scholarly journals Nematode Interactions on Beetle Hosts Indicate a Role of Mouth-Form Plasticity in Resource Competition

2021 ◽  
Vol 9 ◽  
Author(s):  
Tess Renahan ◽  
Ralf J. Sommer

Competition is rampant across kingdoms, arising over potential mates, food resources, and space availability. When faced with opponents, phenotypic plasticity proffers organisms indispensable advantageous strategies to outcompete rivals. This tactic is especially crucial on decaying insect hosts as myriad microbes and numerous nematodes struggle to establish thriving populations and ensure resource availability for future generations. Scarab beetles and their associated nematode symbionts on La Réunion Island have provided exceptional systems to study complicated cross-phylum interactions in soil, and recently we have identified a previously unexplored beetle host, Gymnogaster bupthalma, to be reliably co-infested with diplogastrids Pristionchus mayeri and Acrostichus spp. These nematodes maintain the capacity to plastically respond to environmental conditions by developing disparate mouth forms, a strict bacterial-feeding morph or an omnivorous morph that enables predation on other nematodes. In addition, under stressful settings these worms can enter an arrested development stage called dauer, non-feeding dispersal larvae that resume development into reproducing adults when conditions improve. By investigating this beetle-nematode system in a natural context, we uncovered a novel Pristionchus strategy, wherein dauer dispersal from the carcass is gradual and a reproducing population is sustained. Remarkably, usually preferential-bacterial morph P. mayeri develop as predators in populations dense with competitors.

2018 ◽  
Vol 115 (29) ◽  
pp. 7563-7568 ◽  
Author(s):  
Xinda Lin ◽  
Yili Xu ◽  
Jianru Jiang ◽  
Mark Lavine ◽  
Laura Corley Lavine

Food quality is a critical environmental condition that impacts an animal’s growth and development. Many insects facing this challenge have evolved a phenotypically plastic, adaptive response. For example, many species of insect exhibit facultative wing growth, which reflects a physiological and evolutionary trade-off between dispersal and reproduction, triggered by environmental conditions. What the environmental cues are and how they are transduced to produce these alternative forms, and their associated ecological shift from dispersal to reproduction, remains an important unsolved problem in evolutionary ecology. In this study, we investigated the role that host quality has on the induction of wing development in a wing polyphenic insect exhibiting strong tradeoffs in investment between dispersal and reproduction, the brown planthopper, a serious rice pest in Asia. As rice plants grow, the short-winged brown planthopper dominates the population, but a shift occurs as the plants mature and senesce in the field such that long-winged brown planthoppers emerge and migrate. It remains unknown how changes in the rice plant induce development of the long-winged morph, despite recent discoveries on the role of the insulin and JNK signaling pathways in wing development. We found that by mimicking the glucose concentration of senescing rice plants, we significantly increased the proportion of long-winged female planthoppers. The effects of glucose on wing morph are additive with previously described effects of density. Our results show that host quality both directly regulates phenotypic plasticity and interacts with other factors such as density to produce the appropriate phenotype for specific environmental conditions.


2021 ◽  
Author(s):  
Meryl Theng ◽  
Thomas A. Prowse ◽  
Phill Cassey ◽  
Steven Delean ◽  
Chloe Bracis

Despite decades of extensive animal movement research, we still lack an integrated, process-based understanding behind the movement decisions that individuals make, which ultimately lead to the emergence of home-ranges. Here, we advance toward a more holistic understanding of HR formation, by developing a theoretical model integrating two key processes that have been separately proposed to play important roles in HR formation in territorial animals: (i) optimising resource acquisition by referencing a cognitive memory (i.e., resource memory); and (ii) minimising resource competition through defensive cues (i.e., territoriality). We extend a two-state memory-based model for non-territorial animals to include multiple individuals that interact through scent-mediated conspecific avoidance behaviour. We investigated how the interplay of memory and territoriality influenced: (1) the emergence of individual home-ranges; (2) the relationship between home-range size, density and resource availability; and (3) the response of animal home ranges to perturbations of the conspecific environment (i.e., removing individuals). We showed that integrating both resource memory and territoriality gave rise to spatially distinct and dynamic HRs that follow a negative log-linear relationship with respect to resource distribution (Pearson's r = -0.73, p < 0.01), congruent with empirical evidence. On its own, neither process resulted in a similar response.


2021 ◽  
Vol 28 (1) ◽  
pp. 277-287
Author(s):  
M Khairul Alam

The history of biosystematics research and its impacts on climate goes before political ramifications. Climate change is altering the environments and likely to result in changes in the distribution of species, flowering times; migrate and adapt to the new environmental conditions; or extinction. Adaptive capacity is the ability of the plants to adapt to the impacts of climate change. Adaptation process is going in nature through phenotypic plasticity, natural selection or migration or polyploidization. The options are not mutually exclusive. Phenotypic plasticity may be the most efficient way of adaptation to a new environment. Polyploidization may increase tolerance to diverse ecological conditions and the high incidence of polyploidy in plants indicates its adaptive significance. Population having polyploid pillar complex is a good backup support towards microevolution and speciation, a mode of adaptation. The paper discusses about these biosystematics approaches towards adaptation to new environmental conditions resulting from climate change. It also discusses about the role of taxonomists under the changed circumstances. It is evident from the review that a set of biosystematics data along with other ecological and conservation information needs to be included in Flora and Monographs. It reveals that it was as far as worked out at the Paris Botanical Congress 1954 and put up by Stebbins in a series of proposals, termed as “Stebbins’ Ten Points” that needs further enrichment. Bangladesh J. Plant Taxon. 28(1): 277-287, 2021 (June)


2019 ◽  
Vol 374 (1768) ◽  
pp. 20180174 ◽  
Author(s):  
Rebecca J. Fox ◽  
Jennifer M. Donelson ◽  
Celia Schunter ◽  
Timothy Ravasi ◽  
Juan D. Gaitán-Espitia

How populations and species respond to modified environmental conditions is critical to their persistence both now and into the future, particularly given the increasing pace of environmental change. The process of adaptation to novel environmental conditions can occur via two mechanisms: (1) the expression of phenotypic plasticity (the ability of one genotype to express varying phenotypes when exposed to different environmental conditions), and (2) evolution via selection for particular phenotypes, resulting in the modification of genetic variation in the population. Plasticity, because it acts at the level of the individual, is often hailed as a rapid-response mechanism that will enable organisms to adapt and survive in our rapidly changing world. But plasticity can also retard adaptation by shifting the distribution of phenotypes in the population, shielding it from natural selection. In addition to which, not all plastic responses are adaptive—now well-documented in cases of ecological traps. In this theme issue, we aim to present a considered view of plasticity and the role it could play in facilitating or hindering adaption to environmental change. This introduction provides a re-examination of our current understanding of the role of phenotypic plasticity in adaptation and sets the theme issue's contributions in their broader context. Four key themes emerge: the need to measure plasticity across both space and time; the importance of the past in predicting the future; the importance of the link between plasticity and sexual selection; and the need to understand more about the nature of selection on plasticity itself. We conclude by advocating the need for cross-disciplinary collaborations to settle the question of whether plasticity will promote or retard species' rates of adaptation to ever-more stressful environmental conditions. This article is part of the theme issue ‘The role of plasticity in phenotypic adaptation to rapid environmental change’.


2001 ◽  
Vol 172 (5) ◽  
pp. 533-538 ◽  
Author(s):  
Jean-Dominique Meunier ◽  
Anne Alexandre ◽  
Fabrice Colin ◽  
Jean-Jacques Braun

Abstract Recent studies on the biogeochemical cycle of silica put new constraints into models of genesis and evolution of silica in tropical environments. The role of plants in weathering mass balances are illustrated by phytolith studies. In Dimonika (Congo) latosols, dissolved silica originates mainly from the dissolution of phytoliths rather than from the dissolution of non-biogenic silicates. In andosols from La Reunion island (Indian Ocean), a 15 cm thick, biogenic silica accumulation formed within 4000 years from bamboo forests fires. The turn-over of silica by plants must therefore be taken into account in studies of weathering rates. Weathering rates of trachytic ash layers in La Reunion island show that all the primary minerals are destroyed and that 50% of amorphous secondary Al/Si products are transformed into halloysite. Theses rates, which are faster than the ones obtained in the Hawaii islands, may strongly influence the turn-over of carbon in soils. Besides, phytoliths preserved from dissolution may help to decipher the records of environmental changes in soils. In Salitre (Brazil), the phytolith distribution has been calibrated with charcoal and pollens. The age of phytoliths, which increases with depth, allow to trace the savanna/forest changes.


2009 ◽  
Vol 6 (2) ◽  
pp. 51
Author(s):  
Salina Abdullah ◽  
Ern Chen Loo

Research on social and environmental accounting (SEA) has mainly concentrated on disclosure of SEA by corporate bodies, where investigations on ones attitude towards SEA are rarely discussed. SEA is a medium that develops relationships between business and society, community and nature. In addition, SEA involves a concept of sustain ability; where natural resources need to be sustained for the needs of future generations (Alhabshi et al., 2003). SEA also tries to recognise the role of accounting in sustainable development and the use of environmental resources. There are arguments that the young generations today are not fully aware of preserving these natural resources as well as handling social and environmental issues wisely. This perhaps link closely to their belief and cultural background. Hence, this paper examines the influence of gender and belief factors on the undergraduate students’ attitude towards SEA. Four dimensions of belief (fixed ability, quick learning, simple knowledge and certain knowledge) proposed by Schommer (2005) were adapted to analyse how belief factors have influence on their attitude towards SEA. An independent sample t-test was used to examine the relationship between gender and students’ attitude towards SEA. Spearmen’s correlation was employed to show the relationship between belief and attitude towards SEA. The results revealed that gender differences did not show influences on their attitude towards SEA. It was found that there is a significant relationship between belief and students’ attitude towards SEA. Students who believe on the importance of SEA tend to report positive attitude towards SEA. Perhaps findings of this study may provide some information on the SEA education and further be incorporated in the syllabus.


Author(s):  
H. Frederik Nijhout ◽  
Emily Laub

Many behaviors of insects are stimulated, modified, or modulated by hormones. The principal hormones involved are the same as the ones that control moulting, metamorphosis, and other aspects of development, principally ecdysone and juvenile hormone. In addition, a small handful of neurosecretory hormones are involved in the control of specific behaviors. Because behavior is a plastic trait, this chapter begins by outlining the biology and hormonal control of phenotypic plasticity in insects, and how the hormonal control of behavior fits in with other aspects of the control of phenotypic plasticity. The rest of the chapter is organized around the diversity of behaviors that are known to be controlled by or affected by hormones. These include eclosion and moulting behavior, the synthesis and release of pheromones, migration, parental care, dominance, reproductive behavior, and social behavior.


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