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463 ecological experiment Preprints

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ecological experiment behavioral ecology invertebrate multiple plants terrestrial natural history vertebrate ecosystem ecology description experimental evolution laboratory statistical comparative population ecology method development none of the above ecosystem evolutionary ecology freshwater community ecology sequencing theoretical
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Please note: These are preprints and have not been peer reviewed. Data may be preliminary.
Behavioural adaption of Scaly-sided Merganser (Mergus squamatus) to habitats with dif...
Peizhong Liu
Meihan Liu

Peizhong Liu

and 8 more

September 14, 2022
Abstract: Throughout evolutionary history, animals are finely tuned to adjust their behaviors corresponding to environmental variations. Behavioral flexibility represents an important component of a species’ adaptive capacity in the face of rapid anthropogenetic environmental change, and knowledge of animal behaviours is increasingly recognized in conservation biology. In aquatic ecosystem, variation of water depth is a key factor affecting the availability of food, thus the foraging behaviours of many waterbirds, especially piscivores. In this study, we compared the foraging behaviours of Scaly-sided Merganser (Mergus squamatus), an endangered migratory diving duck endemic to east Asia, in habitats with different water depth, using video camera records obtained from the known wintering sites during three winters from 2018-2020. Further, the energy expenditure of foraging behavior profile and energy intake based on fish sizes were calculated to study the foraging energetics. In total, 200 effective video footages that contained 1,086 minutes with 17,995 behaviours and 163 events of catching fish were recorded. Results showed that 1) time length for fishing (including eye-submerging, head-dipping, diving and food handling) of Mergus squamatus in shallow waters was significantly more than in deep waters; 2) Mergus squamatus spent significantly more time for preparing (including vigilance, preening and swimming) in deep waters than in shallow waters; 3) the mean catch rate was 0.28 fish/minute in shallow waters, which is significantly higher than the value of 0.13 fish/minute in deep waters; 4) despite the distinct foraging behaviour profiles and energy intakes, Mergus squamatus showed similar energetics in shallow and deep waters. We concluded that Mergus squamatus is a good example of behavioural flexibility that aligns with expectations of optimum foraging theory, in that it behaves in accordance to resource availability in different environments, resulting in high foraging efficiency. The behavioural flexibility can be related to its evolution history.
Floral traits and environmental factors regulate insect visits to flowering plants at...
Lichao Feng
Zhiqi Du

Lichao Feng

and 5 more

September 12, 2022
Flower-visiting insects have co-evolved with flowering plants. While it has been shown that floral traits and environmental factors influence insect visitation during the day, it is still unclear how these factors influence their visitation at night. We sampled a montane meadow located near Jilin in northeastern China in July and August of 2019, for 4 nights each month, and two time periods each night. We sampled 94 flower-visiting insect species in total and documented floral traits and ambient factors. We first allocated all the insects to three functional groups (pollination, predation, and herbivory). Most nocturnal insects exhibited predation behavior, and had the highest species turnover rate. We then focused on environmental factors and found that ambient temperature and relative humidity strongly influenced the diversity of flower-visiting insects. In addition, variation partitioning analysis suggested that ambient temperature had a stronger effect on the flower-visiting insects during the early night hours, whereas relative humidity had a stronger effect on them in the later night hours. Finally, focusing on floral traits, most insects preferred flowers with moderately sized corolla diameters (20 to 30 mm). Furthermore, display size had a strong linear correlation with flower-visiting insect species richness and frequency of presence. In sum, our findings suggest that ambient temperature, relative humidity and floral display size strongly regulate the behavior of nocturnal flower-visiting insects.
Far from home: bat activity and diversity in row crop agriculture decreases with dist...
Louis Hunninck
Kjirsten Coleman

Louis Hunninck

and 3 more

September 07, 2022
As demand for food increases, agricultural production is poised to increase dramatically. Pesticides are commonly used to maintain high crop yield, though they have several drawbacks, including reduced efficacy over time and harmful effects to human and ecosystem health. Bats are highly effective predators of crop pests and have great potential to reduce crop damage resulting from insects. However, few studies have investigated how pest control by bats might change over large expanses of continuous row crop agriculture, which is common in the Midwest. Agricultural landscapes offer few roosting opportunities and could be difficult for bats to traverse, which might affect the degree of ecosystem services provided by bats. We hypothesized that with increasing distance into uninterrupted row crop agriculture 1) bat activity would decrease and 2) bat species richness would decrease, but that these effects would be buffered when insect pest abundance is high. We deployed 50 acoustic bat detectors over 10 transects in east-central Illinois from July to September 2021. In each transect, we placed detectors on crop field edges at increasing distance from a large riparian corridor assumed to be frequented by bats. Bat activity was high across the landscape but declined by 56% from the forest edge to 4000m into row crop agriculture, while bat diversity decreased by 34%. Pest abundance seemed to decrease overall bat activity but had no effect on bat diversity. These results indicate that bats, although able to have a large effect on crop pest reduction, might not be as efficient in suppressing crop pests in vast uninterrupted agricultural landscapes which offer scant roost availability. Our work will inform recommendations to landowners and private lands managers on ways to increase bat access to roosts and forest cover near agricultural areas, thereby enhancing the potential for bats to provide pest control services.
Life traits of ground beetle assemblages of spruce forests in north-eastern Poland
Mariusz Nietupski
Agnieszka Kosewska

Mariusz Nietupski

and 2 more

September 05, 2022
Assemblages of epigeic ground beetles living in spruce forests in three age ranges: 20-30 years (A); 40-50 years (B); 70-80 years (C) were submitted for research. The investigations were carried out in spruce forests in north-eastern Poland. In each age forest category, 4 plots with 5 Barber traps were set up. Ground beetle assemblages were compared in terms of their abundance, species richness, and the Shannon H’ Index value. Quantitative ecological description of carabids captured in the analysed age-classes of spruce forests was performed, and the values of the MIB (mean individual biomass) were calculated. To determine the dependencies between the values of the MIB and abundance of Carabidae trophic groups, the Spearman rank correlation coefficient was calculated. The assemblages of ground beetles living in the spruce forests in north-eastern Poland were characterised by quite large species richness. Significant differences were determined in the number of species richness between the Carabidae assemblages inhabiting the analysed age ranges of spruce forests. The oldest spruce stands had a smaller number of species and specimens of ground beetles as well as the highest MIB values in comparison with the younger spruce forests (30 to 50 years old). It was found that high MIB values were positively correlated with the presence of large ground beetle species with higher moisture requirements. Lower values of the MIB index were due to the presence of smaller, macropterous species, with the spring type of breeding and associated with open areas.
The interplay between prior selection, mild intermittent exposure, and acute severe e...
Millicent Ekwudo
Morad Malek

Millicent Ekwudo

and 3 more

March 31, 2022
Hypoxia has profound and diverse effects on aerobic organisms, disrupting oxidative phosphorylation and activating several protective pathways. Predictions have been made that exposure to mild intermittent hypoxia may be protective against more severe exposure and may extend lifespan. Both effects are likely to depend on prior selection on phenotypic and transcriptional plasticity in response to hypoxia, and may therefore show signs of local adaptation. Here we report the lifespan effects of chronic, mild, intermittent hypoxia (CMIH) and short-term survival in acute severe hypoxia (ASH) in four clones of Daphnia magna originating from either permanent or intermittent habitats, the latter regularly drying up with frequent hypoxic conditions. We show that CMIH extended the lifespan in the two clones originating from intermittent habitats but had the opposite effect in the two clones from permanent habitats, which also showed lower tolerance to ASH. Exposure to CMIH did not protect against ASH; to the contrary, Daphnia from the CMIH treatment had lower ASH tolerance than normoxic controls. Few transcripts changed their abundance in response to the CMIH treatment in any of the clones. After 12 hours of ASH treatment, the transcriptional response was more pronounced, with numerous protein-coding genes with functionality in mitochondrial and respiratory metabolism, oxygen transport, and, unexpectedly, gluconeogenesis showing up-regulation. While clones from intermittent habitats showed somewhat stronger differential expression in response to ASH than those from permanent habitats, there were no significant hypoxia-by-habitat of origin or CMIH-by-ASH interactions. GO enrichment analysis revealed a possible hypoxia tolerance role by accelerating the molting cycle and regulating neuron survival through up-regulation of cuticular proteins and neurotrophins, respectively.
Host-specific soil microbes contribute to habitat restriction of closely related oaks...
Yingtong Wu
Alicia Brown

Yingtong Wu

and 2 more

August 23, 2022
Habitat divergence among close relatives is a common theme in ecology. While recent studies have frequently found that the abundance and diversity of plant species are regulated by soil microbes, little is known whether soil microbes can also affect the habitat distributions of plants. To fill in this knowledge gap, we investigated whether interactions with soil microbes restrict habitat distributions of closely related oaks (Quercus spp.) in eastern North America. We performed a soil inoculum experiment using two pairs of sister species that show habitat divergence: Quercus alba (local species) vs. Q. michauxii (foreign), and Q. shumardii (local) vs. Q. acerifolia (foreign). To test whether host-specific soil microbes are responsible for habitat restriction, we investigated the impact of local sister live soil (containing soil microbes associated with local sister species) on the survival and growth of local and foreign species. Secondly, to test whether habitat-specific soil microbes are responsible for habitat restriction, we also examined the effect of local habitat live soil (containing soil microbes within local sister’s habitats, but not directly associated with roots of local sister species) on the seedlings of local and foreign species. We found that local sister live soil decreased the survival and biomass of foreign species’ seedlings while increased those of local species, which supports the roles of host-specific microbes in mediating habitat exclusion. In contrast, local habitat live soil did not differentially affect the survival or biomass of the local vs. foreign sister species, providing no support for the roles of habitat-specific microbes. Our study indicates that soil microbes associated with one sister species can suppress the recruitment of the other host species, contributing to habitat partitioning of the closely related oaks. Our findings emphasize that considering the complex interactions with soil microbes is essential for understanding habitat distributions of closely related plants.
Extrafloral nectar as entrée and elaiosomes as main course for ant visitors to a fire...
Byron Lamont
James Grey

Byron Lamont

and 1 more

August 20, 2022
Thousands of plant species produce both extrafloral nectaries (EFNs) on their leaves and nutrient-rich appendages on their diaspores (elaiosomes). Although their individual ecology is well-known, any possible functional link between them has been ignored. Here, we recognized their co-presence in the shrub, Adenanthos cygnorum (Proteaceae), and studied their function and interaction. We observed that ants frequently visit both structures, seeds are attractive to vertebrate granivores but are released into a leafy cup from where they are harvested by ants and taken to their nests, from which seeds, lacking elaiosomes, germinate after fire. We showed that juvenile plants do not produce EFNs and are not visited by ants. We conclude that EFNs are not just an indirect adaptation to minimize herbivory via aggressive ants (or parasitoid wasps) but specifically enhance reproductive success by inducing ants to visit the plant throughout the year, promoting discovery of the seasonally available, elaiosome-bearing seeds on the plant and transporting them to their nests, so avoiding the risk of granivory should seeds fall to the ground.
Lack of evidence for a fine scale magnetic map sense for fall migratory Eastern North...
Patrick Guerra
Adam Parlin

Patrick Guerra

and 2 more

August 12, 2022
How first-time animal migrants find specific destinations remains an intriguing ecological question. Migratory marine species use geomagnetic map cues acquired as juveniles to aide long-distance migration, but less is known for long-distance migrants in other taxa. We test the hypothesis that naïve Eastern North American fall migratory monarch butterflies (Danaus plexippus), a species that possesses a magnetic sense, locate their overwintering sites in Central Mexico using inherited geomagnetic map cues. We examined whether overwintering locations and the abundance of monarchs changed with the natural shift of Earth’s magnetic field from 2004 to 2018. We found that migratory monarchs continued to overwinter at established sites in similar abundance despite significant shifts in the geomagnetic field, which is inconsistent with monarchs using fine scale geomagnetic map cues to find overwintering sites. It is more likely that monarchs use geomagnetic cues to assess migratory direction rather than location and use other cues to locate overwintering sites.
A GRAIN DIET SUPPLEMENTED WITH INSECTS RATHER THAN FRUITS SUPPORTS A MORE ROBUST BODY...
OJODOMO SIMON
Shiiwua Manu

OJODOMO SIMON

and 3 more

August 12, 2022
1. Omnivores utilise dietary sources which differ in nutrients, hence dietary restrictions due to environmental change or habitat alteration should cause nutrient limitations; and thus, deterioration of body condition if omnivory is obligate. 2. We investigated how the body condition of the Village weaver Ploceus cucullatus (weavers), which forages predominantly on grains, responds to insects and fruits deprivation. 3. Forty wild-caught weavers held in aviaries were fed a combination of grains and fruits, or grains and insects ad libitum for eight weeks. We confirmed diet preference by recording the number of foragers on each diet option per minute for one hour and the amount of food left-over after 3 hours of foraging. Fortnightly, we assessed indices of body condition including body mass, pectoral muscle, and fat scores, Packed Cell Volume (PCV) and Haemoglobin Concentration (HBC). We modelled the number of foragers, food left-over and body condition as functions of diet, while accounting for time (weeks) and sex effects. 4. We confirmed grains as the preferred diet and found that males ate more fruits and insects than females. Weavers fed on grains and fruits lost body and pectoral muscle mass and accumulated less fat than those fed on grains and insects. This effect was sex-dependent: females deprived of insects lost more pectoral muscle mass than males of the same group and males but not females, deprived of fruits accumulated more fat reserve than those deprived of insects. PCV and HBC did not differ between diets but increased over the eight weeks. 5. Weavers are likely obligate rather than facultative omnivores, with insects as being a more nutritive supplement than fruits. We conclude that nutrient limitation arising from environmental change or habitat alteration can impair body condition and affect physiological response to environmental seasonality in other obligate omnivores like the weavers.
Allometric Equation for Biomass Estimation of Pouteria adolfi-friederici (Engl.) Baeh...
Abyot Dibaba Hundie
Teshome Soromessa

Abyot Dibaba Hundie

and 2 more

August 12, 2022
Abstract: This study was conducted in Gerba Dima Forest, South Western Ethiopia to formulate allometric equations for Pouteria adolfi-friederici. Prior to collecting data for tree allometry, the study forest was stratified into 3 forest strata based on altitudinal variation. By employing semi-destructive technique, 30 individuals were systematically selected and sampled for measuring biomass along the three forest strata. Based on the data collected, several equations were developed. Before establishing the allometric equation, scatter plots were used to see whether the relationship between independent and dependent variables was linear. Furthermore, several allometric relationships between independent and dependent variables were tested. The best-fit model developed was validated by testing the regression assumptions. AGB was regressed against the various forms of predictors (i.e., DBH, H and WD) and three allometric models showed significant performance (p < 0.05) on their F-test. Among the three allometric equations which showed significant performance, the selection of the best-fit model was conducted based on their P-value, adjusted r2, AIC, RMSE. The two models are nested to the third model and hence the complete model, lnAGB=1.806+1.419×lnDBH+0.628×lnWD, is selected as the best-fit model against the other two nested models since the p-values of coefficients of the complete model are significant (p < 0.05).
Evolutionary footprints of cold adaptation in arctic-alpine Cochlearia (Brassicaceae)...
Marcus Koch

Marcus Koch

August 22, 2022
As global warming progresses, plants may be forced to adapt to drastically changing environmental conditions. Arctic-alpine plants have been among the first to experience the effects of climate change, as regions at high latitudes and elevations are over-proportionally affected by rising temperatures. As a result, cold acclimation and freezing tolerance may become increasingly crucial for the survival of many plants as winter warming events and earlier snowmelt will cause increased exposure to occasional frost. Studying the evolution of cold adaptation allows us to make assumptions about the future responses of different species to climate change. The tribe Cochlearieae from the mustard family (Brassicaceae) offers an instructive system for studying cold adaptation in evolutionary terms, as the two sister genera Ionopsidium and Cochlearia are distributed among different ecological habitats throughout the European continent and the far north into circumarctic regions. By applying an electrolyte leakage assay to leaves, the freezing tolerance of different Ionopsidium and Cochlearia species was assessed by experimentally estimating lethal freezing temperature values (LT50 and LT100), thereby allowing for a comparison of different accessions in their responses to cold. We hypothesized that, owing to varying selection pressures, geographically distant species would differ in freezing tolerance. Despite Ionopsidium being adapted to hot and dry Mediterranean conditions and Cochlearia species preferring cold habitats, all accessions exhibited similar cold responses. Whether this phenomenon has resulted from an evolutionary adaptation of a common ancestor of the two taxa or has evolved from parallel evolution is yet to be investigated. The results presented in this study may, however, indicate that adaptations to different stressors, such as salinity and drought, may confer an additional tolerance to cold; this is because all these stressors induce osmotic challenges, as demonstrated via metabolomic analysis.
Species richness drove selection of individuals within wetlands based on traits relat...
Lucas Deschamps
Raphaël Proulx

Lucas Deschamps

and 5 more

August 09, 2022
Aim: Selection within natural communities has mainly been studied along large abiotic gradient, while the selection of individuals within population should occur locally under the play of biotic filter. To better seize the role of the latter, we postulated that the hierarchal nature of environmental selection and the multiple dimension of species trait space needed to be accounted for. Methods: We replicated a natural species richness gradient (from 2 to 16 species) within four contrasted wetlands (bog, fen, meadow, marsh), sampling functional traits from random individuals in communities. Developing a hierarchical distributional modelling, we analyzed the variation of the mean and dispersion of functional trait space at the ecosystem, community and species levels. Key results: We found that the abiotic differences between wetlands, which shaped a plant productivity gradient, selected species in regards with their leaf nutrient conservation / acquisition strategy. Within ecosystems, plant species richness was a strong driver of trait variation among both communities and species. Among communities, it shaped the selection of individuals according to their space occupation and leaf adaptations to light conditions. Demographically, some species used intraspecific trait variation to maintain equally dense populations, while others used it to become dominant in favorable conditions. Main Conclusions: Within ecosystems, variation in biotic conditions selects individuals along functional dimensions that are independent to the ones selected across ecosystems. Because intraspecific variations of light-related traits are related to demographic responses, it offers a way to link the study of species richness and eco-evolutionary dynamics.
Elevated nitrogen deposition and co-evolutionary history shape competition between an...
Wen-Gang Zhang
Xing-Jiang Song

Wen-Gang Zhang

and 8 more

August 11, 2022
During the range expansion of invasive plants, competitors shared different co-evolutionary history with invasive plants, as well as population differentiation, would have different effects on the response of invaders to global change factors such as increased nitrogen deposition. Disregard the community responses and potential adaptations of invaders during the range expansion might bring misleading answers. To address these challenges, we conducted a greenhouse experiment to explore the synergistic effects between population differentiation during range expansion and competitors on the invasion of Galinsoga quadriradiata in response to increased nitrogen deposition. Competitors (new or old that shared short or long co-evolutionary history with the invader, respectively) were set to compete with the invasive central and edge populations under different nitrogen addition treatments. Galinsoga quadriradiata from the central population (i.e., with longer residence time since invasion) showed significantly higher total mass, reproduction, interspecific competitiveness when compared to the individuals from the edge population, and the magnitude of response to nitrogen addition treatments was larger in the central population when planted in isolation (single-culture). Nitrogen addition promoted growth and reproductive performance of G. quadriradiata in single-culture, in the presence of competitors this effect was weakened. The old competitors acted more effectively than new competitors in inhibiting the invader performance, mainly for the central population. Our results indicate that population differentiation on growth and competitiveness occurred during the range expansion of G. quadriradiata, with the central population displaying higher invasiveness than the edge population. The co-evolutionary history between invasive species and its competitors has been suggested to be probably not in favor of invasive plants, especially for central populations. Our results highlight the synergistic and non-additive role of population differentiation and shared co-evolution history between invasive species and its competitors in the range expansion of invaders in the context of global change factors.
Synergistic regulation between leaf N and P on Vcmax and Jmax of species in subtropic...
Longkang Ni

Ni

July 28, 2022
A document by Longkang Ni. Click on the document to view its contents.
Assessing the importance of seed priming for seed germination in Muscari.
IMAN ROHOLLAHI
Narjes Labbaf

IMAN ROHOLLAHI

and 2 more

July 26, 2022
Muscari with absorbing color is a widespread and commercial species. As a pot and bedding bulb flower has excellent adaptability and vigorous growth in late winter and early spring. In our experiment, the quantity and uniformity of Muscari propagation by seed and the importance of seed priming will be measured. The selected M. neglectum populations which already were gathered in our previews research and M. armeniacum were evaluated under separated sulfuric acid (5, 15, and 20 min) and hot water (5, 15, and 20 min) scarification plus 15, 30, and 45 days stratification in a completely randomized design, four replications were planted in separate containers. Seeds of M. armeniacum only germinate (70%) by 15 min sulfuric acid plus 45-day stratification treatments. Based on the analysis of variance and mean comparison data that only were reported in M. neglectum, their seeds optimally germinated by 5 and 15 min sulfuric acid treatment plus 45-day stratification. In conclusion, M. neglectum seeds germination is tuned to take place well in mid-winter under natural conditions; on the other hand, 45 days of lengthy constant stratification and 5 min sulfuric acid priming will accelerate M. neglectum seeds germination.
Screening game in plant–pollinator interactions: compound screening mechanism in flow...
Qin-zheng  Hou
Nurbiye  Ehmet

Qin-zheng Hou

and 5 more

July 26, 2022
The screening mechanism is an important component of the screening game between plants and pollinators, and also as a theoretical framework for understanding the maintenance and drivers of co-evolution by animals and plants. However, no previous studies have investigated the composite screening mechanism in plants from biomechanical and morphological perspectives. Thus, we observed and measured the insects and flower traits in different populations of Delphinium caeruleum J., and compared the operative strength of staminodes with the strength that insects were capable of exerting, as well as the length of the nectar spur and proboscis in insects. The flower traits, insect species, visitor frequency, and efficiency differed among three experimental sites. The strength and proboscis length of the insect visitors matched with the operative strength of staminodes and the nectar spur length, whereas the opposite was found for non-visitors. Our results demonstrate that Delphinium caeruleum J. can screen for efficient pollinator insects through a complex mechanism based on a combination of length screening and biomechanical screening. Pollinators contribute significantly to promoting both the convergence and divergence of flower characteristics, which may be a consequence of plants adapting to local pollinators.
First record of White Eared Kob Kobus kob leucotis in Omo National Park, Ethiopia
Tsyon Asfaw
Mihert Ewenetu

Tsyon Asfaw

and 5 more

July 15, 2022
A document by Tsyon Asfaw. Click on the document to view its contents.
Shyer fish are superior swimmers in Siberian sturgeon (Acipenser baerii)
Lingli Xiang
Xiangyuan Mi

Lingli Xiang

and 11 more

July 13, 2022
Differences in individual personality are common amongst animals, which can play an ecological and evolutionary role given links to fitness. Personality affects animal life processes and outputs (e.g., behavior, life history, growth, survival, reproduction), and has become a common theme in animal behavioral ecology research. In the present study, we used Siberian Sturgeon to explore how personality traits of boldness and shyness are related to swimming performance, post exercise recovery and phenotypic morphology. Firstly, our results indicated that the Siberian sturgeon juveniles of shyness were better swimmers, validating evolutionary biology trade-off theory. The critical swimming speed (Ucrit) of the shy groups was higher than that of the bold groups. Secondly, the shy groups were more resilient after exercise fatigue. The swimming fatigue recovery ability, the glucose and lactic acid concentration recovery ability of shy groups were greater than that of bold groups. Thirdly, the shy groups were more streamlined. Compared with bold groups, shy groups had smaller caudate stalk lengths, caudate stalk heights, superior caudal lobes, and inferior caudal lobes. These research results further enrich the theoretical viewpoints of fish behavior biology, more importantly, which provided a good example for studying the relationship between sturgeon’s “personality” and swimming performance.
Local and landscape environmental heterogeneity drive ant community structure in temp...
Antonio J. Pérez Sánchez
Anett Schibalski

Antonio Pérez Sánchez

and 4 more

July 12, 2022
Environmental heterogeneity is an important driver of ecological communities. Here, we assessed the effects of local and landscape spatial environmental heterogeneity on ant community structure in temperate semi-natural upland grasslands of Central Germany. We surveyed 33 grassland sites representing a gradient in elevation and landscape composition. Local environmental heterogeneity was measured in terms of variability of temperature and moisture within and between grasslands sites. Grassland management type (pasture vs. meadows) was additionally included as a local environmental heterogeneity measure. The complexity of habitat types in the surroundings of grassland sites were used as a measure of landscape environmental heterogeneity. As descriptors of ant community structure, we considered species composition, community evenness, and functional response traits. We found that extensively grazed pastures and within-site heterogeneity in soil moisture at local scale, and a high diversity of land cover types at the landscape scale affected ant species composition by promoting nest densities. Ant community evenness was high in wetter grasslands with low within-site variability in soil moisture and surrounded by a less diverse landscape. Fourth-corner models revealed that ant community structure response to environmental heterogeneity was mediated mainly by worker size, colony size, and life history traits related with colony reproduction and foundation. We discuss how within-site local variability in soil moisture and low intensity grazing promote ant species densities, and highlight the role of habitat temperature and humidity affecting on community evenness. We hypothesize that a higher diversity of land cover types in a forest-dominated landscape buffers less favorable environmental conditions for ant species establishment and dispersal between grasslands. We conclude that spatial environmental heterogeneity at local and landscape scale plays an important role as deterministic force in filtering ant species and, along with neutral processes (e.g. stochastic colonization), in shaping ant community structure in temperate semi-natural upland grasslands.
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.
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