Seasonal and microclimatic effects on leaf beetles (Coleoptera, Chrysomelidae) in a tropical forest fragment in northeastern Mexico

Leaf beetles (Coleoptera: Chrysomelidae) constitute a family of abundant, diverse, and ecologically important herbivorous insects, due to their high specificity with host plants, a close association with vegetation and a great sensitivity to microclimatic variation (factors that are modified gradually during the rainy and dry seasons). Therefore, the effects of seasonality (rainy and dry seasons) and microclimate on the community attributes of chrysomelids were evaluated in a semideciduous tropical forest fragment of northeastern Mexico. Monthly sampling was conducted, between March 2016 and February 2017, with an entomological sweep net in 18 plots of 20 × 20 m, randomly distributed from 320 to 480 m a.s.l. Seven microclimatic variables were simultaneously recorded during each of the samplings, using a portable weather station. In total, 216 samples were collected at the end of the study, of which 2,103 specimens, six subfamilies, 46 genera, and 71 species were obtained. The subfamily Galerucinae had the highest number of specimens and species in the study area, followed by Cassidinae. Seasonality caused significant changes in the abundance and number of leaf beetle species: highest richness was recorded in the rainy season, with 60 species, while the highest diversity (lowest dominance and highest H’ index) was obtained in the dry season. Seasonal inventory completeness of leaf beetles approached (rainy season) or was higher (dry season) than 70%, while the faunistic similarity between seasons was 0.63%. The outlying mean index was significant in both seasons; of the seven microclimatic variables analyzed, only temperature, heat index, evapotranspiration and wind speed were significantly related to changes in abundance of Chrysomelidae. Association between microclimate and leaf beetles was higher in the dry season, with a difference in the value of importance of the abiotic variables. The results indicated that each species exhibited a different response pattern to the microclimate, depending on the season, which suggests that the species may exhibit modifications in their niche requirements according to abiotic conditions. However, the investigations must be replicated in other regions, in order to obtain a better characterization of the seasonal and microclimatic influence on the family Chrysomelidae.

Analysis of the suitability of rice farming land as an opportunity for determining the agricultural planting calendar in Ajibarang District, Banyumas Regency, Central Java Province

Ajibarang District is one of the areas in Banyumas Regency with a high level of productivity, but the decrease in rainfall in 2017-2019 caused Ajibarang District to have difficulty in developing their agriculture so that farmers experienced crop failure. The impact that occurs from crop failure causes the land to not be cultivated and if it is cultivated, farmers plant secondary crops. It is also greatly influenced by climate change that occurs. In fact, Ajibarang Subdistrict is included in the B2 Climate Zone with an average rainfall of 1000 - 2000 mm/year which is a climate zone business. The purpose of this study was to determine the opportunities for the rice planting that is very suitable for rice farming. In addition, the Ajibarang Sub-district is also drained by a large river, namely the Serayu River and the Tajum River which are tributaries of the river. So, it is necessary to adjust the climate to be able to determine a suitable planting calendar for agricultural calendar in Ajibarang District. Method The research used is the Forward Sampling and Backward Sampling analysis methods. So, the results of this study resulted in a rice and secondary cropping calendar with three planting seasons in one year and two dry seasons in one year.

Soil enzymatic activity under coffee cultivation with different water regimes associated to liming and intercropped brachiaria

ABSTRACT: This research evaluated the effects of coffee cultivation with two different water regimes associated or not with liming and the presence/absence of brachiaria as intercrop on the activities of the soil enzymes β-glucosidase, arylsulfatase and acid phosphatase. The study was carried out at the experimental farm of Embrapa Cerrados, using the cultivar IAC 144 (Coffea arabica L.), under a clayey dystrophic Cerrado Oxisol. Two water regimes (WR) were considered, WR1 with irrigation shifts throughout the year and WR3 with controlled water stress, for about 70 days, in the dry season. In each water regime, effects of lime application (with/without) and the presence/absence of brachiaria cultivated between the lines of coffee plants were evaluated. The activities of the enzymes β-glucosidase, arylsulfatase and acid phosphatase were evaluated during the rainy and dry seasons. Liming and intercropped brachiaria positively affected the activities of the three enzymes assessed in this study at varying degrees, depending on season and/or the WR. Our findings evidenced that intercropped brachiaria in coffee rows was the factor that most positively impacted soil enzymes activities.

The attack intensity of Paracoccus marginatus Williams & Granara de Willink (Hemiptera: Pseudococcidae) on papaya

The mealybug, Paracoccus marginatus is one of the important insect pests in papaya (Carica papaya L.). The high potential for damage caused by this pest poses a threat to the production of papaya in Indonesia. The aim of this study was to evaluate the intensity of P. marginatus attack on papaya by observing variables such as plant varieties, planting seasons and cultivation methods. The area of observation plots was about 2.000 m2. The cultivation technique applied was monoculture with a spacing of 2.5 m x 2.5 m. Thirty plots of plants were collected from each plot of plants using diagonal sampling technique. The total number of leaves and the number of leaves attacked were recorded. Damage intensity was determined based on the category: no attack (score 0), mild 1-25% (score 1), moderate 26-50% (score 2), severe 51-75% (score 3), and very severe 76-100% (score 4). The attack intensity was higher in the dry season than rainy season. The results show that attack was higher in the dry season that rainy season. The intensity of the attack was also higher in Thai varieties both in the rainy and dry seasons. More intensive pest control shall be applied in the dry season and in the introduced varieties.

Evaluation and Re-estimation of Instream Flow Considering the Water Quality and Aquatic Ecosystem of the Seomjingang River Watershed

In this study, the appropriateness of the current publicly announced and managed instream flow in the Seomjingang River watershed was evaluated based on the water quantity, water quality, and state of the aquatic ecosystem. The stream flow was evaluated based on the observed water flow rate at the Gurye-gun (Songjeong-ri) station that is the main point of the Seomjingang River flow management and located at the lowest downstream of the main stream of the Seomjingang River. Another important reason for choosing this station was that observational data from before the construction of the major dam to the present day were available. The water quality and aquatic ecosystem conditions were reviewed based on the data measured over the past 20 years, and the achievement ratio of instream flow was compared with that of stations in the other major river systems. Based on the evaluation result, the instream flow was re-estimated for the 11 important stations of the Seomjingang River and its two branches. Based on the currently permitted water use of the Seomjingang River, the amount of water required to supply for the instream flow deficit during dry seasons was predicted and presented as a reference for water management work.

Risk of Human Exposure to the Intestinal Schistosome, Schistosoma mansoni, across Seasons along the Senegal River

Background: Schistosomiasis is an emerging disease associated with changes to the environment that have increased human contact rates with disease-causing parasites, flatworms that are released from freshwater snails. For example, schistosomiasis remains a major public health problem in Northern Senegal, where prevalence in schoolchildren often reaches 90%. Aim: This study focuses on the impact of seasonality on the risk of human exposure (RHE) to Schistosoma mansoni, defined as the total number of cercariae (the free-living life stage that infects humans) shed from all Biomphalaria pfeifferi snails collected at a site using standardized methods. We focus on RHE because it is rarely quantified and a recent study demonstrated that snails stop shedding cercariae when snail densities increase and thus per capita snail resources become limited [2], suggesting that densities of snails might not be directly proportional to RHE to schistosomes. Method: We sampled four water access points in three villages every other week during the early (Dry1) and later dry seasons (Dry2) and the rainy season, quantifying the abundance of infected and non-infected snail intermediate hosts, cercariae released per infected snail, and water chemistry. We used simple and multiple linear regressions to assess how seasonality and environmental parameters affect non-infected and infected snail abundance and RHE. Results: Although RHE was found across all seasons, the abundance of infected and non-infected snail intermediate hosts and cercariae, as well as prevalence (23.71%), were all highest in the rainy season. In the rainy season, RHE was positively associated with the density of snail hosts and their periphyton food resource. Conclusion: Although previous studies have examined the influence of seasonality on snail densities, few studies have explored the effects of seasonality on cercarial densities, which is the primary source of infection to humans. Our study demonstrates that cercarial densities are greater in the rainy season than in the early or late dry seasons. Given that cercarial densities directly pose risk of infection to humans, unlike non-infected or infected snails, these finding should help to inform decision making and schistosomiasis control efforts in West Africa.

Assessing the bioconcentration of heavy metals in Nypa Palm (Nypa fruticans (Wurmb) from selected mangrove forests in Rivers State, Nigeria

The bioconcentration of Pb, Zn, Cd, Cr and Ni in tissues of Nypa palm (Nypa fruticans) was investigated during wet and dry seasons from selected mangrove forests, using the randomized complete block design. Soil and plant samples were randomly collected from plant dominated growth stations and analyzed for heavy metal content using the Perkin Elmer Analysts 200 Atomic Absorption Spectrophotometer (AAS). The results obtained showed the bio-transfer factors of heavy metals at wet season as Pb (1.08mg/kg), Zn (1.42 mg/kg), Cd (6.14 mg/kg), Cr (0.56 mg/kg) Ni (0.90 mg/kg) and dry season as Pb (0.86 mg/kg), Zn (1.15 mg/kg), Cd (5.44 mg/kg), Cr (0.66 mg/kg), Ni (1.12 mg/kg). The result further showed the bio-translocation factors of the metals at wet seasons as Pb (0.59 mg/kg), Zn (0.76 mg/kg), Cd (3.25 mg/kg), Cr (0.22 mg/kg), Ni (0.54 mg/kg) and dry season as Pb (0.64 mg/kg), Zn (1.03 mg/kg) Cd (3.07 mg/kg), Cr (0.24 mg/kg), Ni (0.61 mg/kg) respectively. Findings indicate the study plant as a hyper accumulator of Ni, Cd and Zn, and non-hyper accumulator of Cr and Pb. It is thus recommended that N. fruticans be utilized for phytoremediation of Ni, Cd and Zn in polluted mangrove ecosystem.

Impact of Aerial Humidity on Seasonal Malaria: An Ecological Study in Zambia

Background:. Seasonal outbreaks of malaria in many parts of Africa are generally associated with rainfall; in dry seasons malaria declines but does not always cease. We postulated that aerial moisture associated with transpiration of peri-domestic trees may provide conditions to sustain pockets of mosquitoes. This study was designed to investigate this probability. Methods: Using miniature loggers designed to record moisture and temperature, set in trees and vegetation around nine selected homesteads in rural Zambia, we have shown that local tree and plant transpiration affecting the home could support the mosquito where it rests during hot dry seasons. We assessed the conditions which supported resting mosquitoes by recording the malaria case incidence rate measured at nearby health centres and clinics during the dry months. The loggers were placed in trees near the homestead with permission from the householder. No personal data were collected.Results: Data were recorded daily for three contiguous dry seasons, 2017, 2018 and 2019. The results throw a light on conditions that impact the survival of malaria vectors in arid seasons particularly in African situations and suggests how Anopheles arabiensis and other species may survive the dry seasons. Periods of nocturnal aerial moisture correlated with increase in malaria case incidence rates recorded in the local health centres. Discussion: Data were recorded daily for three contiguous dry seasons, 2017, 2018 and 2019. The results throw a light on conditions that impact the survival of malaria vectors in arid seasons particularly in African situations and suggests how Anopheles arabiensis and other species may survive the dry seasons. Periods of nocturnal aerial moisture correlated with increase in malaria case incidence rates recorded in the local health centres. The data also support the idea that mosquito species exist sporadically in widespread population demes of vector species and this likely helps repopulate habitats when the rains return.

Eco-Assessment of Streams of Konya Closed River Basin (Turkey) Using Various Ecoregional Diatom Indices

Ecological assessments of freshwater ecosystems based on diatom metrics are an important issue to attain environmental sustainability. The present study aimed to evaluate differences in the diatom-stressors relationship in relatively least disturbed streams in the Konya closed river basin using multivariate analyses and to bio-assess streams by application of different ecoregional diatom indices. Cocconeis euglypta, Cymbella excisa, Cocconeis placentula, and Achnanthidium minutissimum are the most contributing species to the dissimilarity of sampling stations between rainy and dry seasons and also between altitude (A2 800-<1600 m and A3 ≥1600 m) groups. A strong (82.8%) correlation between diatom species and stressors was expressed by the first two axes of canonical correspondence analysis. Diatom species displayed distinct responses to environmental variables (electrical conductivity, Ni, Cu, B, and altitude) playing important roles on the distribution of diatom species. Diatom indices indicated different ecological statuses of stations from a bad to a high. European diatom indices except Duero Diatom Index-DDI and Trophic Diatom Index-TDI showed well responses to the eco-assessment of streams and indicated high ecological status for the least disturbed sampling stations symbolized as S16, S20, S24, S25, S27-29, S37, and 39. These results were also supported by abiotic evaluation. Among diatom indices, although TIT was more competitive in the bio-assessment of streams, it is necessary to increase its species list by determining their trophic weights in future studies. This indicates that the revision of ecoregional specific diatom metrics with the enhancement of diatom species numbers according to their ecological preferences is needed to correctly interpret the water quality.