Leaf Consumption Research Articles

Survival and nutritional indexes of Spodoptera frugiperda (J.E. Smith, 1797) (Lepidoptera: Noctuidae) maintained in Bt maize for five generations

The selection pressure generated by the incorrect use of Bt maize might result in Spodoptera frugiperda individuals resistant to the toxins synthesized by the plant. In this study was evaluated the nutritional parameters of Spodoptera frugiperda submitted to the maize that synthesize the toxins Cry1F, Cry1A105-Cry2Ab2 and Vip3Aa20, during five subsequent generations of selection pressure. The caterpillars were submitted to the treatments: Non-Bt maize (CONV), Cry1F (Bt1), Cry1A105/Cry2Ab (Bt2) and Vip3Aa20 (VIP1, VIP2 and VIP3) and exposed for a period of four days in each cycle, for five successive generations. The larval survival of S. frugiperda was evaluated in five generations. The consumed leaf area was quantified in the second generation and the nutritional indexes in the latter ones. The results indicate that caterpillars of S. frugiperda from VIPs lineage presented the lowest percentage of survival, with a high Metabolic Cost and a considerable efficiency reduction in the conversion of the digested and ingested food. The lineage maintained in VIP2 showed the lowest leaf consumption (83.13%). However, the action of Vip3Aa20 toxin on S. frugiperda resulted in a higher Metabolic Cost in reduction of leaf area consumption. However, from the third generation on there is a survival of insects exposed to Bt toxins, suggesting the surviving potential of this species in Bt maize subjected to continuous exposure to this technology.

Development, Host Preference and Leaf Consumption of the Lime Swallow Tail Butterfly, Papilio Polytes Romulus Cramer (Papilionidae: Lepidoptera) on Citrus

Studies were conducted to know the developmental period and host preference of the lime swallow tail butterfly, Papilio polytes romulus Cramer and leaf consumption by its larvae on citrus in the laboratory. Ten Citrus host plants such as Kagoji lime-BAU-1, BAU-2, BAU-3, BAU-4, BARI kagoji, elachi lime, sweet orange, orange, jamir and Pumelo were used as study materials. Results revealed that the most preferred host of Papilio polytes romulus L. was Elachi followed by BAU-3 and Orange while the least preferred host was Pumelo. Eggs were pale yellow and spherical. The average length of newly hatched caterpillars, 2nd, 3rd, 4th and 5th instar larvae were 2.32 mm, 10.75 mm, 14.50 mm, 24.80 mm and 39.50 mm, respectively. The mean duration of 1st, 2nd, 3rd, 4th, 5th instar larvae and pre-pupa were 2.20, 2.15, 2.35, 2.25, 2.35 and 1.0 days, respectively. The average length of the pupal stage, adult male and female butterfly were 29.50, 24.00 and 25.75 mm, respectively. The mean longevity of female and male was 6.5 and 3.9 days. The percentage of leaf area consumed was increased with increasing the age of larvae. The highest percentage of leaf area was consumed by the 5th instar larva (100) followed by 4th instar (75) while the lowest percentage of leaf area was consumed by the 1st instar larva (15) in 72 hours after release.
 Asiat. Soc. Bangladesh, Sci. 45(1): 111-125, June 2019

Evaluation of Leaf Consumption and Determination of Economic Injury Level Caused by Plutella xylostella (L.) (Lepidoptera: Plutellidae) in Brassica oleracea var. acephala (Brassicales: Brassicaceae).

Plutella xylostella (L.) is a microlepidopteran found in all brassica-producing regions of the world. However, no economic injury level (EIL) has been established for this pest in collard greens. Therefore, studies evaluating the EIL of P. xylostella in this crop based on the number of caterpillars per plant can assist pest monitoring and the most effective time for pest control, ensuring profits and the use of pesticides only when required. The present study assessed leaf consumption of caterpillars at different levels of infestation and determinined the EIL for P. xylostella in collard greens. Based on the yield reduction index of collard greens for P. xylostella, EIL was estimated for different scenarios of pest control costs, setting the market value of the bunch of collard greens, and, alternatively, with prices varying and the control cost fixed. In simulated scenarios for 7 d after infestation, the number of caterpillars per plant was always below 1.38, whereas for 10 d, the maximum number was 1.25 caterpillars per plant. When simulating scenarios with different market values for the bunch of collard greens the lower the price of the collard greens bunch, the higher the mean number of caterpillars per plant to compensate the application cost. The mean number of caterpillars per plant ranged from 4.59 to 0.38 in the evaluation for 7 d, and from 4.17 to 0.35 caterpillars per plant for 10 d according to the price of the bunch of collard greens.

PENGARUH KONSUMSI DAUN KELOR (Moringa oleifera) TERHADAP VO2MAX DAN LACTATE THRESHOLD

This research aims to determine how the effect of combination of Moringa Leaf consumption with aerobic exercise against VO2Max and Lactate Threshold as ergogenic aids. 16 Taekwondo athletes are participated in this research. Participants are divided into 2 groups: the experimental group, which has been given the treatment of Moringa leaves and aerobic exercise, and the control group, which has been given an aerobic treatment only. The method used is experimental method with randomized pretest-posttest comparison group design. This research took 6 weeks length with aerobic exercise 4 days a week. Moringa leaves consumed at a dose of 2000mg during treatment. The data collection used a Balke Test to measure the VO2max and modified Conconi Test to measure the lactate threshold. The results of this research showed a significant increase in mean before and after treatment in both variables from each group (p <0.05). However, the value of the increase in both variables between the two groups did not show significant difference (p> 0.05). These results, it can be concluded that there is a significant increase of VO2Max and Lactate Threshold between pre test and post test in each group, but there is no significant difference from deviation of increase of between control and experiment group although the experimental group increase is higher than the control group.

Root‐feeding larvae increase their performance by inducing leaf volatiles that attract above‐ground conspecific adults

Abstract Herbivore‐induced changes in plant volatile emissions mediate above–below‐ground interactions by determining host plant colonization of different herbivores. By changing shoot‐emitted volatiles, below‐ground herbivores may use the plant to extend their capacity to interact with above‐ground con‐ and heterospecifics. We investigated the attractiveness of Triadica sebifera plants infested by larvae of a specialist beetle or root‐knot nematodes to above‐ground herbivores. We then determined the contribution of leaf volatiles to the observed recruitment patterns using olfactometer experiments. We also identified volatiles through gas chromatography–mass spectrometry (GC–MS) and electroantennography, and conducted field experiments to confirm their effects. Leaf volatiles induced by the root‐feeding larvae attracted above‐ground conspecific adults in laboratory and field experiments, but repelled a heterospecific specialist weevil, whereas induction by root‐knot nematodes had no effects on either. Greater leaf consumption by conspecific adults increased root nutrients, decreased root defences and facilitated root feeding larval performance. Thus, larvae and adults appear to manipulate their host plant, which increases aggregation above‐ground and feeding below‐ground. Synthesis. The resulting colonization dynamics may shape the composition of plant rhizosphere and phyllosphere herbivore communities by enhancing conspecific establishment and reducing colonization by other herbivores. By modifying above‐ground volatiles and above‐ground herbivore behaviour, root feeders could mediate plant and leaf herbivore interactions and benefit via plant responses to above‐ground feeding.

Per- and polyfluoroalkyl substances (PFASs) in the blood of two colobine monkey species from China: Occurrence and exposure pathways

Per-/polyfluoroalkyl substances (PFASs), which are widely used in industrial and commercial products, have been identified as global and ubiquitous pollutants. Despite this, limited data are available regarding the impacts of PFAS exposure and intake in non-human primates. Here, we report for the first time on the occurrence of PFASs in the blood and dietary sources of two rare and endangered primate species, namely, the golden snub-nosed monkey (Rhinopithecus roxellana) and Francois' leaf monkey (Trachypithecus francoisi). Results showed that perfluorooctanoate (PFOA) and perfluorononanoate (PFNA) were dominant and found at the highest proportions in the blood of both species at the four study sites. The ∑PFAS levels in blood samples from captive golden snub-nosed monkeys in Tongling Zoo (mean: 2.51 ng/mL) and Shanghai Wild Zoo (3.52 ng/mL) near urbanized areas were one order of magnitude higher than the levels in wild monkeys from Shennongjia Nature Reserve (0.27 ng/mL). Furthermore, significant age positive relationships for perfluorodecanoic acid (PFDA), perfluorooctane sulfonate (PFOS), and 6:2 chlorinated polyfluorinated ether sulfonates (6:2 Cl-PFESA) were observed in both golden snub-nosed monkeys at Shanghai Wild Zoo and Francois' leaf monkeys at Wuzhou Breeding Center. In addition, PFAS levels in frequently consumed food and drinking water were analyzed for Francois' leaf monkeys. Results showed that tree leaves accounted for the highest percentage of total daily intake of PFASs, especially PFOA, thus highlighting tree leaf consumption as a primary PFAS exposure route for this species. Overall, however, dietary exposure to PFASs was of relatively low risk to Francois' leaf monkey health.

Public health risks associated with Salmonella contamination of imported edible betel leaves: Analysis of results from England, 2011–2017

Fresh betel leaves (Piper betle L.), imported into the UK are a traditional ready-to-eat food consumed by Asian populations. We report here the consolidation of routinely collected data to model the public health risks from consumption of this food. Amongst 2110 samples collected at Border Inspection, wholesale, catering or retail, Salmonella was detected in 488 (23%) of samples tested between 2011 and 2017 and was the most commonly Salmonella-contaminated ready-to-eat food examined by Public Health England during this period. Using data from multiple samples (usually 5) tested per consignment sampled at Border Inspection, contamination levels were calculated by most probable number: seasonal, temporal and country specific differences were detected. Quantitative contamination data was used to estimate the levels present at retail, and a β-Poisson dose response model the probability of illness was calculated. Using data for products imported from India, the probability of acquiring infection following a single exposure (comprising of a single leaf) was estimated to be between 0.00003 (January–March) and 0.0001 (July–September). Using British Asian population data for individuals over 30 years of age in England in 2011, two estimates of consumption were modelled as 2.1 and 12.8 million servings per annum. Results from the model estimated 160 cases (range 102 to 242) and 960 cases (range 612 to 1456) per year in England for the two consumption estimates and equated to 34 (range 22 to 51) and 204 (range 130 to 310) salmonellosis cases per year reported to national surveillance. Salmonella from 475 of the contaminated samples were further characterised which showed a heterogeneous population structure with 46 S. enterica subsp. Enterica serovars, together with S. enterica subs diarizonae and salamae identified. Isolates from individual consignments were diverse and close genetic relationships between independent isolates were very rare except from within an individual consignment. There were no outbreaks detected as associated with betel leaf consumption. However analysis by whole genome sequencing of the 2014–17 data identified two cases where the clinical isolate had <5 single nucleotide polymorphism differences to isolates from betel leaves which is indicative of a likely epidemiological link and common source of contamination. Due to the diversity of the Salmonella contaminating this product, associations between salmonellosis cases and betel leaf consumption will appear sporadic and unlikely to be detected by current surveillance strategies based on outbreak detection.

Dispersal syndromes can impact ecosystem functioning in spatially structured freshwater populations.

Dispersal can strongly influence ecological and evolutionary dynamics. Besides the direct contribution of dispersal to population dynamics, dispersers often differ in their phenotypic attributes from non-dispersers, which leads to dispersal syndromes. The consequences of such dispersal syndromes have been widely explored at the population and community level; however, to date, ecosystem-level effects remain unclear. Here, we examine whether dispersing and resident individuals of two different aquatic keystone invertebrate species have different contributions to detrital processing, a key function in freshwater ecosystems. Using experimental two-patch systems, we found no difference in leaf consumption rates with dispersal status of the common native species Gammarus fossarum. In Dikerogammarus villosus, however, a Ponto-Caspian species now expanding throughout Europe, dispersers consumed leaf litter at roughly three times the rate of non-dispersers. Furthermore, this put the contribution of dispersing D. villosus to leaf litter processing on par with native G. fossarum, after adjusting for differences in organismal size. Given that leaf litter decomposition is a key function in aquatic ecosystems, and the rapid species turnover in freshwater habitats with range expansions of non-native species, this finding suggests that dispersal syndromes may have important consequences for ecosystem functioning.

Resettlement and landscape-level conservation: Corridors, human-wildlife conflict, and forest use in Central India

Since the origin of the protected area network, authorities have resettled people in the interest of wildlife conservation. However, the impacts of resettlement on wildlife corridors connecting increasingly insular protected areas and the interaction of resettlement with existing human-wildlife conflict (HWC) outside of protected areas remain unclear. Using Kanha National Park (KNP) in central India as a case study, we quantified impacts of 450 households (that were resettled from 2009 to 2013, surveyed in 2016) on non-protected forests at their new settlement locations. We measured forest use for cattle grazing, tendu leaf extraction (a commercial non-timber forest product) and consumption of forest foods. We also quantified HWC risks that resettled households face at their new settlement locations. We use published spatial analyses on designation of the corridor and risks of human wildlife conflict in conjunction with our data to assess post-resettlement impacts at the new settlement locations. Overall, most resettled households (330) have moved to existing villages that lie outside of wildlife corridors around KNP. They comprise <10% of existing populations at most of their new settlement villages. Many resettled households and their non-resettled neighbors face high HWC risks due to the spatial patterns of HWC around KNP. Controlling for assets and proximity to forest, resettled households own more cattle, are less involved in tendu trade, and consume fewer forests foods than non-resettled neighbors. Model results suggest that increasing off-farm economic opportunities would reduce pressures on forest resources for both resettled and non-resettled households. Our findings, while limited to the KNP landscape, provide approaches applicable in other human-dominated places to design resettlement strategies towards landscape-level conservation goals.

Differential resource consumption in leaf litter mixtures by native and non-native amphipods

Leaf litter processing is an essential ecosystem function in freshwater systems, since much of the carbon and nutrients moving through freshwater food webs come from the surrounding terrestrial ecosystems. Thus, it is important to understand how the species performing this function differ, especially because many native species are being replaced by non-native species in aquatic ecosystems. We used a field experiment to examine leaf consumption rates of two common shredding macroinvertebrates (the native Gammarus fossarum and the non-native Gammarus roeselii). Leaves from three species, varying in resource quality, were added both in leaf monocultures and as a three-species mixture. Biomass-adjusted daily consumption rates were similar between the two amphipod species, and each consumed nitrogen-rich alder leaves faster than oak or beech leaves. However, because adult G. roeselii are approximately twice the size of G. fossarum, this led to systematic, though nonsignificant, differences in consumption rates at the per-capita or population level. Furthermore, we found nuanced effects of decomposer identity on leaf decomposition in mixtures. Only G. roeselii showed increased consumption of the preferred resource (alder) in the mixture, while G. fossarum consumed all leaves at the same proportional rates as in monocultures. This is an important distinction, as most measures of macroinvertebrate leaf shredding are made in the laboratory with only a single leaf resource available. Our results, based on a field experiment which could control the presence of dominant macroinvertebrates while still providing natural, biologically realistic context, suggest that even functionally similar species may subtly shift ecosystem processes.

Oak genotype and phenolic compounds differently affect the performance of two insect herbivores with contrasting diet breadth.

Research on plant-herbivore interactions has long recognized that plant genetic variation plays a central role in driving insect abundance and herbivory, as well as in determining plant defense. However, how plant genes influence herbivore feeding performances, and which plant defensive traits mediate these effects, remain poorly understood. Here we investigated the feeding performances of two insect leaf chewers with contrasting diet breadth (the generalist Lymantria dispar L. and the specialist Thaumetopoea processionea L.) on different genotypes of pedunculate oak (Quercus robur L.) and tested the role of leaf phenolics. We used leaves from four clones of 30 Q. robur full-sibs grown in a common garden to estimate the performance of both herbivores in laboratory feeding trials and to quantify the concentration of constitutive chemical defences (phenolic compounds). We found that tree genetics influenced leaf consumption by T. processionea but not by L. dispar. However genetic variation among trees did not explain growth rate variation in either herbivore nor in leaf phenolics. Interestingly, all phenolic compounds displayed a positive relationship with L. dispar growth rate, and leaf consumption by both herbivores displayed a positive relationship with the concentrations of condensed tannins, suggesting that highly defended leaves could induce a compensatory feeding response. While genetic variation in oaks did not explain herbivore growth rate, we found positive genetic correlations between the two herbivores for leaf consumption and digestion. Overall, we found that oak genotype and phenolic compounds partly and independently contribute to variability in herbivore performance. We challenged the current view of plant-insect interaction and provided little support to the idea that the effect of plant genotype on associated organisms is driven by plant defences. Together, our results point to the existence of genetically determined resistance traits in oaks whose effects differ between herbivores and motivate further research on mechanisms governing oak-herbivore interactions.

Toxicity of Methanolic Seed Extract of Barringtonia asiatica L. (Kurz) (Lecythidaceae) from Different Place in Indonesia Against Spodotera litura F (Lepidoptera: Noctuidae)

One of the potential plants to be developed as insecticide is Barringtonia asiatica (Lecythidaceae). Phytochemicals of the same species plant is different in different place and time. This research was conducted to determine toxicity methanolic seed extract of Barringtonia asiatica from different field in Java i.e. Pangandaran, Sindangkerta, Bandung, Jatinangor, and Yogyakarta against Spodoptera litura. The evaluation of toxicity was carried out using feeding method. The result indicated that seed extract of B. asiatica showed value of toxicity from higher to lower were extract of B.asiatica from Pangandaran, Jatinangor, Sindangkerta, Bandung, and Yogyakarta respectively. The extract of B. asiatica showed rendement from higer to lower were extract of B.asiatica from Pangandaran (37.8%), Sindangkerta (36.1%), Yogyakarta (29.3%), Bandung (26.5%) and Jatinagor (25.8%). Methanolic seed extract of B.asiatica from Pangandaran showed the highest toxicity and rendement compared from the other place, with LC at 0.53%. In addition of toxic property, the extract of B. asiatica seed decreased of 50 leaf consumption and pupal weight and lenghtened development time of tested larvae. Keywords: Biology, extract, toxicity, B arringtonia asiatica, Spodoptera litura

Geographic patterns of plant–herbivore interactions are driven by soil fertility

Abstract Aims Geographic patterns of the intensity of plant herbivory in relation to climate factors have garnered little general support and appear to be species specific. However, plant–herbivore interactions are also driven by resource availability, such as soil nutrient content, and it remains unclear whether broad-scale variation in soil factors is reflected in herbivore consumption rates across species’ ranges. Additionally, we know little of how intraspecific variation in tissue quality associates with edaphic and climatic factors, and how this variation controls herbivore consumption. The resource availability hypothesis (RAH) predicts that plant individuals growing in low-resource environments will have lower leaf nutritional quality and more constitutive defenses, which will result in lower rates of leaf consumption. Methods We collected leaves from the old-field dominant species, Solidago altissima L., from 20 sites across 10 degrees of latitude in the Eastern USA to determine the percentage leaf area consumed by insect folivores. We obtained soil and climate data for each site, as well as plant functional and defensive traits, including specific leaf area (SLA), leaf carbon:nitrogen (C:N), and trichome density. Important Findings Although we found no significant latitudinal trend of leaf consumption rate, there was strong evidence that leaf herbivory decreased with leaf C:N and trichome density, which themselves decreased with soil N, supporting our hypothesis that the RAH applies for intraspecific variation across spatial gradients. Additionally, high precipitation seasonality and soil nitrogen predicted decreased herbivory. The results suggest that spatial variation in herbivory can be driven by factors other than herbivore communities and climatic gradients, and that bottom-up processes, where plant traits and soil fertility control leaf consumption, must be incorporated into spatial predictions of herbivory.

Leaf Consumption and Preference to Conyza sp., Conventional and Bt Soybean by Helicoverpa armigera

ABSTRACT: Helicoverpa armigera caterpillars are polyphagous and exhibit high migratory potential. Given the traits of this pest, alternative hosts located in or near the crop stand may support the survival and permanence of H. armigera in the field. The aim of this study was to investigate Conyza sp. as a food source for H. armigera caterpillars in scenarios with conventional and Bt soybean. Two experiments were conducted in biochemical oxygen demand incubators. The first assessed consumption of conventional soybean, Bt soybean and Conyza sp. leaves by 3rd and 5th instar caterpillars, with no choice given (no-choice test). The second test evaluated the food preference of 3rd instar H. armigera larvae, with two choices given (dual-choice test). Fifth instar larvae favored Conyza sp. leaves to Bt soybean, but preferred conventional soybean to both of these options. The survival of 3rd instar caterpillars did not differ statistically regardless of the plant species used as a food source. Fifth instar larvae fed Bt soybean exhibited lower survival rates when compared to Conyza sp. and conventional soybean. In dual-choice test arenas, soybean leaf consumption was superior to Conyza sp. Conventional soybean consumption was also greater when offered in conjunction with Bt soybean. Caterpillars offered Conyza sp. and Bt soybean leaves only consumed the weed species. Conyza sp. plants can serve as a food source for H. armigera larvae, which showed a preference for Conyza sp. leaves to Bt soybean.

广西弄岗黑叶猴栖息地选择与利用

PDF HTML阅读 XML下载 导出引用 引用提醒 广西弄岗黑叶猴栖息地选择与利用 DOI: 10.5846/stxb201807011444 作者: 作者单位: 广西珍稀濒危动物生态学重点实验室,广西珍稀濒危动物生态学重点实验室,广西珍稀濒危动物生态学重点实验室,广西珍稀濒危动物生态学重点实验室,广西珍稀濒危动物生态学重点实验室 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31660616，31672285）；广西自然科学基金项目（2017GXNSFAA198046；2018GXNSFAA281029）；广西研究生教育创新计划项目（XYCSZ2019078） Habitat selection and patterns of habitat use in a group of François' langurs (Trachypithecus francoisi) in Nonggang, Guangxi, China Author: Affiliation: Guangxi Key Laboratory of Rare and Endangered Animal Ecology,Guangxi Key Laboratory of Rare and Endangered Animal Ecology,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:2005年9月至2006年8月对广西弄岗国家自然保护区内一群黑叶猴进行行为观察，采用瞬时扫描法观察并收集猴群的栖息地利用数据，分析黑叶猴对喀斯特石山栖息地的选择与利用规律。结果表明，黑叶猴对不同山体部位的利用有显著性差异（χ2=43.063，df=4，P < 0.001）。黑叶猴对崖壁的利用频率最高（占总记录的36.67%±9.44%），其次是山坡（32.30%±9.57%），对山脚（14.15%±5.01%）、山顶（11.24%±8.42%）和平地（5.63%±2.92%）的利用较少。分析发现，黑叶猴对山体部位的利用没有显著的季节性差异（山顶：Z=-0.160，P=0.837；崖壁：Z=-0.320，P=0.749；山坡：Z=-0.480，P=0.631；山脚：Z=-1.601，P=0.109；平地：Z=0，P=1）。黑叶猴将崖壁作为主要的休息场所，山坡和山脚为主要的移动和觅食场所。黑叶猴对栖息地的利用受食物可获得性的影响。当食物中花的可获得性降低时，猴群增加对山脚的利用；当嫩叶可获得性降低时，猴群增加在崖壁移动的频率；当果实的可获得性升高时，猴群增加在平地觅食的频率。食物组成与黑叶猴栖息地利用也有关系。总体来看，黑叶猴对山顶的利用频率与花的觅食比例呈显著正相关；对山脚的利用频率与果实+种子的觅食比例呈显著正相关。猴群在山顶休息的频率随花和成熟叶的觅食比例的上升而上升；在山脚休息的频率随果实+种子的觅食比例的上升而上升。猴群在山坡觅食的频率随果实+种子的觅食比例的下降而上升；在山脚觅食的频率随嫩叶的觅食比例的下降而上升。另外，平均最低温度与猴群在平地觅食的频率呈负相关关系。分析表明食物的分布和数量对黑叶猴栖息地利用有重要影响，黑叶猴对栖息地的选择是在觅食利益与风险之间进行权衡的结果。 Abstract:A group of François' langurs (Trachypithecus francoisi) was studied in the Nonggang National Nature Reserve, southwest Guangxi, China, from September 2005 to August 2006. An instantaneous scan sampling method was used to collect data on patterns of habitat utilization. The aim of this study was to explore habitat selection by langurs living in a limestone forest. The results indicated that the langurs did not exploit their habitat uniformly and preferentially used particular microhabitats (χ2=43.063, df=4, P < 0.001). For example, the langurs were observed most frequently on cliffs (36.67% ±9.44% of the total record), followed by hill slopes (32.30% ±9.57%), hill bottoms (14.15% ±5.01%), flat zones (11.24% ±8.42%), and hill-tops (5.63% ±2.92%). We found no evidence of seasonal variation in patterns of habitat use (Hill-top:Z=-0.160, P=0.837; Cliff:Z=-0.320, P=0.749; Hill slope:Z=-0.480, P=0.631; Hill bottom:Z=-1.601, P=0.109; Flat zone:Z=0, P=1). However, individual microhabitats were used by the monkeys for different activities. The cliffs were frequently used as resting sites, and the hill slopes and the hill bottoms were used as both moving and feeding sites. Langur habitat use also was influenced by food availability, dietary composition, and climate. When the availability of flowers decreased, the langurs increased the time spent exploring the hill bottom. As flower consumption and mature leaf consumption increased, there was a correlated increase in the use of hilltops. In contrast, when exploiting fruits and seeds, langurs increased the time spent on hill bottoms and hill slopes. Similarly, the frequency of moving on cliffs increased in response to a decrease in the availability of young leaves. The frequency of feeding in the flat zone increased with the availability of fruits. In addition, there was a negative relationship between the average low temperature recorded during the day and the frequency that langurs fed in the flat zone. Our results indicate that the pattern of distribution and quantity of food resources acts as an important determinant of habitat use in François' langurs inhabiting limestone forests in southwest Guangxi. Patterns of habitat use in this primate species may reflect a trade-off between foraging benefits and predation risks. 参考文献 相似文献 引证文献

The distinct phenotypic signatures of dispersal and stress in an arthropod model: from physiology to life history.

Dispersing individuals are expected to encounter costs during transfer and in the novel environment, and may also have experienced stress in their natal patch. Given this, a non-random subset of the population should engage in dispersal and show divergent stress-related responses. This includes physiological shifts as expressed in the metabolome, which form a major part of responses to stress. We analyzed how metabolic profiles and life-history traits varied between dispersers and residents of the model two-spotted spider mite Tetranychus urticae, and whether and how these syndromes varied with exposure to a stressful new host plant (tomato). Regardless of the effect of host plant, we found a physiological dispersal syndrome where, relative to residents, dispersers were characterized by lower leaf consumption and a lower concentration of several amino acids, indicating a potential dispersal-foraging trade-off. As a possible consequence of this lower food intake, dispersers also laid smaller eggs. Responses to tomato were consistent with this plant being a stressor for T.urticae, including reduced fecundity and reduced feeding. Tomato-exposed mites laid larger eggs, which we interpret as a plastic response to food stress, increasing survival to maturity. Contrary to what was expected from the costs of dispersal and from previous meta-population level studies, there was no interaction between dispersal status and host plant for any of the examined traits, meaning stress impacts were equally incurred by residents and dispersers. We thus provide novel insights into the processes shaping dispersal and the feedbacks on ecological dynamics in spatially structured populations.

The Use of Baobab Leaves (Adansonia digitata L.) for Food in Africa: A Review

The Use of Baobab Leaves (Adansonia digitata) for Food in Africa: A Review. The massive long-lived African baobab (Adansonia digitata L.) is a celebrated member of a small pantropical group of trees in the Malvaceae family. Its much-loved fruit is generally considered the tree’s most important food offering, and the baobab is more widely known as a fruit and fiber tree than a vegetable tree. Recent studies indicate that baobab leaves are eaten throughout its range, most notably in West Africa, and there is now ample documentation of the tree being valued in some places chiefly for its edible leaves. This paper presents a review of the use of baobab leaves for food in Africa. It identifies the species as one of Africa’s important leafy vegetables and highlights issues related to baobab management strategies for leaf production, the distinguishing characteristics of palatable leaves, and the seasonal dimension of leaf consumption. The culinary uses of baobab leaves and their nutritiousness are discussed, as well as current efforts to cultivate young baobabs for their leaves. The use of baobab leaves for food outside of Africa is also noted, and several suggestions are offered for future studies of baobab leaf consumption in Africa.

Bioactivity of the organic extracts of Cnidoscolus urens (L.) Arthur (Euphorbiaceae) on the cabbage-caterpillar

The aim of the current study was to identify the phytochemical profile of several different fractions of the ethanolic extract taken from the cansanção-nettle leaves, as well as assess the bioactivity on Ascia monuste orseis. After gathering the plant samples, the species was identified, and the organic extracts were collected after processing was completed in the laboratory. The fractions obtained were as follows: hexane (Hex-F), chloroform (CHCl3-F), ethyl acetate (AcOEt-F) and methanolic (MeOH-F). In the context of the insect, the biological parameters evaluated included the incubation period, egg viability, length of the larval stage and mortality, pupal viability and weight, number of defective adults and leaf consumption. The extracts revealed a large percentage of anthraquinones, coumarins, anthracene derivatives, terpenes and steroids and water-soluble tannins. All the organic extracts were confirmed to exert a negative effect on the embryonic, larval, pupal and adult phases of the cabbage-caterpillar, implying that the chloroform fraction induced 100% mortality in this pierid. It was also possible to verify that all the fractions also affected the feeding behavior of the cabbage-caterpillar, decreasing the leaf consumption by the larvae during the organic extract treatments.

Waterborne and diet-related effects of inorganic and organic fungicides on the insect leaf shredder Chaetopteryx villosa (Trichoptera)

It is well-documented that fungicides can affect crustacean leaf shredders via two effect pathways, namely waterborne exposure and their diet (i.e., via dietary uptake of fungicides adsorbed to leaf material and an altered microorganism-mediated food quality). As a consequence of different life history strategies, the relevance of these effect pathways for aquatic shredders belonging to other taxonomic classes, for instance insects, remains unclear. Therefore, we investigated waterborne and diet-related effects in larvae of the caddisfly leaf shredder Chaetopteryx villosa (Insecta: Trichoptera) and compared our observations to previous reports on effects in adults of the crustacean leaf shredder Gammarus fossarum (Malacostraca: Amphipoda). We assessed acute waterborne effects of an organic fungicide mixture (OFM) and the inorganic fungicide copper (Cu) on the leaf consumption (n = 30) of the fourth-/fifth-instar larvae of C. villosa and their food choice (n = 49) when offered leaf material, which was either conditioned in presence or in absence of the respective fungicide(s). Moreover, the larval leaf consumption (n = 50) and physiological fitness (i.e., growth as well as lipid and protein content) were examined after subjecting C. villosa for 24 days towards the combination of both effect pathways at environmentally relevant concentrations. G. fossarum and C. villosa exhibited similar sensitivities and the same effect direction when exposed to the OFM (either waterborne or dietary pathways). Both shredders also showed the same effect direction when exposed to dietary Cu, while with regards to mortality and leaf consumption C. villosa was less sensitive to waterborne Cu than G. fossarum. Finally, as observed for G. fossarum, the combined exposure to OFM over 24 days negatively affected leaf consumption and the physiology (i.e., growth and lipid reserves) of C. villosa. While no combined Cu effects were observed for larval leaf consumption, contrasting to the observations for G. fossarum, the physiology of both shredders was negatively affected, despite partly differing effect sizes and directions. Our results suggest that C. villosa and G. fossarum are of comparable sensitivity towards waterborne and diet-related organic fungicide exposure, whereas the trichopteran is less sensitive to Cu-based waterborne fungicide exposure. However, when both pathways act jointly, organic and inorganic fungicides can affect the physiology of shredder species with completely different life history strategies. As caddisflies represent a subsidy for terrestrial consumers, these observations indicate that fungicide exposure might not only affect aquatic ecosystem functioning but also the flux of energy across ecosystem boundaries.

Snails prefer it sweet: A multifactorial test of the metal defence hypothesis.

Metal defence against insect herbivory in hyperaccumulator plants is well documented. However, there are contradictory results regarding protection against snails. According to the joint effects hypothesis, inorganic and organic defences cooperate in plant protection. To test this hypothesis, we explored the relationships between snail (Cantareus aspersus) feeding and multiple inorganic and organic leaf components in the Cd hyperaccumulator plant Noccaea praecox. Plants grouped by rosette size growing in nutrient solution supplemented or not with 50 μM Cd were offered to the snails. After 3 days of snail feeding, the plants and snails were analysed. In addition to Cd concentrations, we analysed leaves for nutritional factors (sugar and protein), defence-related compounds (glucosinolates, phenolics, tannins, salicylic acid and jasmonate) and essential mineral nutrients. Cadmium concentrations in the snails and in snail excrements were also analysed. Snails preferentially fed on plants grown without Cd. Medium-sized plants exposed to Cd were the least consumed. Snail excrements from this trial weighed less and had higher Cd concentrations than those from other treatments. Cadmium increased salicylate and jasmonate production. A positive relationship between jasmonate levels and the number of attacked leaves was found. Principal component analysis revealed that leaf sugar concentration was the main factor positively affecting snails' leaf consumption, while leaf Cd had a negative but weaker influence. In conclusion, leaf sugar concentration mainly governs snails' feeding preferences. High leaf Cd concentrations do not deter herbivores from attacking leaves, but they do reduce leaf consumption. Our results clearly support the joint effects hypothesis.