Cooler Hours Research Articles

Foraging strategies of the workers of Odontotermes horni on various organic matter

The study focused on how worker termites of O. horni forage for different food sources. They were found to forage under earthen sheetings of various shapes and sizes, depending on the foraging site and season. Active foraging was observed during cooler hours of the day. This species is efficient in harvesting food without wasting energy while transporting either food or soil particles on the tree trunk.

Developing Early Morning Flowering Version of Rice Variety CO 51 to Mitigate the Heat-Induced Yield Loss

By 2050, the rice production needs to be increased by at least 50% in order to meet the growing food demands of the global population. Among various yield limiting factors, high temperature is fast becoming a major threat to sustain rice yields due to its increased frequency of occurrence and severity of stress events. The development of heat-resilient rice cultivars has been slow due to the lack of relevant donors for heat tolerance traits and limited information regarding the genetic basis of these component traits. The early morning flowering (EMF) trait, contributing to heat escape by promoting flowering/anthesis during cooler hours in the morning is demonstrated to offer protection against high-temperature-induced failure of pollination and fertilization. In this study, evaluation of CO 51, IR64 and IR64-qEMF3 (NIL of IR64 harboring QTL promoting EMF revealed that qEMF3 promoted early morning flowering in IR64-qEMF3 (1½ to 2 h earlier than IR64) and thereby reduced the sterility by about 8.15%. Attempts through marker-assisted backcross breeding led to development of advanced backcross progenies (NILs) of CO 51, harboring qEMF3. Evaluation of 88 BC3F2 progenies identified 19 progenies harboring qEMF3 under homozygous conditions. Evaluation of NILs of CO 51 harboring qEMF3 during summer 2019 revealed that the NILs exhibited early (7.30 a.m.) onset of anthesis by 1½ h and completed its peak anthesis well around cooler hours (9.30 a.m.) of the day and thereby recorded reduced spikelet sterility (7.8–9.0%) than their recurrent parent CO 51 (19.2%). The current study clearly demonstrated the efficacy of early morning flowering in the mitigation of yield losses under high-temperature conditions in a farmer preferred rice variety.

Bio-cultural fire regions of Guinea-Bissau: Analysis combining social research and satellite remote sensing

Ever since colonial times, the rural inhabitants of Guinea-Bissau have been blamed for lighting uncontrolled fires all over the country. Based on in-depth ethnographic research in two regions, a country-level rapid rural appraisal, and analysis of satellite active fire data, this essay shows how burning practices are, however, diversified according to cultural, socio-economic, demographic and agro-ecological conditions, and how they have been changing recently as a locally-developed adaptation to new farming systems. Many new bush-fire uses correspond to current best practices (e.g., use of firebreaks, backfiring, burning at cooler hours of the day), but under a scenario of changing climate and land uses there is room for improving fire management to reduce negative environmental impacts, while preserving cultural, economic and biodiversity benefits generated by some traditional burning practices. The design of public policies for reducing material damages, biodiversity loss, and carbon emissions from fires requires an understanding of their local drivers. Following from that, the development of ecological management practices must engage with farmers’ knowledge and networks/institutions and meet their priorities and needs.

High night‐time temperature during flowering and pod filling affects flower opening, yield and seed fatty acid composition in canola

AbstractWinter canola (Brassica napus L.) is highly sensitive to increasing temperatures during the reproductive and pod‐filling stages. Although the impact of high day‐time temperature stress on yield and quality has been documented in canola, similar information under high night‐time temperature (HNT) stress is not available. Using six hybrids and four open‐pollinated cultivars, we observed a marked shift in peak flowering towards earlier, cooler hours of the morning under HNT. Averaged across two independent experiments, the photochemical efficiency of photosystem II was significantly decreased (3%), with a significant increase in thylakoid membrane damage (13%) in the leaves of susceptible cultivars under HNT stress. Similarly, the susceptible cultivars also recorded significant reduction in biomass (34%), pod number (22%), pod weight (37%) and total seed weight (40%) per plant while the same set of agronomic traits were not affected among the tolerant cultivars. Quantitative impact of heat stress was confirmed with increased sensitivity to HNT exposure from gametogenesis until maturity resulting in a significantly higher yield loss compared to stress exposure from post‐flowering till maturity. HNT significantly decreased oil concentration, but increased protein concentration and saturated fatty acid levels in seeds of the susceptible cultivars. However, HNT had no impact on the unsaturated fatty acids in both hybrids and the open‐pollinated cultivars. Breeding targets based on fatty acid composition for enhancing canola seed quality may not be easily amenable due to the inconsistency documented with the compositional changes under heat stress. In summary, our findings conclude that canola hybrids are better suited to regions experiencing heat stress, compared to open‐pollinated cultivars, indicating the possibility of a complete shift to hybrid canola cultivation under predicted hotter climates in the future.

Heat stress during flowering in cereals - effects and adaptation strategies.

Heat stress during flowering has differential impact on male and female reproductive organ viability leading to yield losses in field crops. Unlike flooded rice, dryland cereals such as sorghum, pearl millet and wheat have optimised their flower opening during cooler early morning or late evening hours to lower heat stress damage during flowering. Although previous studies have concluded that pollen viability determines seed set under heat stress, recent findings have revealed pearl millet and sorghum pistils to be equally sensitive to heat stress. Integrating flower opening time during cooler hours with increased pollen and pistil viability will overcome heat stress-induced damage during flowering under current and future hotter climatic conditions.

Left out in the cold: temperature-dependence of defense in an African ant-plant mutualism.

Many tropical plants are defended by ants, and the costs and benefits of these mutualisms can vary across gradients of herbivory, soil fertility, latitude, and other environmental factors. Yet despite an abundant literature documenting thermal constraints on ant activity and behavior, we know little about whether temperature variation can influence the benefits conferred by ants to plants. We evaluated the effects of dawn-to-dusk fluctuations in temperature on patrolling and aggressive behavior in four arboreal ant mutualists of Acacia drepanolobium trees in central Kenya. We found that ant aggressive behavior significantly increased with branch surface temperature, primarily in the two most aggressive ant species: Crematogaster mimosae and C.nigriceps workers attacked a simulated herbivore at higher rates as surface temperature rose. In a browsing experiment, we found that goats browsed more frequently and for longer durations on C.mimosae-defended trees during cooler times of day, while goat browsing on plants from which ants had been removed was not affected by temperature. Our study demonstrates temperature-dependence in the efficacy of ant defense against herbivory and suggests that these ant-plants may be more vulnerable to herbivory during cooler hours of the day, when many native browsers are most active.

Effect of I/M Se and Vit E administration combined with cooler hours feeding regime on milk production in buffaloes in hot–humid climate of Bundelkhand region.

A farm experiment was carried out to assess the effect of vitamin E and selenium I/M injection on performance of buffaloes during heat stress period in Tikamgarh district of Bundelkhand Agroclimatic zone. A total of 24 animals (80±10 days postpartum and 650±25 kg body weight) were randomly divided in to 3 treatments with 8 buffaloes in each group in a completely randomized design and received a balance feed as per BIS 1992 (Type-II). T2 group was injected with 10 ml from a solution of vitamin E and selenium after interval of 10 days and T3 group was injected I/M with 10 ml from solution of vitamin E and selenium after interval of 15 days. Dry matter intake and milk yield and milk composition in T2 and T3 was observed to be higher (P>0.05) than control group. The respiration rate and pulse rate were observed to be significantly higher (P>0.05) in T1 group than T2 and T3, rectal temperature was also significantly higher in T1 (P>0.05). Thermal heat index was also calculated and reported in this study.

Heat Stress during Flowering Affects Time of Day of Flowering, Seed Set, and Grain Quality in Spring Wheat

ABSTRACTFlowering in wheat (Triticum aestivum L.) is highly sensitive to heat stress. Eleven spring wheat genotypes were exposed to heat stress (34/16°C, day/night temperature) during flowering to investigate the impact on time of day of flowering, seed set, grain yield, and quality under controlled environment chambers. In general, all 11 wheat genotypes recorded peak flowering during cooler hours of the day (i.e. either early in the morning or late in the evening). The trend was more pronounced under heat stress, providing first evidence of an alternative mechanism (i.e. heat escape in wheat minimizing damage during flowering). On average, significant reduction in net CO2 assimilation (17%), starch (25%), and protein content in grain (21%), seed set (7–19%), kernel weight (11–15%), and grain yield (22–38%), but with 17% increase in flag leaves proline concentration, was recorded under heat stress over control. The negative impact of heat stress on seed set was greater among the primary spikes than for the main spike. This differential impact is mainly attributed to limited plasticity of early reproductive processes such as gametogenesis to escape heat stress, unlike heat escape phenomena observed at flowering. KSG1203 and KSG41 exhibited heat escape strategy, whereas KSG1194 emerged as a true heat‐tolerant line. Systematic characterization of time of day of flowering to introduce the heat escape trait and developing heat tolerance strategies for early reproductive stages in ongoing wheat breeding programs is an ideal strategy to minimize heat stress damage.

Sheep’s intake behavior on different structures grass

Sheep are gregarious animals and spend time with food intake inserted with one or more periods of rumination or leisure. The peaks of grazing and ruminating usually happen in the cooler hours of the day, keeping in idle at times of higher temperatures. These animals modify one or more components of their ingestive behavior seeking to overcome limiting conditions for their consumption and get the necessary amounts of nutrients for the maintenance and production. Thus, this review has as an objective to discuss these items that affect the sheep’s intake behavior at pasture. The feeding behavior study cooperates in solving problems related to the decrease in consumption in critical times for milk or meat, through of management practices, installation design and supply diet with quantity and quality.

The onchocerciasis chronicle: from the beginning to the end?

The year 2012 marks the 25th anniversary of the donation of ivermectin to fight onchocerciasis and the projected date for elimination of transmission of the disease in the Americas. This review looks at the history of onchocerciasis, from its discovery through to 2025, by which time it is projected that the disease will have been eliminated as a public health problem, except in a handful of sub-Saharan countries, where it should be well on the way towards elimination.

Sun safety: what are the health messages?

Solar ultraviolet radiation (UVR) is a human carcinogen. The UK and the worldwide incidence of cutaneous (skin) melanoma are rising. It is now the second most common cancer in 15-34 year-olds in the UK, increasing by 49% in 1991-2000. The UK government prioritized skin cancer in 1992 in their public health strategy The Health of the Nation, and set the target for reducing the yearly rise in skin cancer incidence by 2005. In 1998 in the Saving Lives: Our Healthier Nation strategy, targets were set to reduce the death rate from cancer, including skin cancer, by 20% by 2010. As a consequence of these targets, since the mid-1990s public health campaigns to reduce sun exposure and skin cancer incidence in the UK have used specific interventions for at-risk groups and the mass media to reach the general population. Evidence indicates a shift in knowledge, with further work required to increase change in behaviour and attitudes. An associate health problem is vitamin D deficiency, which is prevalent across certain UK population groups. The main childhood health problem associated with vitamin D deficiency is the development of rickets, with evidence indicating those at high risk are exclusively breastfed dark-skinned infants, the elderly, those with dark skin pigmentation, and certain cultural groups that cover their bodies in clothing. Adolescents are the group with the highest incidence of low vitamin D status in the UK, with children of Asian descent at higher risk than Caucasian children. Increasing the outdoor activity levels of children in winter and during the cooler hours in summer is one way of increasing safe sun exposure. It is imperative to educate the general public on the risk of vitamin D deficiency, and offer advice on safe sun exposure, dietary sources of vitamin D, and dietary supplements. More research is required on recommendations for daily vitamin D supplements to determine optimal vitamin D levels in different population groups. There also needs to be reliable and accessible evidence on the links between vitamin D deficiency and lack of sun exposure, with sun safe messages adjusted accordingly.

COMPORTAMENTO DE BUBALINOS A PASTO FRENTE A DISPONIBILIDADE DE SOMBRA E ÁGUA PARA IMERSÃO

Water buffaloes are particularly intolerant to direct solar radiation. During the warm periods of the day, the animals tend to search for mud or water puddles to refresh themselves, and they usually graze only during the cooler hours. This trial, proposes to study possible handling solutions for buffalo producers using the behavioral responses. 10 female buffaloes aging 24 months were observed for 3 days (from 06:00 to 18:00 h) in each of the handling systems:with natural and artificial shade (S); with artificial shade and pond (SA); with pond (A). The animals were observed in their location (under sun, under shadow, in water), attitude (standing, laying) and activity (grazing, ruminating, etc.). The animals spent more than 60% of the time in the sun (S:63,9%, SA: 64,5%, A: 71,9%), mostly ruminating. In the shade or in the pond, the main behaviors were rumination and inactivity. The use of the pond was remarkably preferential (SA: 237,7 minutes, A: 205,1 minutes). The results revealed a demand for any protection device against solar radiation for buffaloes on hot days, and, whenever available; water for immersion must be a priority. KEY-WORDS: Ethology, grazing, water buffaloes, welfare.

Competition trade‐offs in the organisation of a Mediterranean ant assemblage

Abstract 1. The organisation of an ant assemblage inhabiting an olive orchard in central Italy was analysed and patterns of dominance among ant species were described in order to assess (i) the relationship between thermal dependency and degree of behavioural dominance, and (ii) the relationship between dominance and discovery ability.2. Activity patterns of the most abundant species on trees were examined in a sample of 120 trees during spring and summer. The degree of behavioural dominance and the ability of different species to discover new food sources were assessed using tuna baiting on a subset of 80 trees.3. Different ant species showed contrasting patterns of activity. Some species (such as Lasius lasioides, Camponotus lateralis, and Camponotus piceus) were most active during the warmer part of the day, while others restricted their activity to the cooler hours (Camponotus aethiops and Plagiolepis pygmaea). Some species (such as Crematogaster scutellaris) were active irrespective of the time of day.4. No clear relationship was observed between temperature of maximal activity and degree of behavioural dominance. There was, however, a positive relationship between behavioural dominance and thermal range of activity. A positive relationship between dominance and ability to find resources, with the most behaviourally dominant and aggressive species being most efficient in finding food items, was also observed.5. The results support the idea that the temperature–dominance relationship is much more complex in Mediterranean‐type habitats than in other ecosystems. Of particular interest is the positive dominance–discovery relationship. This finding contrasts with previous investigations, which reported a negative relationship between dominance and discovery ability and suggested that this pattern plays a role in promoting the coexistence of species in ant communities.

Effects of solar radiation, dietary energy, and time of feeding on thermoregulatory responses and energy balance in cattle in a hot environment.

Ten growing heifers were either exposed to or protected from solar radiation, offered a diet of either high (H) or low (L) ME, and fed either in the morning or afternoon during a hot summer. Heifers that consumed the H diet had a greater water intake, DMI, metabolizable energy intake, energy expenditure, and retained energy than heifers that consumed the L diet. Solar radiation did not have an effect on any of these variables. Furthermore, dietary energy and time of measurement had an effect on rectal temperature (Tr), respiration rate (RR), heart rate (HR), and rate of oxygen uptake (VO2); solar radiation had an effect on Tr and RR but not on HR and VO2; and time of feeding had an effect only on VO2. Heifers coped with greater heat loads by increasing RR and the difference in Tr between morning and afternoon. It seems that a lowered body temperature in the morning is a physiological mechanism used by animals to prepare for the heat load that develops during the day. Heat production (HP) and HR throughout the day were affected mainly by the time of feeding and not by the environmental heat load. Feeding in the afternoon increased HP in the cooler hours of the day when heat losses from the animal through conduction and radiation were more efficient. With a pending high heat load situation, reducing feed quality and(or) changing the time of feeding to the late afternoon could be beneficial to the animals in reducing their heat loads.

Effect of morning vs evening feeding of limit-fed Holsteins during summer months (1994)

Thirty-eight Holstein steers (avg 339 lb) were grouped into four weight blocks, with two pens per block. Within each block, cattle in one pen were fed at 8:00 a.m. and those in the other at 8:00 p.m. All cattle were limit-fed to achieve a programmed rat e of gain of 2.2 lbs/d using NRC net energy equations. The trial lasted from July 13 through September 6, 1993. With the same quantity of feed, cattle fed in the evening gained 18% faster than cattle fed in the morning (P<.02) resulting in better feed efficiency for the evening-fed cattle (P<.06). Average high temperature for the 56-day period was 88F, average low temperature was 69 ÌŠF, average relative humidity was 73%, and average wind speed was 1.8 mph. Feed tended to be consumed within a 3-hour period, regardless of time of feeding. Because the effective ambient temperature frequently rose above the upper critical temperature for cattle (77 ÌŠF), animals needed to expend energy to dissipate excess heat. These results indicate that cattle limit-fed during the summer may utilize metabolizable energy more efficiently if allowed to ferment the bulk of their feed during the cooler hours of the evening.

Water and Energy Limitations on Flight Duration in Small Migrating Birds

-We examined the physiological limitations to flight duration in small migrating birds with a computer-simulation model. Given preflight body mass, fat and water contents, and flight-path meteorological data, we calculated water and energy budgets and possible flight time. The model can be applied to birds of any size that migrate by flapping flight. As an example, we simulated the flight of small Palearctic passerines (body mass = 10 g) during their annual migration over the Sahara desert. Sensitivity analysis of model input variables indicated that oxygen extraction and expired air temperature are the most important physiological variables in a bird's water budget and can profoundly influence flight duration. This manifests the importance of: (1) efficient cooling in the nasal passages of flying birds; and (2) the choice of flight altitude (which affects both ambient air temperature and expired air temperature). The model predicted that: (1) Prior to migration, these birds must have stored fat comprising at least 22% of their initial body mass; otherwise, they cannot complete their journey. (2) In relatively fat birds (stored fat > 0.22 body mass), dehydration rather than energy will limit flight duration. (3) Birds should fly at an altitude not exceeding 1,000 m to cross the Sahara successfully. (4) Even in low-flying fat birds, flight duration will be limited by their stringent water budget. The model further predicted that small passerines cannot cross the Sahara in a 30to 40-h nonstop flight, as commonly accepted, but should confine flying to the cooler hours (i.e. nights) and rest during the day in order to avoid elevated rates of water loss due to higher ambient air temperatures. Available data and observations of birds trapped at stopover sites in the Sahara support these predictions. Received 26 February 1991, accepted 13 January 1992. LONG-DISTANCE flight over seas or deserts is perhaps the most risky and physiologically challenging event in the life cycle of migratory birds (Moreau 1961, Wilson 1981). Reports of high attrition among migrants and of exhausted birds found severely dehydrated and/or fat depleted (Serle 1956, Odum et al. 1964, Rogers and Odum 1964, Johnston 1968, Wilson 1981) raised the question: Is water or energy the greater physiological limitation to bird flight duration? Energy, rather than water, is currently considered the major factor limiting bird flight duration because dehydration can be avoided by flying at high altitudes where air temperatures are low (Blem 1976, Torre-Bueno 1978, Skadhauge 1981, Dawson 1982, Biesel and Nachtigall 1987, Biebach 1990). However, this paradigm has not been substatiated with empirical field

Insecticidal Control Trials Against the Oriental Fruitfly, Dacus dorsalis Hendel on Mango in Tamil Nadu

Among the various insects affecting mango, the oriental fruitfly, Dacus dorsalis H., is a serious pest. The fly makes a dark puncture during oviposition and the maggots that hatch out from the eggs feed on the pulp of the fruit for a few days and thus cause a brown rotten patch on the fruit surface. The fruits eventually fall and the maggots come out of the fruits to pupate in the soil. Their attack not only reduces the yield but also affects the quality of fruits. Ayyar (1940) recommended plant sanitation in orchards by destruction of fallen and badly infested fruits as the most important measure against the fruitfly. Giang et al (1956) reported that DDVP is very effective against the pest in Hawaii and its residues virtually disappear in 72 hours. Narayanan and Batra (1960) advocated spraying of diesel oil emulsion (diesel oil one gallon plus soft soap one pound plus water one gallon, diluted eight times) during the night and cooler hours of the morning when the flies congregate in large numbers. Field trials were undertaken at the Model Orchard cum Nursery, Thimmapuram and the Fruit Research Station, Kanyakumari on Neelum and Bangalora varieties during 1964-67 with a view to evaluate the efficacy of modern synthetic insecticides in controlling the pest and the results are presented in this paper.

Studies on miliaria rubra.

During the season of May through August in this part of the country (San Antonio, Texas), high temperatures and humidities combine to predispose the population to miliaria. Through the medium of universal air conditioning and acclimatization, the civilian population exercises involuntary control of this condition; however, no such control measures are available or desirable at Lackland Air Force Base, the sole basic training center for airmen in the United States Air Force. Young American men from all walks of life and all geographical regions of the U.S. come to this base for indoctrination and training in the U.S. Air Force. During the summer months, heat acclimatization becomes a major problem for many of them. To some extent this is alleviated by scheduling heavy labor periods during cooler hours of the day, adjusting the workload to fit high temperatures and high humidity periods, and conducting an active educational program in the

Growth of Chickens Fed Only During the Cooler Part of the Day

THE data of Heywang (1944) show that the growth of young chickens is stimulated to some extent during hot weather when they receive artificial light either all night or from midnight to daylight, thus permitting them to eat during the cooler hours of the day. Because of this finding, it seemed probable that young chickens would grow much faster during hot weather if they were allowed to eat during only the cooler hours instead of only during the daytime hours (the usual method).In order to obtain information on this point, a series of experiments was conducted at the Southwest Poultry Experiment Station, Glendale, Arizona. This station is located in a region with a subtropical, semiarid climate, where summer temperatures are high, but where the nights are much cooler than the days. The data obtained in these experiments on the weight, feed consumption, and efficiency of feed utilization of the .