Causes and Consequences of Behavioral Interference between Species

Behavioral interference between species, such as territorial aggression, courtship, and mating, is widespread in animals. While aggressive and reproductive forms of interspecific interference have generally been studied separately, their many parallels and connections warrant a unified conceptual approach. Substantial evidence exists that aggressive and reproductive interference have pervasive effects on species coexistence, range limits, and evolutionary processes, including divergent and convergent forms of character displacement. Alien species invasions and climate change-induced range shifts result in novel interspecific interactions, heightening the importance of predicting the consequences of species interactions, and behavioral interference is a fundamental but neglected part of the equation. Here, we outline priorities for further theoretical and empirical research on the ecological and evolutionary consequences of behavioral interference. Aggressive and reproductive forms of behavioral interference between species are widespread in animals and share many parallels in their underlying causes and their ecological and evolutionary effects.Behavioral interference can determine whether species coexist and, thus, affects species ranges, the persistence of native species, and the spread of invasive species.As species ranges shift under environmental change and new interspecific interactions arise, it will be important to incorporate knowledge of behavioral interference into ecological forecasts and conservation planning.Behavioral interference can drive both divergent and convergent character displacement processes and thereby contribute to phenotypic diversity and speciation.Evidence is accumulating that behavioral interference has shaped large-scale ecological and evolutionary patterns

Rna Compaction in the Presence of Polyvalent Cations

The effects of polyvalent cations on the effective size and charge of double-stranded DNA (dsDNA) have been well studied. In the presence of polyvalent cations, dsDNA in dilute solution undergoes a single-molecule, first-order phase transition, otherwise called condensation: more explicitly, upon onset of 90% neutralization of the phosphate backbone, the DNA undergoes discontinuous compaction into tightly wound toroids. However, the effects of these cations on long single-stranded RNAs (ssRNA) have not been well characterized. In this study we use centrifugation methods to examine the effective size of long ssRNAs in solutions of increasing concentration of the tetravalent cation spermine. In contrast to the case of dsDNA, we find only a continuous decrease in the size of ssRNA upon increase in spermine concentration. However, the decrease is significant enough to suggest that RNA molecules longer than viral genomes can be packaged in vitro into virus-like vectors for gene delivery

Data from: Flexible mate choice may contribute to ecotype assortative mating in pumpkinseed sunfish (Lepomis gibbosus)

Gene flow is expected to limit adaptive divergence but the ecological and behavioural factors that govern gene flow are still poorly understood, particularly at the earliest stages of population divergence. Reduced gene flow through mate choice (sexual isolation) can evolve even under conditions of subtle population divergence if intermediate phenotypes have reduced fitness. We indirectly tested the hypothesis that mate choice has evolved between coexisting littoral and pelagic ecotypes of polyphenic pumpkinseed sunfish (Lepomis gibbosus) that have diverged in morphology and resource use and where intermediate phenotypes have reduced performance. We assessed the ecotype of nesting males and females using stable isotope estimates of diet and a divergent male morphological trait, oral jaw width. We found positive assortative mating between ecotypes in a common spawning habitat along exposed lake shorelines, but contrary to expectations, assortative mating was variably expressed between two sampling years. Although the factors that influence variable assortative mating remain unclear, our results are consistent with mate choice being expressed by ecotypes. Despite being variably expressed, mate choice will reduce gene flow between ecotypes and could contribute to further adaptive divergence depending on its frequency and strength in the population. Our findings add to a growing body of evidence indicating mate choice behaviour can be a plastic trait, an idea that should be more explicitly considered in empirical studies of mate choice as well as conceptual frameworks of mate choice evolution and adaptive divergence