Phenotypic plasticity in hybridizing Carpobrotus spp. (Aizoaceae) from coastal California and its role in plant invasion

2000 ◽  
Vol 77 (10) ◽  
pp. 1411-1418 ◽  
Author(s):  
Ewald Weber ◽  
Carla M D'Antonio

Carpobrotus edulis (L.) N. E. Br., an exotic perennial that invades the coastal habitats of California, hybridizes with the presumed native Carpobrotus chilensis (Mol.) N. E. Br. To investigate the potential role of hybrids in the invasion process by C. edulis, we compared the growth and plasticity of clones of hybrids and parental species. Ramets of three hybrid classes and both parental species were grown in a common garden with four different environments. Both the parental species and the hybrids exhibited strong plastic responses to the test environments for characters describing clonal growth and physiology. Carpobrotus edulis consistently had the largest biomass, but C. chilensis produced longer branches. Carbon isotope ratios (<$QFD0E00000010446D80BFFEFF88A6750DA8D9C8282ADCC6210090483DA6ECD7658F80>13C) showed only weak differences among morphotypes. Hybrids were mostly intermediate relative to parental species in both growth and physiological characters. The intermediacy of hybrids in their response to environmental variation indicates that they do not have inferior growth compared with parental species. The high amount of plasticity of the hybrids and C. edulis, as well as their overall similarity, may account for their invasion success in different habitats of coastal California.

Genome ◽  
2020 ◽  
pp. 1-11
Author(s):  
Bahar Patlar ◽  
Alberto Civetta

It has long been acknowledged that changes in the regulation of gene expression may account for major organismal differences. However, we still do not fully understand how changes in gene expression evolve and how do such changes influence organisms’ differences. We are even less aware of the impact such changes might have in restricting gene flow between species. Here, we focus on studies of gene expression and speciation in the Drosophila model. We review studies that have identified gene interactions in post-mating reproductive isolation and speciation, particularly those that modulate male gene expression. We also address studies that have experimentally manipulated changes in gene expression to test their effect in post-mating reproductive isolation. We highlight the need for a more in-depth analysis of the role of selection causing disrupted gene expression of such candidate genes in sterile/inviable hybrids. Moreover, we discuss the relevance to incorporate more routinely assays that simultaneously evaluate the potential effects of environmental factors and genetic background in modulating plastic responses in male genes and their potential role in speciation.


2018 ◽  
Vol 285 (1871) ◽  
pp. 20171936 ◽  
Author(s):  
Tobin D. Northfield ◽  
Susan G. W. Laurance ◽  
Margaret M. Mayfield ◽  
Dean R. Paini ◽  
William E. Snyder ◽  
...  

At local scales, native species can resist invasion by feeding on and competing with would-be invasive species. However, this relationship tends to break down or reverse at larger scales. Here, we consider the role of native species as indirect facilitators of invasion and their potential role in this diversity-driven ‘invasion paradox’. We coin the term ‘native turncoats’ to describe native facilitators of non-native species and identify eight ways they may indirectly facilitate species invasion. Some are commonly documented, while others, such as indirect interactions within competitive communities, are largely undocumented in an invasion context. Therefore, we use models to evaluate the likelihood that these competitive interactions influence invasions. We find that native turncoat effects increase with the number of resources and native species. Furthermore, our findings suggest the existence, abundance and effectiveness of native turncoats in a community could greatly influence invasion success at large scales.


2014 ◽  
Vol 60 (3) ◽  
pp. 401-409 ◽  
Author(s):  
Sandra Hudina ◽  
Karlo Hock ◽  
Krešimir žganec

Abstract Traits that aid in the invasion process should exhibit a gradient across the expansion range in response to changing selection pressures. Aggression has been repeatedly associated with invasion success in many taxa, as it may help invaders to wrestle the resources from other species which enhances their success in a novel environment. However, aggression primarily allows individuals to overcome conspecific rivals, providing advantages in competition over resources. Agonistic prowess could therefore increase fitness at both ends of the expansion gradient. Here we review the role of aggression in range expansion of invasive species, and its potential role as a driver of range expansion. We analyze how these different mechanisms could affect trait variation in expanding and invasive populations. Specifically, we look at how aggression could help dilate the edges of a population through niche competition, as well as lead to exclusion from the center (i.e. areas of high population density) by the conspe-cifics. Both of these processes will result in a characteristic spatial distribution of phenotypes related to aggression that could provide insights into the ecological pressures and dynamics of expanding populations, potentially providing clues to their success as niche competitors and invasive species.


2010 ◽  
Vol 3 (3) ◽  
pp. 208-218 ◽  
Author(s):  
Melinda A. Gammon ◽  
Eric Baack ◽  
Jennifer Forman Orth ◽  
Rick Kesseli

AbstractHybridization between two introduced plant species can influence the invasion capabilities of the exotic taxa, but the role of hybridization will likely differ in different invasions, even of the same species. Until now, studies concerning the ploidy of Japanese knotweed, giant knotweed, and their hybrids have been conducted in Europe or native ranges in Asia. Here, we assess the role of hybridization and ploidy in a U.S. invasion. We use flow cytometry to characterize DNA content in (1) established families in a common garden, (2) seedlings grown from common garden parents, and (3) wild populations. We also measured fertility in the garden and the field and vegetative growth traits in the garden. Although the majority of our parental and hybrid samples had ploidy levels previously documented in Europe (4X and 8X for parental species; 6X for hybrids), we found a wider range of knotweed cytotypes established in our garden (4X, 6X, 7X, 8X, 9X, and 10X) and additionally detected 5X, 11X, 12X, and possibly 14X ploidy levels in progeny from garden seed parents. The unexpected cytotypes were not confined to the greenhouse or common garden, in that all < 11X ploidy levels were also found in field populations in Massachusetts. In several cases, these data contradicted our expectations on the basis of morphological and molecular analysis, suggesting both significant introgression and the introduction of multiple cytotypes from Asia. With one exception (14X), we found all cytotypes were capable of strong vegetative growth, seed set, and the production of viable pollen. Without barriers to sexual reproduction, introgression is expected to progress, creating a progressively more diverse swarm of invasive genotypes.


Plants ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 108
Author(s):  
Corli ◽  
Sheppard

Alien plants benefit from auto-fertility to spread over areas where the lack of co-evolved mutualists would otherwise limit invasion success. However, the widespread generalists among mutualists and their large geographical ranges allow alien plants to be integrated into networks. The role of residence time also has to be accounted for, as it takes time for a species to spread and adapt to a new area. We investigated how residence time, auto-fertility and pollinator dependence affect reproductive output and invasion success of Asteraceae in Germany. We conducted a multi-species common-garden experiment along an alien–native continuum including 42 species of natives, archaeophytes and neophytes (casual and established), subjecting plant individuals either to free access or exclusion of pollinators. Pollinator dependence does not play a crucial role in invasion success, with most Asteraceae being able to self-fertilize. Surprisingly, both established neophytes and natives showed higher abilities to self-fertilize, while archaeophytes and casual neophytes were more attractive to pollinators. In contrast to casual neophytes, the established neophytes’ strategy was associated with a large reproductive output. Yet, auto-fertility was not associated with range size, since archaeophytes reached the largest range sizes. Elucidating how breeding systems affect invasion success is crucial for predicting and managing invasions.


2019 ◽  
Vol 47 (5) ◽  
pp. 1393-1404 ◽  
Author(s):  
Thomas Brand

Abstract The Popeye domain-containing gene family encodes a novel class of cAMP effector proteins in striated muscle tissue. In this short review, we first introduce the protein family and discuss their structure and function with an emphasis on their role in cyclic AMP signalling. Another focus of this review is the recently discovered role of POPDC genes as striated muscle disease genes, which have been associated with cardiac arrhythmia and muscular dystrophy. The pathological phenotypes observed in patients will be compared with phenotypes present in null and knockin mutations in zebrafish and mouse. A number of protein–protein interaction partners have been discovered and the potential role of POPDC proteins to control the subcellular localization and function of these interacting proteins will be discussed. Finally, we outline several areas, where research is urgently needed.


Author(s):  
Katherine Guérard ◽  
Sébastien Tremblay

In serial memory for spatial information, some studies showed that recall performance suffers when the distance between successive locations increases relatively to the size of the display in which they are presented (the path length effect; e.g., Parmentier et al., 2005) but not when distance is increased by enlarging the size of the display (e.g., Smyth & Scholey, 1994). In the present study, we examined the effect of varying the absolute and relative distance between to-be-remembered items on memory for spatial information. We manipulated path length using small (15″) and large (64″) screens within the same design. In two experiments, we showed that distance was disruptive mainly when it is varied relatively to a fixed reference frame, though increasing the size of the display also had a small deleterious effect on recall. The insertion of a retention interval did not influence these effects, suggesting that rehearsal plays a minor role in mediating the effects of distance on serial spatial memory. We discuss the potential role of perceptual organization in light of the pattern of results.


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