Water loss from Jackass Penguin Spheniscus demersus eggs during natural incubation

The water budget of incubating Jackass Penguin eggs was studied on Marcus Island, South Africa, and complementary measurements were made in the laboratory. The mean ambient temperature was 16-5 "C and the mean humidity was 12-4 Torr (89% relative humidity). The temperature of incubated live and water-filled eggs ranged between 14^oCand 37 ^oC. The mean calculated egg temperature was 34-9' C. The mean brood patch temperature was 37-1 ^oC, slightly lower than the cloacal temperature (37.8 ^oC). The mean brood patch area was about 38 cm². The rate of water loss was 411 mg day^-1. The total diffusive water loss during 37 days of incubation was, as predicted, 15-2% of the initial 100-3 g egg mass. The total pore number was 6245 per egg and the shell thickness was 577 fira. It is suggested that the eggshell parameters, incubation length and nesting behaviour are compensated in such a way that an egg-to-nest water vapour pressure difference lower than commonly found is sufficient to bring about the normal total water loss.     

The activation of resting tsetse flies (Glossina) in response to visual and olfactory stimuli in the field

ABSTRACT Studies were conducted in Zimbabwe of the responses of Glossina morsitans morsitans Westwood and Glossina pallidipes Austen resting in a refuge to various host stimuli. Tsetse took off in response to 100% ox odour, 0.08% carbon dioxide or a visual stimulus consisting of a 0.75 × 0.75 m black target placed c . 5 m from the refuge moving at 4^o s^-1, but the level of response was low with only 35%, 19% and 29% responding, respectively. Tsetse did not take off in response to any one of 25% ox odour, 0.8% carbon dioxide, acetone (3 μg 1^-1) or octenol (0.03 μg 1^-1). In the absence of any host stimuli, flies emerged from the refuge later on hotter days (35–37^oC) than on cooler days (32–34.5^oC). Male G.pallidipes emerging later in the afternoon contained significantly more haematin than those emerging relatively earlier. There were no significant differences between the responses of G.m. morsitans and G.pallidipes. It is suggested that the initial activation of resting flies is primarily mediated through endogenous, rather than host, stimuli.     

Direct and indirect effects of light on stomata. I. In Scots pine and Sitka spruce

Abstract. The response of stomatal conductance to broadband blue and red light was measured in whole shoots of Scots pine and Sitka spruce, two species which have low stomatal sensitivity to CO². In Scots pine, blue light was more than three times more effective than red light (on an incident quantum basis) in opening stomata, particularly at low quantum flux densities (<100μmiol m⁻² s⁻¹). However, the apparent quantum yield of net CO² assimilation rate in blue light was only half that in red light. The contrasting effects of red and blue light on conductance and assimilation led to higher intercellular CO² concentrations (C_i) in blue light (up to 100 μmol mol⁻¹ higher) than in red light. Similar results were obtained with Sitka spruce shoots, though differences in the effectiveness of red and blue light were less marked. In both species, both red and blue light increased conductance in normal and CO²-free air, indicating that neither red nor blue light exert effects through changes in C_i or mesophyll assimilation. However, decreases in C_i caused increases in conductance in both red and blue light, suggesting that these direct effects of light are not wholly independent of CO².     

Development rates of some pre-adult stages in blowflies with reference to low temperatures

Abstract. Duration of some pre-adult stages of Calliphora vicina Robineau-Desvoidy, C.alpina Zett., C.vomitoria Linn., Phormia terraenovae R.-D. and Lucilia sericata Meig. were determined at 3.5–26^oC, in the context of use of these insects in forensic estimates of post-mortem intervals. Egg development in C. vicina occurs down to at least 3.5^oC, larval growth to 4^oC and puparial formation, development and perfect adult emergence to 5^oC. Growth curves by successive weighing of individual larvae showed specific differences in rates of development of the above species at constant temperatures. Alternating temperatures for 12 h periods (such as 10^oC and 20^oC) to simulate diurnal changes, usually, but not at all temperature pairs tested, caused acceleration of growth relative to the corresponding constant temperature (15^oC in the above case), in C.vomitoria, P.terraenovae and L.sericata , but usually caused retardation of larval growth in C.vicina. In this species, larvae as single individuals on beef liver in small tubes grew on average at the same rates as those (50–100 larvae) growing communally. All species showed variation in larval growth between individuals, more marked in C.vicina , and slower-growing larvae showed increased unexplained mortality. Because of this and to avoid complication by fast-growing larvae from later laid egg batches on a carcass, growth curves given are those of mean weights of the heaviest 25% (upper quartile) of groups of 40–90 feeding larvae. Variation in growth rates, and acceleration or retardation of growth in different species under alternating temperatures, thus affect suggested procedures in obtaining estimates of post-mortem intervals using these insects.     

Studies on the survival and transmission of Xanthomonas manihotis on cassava seed

Cassava seed which had been stored at 5 ^oC and 60% r.h. for 2–51 months was assayed for the presence of Xanthomonas manihotis by a leaf-infiltration technique, using as inoculum the supernatant from seeds soaked in sterile water at 30 ^oC for 2–4 h. The threshold of sensitivity of the assay method was 10⁵ cells/ml. Twenty out of 50 samples yielded the pathogen. The infested seed had been in storage for 2–18 months. Bacteria reisolated from infiltrated leaves were identical to X. manihotis in cultural characteristics, phage type and pathogenicity. Surface sterilisation or hot air treatment for 24 h at 65^oC or lower did not eliminate the pathogen from infested seed. Soaking of infested seed in hot water at 60 ^oC for 20 min reduced the number of bacteria to less than the minimum detectable level without appreciably reducing germination. Cassava bacterial blight was observed in 8-wk-old seedlings which had been planted during the dry season at a site where infection from outside sources was unlikely. It is postulated that a low percentage of successful seed transmissions of X. manihotis can occur under favourable environmental conditions.     

The influence of environmental parameters on the bacterial populations of thermal springs in West Bengal, India

The physico-chemical characteristics and the bacterial populations of three thermal springs in West Bengal have been examined. The springs range in temperature from 42^o C (Saubhagya Kund) to 65^o C (Agni Kur.d). The levels of carbonate and bicarbonate alkalinity, total hardness and the ppm of chloride, phosphate and silicate as well of dissolved oxygen were measured at monthly intervals. Estimates of the bacterial populations were obtained from cultures. Water samples incubated at 37^oC for enumeration of mesophilic microbes, at 50^o C for thermo-tolerant bacteria and at 60^o for strict thermophiles. Tests for coliform organisms were carried out at 37^o C and at 50^o C.
All three springs show seasonal variation in their physico-chemical characteristics and in their bacterial populations. The cooler springs have large populations of mesophilic and thermotolerant bacteria but fewer thermophilic types. In the two hot springs (Saubhagya Kund and Swetganga), the differences of mean bacterial populations observed between 37^o and 50"C and between 50^o and 60^o C are highly significant ( P < 0.01), in the third (Agni Kund) the differences are also significant ( P < 0.01) but the population showed a rising trend with the temperature. Of the biotic and abiotic factors which could be involved in the observed seasonal variation in the bacterial populations, only the fluctuations in the phosphate levels were found to show a significant correlation (0.001 < P < 0.01).     

Thermoregulation in four Australian lizards of the genus Egernia (Sauria: Scincidae)

Mean thermal preferenda for the head and body were found to be similar in Egernia whitei, E. cunninghami, and E. bungana (range in T_H= 33.6^o -33.8^o C; range in T_B= 34.0^o-35.3^oC). However, those for E. majors were significantly lower (T_H= 31.1^o C, T_B=32.9^oC). Significant differences were found between mean head and body preferred temperatures in E. cunninghami and E. major. Higher temperatures were tolerated by the body than the head in all four species. Gaping was not observed to occur prior to cessation of respiration in any of the four species during radiant or solar heating. Based upon thermal preferenda and critical thermal maxima data, thermal safety margins for body temperature were calculated for E. whitei and E. cunninghami Postural orientation to the sun's rays increased and decreased heat gain. The seeking of shade was the most effective method employed by all four species for reducing head and body temperature.     

Energy and ration requirements of juvenile Pacific halibut (Hippoglossus stenolepis) based on energy consumption and growth rates

Growth of captive juvenile Pacific halibut was linearly related to energy consumption (J g⁻¹ day⁻¹) at 4°C by the following equation: growth (% body weight (b.w.) day⁻¹)=0–007 (consumption J g⁻¹ day⁻¹)– 0.192; r² =0.81. Weight gain was independent of size for fish between 9 and 7000 g when growth was expressed as a function of consumption in J g⁻¹ day⁻¹. Maintenance ration determined in feeding–growth experiments averaged 27.4 J g⁻¹ day⁻¹ at 4–0°C. Small halibut ate significantly more food than large fish. Single meals following 2 day fasts averaged 4.1% b.w. for halibut under 100 g, 1.72% b.w. for 1.2 kg fish and 1.1% B.W. for 6.8 kg fish. Both large and small size categories of halibut tended to evacuate their meal in about 3 days even though small fish ate relatively larger meals. Minimum estimates for daily ration to achieve growth rates observed in the Gulf of Alaska were approximately 0.5 to 2.4% b.w. day⁻¹ depending on fish size and whether northern shrimp or yellowfin sole were their prey.     

Thermal response and reversibility of diapause in the eggs of Locusta migratoria

Abstract. Eggs of a local population of Locusta migratoria L. (Orthoptera: Acrididae) collected near Hirosaki (40.5^oN) entered diapause when incubated at temperatures between 20 and 35^oC. For diapause development the optimum temperature was 10^oC. The lower thermal threshold for post-diapause development was 14.7^oC. After chilling at 10^oC for 20 days, the rate of hatching varied with incubation temperature, being 0, 61% and 81% at 20, 25 and 30^oC, respectively. After chilling for 40 days or more, however, almost all eggs hatched at 20–30^oC. Diapause with a reduced intensity seemed to be eliminated easily by a high temperature of 25 or 30^oC.
When eggs chilled at 10^oC for 20 days were kept at 20^oC for 7 days or more before incubation at 25^oC, almost all eggs maintained diapause. Most eggs chilled at 10^oC for three 10 day periods separated by 3 days of warming at 25^oC failed to terminate diapause. Daily alternations of 10^oC (18 h) and 25^oC (6h) decreased the diapause-terminating effect of chilling. These facts suggest that diapause intensity can be restored if eggs chilled insufficiently are exposed to a moderately high temperature. This reversible change in diapause intensity would play an important role in maintaining diapause before winter.     

EFFECTS OF TEMPERATURE ON CERTAIN POPULATION PARAMETERS OF LIRIOMYZA SATIVAE BLAN-CHARD (DIPTERA: AGROMYZIDAE)

Abstract  Effects of temperature on population parameters and the intrinsic rate of natural increase of the leafminer, Liriomyza sativae Blanchard, were studied at constant temperatures, 15, 20, 25, 30 and 3593 80% RH and a photoperiod of 12 :12 (L:D) in the laboratory with Phaseolus vulgaris as the host plant. Developmental time of the immature stage decreased from 38 d at 15C to lld at 35⁹3 Regression equations relating temperature ( t ) to development rates ( y ) for egg, larval and pupal stages, were y = 1.7862t - 13.841, y = 1.162 t - 4.946 and y = 0.634 t - 5.146, respectively. Longevity of female adult decreased from 20 d at 15°C to 9 d with temperature up to 35C The most favorable temperature range for reproduction was 20°C - 30^oC in which the fecundity ranged from 158 to 282 eggs per female. The lowest total mortality was 9% at 25^oC and the highest was 49% at 35 93 High intrinsic rate of natural increase ( r_m ) was 0.27 and high net reproductive rate ( R₀ ) was 116.8 at temperature range between 25 t and 30 t indicating that this range was optimal for population growth and that population density might increase 117 times per generation under this temperature condition. Mean generation time (T) and time for population to double (t) decreased as temperature increased, showing a negative linear trend with temperature. The relationship between finite rate of increase (A) and temperature, however, was a positive linear regression.     

Properties of lucerne transient streak virus, and evidence of its affinity to southern bean mosaic virus

A virus obtained from naturally infected lucerne ( Medicago sativa ) in New Zealand reacted with antiserum to an Australian isolate of lucerne transient streak virus (LTSV). Some plants infected with New Zealand isolates showed yellow flecks along lateral veins of leaves; symptoms were transient in some lucerne plants but persistent in others. A New Zealand isolate (LTSV-NZ) infected 14 of 39 plant species tested by mechanical inoculation, but was not transmitted by five aphid species. In sap of Nicotiana clevelandii , LTSV-NZ was infective after storage for 4 wk at 20 ^oC, diluting to 10^-5, or heating for 10 min at 70 ^oC. Purified virus preparations contained a single electrophoretic component and a single sedimenting component (s_20w= 112 S ) which formed a single buoyant density component in CsCl (1.37 g cm^-3) but two density components in Cs₂SO₄ (1.26 and 1.32 g cm^-3). LTSV-NZ particles were stable in 10 ITIM EDTA at pH 5, but not at pH 8, being degraded into two sedimenting components of 105 S and 92 S. Particles contained c. 18% RNA in the form of one single-stranded RNA molecule of mol. wt 1–4 times 10⁶, and a polypeptide of mol. wt c. 32 400. LTSV-NZ was serologically unrelated to 24 other isometric plant viruses. However, its properties are similar to those of southern bean mosaic virus and allied viruses. The present cryptogram of LTSV is R/l: 1–4/(18):S/S:S/*.     

Assessment of phosphine fumigation as a plant quarantine measure against Spodoptera littoralis

In laboratory tests first instar larvae of Spodoptera littoralis were killed by phosphine fumigations of 24 and 48 h at a concentration x time product (CTP) of 36 mg h/1. Eggs aged 1–2 days were, however, tolerant to phosphine at a CTP of 144 mg h/1 and this CTP caused severe damage to chrysanthemum cuttings (cv. Freedom). When eggs aged < 1 day and 1–2 days old were preconditioned at 20 ^oC for 72 h before phosphine fumigation, complete mortality occurred at CTPs at and above 36 mg h/1. Preconditioning for 48 h at 20 ^oC and for 48 and 72 h at 15 ^oC did not produce 100% mortality at a CTP of 288 mg h/1. It was suggested that eggs of S. littoralis pass through a phase of tolerance to phosphine which at 20 ^oC lasts about 4 days after oviposition.
There was no indication that phosphine was toxic to chrysanthemum cuttings (cv. Pollyanne) at concentrations of 0–75 mg/1 (CTPs of 18 and 36 mg h/1). Storage at 15 ^oC was not damaging to cuttings but at 20 ^oC some damage became apparent.     

Temperature-dependent development and survival of the lesser mealworm, Alphitobius diaperinus

Abstract. Development, growth and survival of the lesser mealworm, Alphitobius diaperinus (Panzer), were determined at six constant temperatures. No egg hatch or larval development occurred at 17^oC. At temperatures of 20, 25, 30, 35 and 38^oC the median development times (days), respectively, were for eggs (13.4, 6.0, 4.4, 2.6 and 2.6), larvae (133.0, 46.0, 26.2, 22.4 and 23.9), pupae (17.0, 8.0, 5.5, 4.0 and 4.1), and from oviposition to adult emergence (164.4, 60.2, 37.9, 29.0 and 30.8). The Sharpe & DeMichele (1977) model was used to describe the temperature-dependent development. The mean egg survival (hatching) ranged from 61% to 86%, with lowest hatch at 20^oC. Survival of the larvae and pupae ranged from 32% to 73% and from 85% to 95%, respectively, with lowest survival at 20^oC. Pupae had significantly lower weights at 35^oC and adults at 38^oC than at the other temperatures. Female pupae (20 mg) and female adults (16 mg) were significantly heavier than male pupae (17 mg) and male adults (13 mg). Adults (0.5–9 months old) laid 4–7 eggs per female per day at 25^oC.     

Energetics and foraging behaviour of the European seed harvesting ant Messor capitatus: I. Respiratory metabolism and energy consumption of unloaded and loaded workers during locomotion

Abstract The respiratory metabolism of workers of Messor capitatus (Latreille) was measured using standard micro-Warburg techniques on single individuals. The experiments were carried out at 10, 20, 25, 30 and 40^oC, and the respiratory quotient (RQ), measured for the same individuals at 30^oC, was found to be 0.77. The specific respiratory rate (y , in μl O₂/mg dry weight/h) could be described by the following equation: Iny = -2.24 + 0.098r -0.258 In W; where T is temperature and W is the dry weight in mg. The Q₁₀ for M. capitatus in the temperature interval 20–30^oC was 3.4, a higher value than for other ants.
The energy costs of movement and carrying were determined by using the RQ to convert the continuous measurement of CO₂ produced at 30^oC by Enfiuran anaesthetized workers ('resting metabolism'), by running workers and by workers loaded with a 20 mg weight to units of energy. The resting metabolism was 10.0±1.0 mJ/mg fresh weight/h. The cost of running ( Y in joule per km) could be described by: Y = 3.865 + 0.363 Wf , where Wf is fresh weight in mg. The cost of transport for all experiments could be expressed as 0.64 × the cost of running.     

Glucose fermentation to acetate and alanine in resting cell suspensions of Pyrococcus furiosus: Proposal of a novel glycolytic pathway based on 13C labelling data and enzyme activities

Abstract Suspensions of maltose-grown cells of the hyperthermophilic archaeon Pyrococcus furiosus , when incubated at 90°C with 35 mM [1-¹³C]glucose or [3-¹³C]glucose, consumed glucose at a rate of about 10 nmol min⁻¹ (mg protein)⁻¹. Acetate (10 mM), alanine (3 mM), CO₂ and H₂ were the fermentation products. The ¹³C-labelling pattern in alamine and acetate were analyzed. With [1-¹³C]glucose the methyl group of both alanine and acetate was labelled; with [3-¹³C]glucose only the carboxyl group of alanine was labelled whereas acetate was unlabelled. Extracts of maltose-grown cells contained glucose isomerase (12.8 U mg⁻¹, 100°C), ketohexokinase (0.23 U mg⁻¹, 100°C), and fructose 1-phosphate aldolase (0.06 U mg^{−1, 100°C). Enzymes catalyzing the formation of fructose 1,6-bisphosphate from fructose 1-phosphate or fructose 6-phosphate could not be detected. As publihed previously by our group and other authors P. furiosus also contains enzymes of glyceraldehyde conversion to 2-phosphoglycerate according to a non-phosphorylated Entner-Doudoroff pathway, of dihydroxyacetone phosphate conversion to 2-phosphoglycerate according to the Embden-Meyerhof pathway, and of 2-phosphoglycerate conversion - via pyruvate - to acetate and alanine. Based on the enzyme activities in P. furiosus , the following pathway for glucose degradation to alanine and acetate in cell suspensions is proposed which can explain the [13}C]glucose labelling data: glucose→ fructose → fructose 1- phosphate → dihydroxyacetone phosphate + glyceraldehyde and further conversion of both trioses to alanine and acetate via pyruvate.     

Growth, dry matter partitioning, and diurnal activities of RuBP carboxylase in citrus seedlings maintained at two levels of CO2

The long-term response of citrus rootstock seedlings to CO₂ enrichment was examined in Carrizo estrange ( Poncirua trifoliata (L.) Raf. x Citrus sinensis (L.) Osbeck] and Swingle citrumelo ( P. trifoliate x C. parodist Macf.]. Plaotlets 14 weeks old were transferred to outdoor controlled-environment chambers and maintained for 5 months from Feb. 14 to July 21. During this period, new growth (cm) of citrange and citrumelo shoots at 660 μl1⁻¹ was 94 and 69% greater, respectively, than at 330 μ1 1⁻¹. Total dry weight of both rootstock shoots had increased by over 100%. Growth of few species is affected this markedly by elevated CO₂ levels.
More carbon was partitioned to above-ground organs in CO₂-enriched citrus seedlings. Stem dry matter per unit length was also 32 and 44% greater in citrange and citrumelo, respectively. Total leaf area was increased by 124% in citrange and 85% in citrumelo due to greater leaf number and size. Variations in overall relative growth rate appeared to be related to the rapid, sequential, flush-type growth in citrus, in which an entire shoot segment with its associated leaves remains an active sink until fully expanded. RuBP carboxylase (EC 4.1.1.39) activity in leaves of recently-expanded flushes was higher in citrumelo plants grown at 660 vs 330 μ1 1⁻¹ CO₂ and changed diurnally for citrange (but not citrumelo) leaves at both CO₂ levels. The results are consistent with the hypothesis that positive long-term effects of CO² enrichment may be greater in species or during growth periods where sink capacity for carbon utilization is high.     

Shifts in the optimal temperature for nocturnal CO2 uptake caused by changes in growth temperature for cacti and agaves

When the day/night air temperatures were raised from 10°C/10°C to 30°C/30°C, the optimal tempearture for nocturnal CO² uptake by six species of cacti and three species of agave shifted from an average of 12°C to an average of 20°C. The maximum rate of CO² uptake was higher for Agave americana at the higher ambient temperature, lower for A. deserti , and much lower for A. utahensis , consistent with the relative mean temperatures of their native habitats. For the cactus Coryphantha vivipara , which had the greatest temperature shift observed (13°C), the halftime was 8 days for the upward shift and 4 days for the downward shift. The halftimes for the comparable shifts averaged 1.6 days for three other species of cacti and less than 1 day for two agave species. The shifts in the optimal temperature for nocturnal CO² uptake were in response to changes in nighttime temperature, at least for C. vivipara , and reflected temperature responses of both the stomates and the chlorenchyma.     

Effects of temperature on virogenesis of bluetongue virus serotype 11 in Culicoides variipennis sonorensis

Abstract. Culicoides variipennis sonorensis females were fed bluetongue virus serotype 11 mixed in sheep blood and were held at constant temperatures of 32, 27, 21 and 15^oC. Virogenesis, as measured by enzyme-linked immunosorbent assay (ELISA), proceeded significantly faster at higher temperatures. Based on ELISA absorbance ≥0.2, some flies first were categorized as infected after 1 day, 2 days and 4 days at 32, 27 and 21^oC, respectively. Peak levels of virus antigen were seen after 5–7, 7–13 and 18–22 days for flies held at 32, 27 and 21^oC, respectively. There was no significant virus replication in flies held at 15^oC for 22 days, but latent virus replicated and was detected easily (44% infection) 4–10 days after these flies were transferred to 27^oC. The implications for temperature effects on bluetongue epizootiology are discussed.     

Effects of temperature on development of Otiorrhynchus sulcatus (Coleoptera: Curculionidae)

Development of the black vine weevil, Otiorrhynchus sulcatus , was investigated at constant temperatures from 9 to 27 ^oC. Pre-adult development was completed in 200 and 130 days at 15 and 24 ^oC, respectively. Eggs and larvae developed at 27 ^oC, but no pupation took place at this temperature. The developmental threshold temperatures for eggs, larvae + pre-pupae and pupae were 6, 2–6 and 12 ^oC, respectively. Reproductive maturation of females took place at temperatures from 12 to 27 ^oC, but only a few females became reproductive at 12 ^oC. Most females at 12 ^oC, like those at 9 ^oC, had a short maturation feed, but the ovaries did not develop. The pre-oviposition period was temperature dependent. The females showed a cyclic oviposition pattern with three peaks. The significance of soil temperatures for the phenology and distribution of O. sulcatus in Norway is discussed.     

The effect of temperature and inoculation access period on the transmission of barley yellow dwarf virus byRhopalosiphum padi (L.) and Sitobion avenae (F.)

Winged individuals of Rhopalosiphum padi and Sitobion avenae transmitted the PAV-like and MAV-like isolates of barley yellow dwarf virus respectively. Success of transmission after inoculation access periods of 2, 6, 12, 24, 48 and 72 h were examined and survival, reproduction and movement of the aphid vectors were recorded at these times. The experiment was done at four different temperatures: 6^oC, 12^oC, 18^oC and 23^oC. For both isolates the inoculation efficacy did not increase after a 24 h inoculation access period and there was no difference in inoculation efficiency at the three highest temperatures, that at 6^oC being significantly lower than at 12^oC to 23^oC. The results suggest that autumn temperature is a critical factor for BYDV epidemiology in Britain with a small increase in autumn temperature leading to greatly increased infection rates.