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492 ecological experiment Preprints

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ecological experiment behavioral ecology ecosystem function invertebrate multiple terrestrial vertebrate plants ecosystem ecology description experimental evolution laboratory marine statistical comparative population ecology method development ecosystem evolutionary ecology freshwater community ecology
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Please note: These are preprints and have not been peer reviewed. Data may be preliminary.
Recovery from heat-induced infertility -- a study of reproductive tissue responses an...
Berta Canal
Claudia Fricke

Berta Canal

and 1 more

July 12, 2022
The predicted temperature increase caused by climate change is a threat to biodiversity. Male reproduction is particularly sensitive to elevated temperatures resulting in sterility. Here we investigate temperature induced changes in reproductive tissues and the fertility reduction in male Drosophila melanogaster. We challenged males during development and either allowed them to recover or not in early adulthood, while measuring several determinants of male reproductive success. We found significant differences in recovery rate, organ sizes, sperm production and other key reproductive traits among males from our different temperature treatments. Spermatogenesis and hence sperm maturation was impaired before reaching the upper thermal sterility threshold. While some effects were reversible, this did not compensate the earlier damage imposed. Surprisingly, developmental heat stress was damaging to accessory gland growth and female post mating responses mediated by seminal fluid proteins were impaired regardless of the possibility of recovery. We suggest that sub-lethal thermal sterility and the subsequent fertility reduction is caused by a combination of malfunctioning reproductive traits: inefficient functionality of the accessory gland and alteration of spermatogenesis.
Ecological significance of deceptive pollination in Papilionanthe teres
tingting Yang
xiang Zhou

tingting Yang

and 1 more

July 05, 2022
Though some hypotheses have obtained theoretical and empirical supports, it remains largely unknown in the aspect that how deception increases orchid fitness. This study used food-deceptive Papilionanthe teres as experimental material to explore the ecological significance of orchid deceptive pollination. Deception together with obvious pollinarium bending increases P. teres fitness by means of decreasing geitonogamy under the natural conditions. The proportions of full seeds, single fruit weight and seed weight per fruit after self-pollination and nectar addition were significantly lower than that after cross-pollination and natural conditions (all p < 0.05). Seed viability (seed growth and development rate) after cross-pollination and natural condition were significantly higher than that after self-pollination and nectar addition (all p < 0.05). However, there was no significant difference in all the above parameter values of fruits and seeds between cross-pollination and natural conditions (all p > 0.05). These results confirmed that P. teres has high level of genetic load, and self-fertilization or geitonogamy will cause serious inbreeding depression. These conclusions support the outcrossing hypothesis that ecological significance of P. teres deception is to promote outcrossing and improve the ability of the offspring to adapt to the environment.
Diversity, relative abundance and distribution of medium and large mammals in Mago Na...
Girma Mengesha

Girma Mengesha

June 23, 2022
The objective of this study was to investigate diversity, relative abundance, and distribution of medium and large mammals in Mago National Park (MNP), Southern Ethiopia. Data collection was conducted during dry and wet seasons. A systematic sampling design was used to establish line transects along the three main habitat types, namely: Woodland, Acacia savanna, and Riverine forest. A total of 45 line transects were established through the habitats, varing in length from 1.5 to 5 km, depending on the size of the habitat. Twenty-eight medium and large mammals species were recorded in the area belonging to 8 families and 5 orders. Order Artiodactyla had the highest number of species (14 species), followed by Carnivora (8 species), whereas Perissodactyla and Proboscidea were represented by one species each. During both seasons, the highest species diversity (H’ = 2.81, and H’=2.96) was recorded in woodland habitat, but the lowest ( H’ =2.5 and H’= 2.67) in riverine forest. In terms of abundance, Tragelaphus imberbis 1773±86 (12%) was the most abundant species, while Vulpes chama was the least abundant species 104 ±13 that contributed less than 1% of the total. Most of the mammals species occurred in woodland habitat as compared to the other habitat types. Seasonal variation in abundance (number) of individuals of medium and large mammals was significantly different (X2 = 91.651, df =1, p<0.05). However, variation in species composition was not significant (X2 = 0.018, df = 1, P<0.05). It can be concluded that, Mago National Park harbour high species diversity of medium and large mammals. Conservation efoforts that could suatain the high diversity pf the species in the area in needed to main the diversity.
Structure and characteristics of plant-frugivore network in Guilin Botanical Garden
GuoHai Wang
Yang Huang

GuoHai Wang

and 7 more

June 22, 2022
The interaction between plants and frugivores plays a critical role in sustaining ecosystem function and community diversity, but little is known about the structure of interaction networks between fruit plants and frugivore birds in urban green spaces. We observed the interactions between plants and birds throughout the year in the Guilin Botanical Garden and assessed the characteristics of the total plant-frugivore and seasonal networks. We also analyzed the relationship between the network roles of species and ecological traits to explore the structure and characteristics of the plant-frugivore network. The interactions between a total of 14 frugivore birds and 13 fruit plant species were analyzed in the study area, the autumn and winter interaction connections contributed 38.79% and 33.15% to the total network, respectively. The specialization (H2´), and interaction evenness (E2) of the network were higher in spring and summer than that in autumn and winter. However, connectance (C), nestedness, and interaction diversity (H2) were contrary to the specialization and interaction evenness of the network. Compared to the networks (N=1000) generated by the null model, the observed network exhibited lower connectance (C), interaction diversity(H2), interaction evenness (E2), and higher nestedness and specialization (H2´). A correlation analysis combining ecological traits and network roles showed that plants with black fruit had higher species strength, whereas the other traits of plants and birds were not significantly correlated with their network parameters.
Evolution of population dynamics following invasion by a non-native predator
Sigurd Einum
Emil Ullern

Sigurd Einum

and 3 more

June 21, 2022
Invasive predatory species are frequently observed to cause evolutionary responses in prey phenotypes, which in turn may translate into evolution of the prey’s population dynamics. Research has provided a link between rates of predation and the evolution of prey population growth in the lab, but studies from natural populations are rare. Here we tested for evolutionary changes in population dynamics parameters of zooplankton Daphnia pulicaria following invasion by the predator Bythotrephes longimanus into Lake Kegonsa, Wisconsin, US. We used a resurrection ecological approach, whereby clones from pre- and post-invasive periods were hatched from eggs obtained in sediment cores and were used in a 3-month growth experiment. Based on these data we estimated intrinsic population growth rates (r) and carrying capacities (K) using theta-logistic models. We found that post-invasion Daphnia maintained a higher r and K under these controlled, predation-free laboratory conditions. Thus, whereas previous experimental evolution studies of predator-prey interactions have demonstrated that genotypes that have evolved under predation have inferior competitive ability when the predator is absent, this was not the case for the Daphnia. Given that our study was conducted in a laboratory environment and the possibility for genotype-by-environment interactions, extrapolating these apparent counterintuitive results to the wild should be done with caution. However, barring such complications, we discuss how selection for reduced predator exposure, either temporally or spatially, may have led to the observed changes. This scenario suggests that complexities in ecological interactions represents a challenge when predicting the evolutionary responses of population dynamics to changes in predation pressure in natural systems.
New evidence for seed transmission of reptiles in arid areas of China
Zhenyuan Duan
Lei Shi

Zhenyuan Duan

and 1 more

June 20, 2022
Abstract: Diet and trophic niche of Teratoscincus roborowskii was analyzed by pellets analysis technique. A total of 263 pellets of Teratoscincus roborowskii were collected from the Turpan Botanic Garden in Turpan City from July to Octobor, 2016, . Food composition and proportion of Teratoscincus roborowskii were identified by comparative analysis. The number of food components in the fecal samples was identified, and the numeric frequency, biomass ratio and frequency of occurrence of each component were counted and then the monthly Shannon-wiener diversity index, Shannon evenness index and diet niche width were analyzed. The results show that the Teratoscincus roborowskii mainly feed on insects and caper fruit in the Turpan Botanic Garden. Insects are the most common food for the Teratoscincus roborowskii, the frequency of occurrence which in each month is the largest; caper fruit was the most food intake in July and August, and that of insects is the most one on September and October. There are some differences in the composition of food in different months, which may be related to changes of food availability. The results of the feeding habit analysis show that the Teratoscincus roborowskii may play an active role in the dispersal of caper seed.
“Realistic strategies” and neutral processes drive the community assembly based on le...
Lijuan Zhao
Wenhua Xiang

Lijuan Zhao

and 10 more

June 16, 2022
We sought to assess effect of plant environmental adaptation strategies and evolutionary history and quantify the contribution of ecological processes to community assembly by measuring functional traits and phylogenetic composition in local forest community. We selected 18 dominant tree species in a Lithocarpus glaber–Cyclobalanopsis glauca evergreen broad-leaved forest and measured nine leaf functional traits and phylogenetic data of each species. We analyzed the variation in traits and trade-off relationships, tested phylogenetic effects on leaf functional traits, explored the influence of phylogeny and environment on leaf functional traits, and distinguished the relative effects of spatial and environmental variables on functional traits and phylogenetic compositions. The results showed the following: (i) Leaf traits had moderate intraspecific variation, and significant interspecific variation existed especially among life forms. (ii) Significant phylogenetic signals were detected only in leaf thickness and leaf area. The correlations among traits both supported “the leaf economics spectrum” at the species and community levels, and the relationships significantly increased or only a little change after removing the influence of phylogeny, which showed a lack of consistency between the leaf functional trait patterns and phylogenetic patterns. We infer the coexistent species tended to adopt “realism” to adapt to their habitats. (iii) Soil total potassium and phosphorus content, altitude, aspect, and convexity were the most critical environmental factors affecting functional traits and phylogenetic composition. Total environmental and spatial variables explained 63.38% of the variation in functional trait composition and 47.96% of the variation in phylogenetic structures. Meanwhile, the contribution of pure spatial factors was significantly higher than that of the pure environment. Neutral- theory-based stochastic processes played dominant roles in driving community functional trait assembly, but niche-theory-based determinative processes such as environmental filtering had a stronger effect on shaping community phylogenetic structure at a fine scale.
Crop diversity and susceptibility of crop fields to elephant raids in eastern Okavang...
Tiroyaone Albertinah Matsika
Gaseitsiwe Masunga

Tiroyaone Albertinah Matsika

and 7 more

June 08, 2022
Abstract 1. Elephants frequently raid farmers’ crops within their ranges in Africa and Asia. This can have a large impact on agricultural productivity and food security for farmers. 2. Previous studies have examined susceptibility of crop fields to elephant raids using field characteristics such as field size and proximity to water sources. However, there are limited studies investigating how different crop types, individually and in their combinations influence crop susceptibility to elephant raiding. Also, spatio-temporal patterns in elephant crop raids in agro-ecological landscapes have not been extensively examined. 3. This study utilised data collected from crop fields raided by elephants between 2008 and 2018. Data on crops grown, the number of crop-raiding incidences for each crop, and elephant raiding incidences were recorded for each field assessed. Incidence risks (IR) and field risk value (RV) were computed using an adaptive epidemiological approach. 4. The results showed that elephant crop raiding incidents varied significantly amongst crop types, and over space and time (P<0.0001). Cereal crops (millet: Eleusine conaracana, maize: Zea mays) incurred a higher number of crop raiding incidents compared with leguminous crops (cowpea: Vigna unguiculata; groundnut: Arachis hypogea). Field RVs significantly varied depending on which crop was present in the field. There was a significant negative correlation between the number of crop types and the susceptibility of the field to raiding (R2 = -0.680, P<0.0001). 5. Our results suggest that the susceptibility of the fields to elephant raids could be minimised by selecting crop types and combinations less susceptible to elephant damage, thus enhancing food security for local subsistence farmers. Keywords: crop raiding, crop species, incidence risks, field risk value, food security, human-elephant conflict
Plant-soil feedback from eastern redcedar (Juniperus virginiana) inhibits the growth...
Leland Bennion
David Ward

Leland Bennion

and 1 more

June 06, 2022
1. The encroachment of woody plants into grasslands is an ongoing global problem that is largely attributed to anthropogenic factors such as climate change and land management practices. Determining the mechanisms that drive successful encroachment is a critical step towards planning restoration and long-term management strategies. Feedbacks between soil and aboveground communities can have a large influence on the fitness of plants and must be considered as potentially important drivers for woody encroachment. 2. We conducted a plant-soil feedback experiment in a greenhouse between eastern redcedar Juniperus virginiana and four common North American prairie grass species. We assessed how soils that had been occupied by redcedar, a pervasive woody encroacher in the Great Plains of North America, affected the growth of big bluestem, little bluestem smooth brome, and western wheatgrass over time. We evaluated the effect of redcedar on grass performance by comparing the height and biomass of individuals of each grass species that were grown in live or sterilized conspecific or redcedar soil. 3. We found that redcedar created a negative plant-soil feedback that limited the growth of two species. These effects were found in both live and sterilized redcedar soils, indicating redcedar may exude an allelochemical into the soil that limits grass growth. 4. Synthesis. By evaluating the strength and direction of plant-soil feedbacks in the encroaching range, we can further our understanding of how woody pants successfully establish in new plant communities. Our results demonstrate that plant-soil feedback created by redcedar inhibits the growth of certain grass species. By creating a plant-plant interaction that negatively affects competitors, redcedars increase the probability of seedling survival until they can grow to overtop their neighbors. These results indicate plant-soil feedback is a mechanism of native woody plant encroachment that could be important in many systems yet is understudied.
Modeling Habitat Suitability of Hippophaerhamnoides L. Using MaxEnt under Climate cha...
Xiaohui HE
Si J. H.

Xiaohui HE

and 8 more

May 31, 2022
Hippophaerhamnoides is widely known for its important ecological, economic, and social benefits. It is known as the pioneer plant of soil and water conservation, with homology in food and medicine. Here we used occurrence data and environmental (climate and soil) variables to simulate and predict the habitat distribution for H. r. sinensis and H. r. trkestanica in China, both at the current time and in the 2050s (2041-2060). Our aim was to analyze the dominant factors effecting its distribution using MaxEnt and the spatial analysis of geographic information system. The results indicated that H. r. sinensis is mainly distributed in Shaanxi, Shanxi, Sichuan, Qinghai, Gansu, Ningxia, Tibet, and Inner Mongolia, and is mainly affected by bio13 (precipitation of the wettest month), bio11 (mean temperature of the coldest quarte) and bio3 (Isothermality). The suitable habitat of H. r. trkestanica is mainly distributed in Xinjiang, and Tibet, and is mainly affected by bio13 (precipitation of the wettest month), bio2 (mean diurnal range) and bio15 (precipitation seasonality). Although, the two subspecies tend to expand and migrate toward lower latitude under future climate scenarios, there are some differences. H. r. sinensis will migrate westward, while H. r. trkestanica will migrate eastward as a whole. They have a high stability of suitable habitat and are not at risk of extinction in the future. The study’s findings help to clarify the resource reserve of Hippophaerhamnoides L. in China, which will help to guide the protection of wild resources and to popularize artificial planting in suitable areas, and provides scientific basis for the protection of ecological environment.
Influence of edaphic conditions on aboveground biomass in areas post-mining in the Co...
Harley Quinto Mosquera
Jhon Jerley Torres Torres

Harley Quinto Mosquera

and 2 more

May 30, 2022
Mining is one of the main drivers of deforestation of tropical forests. This activity affects the storage of aboveground biomass of these ecosystems; and, therefore, its ability to contribute to the mitigation of global climate change. The influence of soils on the aboveground biomass of areas post-mining in the Colombian Pacific was evaluated. For this, plots were established in areas post-mining and with different successional ages (12-15 years, 30-35 years and mature forest). The aboveground biomass and physicochemical parameters of the soil were measured. A aboveground biomass of 15.58 t ha-1, 35.17 t ha-1, and 178.32 t ha-1 was recorded at 12-15 years, 30-35 years and mature forest, respectively. The aboveground biomass was positively correlated with organic matter (OM), calcium (Ca), magnesium (Mg), CICE, total nitrogen (N) and silt; whereas, with sand, aluminum (Al) and potassium (K) content the relationship was negative. It was evidenced that the relationship between aboveground biomass and soils was different in each successional age. When evaluating the changes of aboveground biomass and soils in the successional, it was observed that the aboveground biomass and total N increased with the recovery time; while the P and K decreased with succession. On the other hand, the contents of OM, Mg, Al, Ca and CICE, showed curvilinear tendencies, since they increased in the first stages, and then in the advanced successional stages they decreased. In summary, the results showed that the aboveground biomass of areas post-mining was limited by multiple soil nutrients.
Effect of grazing intensity on plant–soil C:N:P stoichiometry within a desert grassla...
Wan Tao

Wan Tao

May 30, 2022
Background and aims High-intensity grazing in Mongolian grasslands has led to the general deterioration of biodiversity and ecosystem functioning. Abundant evidence shows that grazing affects the structure and function of grassland ecosystems, especially under overgrazing. Methods We examined the effects of three grazing intensities (0, 1.92, and 3.08 sheep ha-1 a-1) on plant commu-nities, plant and soil C, N and P contents, and plant and soil C:N:P stoichiometry in a desert grassland in different years. Results Grazing did not affect plant coverage, richness, or N:P, and the plant community biomass, litter bio-mass and C:N and C:P were highest under a zero grazing intensity. Soil C:N changed with the year and grazing intensity. However, soil C:P and N:P were higher in 2018 than in 2016 and 2017. Conclusions Our study suggested that grazing promoted the flow of N between plants and the soil, especially at 3.08 sheep ha-1 a-1. Under grazing stress, plants maintained the potential for compensatory growth. Further-more, N was shown to be the limiting fertilizer component for plants growing in this area among the three grazing intensities.
Patterns of stress response to foreign eggs by a rejecter host of an obligate avian b...
Mikus Abolins-Abols
Mark Peterson

Mikus Abolins-Abols

and 6 more

May 27, 2022
One of the most effective defenses of avian hosts against obligate brood parasites is the ejection of parasitic eggs from the nests. Despite the clear fitness benefits of this behavior, individuals within so-called “egg rejecter” host species still show substantial variation in their propensity to eliminate foreign eggs from the nest. We argue that this variation can be further understood by studying the physiological mechanisms of host responses to brood parasitic egg stimuli: independent lines of research increasingly support the hypothesis that stress-related physiological response to parasitic eggs may trigger egg rejection. The “stress-mediated egg rejection” hypothesis requires that hosts activate the stress-response when responding to parasitic eggs. We tested this prediction by experimentally parasitizing incubating American robins Turdus migratorius, an egg rejecter host to obligate brood parasitic brown-headed cowbirds Molothrus ater, with mimetic or non-mimetic model eggs. To assess the stress response, we measured the heart rate in incubating females immediately after experimental parasitism. We also measured plasma corticosterone and, in a subset of birds, used RNA-sequencing to analyze the expression of proopiomelanocortin (POMC), a precursor of adrenocorticotropic hormone (ACTH), two hours after experimental parasitism. We found that egg type had no effect on heart rate. Two hours following experimental parasitism, plasma corticosterone did not differ between the differently colored model egg treatments or between rejecter and accepter females within the non-mimetic treatment. However, females exposed to non-mimetic eggs showed an upregulation of POMC gene expression in the pituitary compared to females treated with mimetic eggs. Our findings suggest that parasitic eggs may activate the stress-related hypothalamic-pituitary-adrenal axis in an egg-rejecter host species, although the dynamics of this response are not yet understood.
Temporal and biting dynamics of the malaria vectors Anopheles gambiae and Anopheles c...
Claire Sangbakembi-Ngounou
Carine Ngoagouni

Claire Sangbakembi-Ngounou

and 6 more

May 27, 2022
The chromosomal rearrangement 2La has been directly involved in the ecological and deadly epidemiological success of the malaria mosquitoes Anopheles gambiae and Anopheles coluzzii in sub-Saharan Africa. However, little is known about the biological and ecological factors that drive the local and temporal dynamics of this inversion in both species. Here, we performed a year-round longitudinal survey in Bangui, Central African Republic. We monthly sampled An. gambiae and An. coluzzii mosquitoes indoor and outdoor using human landing catches for 48 hours non-stop. We molecularly karyotyped all specimens to study the 2La inversion frequency variations, and monitored the mosquito spatial and temporal biting behavior throughout the year. In total, we successfully karyotyped 5121 An. gambiae and 986 An. coluzzii specimens. The 2La inversion frequency was higher in An. coluzzii than in An. gambiae across the year. In An. gambiae and An. coluzzii, the inversion frequency or karyotypes did not influence the biting behavior, either location or time. Moreover, the inversion frequency variation in both species was also independent of local climatic changes. Overall, our results revealed that in Bangui, the 2La inversion segregates at different frequency in each species, but this is not influenced by their trophic behavior. Studying the impact of urban settings and the population genetic structure of these two An. gambiae complex members could bring insights into the intrinsic relationship between 2La inversion and local conditions. More studies are needed to understand the polymorphic equilibrium of this inversion in Bangui.
Effects of food plants on life-history traits of the newly invasive fall armyworm Spo...
Li-Li Huang
Fangsen Xue

Li-Li Huang

and 5 more

May 26, 2022
The fall armyworm (FAW) Spodoptera frugiperda has invaded Jiangxi Province, Southeast China for the past three years. Although the FAW displays a very wide host range, one of its main host plants in Jiangxi Province is still field corn. This study systematically investigated the effects of food plants (corn, peanut, soybean and sugarcane) on life-history traits of FAW and tested the leaf contents of the total flavonoids, reducing sugars, sucrose and C/N ratio. We found that the FAW fed on corn leaves showed significantly shorter larval and pupal development times, larger body weight, higher growth rate, lower weight loss, smaller SSD, shorter preoviposition period and higher fecundity than those fed on peanut, soybean and sugarcane leaves. The pupal development stage was significantly longer in males than females, showing a protogyny phenomenon. Food plants changed the relationships between larval development time and pupal weight and between fecundity and longevity. The corn leaves showed significantly higher contents of reducing sugars and sucrose, lower content of the total flavonoids, and a moderate C/N ratio, suggesting that the corn leaf tissues are more nutritive. These findings may help us to understand why the FAW mainly infests corn plants and may be critical for the development of strategies to predict infestation levels.
Intraspecific variation in growth response to drought stress across geographic locati...
Catherine Kiwuka
Jan Vos

Catherine Kiwuka

and 6 more

May 26, 2022
Uganda lies within the drier end of the natural distribution range of Coffea canephora and contains unexplored genetic material that could be drought-adapted and useful for developing climate-resilient varieties. Using experimental treatments, (i) ample and (ii) restricted-water, response of 148 genotypes were studied comprising wild, feral and cultivated C. canephora. Biomass allocation, standing leaf area and leaf area growth data were collected. Linear mixed effect models and PCA were used to analyse effect of drought on genotypes from different: (i) cultivation status, (ii) genetic groups and (iii) locations. We assessed the relationship between drought tolerance for relative growth rate in leaf area (RGRA), total number of leaves (TNL), total leaf area (TL) and total leaf dry weight (TLDW) of genotypes at final harvest. Restricted-water reduced RGRA across genetic groups (3.2 – 32.5%) and locations (7.1 – 36.7%) but not cultivation status. For TNL, TL and TLDW, genotypes that performed well in ample-water performed worse under restricted-water, indicating growth-tolerance trade-off. Drought tolerance in RGRA and TNL were negatively correlated with wetness index suggesting some degree of adaptation to local climate. Findings indicate a growth-tolerance trade-off within this tropical tree species and drought tolerance of Uganda’s C. canephora is somewhat associated with local climate.
Effects of pH and calcium salt stress on the seed germination performance of three he...
Zhaoyi Wang
Sihui Tian

Zhaoyi Wang

and 7 more

May 23, 2022
Seed germination is critical for successful crop production, and the sensitivity to pH and salt stress depends on the plant’s tolerance mechanisms. In view of the characteristics of calcium-rich and acidic soils in the karst areas of Guizhou Province, China, the effects of pH stress and calcium stress on the seed germination characteristics of three herbages were studied with the goal of exploring and revealing the mechanism of adaptation of the three herbages to an acidic soil environment and providing a theoretical basis for the selection and cultivation of acid-tolerant herbages in southwest China. In this study, six concentration gradients of CaCl2, including 0, 25 mmol/L, 50 mmol/L, 100 mmol/L, 150 mmol/L, and 200 mmol/L, and seven pH gradients, including 4.55, 5.35, 6.61, 7.03, 8.0, and 9.18 were established, respectively. The germination rate, germination potential and germination index of the seedlings were measured for each seed germination and seedling growth stage of orchardgrass, perennial ryegrass, and alfalfa, respectively. The results showed that when the concentration of salt stress began to change, the herbage seeds could adapt to salt stress at an appropriate pH condition. When only the pH value or CaCl2 concentration changes, the increase in pH and CaCl2 will inhibit the growth of shoots and roots. Weak acid can promote the growth of shoots and young roots, while alkaline conditions can inhibit their growth. The effect of a low concentration of CaCl2 was not apparent, while a high concentration of CaCl2 clearly inhibited the plants. The optimal pH and CaCl2 of the bud and root lengths changed after the interaction. In conclusion, there is a substantial difference between pH and calcium salt stress, and the interaction between pH and calcium salt concentration has a substantial influence on the salt and alkali tolerance of the three types of seeds.
Feeding interaction of exotic Oreochromis niloticus (Linnaeus, 1758) versus native Co...
Arthertone Jere
Wilson Jere

Arthertone Jere

and 3 more

May 19, 2022
Evaluating the feeding interaction of fishes is fundamental in understanding the impacts of introduced species on the community structure and ecosystem function of native species. In the Zambian Rivers, studies have shown that native species has been impacted upon by exotic Oreochromis niloticus, but few studies have investigated feeding interactions between exotic Oreochromis niloticus which is omnivorous and aquaculture preferred herbivorous native species (Coptodon rendalli) in the natural distribution. We analysed the stomach contents of 368 specimens of the fishes to examine the feeding interactions between O. niloticus and C. rendalli in the upper Kabompo River, northwest of Zambia. Both species were grouped into size classes of <50, 51−100 and 101−150 mm total length (TL). However, in the size classes 51-100 mm and 151-100 mm O. niloticus had a larger dietary niche because of its generalist diet than the native species, whose diet mainly comprised of diatoms and algae. There was no significant ontogenetic diet shift for both species, except for O. niloticus in size class 101-150 mm, whose diet consisted mainly of zooplanktons and micro fauna. The results showed an interspecific competition in their size classes, except for 101-150 mm size class, that indicated low dietary overlap. This poses major impacts on food web structure and may explain population decreases of some native species in the upper Kabompo River. Future studies are required to further understand feeding interaction between the exotic and other native fishes in the Kabompo River and other rivers across African where the species coexist.
Effects of Gopher Tortoise (Gopherus polyphemus) Exclusion on Plant Assemblages in a...
Robin Lloyd
Jeremiah Henning

Robin Lloyd

and 2 more

May 19, 2022
Herbivory serves as a critical top-down mechanism within plant communities by regulating biodiversity, productivity, and ecosystem function. While top-down impacts of mammalian herbivores have garnered significant attention in the literature, fewer studies have investigated the role of herbivorous reptiles in regulating plant communities, which can serve as crucial herbivores in some ecosystems. In Southeastern United States coastal plain long-leaf pine forests, the gopher tortoise (Gopherus polyphemus) is a keystone species that may suppress plant productivity and promote local diversity within hyper-diverse understory plant communities. In January 2019, we established tortoise-exclusion plots within an active gopher tortoise population at Splinter Hill Bog Preserve in southwest Alabama, USA. We measured the response of plant species diversity, composition. and productivity through a single growing season to quantify the short-term impacts of tortoise-excluded plots on understory plant communities. We found that plots excluded tortoises had 35% more plant cover with a 15% reduction in plant richness, 6% reduction in evenness, and 12% reduction in Shannon’s diversity relative to control plots. Within a single growing season, we found that tortoise exclusion explained 5% of the variation within overall plant community composition. Our results provide clear evidence on the role of gopher tortoise herbivory for the maintenance of plant diversity within the species-rich longleaf pine forests of the Southeastern United States, even at short time scales and in an heterogeneous environment.
Performance of the newly invasive fall armyworm Spodoptera frugiperda on different fo...
Li-Li Huang
Fangsen Xue

Li-Li Huang

and 5 more

May 07, 2022
The influence of four food plants (corn, peanut, soybean and sugarcane) on life-history traits of the fall armyworm (FAW) Spodoptera frugiperda was examined in the laboratory at 25±1 °C and a photoperiod of L:D 15:9 (15 h light:9 h dark). The leaf contents of the total flavonoids, reducing sugars, sucrose and C/N ratio were also tested. The FAW fed on corn leaves showed significantly shorter larval and pupal development times, larger body weight, higher growth rate, lower weight loss, smaller SSD, shorter preoviposition period and higher fecundity than those fed on peanut, soybean and sugarcane leaves. However, FAW successfully completed its whole life cycle and exhibited higher fecundity in peanut, soybean and sugarcane. The FAW showed a protogyny phenomenon because the pupal development stage was significantly longer in males than females. There was a positive relationship between pupal weight and fecundity. However, the relationships between larval development time and pupal weight and between fecundity and longevity were different among different food plants. The leaf contents of the total flavonoids, reducing sugars, and sucrose and the C/N ratio differed significantly among the different food plants. We discuss the influences of these leaf nutritional contents on larval development time and pupal weight. These findings can help us to better understand the variation in life-history traits of the FAW and may be critical for the development of strategies to predict infestation levels.
Distribution, characteristics and classification of Caryopteris mongholica community...
Xiao Yu
Ruoxuan Ji

Xiao Yu

and 6 more

May 06, 2022
Abstract: Caryopteris mongholica is a rare resource plant distributed in typical steppe, desertified steppe and desert areas. Based on field survey data sampled during the growing seasons from 2018 to 2021, combined with relevant previous literature, this study analyzed the distribution and environmental characteristics of C. mongholica population, the characteristics, classification and species diversity of C. mongholica community, and the influence of environmental factors. The results showed that: (1)The C. mongholic population was mainly distributed in the east, middle and west of Inner Mongolia Autonomous Region, the north of Loess Plateau, Hexi corridorm, Qilian Mountains and other northwest temperate desert or steppe areas in China. It was the dominant species or companion species in the community. (2) According to the survey of 40 sample plots, a total of 141 species of seed plants were recorded, belonging to 110 genera of 37 families, and families of Compositae, Leguminosae and Gramineae played crucial roles in the species composition. Among them, 42 of these species were shrubs and dwarf/semi-shrubs, 76 were perennial herbs, 23 were annuals and biennials. In the class of species presence, 88.02% were occasional species with frequency distribution smaller than 20%. Typical xerophytes occupied the main advantage(32.39%) in the water ecological types. East Palearctic elements(25.35%) were the major floristic geographic elements. (3) Based on the life form and dominance of species, the C. mongholica communities were divided into 6 major association groups,which were further divided into 23 associations. (4)Precipitation, solar radiation and other environmental factors significantly affect the distribution of C. mongholica population and the species diversity of the community. Key word: Caryopteris mongholica, population distribution, community characteristic, species diversity
Filtration and respiration responses of mussels (Mytilus edulis) to trematode parasit...
Maral khosravi
David Thieltges

Maral khosravi

and 4 more

May 06, 2022
As a foundation species in shallow-water ecosystems, the mussel Mytilus edulis exposed to abiotic and biotic stressors. In particular, heat stress can have detrimental effects on mussel performance and biotic interactions with parasites may exacerbate those effects. This study explores the metabolic responses of mussels to infections with the trematode Renicola roscovita, under mild and transient heat exposures. Using controlled laboratory infections, a first experiment investigated the responses of infected and uninfected small mussels (2 cm), to a 24-hour exposure to a mild temperature followed by an acute heat ramp and subsequent cooling. The results indicated that trematode infections reduced mussel filtration by, on average, 13%, and that infections exacerbated the impact of the transient heat exposure, as indicated by a larger difference (33%) between infected and uninfected mussels in the post-heat recovery phase. However, these differences were statistically not significant, owing to generally large variation among mussels and low sample sizes. In a second experiment, we further investigated how mussel size (2 and 4 cm) affected infection impacts on mussel performance under constant exposure to a mild temperature. We found that infections reduced mussel filtration at similar rates (11% and 12% for small and large mussels, respectively) compared to the first experiment, albeit statistically significant only for large mussels. In both experiments, no discernible impact on the mussel respiration rate was found. Interestingly, we found positive relationships between mussel filtration capacity and infection intensity, suggesting that mussel phenotypes with generally higher filtration capacity may be more prone to infections. Overall, our results suggest that R. roscovita metacercariae infections can lower the ability of hosts to sustain optimal energy supply, which in turn may exacerbate the negative effects of heat stress. The role of mussel phenotypic variation in filtration capacity in driving infection levels and subsequent effects warrants further investigation.
Development of a new apparatus to partition ant body size reveals their respective fu...
Taylor Bogar
Sabine Nooten

Taylor Bogar

and 2 more

April 29, 2022
A document by Taylor Bogar. Click on the document to view its contents.
Sexual perception does not modulate male short-term fitness components in Drosophila...
Quentin Corbel
Claudia Londoño-Nieto

Quentin Corbel

and 2 more

April 27, 2022
Phenotypic plasticity in reproductive behaviour can be a strong driver of individual fitness. For example, in species with high intra-sexual competition, changes in socio-sexual context can trigger quick adaptive plastic responses in males. In particular, a recent study in the vinegar fly (Drosophila melanogaster) shows that males respond adaptively to perception of female cues in a way that increases their reproductive success, but we ignore the underlying mechanisms of this phenomenon. Here, we aimed to fill this gap by investigating the short-term effects of female perception on male pre- and post-copulatory components of reproductive success: a) mating success, b) mating latency and duration, c) sperm competitiveness, and d) ejaculate effects on female receptivity and oviposition rate. We found that brief sexual perception increased mating duration, but had no effect on the main pre- or post-copulatory fitness proxies. These results tie up with previous findings to suggest that male adaptive responses to sexual perception are not due to a short-term advantage, but rather to fitness benefits that play out across the entire male lifespan.
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