Effects of weather conditions on selected airborne fungal spores in the southern part of the state of Enugu,Nigeria

A study of airborne fungal spore was carried out at nine locations in the southern part of the state of Enugu, Nigeria, from March 2005 to February 2006. The aim of the study was to ascertain the variations in selected fungal spore types at the sites owing to weather conditions. The variation in airborne fungal spores of 14 taxa was studied using modified Tauber pollen traps including Alternaria, Corynespora, Curvularia, Drechslera type, Endophragmiella, Botryodiplodia, Ganoderma, Gliomastrix, Nigrospora, Pithomyces, Spegazzinia, Sporidesmium, Tetraploa and Ustilago. The frequency of the spore types recorded showed considerable variation. The highest spore counts were recorded in July, June and October. The highest numbers of fungal spores were recorded during the rainy season (June–October) to early dry season (November–December). The peak of occurrence of most selected fungal spore types was July. The highest percentages of fungal spores were documented at the recording stations Mgbowo Junction, UNTH Ituku Ozalla and Oji River Express Junction. Spearman’s correlation analyses were performed for the monthly amounts of the fungal spore types and monthly meteorological factors. The numbers of Curvularia, Nigrospora and Sporidesmium was significantly correlated with relative humidity, while those of Endophragmiella, Pithomyces and Nigrospora were significantly correlated with temperature. A significant correlation was also found between the number of Nigrospora spores and light intensity and Sporidesmium spores and wind velocity. Relative humidity and temperature seem to be the most important weather conditions affecting the frequency of the selected spore types in the atmosphere.     

Termites like it hot and humid: the ability of arboreal tropical termites to mediate their nest environment against ambient conditions

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Effects of nest temperature and moisture on phenotypic traits of hatchling snakes (Tropidonophis mairii, Colubridae) from tropical Australia

Previous research on developmentally plastic responses by reptile embryos has paid relatively little attention to tropical species, or to possible interactions between the effects of thermal and hydric regimes. In the present study, eggs of keelback snakes ( Tropidonophis mairii ), from a tropical area with strong temporal and spatial variation in soil temperatures and moisture levels, were incubated. The phenotypic traits of hatchling snakes (body size, shape, muscular strength) were affected by moisture content of the incubation medium (vermiculite plus 100% vs. 50% water by mass), by mean incubation temperatures (25.7 vs. 27.9 °C) and by diel thermal variation (diel range 6.0 vs. 8.4 °C). Interactions between these factors were negligible. Cooler, more thermostable, moister conditions resulted in larger offspring, a trait under strong selection in this population. Thermal and hydric conditions covary in potential nest-sites (e.g. deeper nests are more thermostable as well as moister). This covariation may influence the evolution of reaction norms for embryogenesis. For example, if moister nests enhance offspring fitness and are cooler, then selection will favour the ability to develop in cool as well as moist conditions. Thus, the evolution of optimal incubation conditions with respect to one variable (e.g. temperature) may be driven by patterns of association with another variable (e.g. soil moisture) among natural nest-sites. Perhaps for this reason, the thermal optimum for incubation is surprisingly low in this tropical species.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 89 , 159–168.     

Effect of weather conditions on the flight activity of Nigerian blackflies (Diptera: Simuliidae)

Abstract. A vehicle-mounted net was used to make hourly catches of blackflies at 700–1000 m altitude in the River Assob valley, central Nigeria, on 20 days during the dry season. Pearson Correlation Matrix analysis of the collection data and meteorology showed that the main factors affecting flight activity of each of the four most abundant blackfly species were primarily light intensity and secondly wind velocity, whereas relative humidity was the least important factor. Right activity showed a negative linear regression against wind, with some activity occurring in wind speeds up to 15 km/h. Distance-weighted least-squares (DWLS) regressions showed little correlation of temperature with activity for Simulium hargreavesi and S.adersi , but S.squamosum and S.vorax had small peaks at 28C and 31C, respectively. DWLS regression against light intensity showed an activity peak at 6000 lux, except in Simulium adersi.     

Diapause termination in two species of tropical butterfly, Euploea core (Cramer) and Euploea sylvester (Fabricius) (Lepidoptera: Nymphalidae)

Abstract This study examined the factors used as cues for diapause termination by two Euploea species. Euploea core and E. sylvester were collected from two overwintering sites at Chillagoe, Queensland. Under tropical wet-season conditions, more butterflies terminated diapause (approximately 60%) than those kept under dry-season conditions (approximately 40%). However, 100% diapause termination occurred only when butterflies were kept under wet-season conditions and were fed with honey. For reproductive success, Euploea species need to terminate diapause rapidly to synchronise oviposition with fresh, rapid growth of their larval host plants, which often occurs after rain. The presence of rainfall, increased temperature and long days alone is not a fail-safe set of cues for this event. Our results suggest that food (as nectar), in conjunction with these combined environmental factors, provide Euploea species with a reliable signal that larval host resources are available for oviposition.     

Effects of vegetation and weather on trap catches of Glossina fuscipes fuscipes near Lake Victoria, Kenya

Glossina fuscipes fuscipes Newstead was sampled in isolated thickets and forest patches near Lake Victoria, Kenya using unbaited biconical traps, between March 1992 and June 1993. Traps set at 1 m from the forest edge caught 3.3 times as many males and 5 times as many females as those set inside or 10 m away. The corresponding figures at 1 m from the edge of thicket were about 1.43 and 1.64 times, respectively. Hourly catches of males and females were positively correlated with temperature, light intensity and host (monitor lizard) prevalence, and negatively correlated with relative humidity. Light intensity and temperature were the most important variables affecting the catches of each sex. The results are discussed in relation to control and monitoring of G. f. fuscipes using traps.     

Influence of environmental factors on daily flight activity of the filbertworm, Melissopus latiferreanus (Lepidoptera, Olethreutidae)

ABSTRACT.

• 1 Flight of Melissopus latiferreanus (Walsinghzm), the filbertworm, was influenced by a number of environmental factors including temperature, wind, and rainfall.
• 2 Few M. latiferreanus moths were trapped in light or suction traps or found in sweep nets samples when air temperatures were above 31°C or below 15°C. Moth captures were optimum when prevailing temperature was between 21 and 26°C.
• 3 Typically moth flights began at about sunset and continued throughout the night with a peak at 22.00 hours, about an hour after sunset.
• 4 Very few moths were trapped under showery and gusty conditions when wind velocity was over 16km h^?1.
• 5 More moths were captured in light traps during dark nights than on full moon nights. The pattern of captures indicated that females flew earlier than males.

     

Influence of weather conditions on hiking behavior

This study determines the major weather factors affecting hiking activity and builds a prediction model to estimate participation. An empirical assessment of hiking participation using weather factors was demonstrated for trails on Kuanyin Mountain, Taiwan. By adapting the concepts of the range of tolerance and the eclectic model, a nonlinear function was used to explain hiking participation with weather factors. Stepwise multiple-regression analysis was carried out to determine the major weather factors affecting hiking participation. The results indicate that not only did participation vary with the season but hiking behavior was affected by different weather factors in each season. The explanation rates for the seasons exceeded 90% except that for spring.     

Metapopulation dynamics in a changing climate: Increasing spatial synchrony in weather conditions drives metapopulation synchrony of a butterfly inhabiting a fragmented landscape

Habitat fragmentation and climate change are both prominent manifestations of global change, but there is little knowledge on the specific mechanisms of how climate change may modify the effects of habitat fragmentation, for example, by altering dynamics of spatially structured populations. The long‐term viability of metapopulations is dependent on independent dynamics of local populations, because it mitigates fluctuations in the size of the metapopulation as a whole. Metapopulation viability will be compromised if climate change increases spatial synchrony in weather conditions associated with population growth rates. We studied a recently reported increase in metapopulation synchrony of the Glanville fritillary butterfly (Melitaea cinxia) in the Finnish archipelago, to see if it could be explained by an increase in synchrony of weather conditions. For this, we used 23 years of butterfly survey data together with monthly weather records for the same period. We first examined the associations between population growth rates within different regions of the metapopulation and weather conditions during different life‐history stages of the butterfly. We then examined the association between the trends in the synchrony of the weather conditions and the synchrony of the butterfly metapopulation dynamics. We found that precipitation from spring to late summer are associated with the M. cinxia per capita growth rate, with early summer conditions being most important. We further found that the increase in metapopulation synchrony is paralleled by an increase in the synchrony of weather conditions. Alternative explanations for spatial synchrony, such as increased dispersal or trophic interactions with a specialist parasitoid, did not show paralleled trends and are not supported. The climate driven increase in M. cinxia metapopulation synchrony suggests that climate change can increase extinction risk of spatially structured populations living in fragmented landscapes by altering their dynamics.     

Influence of litter and weather on seedling recruitment in a mixed oak-pine woodland

The effects of regular litter removal and annual variation in temperature and precipitation on seedling recruitment of species differing in their seed size and mode of dispersal were studied in a 16-year (1984-1999) experiment in a mixed oak-pine wood in southern Poland. Litter was the most important factor in determining spatial variability in seedling recruitment, whereas differences in climatic conditions among years, especially temperature fluctuations in late winter and early spring, determined the temporal variability in seedling recruitment. Compared with control plots, significantly more new individuals of bryophytes and seedlings as well as a number of new species of vascular plants were noted in the litter-removal plots over the 16-year study. Litter strongly impeded seedling emergence of small-seeded species. The negative effect of litter on seedling recruitment of large-seeded species and the recruitment of new shoots in species growing clonally was much weaker. There was a significant positive correlation between the numbers of seedlings in the litter-removal and control plots and temperatures in January to March. In the litter-removal plots this mainly affected small-seeded species. Seedling recruitment was less consistently related to variation in precipitation. Positive relationships were found only between the number of seedlings of large-seeded species in the litter-removal plots and precipitation in July of the current year and in September of the previous year, and between the number of seedlings in the control plots and precipitation in September and November of the previous year.     

赤眼蜂在田间环境下的存活时间及其影响因子研究

目前,淹没式释放是赤眼蜂田间应用的主要方式,在这种释放方式下成虫羽化后在田间的存活时间是影响其防治效果的一个重要因素。本研究以松毛虫赤眼蜂雌成虫为材料,将赤眼蜂引入固定在桃树上的透气的塑料管中,研究了田间不同地面植被（紫花苜蓿和自然生杂草）和不同试验日期（5月31日、6月5日、7月17日、7月24日、8月24日和8月30日）温度、湿度、食物和叶片等因子对成虫存活时间的影响。结果表明：不同地面植被和不同试验日期松毛虫赤眼蜂成虫的存活时间差异显著,成虫的存活时间紫花苜蓿区明显长于自然生杂草区;5月31日和6月5日试验日期的成虫存活时间最长,7月17日和7月24日试验日期成虫的存活时间最短。成虫的存活时间与温度和湿度都呈显著负相关,但温度对成虫存活时间的影响更为显著。松毛虫赤眼蜂羽化后补充营养可以显著延长成虫的存活时间;食物充足的条件下,桃叶的存在使成虫的存活时间明显延长。结论认为,在田间环境下温度和食物是影响赤眼蜂成虫存活时间的主要因子。     

Like mother, like daughter: inheritance of nest-site location in snakes

A trait can be passed from parents to offspring even if it has no genetic basis. For example, if daughters return to reproduce at the same sites where they were hatched themselves, nest-site location is consistent within matrilineages. Most cases of natal homing (nest-site philopatry) across generations have been inferred from molecular evidence rather than directly demonstrated, and involve species with low dispersal abilities. However, some animals disperse long distances but then return to their own place of birth to reproduce, based on cues imprinted early in their own development. Our field studies on tropical natricine snakes (Tropidonophis mairii, Colubridae) show that when they are ready to nest, females return to the sites where their mothers were captured pre-nesting, and where they themselves were released as hatchlings.     

Survival of Bemisia tabaci adults under different climatic conditions

The ability of the sweet potato whitefly, Bemisia tabaci Gennad., to survive a range of environmental conditions was investigated in the laboratory. The range of temperature and humidity investigated corresponds to the normal climatic range during B. tabaci's summer migration in Israel. Adult whiteflies confined to small test cages were exposed to combinations of temperature (25, 30, 35, and 41 °C) and relative humidity (20, 50, 80, and 100%) for periods of 2, 4, or 6 h.A logistic regression model describing the four-dimensional surface defining percent survival as a function of time, temperature, and humidity was developed. Using stepwise regression to exclude non-significant terms, the linear predictor included temperature, and the products of temperature and time, and humidity and time. The model accounted for 75% of the variance. A reparameterization of the fitted regression model suggests that survival potential is conditioned by temperature conditions prevailing during the previous 10 h.Whitefly survival after 2 h exposure ranged from 90% survival at 20°C and 100% RH, to <2% survival at 41°C and 20% r.h.. No whiteflies survived more than 2 h exposure at these latter extremes of temperature and humidity. Survival rates decreased slightly after experimental whiteflies were kept in a cage with food a further 20 h at 25±2°C, 55±5% r.h. Investigations of the effects of hunger and virus infection, showed that both increased mortality.     

Influence of humidity on production of pelleted fungal inoculum

One of the practical problems in scaling-up the production of fungal inocula for environmental applications is how to provide essential humidity for fungal growth. Pelleted solid substrate was used as a fungal biomass carrier. It was coated with alginate or agar hydrogels that contained mycelial fragments of the white-rot fungi Trametes versicolor or Irpex lacteus. To follow fungal growth and formation of mycelial coat over pelleted substrate, the fluorescein-diacetate hydrolysing activity (FDA) assay and visual inspection were used. Both fungi were able to overgrow the pelleted substrate in 5–6 days, at a relative humidity (RH) of 86.3% or higher. The enrichment of alginate hydrogel with nutrients or coating of pelleted substrate with more hydrophilic agar hydrogel enabled I. lacteus to overgrow the pellets at a lower RH of 83.6%. Fungal inocula produced at lower RH possessed lower final moisture contents and had greater mechanical strength. Conditioning of T. versicolor mycelial fragments, by a 3-h incubation in fresh growth medium, enhanced fungal growth over the pelleted substrate. A mathematical model was used to simulate and to explain moisture distribution in a hydrogel-coated pellet and the formation of mycelial coat, for various conditions of fungal inocula production.     

Repeatability and heritability of reproductive traits in free-ranging snakes

The underlying genetic basis of life-history traits in free-ranging animals is critical to the effects of selection on such traits, but logistical constraints mean that such data are rarely available. Our long-term ecological studies on free-ranging oviparous snakes (keelbacks, Tropidonophis mairii (Gray, 1841), Colubridae) on an Australian floodplain provide the first such data for any tropical reptile. All size-corrected reproductive traits (egg mass, clutch size, clutch mass and post-partum maternal mass) were moderately repeatable between pairs of clutches produced by 69 female snakes after intervals of 49-1152 days, perhaps because maternal body condition was similar between clutches. Parent-offspring regression of reproductive traits of 59 pairs of mothers and daughters revealed high heritability for egg mass (h2= 0.73, SE=0.24), whereas heritability for the other three traits was low (< 0.37). The estimated heritability of egg mass may be inflated by maternal effects such as differential allocation of yolk steroids to different-sized eggs. High heritability of egg size may be maintained (rather than eroded by stabilizing selection) because selection acts on a trait (hatchling size) that is determined by the interaction between egg size and incubation substrate rather than by egg size alone. Variation in clutch size was mainly because of environmental factors (h2=0.04), indicating that one component of the trade-off between egg size and clutch size is under much tighter genetic control than the other. Thus, the phenotypic trade-off between egg size and egg number in keelback snakes occurs because each female snake must allocate a finite amount of energy into eggs of a genetically determined size.     

Effect of environment and formulation on the absorption and translocation of fenridazon in wheat (Triticum aestivum L.)

Fenridazon [potassium 1-(p-chlorophenyl)-1,4-dihydro-6-methyl-4-oxopyridazine-3-carboxylate] is a registered chemical hybridizing agent causing male floral sterility and is used for the production of hybrid wheat (Triticum aestivum L.). Foliar absorption and translocation of fenridazon to the floral primordia was decreased at 4°C compared to 24°C. At 24°C, an increase in relative humidity from 40% to 85% increased fenridazon absorption 2.5 and 1.7 times when surfactants A and B, respectively, were used. Because of the increased absorption of fenridazon with increased relative humidity, the amount of fenridazon in the floral primordia was similarly increased 2.2 and 1.5 times for surfactant A and B, respectively. Although the amount of fenridazon in the floral primordia was increased with increased relative humidity, fenridazon translocation rate was not altered by relative humidity. The effects of irradiance on fenridazon absorption were minimal, but its translocation was decreased with low irradiances.J. Paper No. 11320, Purdue Agric. Exp. Station.     

湿度对三角新小卷蛾实验种群生长的影响

在相对湿度(RH)为55%、65%、75%、85%和95%条件下,观察湿度对三角新小卷蛾Olethreutes leucaspis Meyrick各虫态生长、发育及存活的影响,组建三角新小卷蛾实验种群生命表。结果表明:在RH为55%-95%条件下,三角新小卷蛾卵、幼虫、蛹和世代的发育历期在RH为85%时最短,发育历期分别为1.67、12.46、7.67和25.42 d。高湿条件下卵、幼虫和蛹的存活率较高。三角新小卷蛾各虫态发育历期、存活率与相对湿度呈抛物线关系。在RH为55%-95%条件下该虫内禀增长力(rm)均大于0,种群趋势指数(I)均大于1,该虫种群呈增长趋势。三角新小卷蛾发育适宜的RH为75%。     

1982-2020年东北森林带植被绿度时空变化特征

植被绿度变化（绿化或褐化）的时空格局研究有助于了解生态系统结构和功能的变化,制定适应气候变化的生态系统管理政策。在全球气候变化加剧的背景下,过去40a间东北森林带植被绿度如何变化仍不清楚。基于气象再分析数据分析了1982-2020年来东北森林带的气候变化趋势,以叶面积指数（LAI）作为植被绿度的衡量指标分析了东北森林带中大兴安岭、小兴安岭和长白山脉植被绿度的时空变化格局和影响因素。研究发现：1982-2020年东北森林带气候趋势呈现"暖干化"特征。研究区植被绿度总体呈绿化趋势,但2000年后植被绿度变化呈降低趋势的区域增加了7.23倍,主要位于大兴安岭西北部。影响因素分析表明,1982-2000年温度和土壤水分是植被绿度增加的主要驱动因素;而2000年之后,区域内植被绿化的主要驱动因素为土壤水分的增加,降雨和相对湿度降低引起的水分胁迫导致大兴安岭西北部植被褐化加剧。研究结果为揭示东北森林带固碳能力变化、制定适应气候变化的林业管理对策提供了科学参考。