundwater (Dovedale). 3. A strong association exists between the emergence cycle of E. danica and GDDs at each site. Beresford Dale accumulated on average 374 more GDDs than Dovedale. After warm summers E. danica emerged after only 1 year in Beresford Dale but began to revert to a bi‐annual cycle after the particularly wet/cool year of 2012. In Dovedale, E. danica maintained a 2‐year cycle throughout the monitoring period in spite of the phenology changes observed 8 km upstream. 4. Data from the present study suggest that habitats near cool groundwater may provide important refugia for populations of insects, potentially delaying permanent shifts in phenology under climate change. However, an ability to detect changes in the thermal triggers and phenological response may be hindered by conventional spot sampling protocols.