Search Results (38)

The prolonged arms race between plants and their antagonists has resulted in the evolution of multiple plant defence mechanisms to combat attacks by pests and pathogens. Silicon (Si) accumulation occurs mainly in grasses and provides a physical barrier against antagonists. Biochemical pathways may also be involved in Si-mediated plant resistance, although the precise mode of action in this case is less clear. Most studies have focussed on Si-based effects against single attackers. In this review, we consider how Si-based plant resistance operates when simultaneously and/or sequentially attacked by insect herbivores, fungal phytopathogens, and plant parasitic nematodes and how the plant hormones jasmonic acid (JA) and salicylic acid (SA) are involved. Si defence may mediate both intra- and interspecific competition and facilitation. Si has been found to impact plant-mediated interactions between insect herbivores within the same feeding guild and across different feeding guilds, with varying patterns of JA and SA. These results suggest that hormonal crosstalk may play a role in the Si-mediated effects, although this finding varied between studies. While some reports support the notion that JA is linked to Si responses, others indicate that Si supplementation reduces JA production. In terms of phytopathogens, SA has not been found to be involved in Si-mediated defences. Improving our understanding of Si-mediated plant defence could be beneficial for sustainable agriculture under future climates. Full article

Eotetranychus sexmaculatus has long been recognized as an important spider mite pest of rubber trees. Recently, increasing damage from Oligonychus biharensis has elevated its importance as a key spider mite pest. These two species share highly overlapping ecological niches, with outbreaks strongly associated with high temperatures and drought stresses. However, little is known regarding the potential competition between these spider mite species and the role of temperature in shaping these interactions. This study investigates the development and reproduction of E. sexmaculatus and O. biharensis at varying population densities, and evaluates their dynamics at 27 °C, 30 °C, and 33 °C. Five initial population densities of E. sexmaculatus and O. biharensis were evaluated in mixed populations: 0:30, 10:20, 15:15, 20:10, and 30:0. The results demonstrate both intra- and interspecific competition between E. sexmaculatus and O. biharensis. At all three intraspecific densities, the survival rate and lifespan of both species declined as density increased, with fecundity also decreasing at higher densities. Single-species populations of each mite were larger in number when compared with mixed populations. Across all treatments, the mean and peak values of the intrinsic rate of increase (r_m) were greater in O. biharensis than in E. sexmaculatus. Additionally, increasing temperatures accelerated the displacement of E. sexmaculatus by O. biharensis, regardless of the initial population density. When the mixed populations of E. sexmaculatus and O. biharensis were at densities of 10:20, the highest interspecific competition coefficients were obtained at 33 °C, with values of 0.6591. In conclusion, O. biharensis consistently outcompeted E. sexmaculatus at all tested temperatures, irrespective of initial densities, providing valuable insights into the competitive dynamics of dominant rubber tree pests. Full article

Sunlight and the heat it provides are important ecological resources for reptiles especially for those species living in temperate zones that bask extensively to maximize heat uptake. Sun basking has both benefits and costs for reptiles, giving heat that provides the energy to drive physiology but basking in open patches increases risk of predation due to higher visibility. Prime basking sites are believed to increase benefits for reptiles that include, in addition to open sunlit areas, facilitate detection of predators and prey and escape to nearby refuges. However, if such sites are limited, both inter and intra-specific interference may occur and this kind of competition may impact on a reptile’s ability to access prime basking sites, and as a consequence, its capacity to thermoregulate to optimum body temperatures. This may be especially important for juveniles, for whom rapid growth is a key factor in survivorship. We studied communal basking and interaction events at prime basking sites in the European green lizard, Lacerta bilineata, in a hedgerow in western France. We compared basking behaviour of adults and juveniles with sympatric adult wall lizards Podarcis muralis using non-invasive photographic-mark-recapture. Adult L. bilineata were more evenly distributed across basking sights compared to juveniles but significant differences were only detected between males and juveniles. Juvenile L. bilineata abandoned basking sites at the approach of both adult males and females and were aggressively removed by adult male L. bilineata. We found inter-specific communal basking between both adult and juvenile L. bilineata with adult wall lizards P. muralis. Communal basking was observed between male and female L. bilineata but not between adult males or between adult female L. bilineata. Communal basking was in proportionally greater frequency in juveniles compared to adult L. bilineata. Full article

Essential oils (EOs) are mixtures of volatile organic compounds that mediate plant interactions and are also appreciated for their biological properties in aromatic plants. However, the study of EOs in wild plants with biological activity has been neglected. Ipomoea murucoides is a wild species with allelopathic and insecticide activities; however, the climate factors associated with EOs and their role in intra- and interspecific interactions are still unknown. We investigated the effects of temperature, rain, and solar irradiance for two years on the EOs of I. murucoides and documented the effect of herbivory (without, <20%, >20%, and mechanical damage) on their composition. We evaluated the receptivity to possible infochemicals in conspecific and congeneric neighbors to I. murucoides plants exposed to methyl jasmonate (MeJA), herbivory by Ogdoecosta biannularis and without an elicitor. We measured the stomatal density and aperture in the second leaf generation of the neighbor plants. The year and herbivory >20% affected the composition of EOs. Nerolidol could be a biological marker for herbivory. We concluded that herbivory and rain irregularity contribute to EOs changing. The response in the stomatal density in plants not consumed by I. pauciflora but near I. murucoides under MeJA or herbivory gives evidence of interspecific plant–plant communication. Full article

Since Darwin, many evolutionary and behavioral researchers have considered the role of phenotypic traits that favor the domestication of nonhuman animals. Among such proposed traits are a species’ social structure, level of intra- and interspecific agonistic interactions, sociosexual behaviors, parental strategies, reaction to humans, habitat preference, dietary habits, developmental trajectories, and utility to humans. However, little to no comparative phylogenetic evidence exists concerning the importance of these attributes for the domestication of animals. Moreover, rather than considering domestication as a dichotomous event (non-domesticated vs. domesticated), humans and their potential domesticates encountered numerous socioecological challenges/obstacles during the domestication process before reaching the stage of full domestication. The present study explored the influence of adult body mass, gregariousness, dietary breadth, and reaction to humans on the domestication process of ungulates. The phylogenetic comparative model revealed that capture myopathy (CM), as a proxy for reaction to humans, negatively and significantly influenced the domestication process. The present paper also explored the evolution of CM in equine species in response to the presence of large carnivoran predators during the Pleistocene. Ecologies that preserved most of the large carnivoran predators of equine species also featured more equine taxa with CM (e.g., zebras), which were thus less suitable for domestication. Full article

Understanding the biodiversity–productivity relationship (BPR) is crucial for biodiversity conservation and ecosystem management. While it is known that diversity enhances forest productivity, the underlying mechanisms at the local neighborhood level remain poorly understood. We established a 9.6 ha dynamic forest plot to study how neighborhood diversity, intraspecific competition, and interspecific competition influence tree growth across spatial scales using linear mixed-effects models. Our analysis reveals a significant positive correlation between neighborhood species richness (NSR) and relative growth rate (RGR). Notably, intraspecific competition, measured by conspecific neighborhood density and resource competition, negatively impacts RGR at finer scales, indicating intense competition among conspecifics for limited resources. In contrast, interspecific competition, measured by heterospecific density and resource competition, has a negligible impact on RGR. The relative importance of diversity and intra/interspecific competition in influencing tree growth varies with scale. At fine scales, intraspecific competition dominates negatively, while at larger scales, the positive effect of NSR on RGR increases, contributing to a positive BPR. These findings highlight the intricate interplay between local interactions and spatial scale in modulating tree growth, emphasizing the importance of considering biotic interactions and spatial variability in studying BPR. Full article

Plant–plant interactions are a central driver for plant coexistence and community assembly. Chemically mediated plant–plant interactions are represented by allelopathy and allelobiosis. Both allelopathy and allelobiosis are achieved through specialized metabolites (allelochemicals or signaling chemicals) produced and released from neighboring plants. Allelopathy exerts mostly negative effects on the establishment and growth of neighboring plants by allelochemicals, while allelobiosis provides plant neighbor detection and identity recognition mediated by signaling chemicals. Therefore, plants can chemically affect the performance of neighboring plants through the allelopathy and allelobiosis that frequently occur in plant–plant intra-specific and inter-specific interactions. Allelopathy and allelobiosis are two probably inseparable processes that occur together in plant–plant chemical interactions. Here, we comprehensively review allelopathy and allelobiosis in plant–plant interactions, including allelopathy and allelochemicals and their application for sustainable agriculture and forestry, allelobiosis and plant identity recognition, chemically mediated root–soil interactions and plant–soil feedback, and biosynthesis and the molecular mechanisms of allelochemicals and signaling chemicals. Altogether, these efforts provide the recent advancements in the wide field of allelopathy and allelobiosis, and new insights into the chemically mediated plant–plant interactions. Full article

Tertiary relict plants are of great scientific value in the study of flora evolution, angiosperm systems, and ancient origins. Paying attention to their spatial patterns can better reflect the change dynamics of the species to implement targeted protection countermeasures. In this study, we investigated the spatial patterns of Tetracentron sinense Oliver, a tertiary relict plant, and further studied the intra- and interspecific and environmental factors impacting the patterns. The results reveal that most of the individuals of T. sinense were distributed in the 1700–1800 m altitudinal belt, and they were highly aggregated at a small scale. The young trees showed a positive interaction with adult trees. The dominant species showed a positive interaction with T. sinense; the interaction gradually became non-significant or negative as the scale increased. The key abiotic factors affecting the distribution of T. sinense were altitude, litter depth, zinc, and calcium. These results highlight the intra- and interspecific interactions and environmental factors influencing the spatial pattern of T. sinense. Our results provide new insights into tertiary relict species’ spatial patterns and nearline factors. Moreover, these findings have relevant implications for conserving and managing tertiary relict plants in a constantly fragmented habitat. Full article

Communication through airborne volatile organic compounds (VOCs) and root exudates plays a vital role in the multifarious interactions of plants. Common ragweed (Ambrosia artemesiifolia L.) is one of the most troublesome invasive alien species in agriculture. Below- and aboveground chemical interactions of ragweed with crops might be an important factor in the invasive species’ success in agriculture. In laboratory experiments, we investigated the contribution of intra- and interspecific airborne VOCs and root exudates of ragweed to its competitiveness. Wheat, soybean, and maize were exposed to VOCs emitted from ragweed and vice versa, and the adaptation response was measured through plant morphological and physiological traits. We observed significant changes in plant traits of crops in response to ragweed VOCs, characterized by lower biomass production, lower specific leaf area, or higher chlorophyll contents. After exposure to ragweed VOCs, soybean and wheat produced significantly less aboveground dry mass, whereas maize did not. Ragweed remained unaffected when exposed to VOCs from the crops or a conspecific. All crops and ragweed significantly avoided root growth toward the root exudates of ragweed. The study shows that the plant response to either above- or belowground chemical cues is highly dependent on the identity of the neighbor, pointing out the complexity of plant–plant communication in plant communities. Full article

The present paper is a summary of the authors’ theoretical and experimental research dealing with the patterns of stable equilibrium coexistence of microbial populations in flow systems interacting through specific density-dependent growth regulators (RFs). The discovered “paradoxical” lack of dependence of the background steady-state levels (concentrations) of RFs on their input values is confirmed experimentally and theoretically through the introduced sensitivity coefficients. This effect has been termed “autostabilization” of RFs. An important theorem (formula) of “quantization” suggesting the integer value of the sum of all sensitivity coefficients, which is equal to the difference between the number of RFs and the number of populations of one trophic level, has been proven. A modification of the “quantization” formula for an arbitrary trophic web is shown. A new criterion for intra- and inter-population microbial interactions for RFs is proposed—the response of growth acceleration to a perturbation in population size. This criterion makes it possible to quantify interspecific complex relationships, which has been previously impossible. The relationship between the new coefficients of inter-population interactions and the accuracy of model verification has been shown theoretically. Based on this criterion and the autostabilization effect, a method for experimental search for unknown RFs is proposed. Full article

Competitive interactions come in a variety of forms and may be modulated by the size and number of individuals involved, and/or the resources available. Here, intra- and interspecific competitive behaviours for food (i.e., foraging/food search and feeding/food ingestion) were experimentally characterized and quantified in four co-existing deep-sea benthic species. Three sea stars (Ceramaster granularis, Hippasteria phrygiana, and Henricia lisa) and one gastropod (Buccinum scalariforme) from the bathyal Northwest Atlantic were investigated using video trials in darkened laboratory conditions. A range of competitive or cooperative behaviours occurred, depending on species (conspecific or heterospecific), comparative body size, and the number of individuals involved. Contrary to expectations, small individuals (or smaller species) were not always outcompeted by larger individuals (or larger species) when foraging and feeding. Moreover, faster species did not always outcompete slower ones while scavenging. Overall, this study sheds new light on scavenging strategies of co-existing deep-sea benthic species in food-limited bathyal environments, based on complex behavioural inter- and intraspecific relationships. Full article

Diverse ecologically important metabolites, such as allelochemicals, infochemicals and volatile organic chemicals, are involved in marine organismal interactions. Chemically mediated interactions between intra- and interspecific organisms can have a significant impact on community organization, population structure and ecosystem functioning. Advances in analytical techniques, microscopy and genomics are providing insights on the chemistry and functional roles of the metabolites involved in such interactions. This review highlights the targeted translational value of several marine chemical ecology-driven research studies and their impact on the sustainable discovery of novel therapeutic agents. These chemical ecology-based approaches include activated defense, allelochemicals arising from organismal interactions, spatio-temporal variations of allelochemicals and phylogeny-based approaches. In addition, innovative analytical techniques used in the mapping of surface metabolites as well as in metabolite translocation within marine holobionts are summarized. Chemical information related to the maintenance of the marine symbioses and biosyntheses of specialized compounds can be harnessed for biomedical applications, particularly in microbial fermentation and compound production. Furthermore, the impact of climate change on the chemical ecology of marine organisms—especially on the production, functionality and perception of allelochemicals—and its implications on drug discovery efforts will be presented. Full article

Plants readily communicate with their pollinators, herbivores, symbionts, and the predators and pathogens of their herbivores. We previously demonstrated that plants could exchange, relay, and adaptively utilize drought cues from their conspecific neighbors. Here, we studied the hypothesis that plants can exchange drought cues with their interspecific neighbors. Triplets of various combinations of split-root Stenotaphrum secundatum and Cynodon dactylon plants were planted in rows of four pots. One root of the first plant was subjected to drought while its other root shared its pot with one of the roots of an unstressed target neighbor, which, in turn, shared its other pot with an additional unstressed target neighbor. Drought cuing and relayed cuing were observed in all intra- and interspecific neighbor combinations, but its strength depended on plant identity and position. Although both species initiated similar stomatal closure in both immediate and relayed intraspecific neighbors, interspecific cuing between stressed plants and their immediate unstressed neighbors depended on neighbor identity. Combined with previous findings, the results suggest that stress cuing and relay cuing could affect the magnitude and fate of interspecific interactions, and the ability of whole communities to endure abiotic stresses. The findings call for further investigation into the mechanisms and ecological implications of interplant stress cuing at the population and community levels. Full article

Fruit color is an important trait in peach from the point of view of consumer preference, nutritional content, and diversification of fruit typologies. Several genes and phenotypes have been described for peach flesh and skin color, and although peach color knowledge has increased in the last few years, some fruit color patterns observed in peach breeding programs have not been carefully described. In this work, we first describe some peach mesocarp color patterns that have not yet been described in a collection of commercial peach cultivars, and we also study the genetic inheritance of the red dots present in the flesh (RDF) and red color around the stone (CAS) in several intra- and interspecific segregating populations for both traits. For RDF, we identified a QTL at the beginning of G5 in two intraspecific populations, and for CAS we identified a major QTL in G4 in both an intraspecific and an interspecific population between almond and peach. Finally, we discuss the interaction between these QTLs and some other genes previously identified in peach, such as dominant blood flesh (DBF), color around the stone (Cs), subacid (D) and the maturity date (MD), and the implications for peach breeding. The results obtained here will help peach germplasm curators and breeders to better characterize their plant materials and to develop an integrated system of molecular markers to select these traits. Full article

Competitive behavioural interactions between invasive and native freshwater crayfish are recognised as a key underlying mechanism behind the displacement of natives by invaders. However, in situ investigations into behavioural interactions between invasive and native crayfish are scarce. In Australian freshwater systems, the invasive Cherax destructor has spread into the ranges of many native Euastacus species, including the critically endangered Euastacus dharawalus. Staged contests between the two species in a laboratory setting found E. dharawalus to be the dominant competitor, however, this has yet to be corroborated in situ. Here, we used baited remote underwater video (BRUV) to examine in situ intra- and inter-specific behavioural interactions between E. dharawalus and C. destructor. We sought to evaluate patterns of dominance and differential contest dynamics between the species to provide indications of competition between the two species. We found E. dharawalus to be dominant over C. destructor based on pooled interspecific interaction data and size-grouped interactions where C. destructor was the smaller opponent. Alarmingly, however, when C. destructor was within a 10% size difference the dominance of E. dharawalus was lost, contrasting with the outcomes of the laboratory-staged study. In addition, we report that small C. destructor initiated significantly more contests than larger conspecifics and larger E. dharawalus, a pattern that was not observed in smaller E. dharawalus. Further, intraspecific interactions between C. destructor were significantly longer in duration than intraspecific interactions between E. dharawalus, indicating a willingness to continue fighting. Concerningly, these outcomes point towards inherent and greater aggressiveness in C. destructor relative to E. dharawalus and that only larger E. dharawalus hold a competitive advantage over C. destructor. Therefore, we conclude that C. destructor represents a substantial threat to E. dharawalus through competitive behavioural interactions. Further, due to the disparity between our findings and those produced from laboratory-staged contests, we recommend the use of in situ studies when determining the behavioural impacts of invasive crayfish on natives. Full article