Reach Maximum Size Research Articles

A Local Approach to Better Understand the Spread and Population Growth of the Monk Parakeet as an Invasive Species

Invasive exotic species are currently a topic of interest for environmental management agencies and the media. This is due to the socio-economic and environmental problems that they are causing or may cause. The Monk Parakeet is a clear example of this, especially in some large cities, where populations are growing quickly, and their distribution continues to expand. In our study, we focused on a population that has been closely monitored during the last 25 years to understand its growth and change on a local scale to determine the maximum sustainable population size in the invaded area and to check when this population began to act as a source of new breeding colonies to adjacent areas. The first breeding of the species occurred in 2002, and from then, the average growth rate (r) of the population was 0.191 until 2016, when it stabilized and declined slightly (r = −0.043). The maximum growth rate occurred during the years 2002 and 2007 and was 0.314. The results obtained give us information about the carrying capacity of the study area, allowing us to explain the dispersal process of the species to neighbouring areas, with populations that have reached maximum size serving as sources of individuals dispersing to suitable areas. In our study area, the species shows a strong preference for building its nests in palm trees and electric utility structures. Our study’s local focus on studying the population dynamics of an invasive species may allow us to understand the increased range of the species on a larger scale, which is necessary in order to be able to design appropriate and effective management strategies.

First hatchery bred streaked spinefoot rabbitfish (Siganus javus) in Sabah, Malaysia

The present study aims to expand the market potential of the streaked spinefoot rabbitfish (Siganus javus) in Malaysia and provide consumers more choices of affordable protein source from aquaculture. Spawning hehavior of S.javus was recorded in a week after the new moon in October 2019 and January 2020. Spawning occurred between midnight and early morning, and the eggs hatched about 16 to 18 hours later. Throughout the incubation and larvae rearing period, water temperature was maintained at 30 to 31 °C. Water salinity, pH and DO were 31 to 33 ppt, 7.8 to 8, and 5 to 7 mg/l, respectively. Eggs diameter ranged from 0.550 to 0.603 mm. At 1 day after hatched (d AH), eyes of the larvae were formed but unpigmented and mouth structure was not developed. At 2 d AH, the pigmentation of eyes darkened, digestive tract formed, and anus and mouth opened. At 3 d AH, the lower jaw began to show movement, indicating that the ability of larvae to indulge in feeding. The buds of dorsal and ventral fins started to develop and elongate from 9 d AH and were covered with melanophores. At 25 d AH, the body of the larvae turned brownish and abdominal cavity was deeply pigmented, indicating the onset of metamorphosis. By the age of 30 d AH, the larvae completed development into juvenile stage. At 270 d AH, the juvenile reached maximum size of 21 cm in total length. This study was the first successful attempt at naturally spawning and hatchery rearing of S. javus into juvenile stage in the country. The development of a complete larval rearing protocol for S. javus could provide information of practical importance in hatchery breeding of other rabbitfish species.

Leaf-litter consumption slows crab growth but transforms mangrove food chains

Leaf litter consumption has implications for growth and nutrient balances of mangrove crabs and mangrove trophic pathways. This study (1) addressed the impact of leaf litter quality and quantity on crab life history and growth, and (2) proposed keystone roles of crabs in mangrove material fluxes. Estimates of crab standing stocks, growth, and carbon and nitrogen mass balances were obtained for a field population of Parasesarma messa, a primary consumer of leaf litter in Queensland mangroves. P. messa exhibited slow growth and individuals took >>4 yr to reach maximum size. Females appeared to breed once per year with high reproductive effort relative to other crabs. An apparent trade-off between growth and reproduction in the dry-wet transition season was caused by a shortage of available leaf litter. A nitrogen mass balance indicated that the population ingested twice the amount of nitrogen that could be supplied by leaf litter. Assuming mortality was mainly due to predation, the estimated loss to predators (28 kg ha-1 yr-1) supported a hypothesis that crab consumption by fish short-circuits mangrove food chains. Faecal production by crabs (0.48 Mg C ha-1 yr-1 and 0.03 Mg N ha-1 yr-1) represents a substantial contribution to deposit-feeding food chains. P. messa is a keystone species whose impact on ecosystem processes is large relative to its abundance and biomass.

Relationship of quality formation and ultrastructure of cotyledon cells in two quality types of peanut

Aims There are great differences in yield and quality of different quality types of peanut(Arachis hypogaea),and there is a significant negative correlation between different quality traits in one cultivar.We conducted an experiment to study the differences of quality formation and cell ultrastructure in different quality types of peanut.Methods A high-protein variety,'XB023',and a high-fat variety,'Luhua 9',were planted in an agricultural experiment station field with a randomized block design in the 2010-2011 growing season.We observed the protein,fat and soluble sugar content of seeds while the pegs grew into the soil for 10-60 days,the components of amino acids and fatty acids and the changes of ultrastructureincotyledoncellsduringdifferentdevelopmentphases.Important findings The protein content of 'XB023' was lower than that of 'Luhua9' in the earlier stage of seed development,but significantly higher in the late development phase.The essential amino acid contents of 'XB023' were higher than those of 'Luhua 9',with glutamate,lysine and leucine contents being significantly different.Accumulation of fat in 'XB023' was lower than that of 'Luhua 9' throughout the development phases,and fat content of 'XB023' decreased in the late stage.The content of soluble sugar and the oleic/linoleic(O/L) ratio of 'XB023' were significantly lower than in 'Luhua 9'.Starch grains,lipid bodies and protein bodies in cotyledon cells of the two varieties had begun to form while the pegs grew into the soil 10 days.With the number of lipid bodies and protein bodies increasing ceaselessly,the size of starch grains increased at first and then narrowed gradually with cotyledon development.The time when lipid bodies of 'XB023' reached maximum size was earlier than that of 'Luhua 9',and the time of rapid accumulation of lipid bodies in 'Luhua 9' was longer than that of 'XB023'.The protein bodies of the two varieties both reached the maximum size when the pegs grew into the soil for 40 days.The number of protein bodies of 'XB023' grew fast during the late period.The protein content of seeds was determined by size and number of protein bodies,and the fat content was mainly determined by the number of lipid bodies in the cotyledon cells.

In situ growth rate of Solen cylindraceus (Mollusca: Euheterodonta: Solenidae) in the St Lucia estuarine lake, South Africa

Solen cylindraceus, an infaunal bivalve, can reach a maximum length of 95 mm. However, in the St Lucia estuarine system specimens are seldom larger than 55 mm. Thus, the primary aim of this study was to investigate the growth rate and morphometrics of S. cylindraceus in St Lucia. Growth lines of this species are too indistinct and irregular to be of any use. This study, therefore, adopted a more direct method of monitoring the shell length of individuals, by caging them in situ. Shell measurements were taken from the individuals in cages and the surrounding environment at monthly intervals for one year. Thereafter, salinities decreased below their tolerance range and the experiment was terminated. Caged and uncaged animals had a shell length of 31.0 ± 4.5 and 31.7 ± 2.3 mm after a year of growth, respectively. An overall growth rate of 0.049 ± 0.059 mm/d was derived for the caged animals. In conclusion, first year growth rates appeared lower than previously recorded for S. cylindraceus. Additionally, it appears that animals are unable to survive in the prevailing harsh environment of St Lucia to reach maximum size.

Growth and Quality Response of Five Landscape-grown Herbaceous Perennials to Nitrogen Fertilization at Five Rates

There is limited research regarding proper fertilization rates and timing for landscape-grown herbaceous perennials. Most current nitrogen (N) fertilizer recommendations for landscape-grown perennials are based on rates for woody landscape plants or on rates for greenhouse-grown perennials. In addition, most fertilizer guidelines are defined to achieve peak growth, which may not be the best indicator of desirable plant quality. Basing fertilizer input rates on plant quality levels rather than maximum growth may result in a lower fertilizer application rate and a reduction in excess fertilizer available for leaching. The objective of this research was to evaluate the response of landscape-grown herbaceous perennials to N fertilizer applied at five rates. Five herbaceous perennials [bush daisy (Gamolepis chrysanthemoides), ‘New Gold’ lantana (Lantana ×hybrid), ‘Mystic Spires’ salvia (Salvia longispicata ×farinacea), ‘Evergreen Giant’ liriope (Liriope muscari), and ‘White Christmas’ caladium (Caladium bicolor)] were transplanted into raised landscape beds containing subsoil fill in U.S. Department of Agriculture (USDA) hardiness zone 9a. Controlled-release N fertilizer was applied at an annual N rate of 0, 2, 4, 6, and 12 lb/1000 ft2 for 96 weeks. Plant size index (SI), tissue chlorophyll, and plant quality were measured every 6 weeks for 96 weeks. Flower cover was determined every 6 weeks from 42 to 96 weeks. Shoot biomass and tissue total Kjeldahl N (TKN) were measured at 96 weeks after planting (WAP). Regression analyses suggested that some species required in excess of 12 lb/1000 ft2 N to reach maximum size, chlorophyll content, and shoot biomass. However, plants exhibited quality ratings of good to excellent at annual N rates of 2 to 4 lb/1000 ft2 N per year. We suggest that these low to moderate levels of N fertilization (2 to 4 lb/1000 ft2 N per year) will provide sufficient N to produce acceptable size and quality herbaceous perennials in the landscape.

Characteristics of Precipitating Convective Systems in the Premonsoon Season of South Asia

AbstractTropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) data obtained over South Asia during eight premonsoon seasons (March–May) show that the precipitation is more convective in nature and more sensitive to synoptic forcing than during the monsoon. Over land areas, most rain falls from medium-sized systems (8500–35 000 km2 in horizontal area). In continental regions near the Himalayas, these medium-sized systems are favored by 500-mb trough conditions and are of two main types: 1) systems triggered by daytime heating over high terrain and growing to reach maximum size a few hours later and 2) systems triggered at night, as moist upstream flow is lifted over cold downslope flow from the mountains, and reaching maximum development upstream of the central and eastern Himalayas in the early morning hours. Systems triggered by similar mechanisms also account for the precipitation maxima in mountainous coastal regions, where the diurnal cycles are dominated by systems triggered in daytime over the higher coastal terrain. Medium-sized nocturnal systems are also found upstream of coastal mountain ranges. West-coastal precipitation systems over India and Myanmar are favored when low pressure systems occur over the upstream oceans, whereas Indian east-coastal systems occur when high pressure dominates over Bangladesh. Over the Bay of Bengal, the dominant systems are larger (>35 000 km2), and have large stratiform components. They occur in connection with depressions over the Bay and exhibit a weaker diurnal cycle.

A UNIQUE LIFE CYCLE AND PERENNATION IN A COLORLESS CHRYSOPHYTE SPUMELLA SP.(1).

Life cycle and perennation of a colorless chrysophyte, Spumella sp., isolated from an ephemeral ditch were investigated. From a single resting cyst (statospore), only one nonmotile cell germinated. Shortly after germination, the cell generated flagella, started to swim, and formed a gelatinous sphere. The cell itself retained the ability to swim within the sphere. Cells fed on bacteria inhabiting the sphere and grew by longitudinal binary cell division very rapidly. The gelatinous sphere gradually enlarged as the number of cells increased. When it reached maximum size (∼500 μm in diameter), the gelatinous substance of the sphere weakened, and the sphere gradually broke into several pieces, forming cleavages between them. Cells swam away through the cleavages. Five to ∼40 swimming cells soon gathered and formed a swarm. In the swarm, some cells cannibalized other sibling cells and enlarged, resulting in giant cells that were two to three times larger in diameter than ordinary cells. The giant cells soon started statospore formation. Statospore formation was independent of any changes of environmental factors, such as increase or decrease in temperature or changes in nutrient or light levels, which are known to induce resting-cyst formation in other groups of algae and protists. Statospore formation started when cells divided 15 to 16 times after germination. This is congruent with the idea that statospore formation in planktonic chrysophytes directly depends on cell density. An extraordinarily high growth rate and cannibalism involved in the initiation of statospore formation are interpreted as adaptations to achieve the perennation in ephemeral aquatic environments.

Visual Observation of a Sound-Induced Bubble in Liquid 3He–4He Mixtures

We report visual observation of a sound-induced bubble in superfluid 3He–4He liquid mixtures using a high-speed camera at a rate of 1 msec/frame. The experiments were performed in the 3He dilute phase of phase-separated mixtures at 300 mK. The resonant frequency of the piezoelectric transducer was 9.36 MHz and the diameter of the active electrode was about 4 mm. When an acoustic wave pulse of sufficient magnitude was applied to the dilute phase from the transducer under saturated vapor pressure, a single bubble was nucleated on the active area. The bubble expanded almost spherically on the transducer, as it reached maximum size, it started shrinking, detached from the transducer, and collapsed. We also investigated the motion of the bubble in mixtures with a 3He concentration of 25% at 750 mK. In this case, the bubble grew elliptically on the transducer and detached from it without much change in shape.

REPRODUCTIVE CYCLE OF MALE AND FEMALE SPINY LIZARDS, SCELOPORUS MELANORHINUS, IN A TROPICAL DRY FOREST

Abstract Male and female reproductive cycles are described for Sceloporus melanorhinus in Chamela, Jalisco, Mexico. Both males and females reached sexual maturity at 62 mm snout–vent length. Testes mass of adult males began to increase in March, reached maximum size in July, and began to decrease in August and September, reaching minimum size in October and November. Testes size was associated with increasing photoperiod, but not with temperature or precipitation. Enlarged vitellogenic follicles first appeared in May, and oviductal eggs were found from June to September. Vitellogenesis, follicular growth, and egg production were correlated with increasing photoperiod, temperature, and precipitation. Females produced a single clutch during the reproductive season. Mean clutch size based on oviductal eggs was 7.7 (range = 5 to 9). Clutch size was not correlated with female snout–vent length.

Microbubble Formation Dynamics Under High Heat Flux on Heaters with Different Aspect Ratios

Extensive studies of vapor bubble in water on microbubble growth and collapse process on microheaters with heat fluxes of 1.2, 1.4, and 1.6 GW/m 2 are performed. The 4 μs heat pulse is applied to 30 × 30 μ m 2 , 30 × 60 μ m 2 , and 20 × 60 μ m 2 heaters for undergone the nucleate boiling. Sequential images during the micro bubble growth process are recorded by the microscopic flow visualization method coupled with phase-averaged technique. The analysis of the top view images show that the increase of aspect ratio of rectangular shape heater changes the bubble shape into ellipsoid with larger ratio of axes, slower rates of bubble growth and collapse, longer bubble lifetime, later time to reach maximum size but play small roles on incipience nucleation, and vapor formation temperature. While the change of high heat flux shifts the incipience time at nucleation temperature, time to vapor sheet formation, time to reach maximum size and thus the bubble lifetime. With side view of bubble images, not only histories of extension of bubble in height but also histories of the contact angle can be provided. Therefore, the correlations of contact angle/surface tension force and boundary moving speed of bubble boundary as well as the determination of major driving mechanism in bubble growth/collapse process can be identified.

Effects of Temperature on the Early Development, Growth, and Survival of Shortnose Sturgeon, Acipenser brevirostrum, and Atlantic Sturgeon, Acipenser oxyrhynchus, Yolk-Sac Larvae

We reared shortnose and Atlantic sturgeons at different temperatures after hatch and measured yolk utilization rate and efficiency (YUE), maximum standard length, survival and development of escape response. Newly hatched Atlantic sturgeon, were smaller in size, more efficient at utilizing yolk (incorporating yolk to body tissue) and reached developmental stages sooner than shortnose sturgeon reared at the same temperatures (13–15°C). Within each species, decreasing temperature delayed yolk absorption, escape initiation, time to reach maximum size, and time to 100% mortality. However, YUEs and the size of the larvae at these 'stages' were independent of rearing temperature for both species. These results suggest that even as temperature drives metabolic processes to speed up development, these two species are still extremely efficient at transferring yolk energy to body tissues. The lower efficiencies experienced by larval shortnose may reflect difference in yolk quality between the two species and/or the Atlantic sturgeon's higher conversion efficiency. The ability of these two sturgeon species to develop successfully and efficiently under a wide range in temperatures may provide a competitive advantage over more stenothermic species and explain their persistence through evolutionary time.

Endo-β-mannanase activity is associated with the completion of embryogenesis in imbibed carrot (Daucus carota L.) seeds

AbstractDevelopment of the rudimentary embryo in mature carrot (Daucus carota) seed during imbibition was characterized. The small embryo in the carrot seed, located in the micropylar region, elongated into the lateral part during imbibition and attained about two-thirds the length of the seed before radicle protrusion. Developing embryos excised from imbibed seeds were only capable of germinating in both water and Murashige–Skoog (MS) medium when they reached maximum size. The corrosion cavity into which the embryo grew enlarged concomitantly with endosperm degradation. The expression of endo-β-mannanase (EC 3.2.1.78), which is assumed to be involved in endosperm degradation, was characterized. A cDNA encoding an endo-β-mannanase was obtained by reverse transcription polymerase chain reaction (RT-PCR) using total RNA extracted from 24-h-imbibed carrot seeds. The full-length cDNA (DcMAN1) exhibited 64% deduced amino acid sequence identity with tomato (Lycopersicon esculentum) seed germination-associated mannanase (LeMAN2). DcMAN1 mRNA and endo-β-mannanase activity were first detected in the micropylar-half seed and then in the lateral-half seed. The timing of the appearance of DcMAN1 mRNA and endo-β-mannanase activity in the lateral-half seed corresponded with that of embryo development into this region. These results suggest that the expression of DcMAN1 and endo-β-mannanase activity in imbibed carrot seeds is associated with the enlargement of the corrosion cavity, which accompanies embryogenesis.

The role of epicormic shoot production in maintaining foliage in old Pseudotsuga menziesii (Douglas-fir) trees II. Basal reiteration from older branch axes

Basal reiteration (epicormic shoot production from older branch axes) occurred continuously and repeatedly in branches of 450-year-old Pseudotsuga menziesii (Mirb.) Franco var. menziesii (coastal Douglas-fir) trees reproducing sections of branches comprising less than 100 to as many as 10 000 foliated shoots. Basal reiteration occurred mostly from primary and secondary branch axes but also occurred from higher-order axes if lower-order axes had died back. Basal reiteration occurred in distal sections of upper-crown branches, while it occurred in more proximal sections of middle- and lower-crown branches, indicating that basal reiteration works to distribute foliage more uniformly within branches that have reached maximum size. Basal reiteration occurred repeatedly producing two to six generations of reiterated axes within branches. Less than 22.5% of foliated shoots on branches were produced by sequential branching of the primary axis. Basal reiteration also maintained a constant rate of new shoot production within the branch. Growth-ring analysis showed that basal reiteration occurred over a wide range of axis ages (5–58 years). In conjunction with previous studies, we showed that adaptive reiteration of various architectural units by epicormic shoot production is an inherent process that maintains foliage in the crown of old P. menziesii trees.Key words: branch growth, branching pattern, crown maintenance, longevity.

The role of epicormic shoot production in maintaining foliage in old Pseudotsuga menziesii (Douglas-fir) trees

Shoots and foliage on branches of old Pseudotsuga menziesii (Mirb.) Franco var. menziesii (coastal Douglas-fir) trees are constantly renewed by epicormic shoot production. Epicormic shoots are produced in all parts of the crown, and epicormic buds remain dormant for 5 or 6 years on average. Epicormic shoot production results in reiteration of shoot cluster units (SCUs), an architectural unit of shoot organization within branches. Five phases of SCU development were identified based on relative age structures of regular and epicormic shoots. SCUs produce epicormic branchlets as early as 3 or 4 years of age, and peak production occurred around 6-13 years. Epicormic branchlets occur toward the proximal end of main axes of SCUs, where regular lateral branchlets are no longer producing new shoots. In some lower-crown branches, nearly 50% of shoots and foliage are epicormic shoots. Demographic analysis of SCUs showed that upper-crown branches are still growing in size, while mid- and lower-crown branches have reached maximum size, and are being maintained by reiteration of SCUs. Epicormic shoot production maintains shoots and foliage of old P. menziesii trees after height growth and crown expansion have stopped and may contribute to prolonging tree longevity.Key words: aging, branch growth, epicormic shoots, longevity, Pseudotsuga menziesii, reiteration.

Visualization and temporal/spatial characterization of cardiac radiofrequency ablation lesions using magnetic resonance imaging.

The purpose of this study was to describe a system and method for creating, visualizing, and monitoring cardiac radiofrequency ablation (RFA) therapy during magnetic resonance imaging (MRI). RFA was performed in the right ventricular apex of 6 healthy mongrel dogs with a custom 7F nonmagnetic ablation catheter (4-mm electrode) in a newly developed real-time interactive cardiac MRI system. Catheters were positioned to intracardiac targets by use of an MRI fluoroscopy sequence, and ablated tissue was imaged with T2-weighted fast spin-echo and contrast-enhanced T1-weighted gradient-echo sequences. Lesion size by MRI was determined and compared with measurements at gross and histopathological examination. Ablated areas of myocardium appeared as hyperintense regions directly adjacent to the catheter tip and could be detected 2 minutes after RF delivery. Lesions reached maximum size approximately 5 minutes after ablation, whereas lesion signal intensity increased linearly with time but then reached a plateau at 12.2+/-2.1 minutes. Lesion size by MR correlated well with actual postmortem lesion size and histological necrosis area (55.4+/-7.2 versus 49.7+/-5.9 mm(2), r=0.958, P<0.05). RFA can be performed in vivo in a new real-time interactive cardiac MRI system. The spatial and temporal extent of cardiac lesions can be visualized and monitored by T2- and T1-weighted imaging, and MRI lesion size agrees well with actual postmortem lesion size. MRI-guided RFA may be a useful approach to help facilitate anatomic lesion placement and to provide insight into the biophysical effects of new ablation techniques and technologies.

Pupillometry in seals and sea lions: ecological implications

Phocid and otariid pinnipeds forage almost exclusively under water, where observing them is difficult. As a result, little is known of how their senses are used while diving to locate and capture prey. In this study we used pupillometric methods to describe the relative visual abilities of three pinniped species: the northern elephant seal (Mirounga angustirostris), the harbor seal (Phoca vitulina), and the California sea lion (Zalophus californianus). The range of pupillary area and lower limit of pupillary adjustment were determined for each species. The northern elephant seal exhibited the largest range of pupillary area of the species examined. Furthermore, the elephant seal's pupil was found to reach maximum size only under extremely dim conditions. Both the harbor seal and California sea lion exhibited maximum pupillary dilation in conditions several log units brighter. These results indicate that the elephant seal's visual system is designed to function in dimmer conditions and to respond to greater changes in light levels than those of the harbor seal and sea lion. Such findings support the hypothesis that the visual systems of these pinnipeds are adapted for use in their respective foraging environments, and thus suggest that the visual sense is probably an important sensory modality used to locate and capture prey while diving.

Size dependence of composition, photosynthesis and growth in the colony-forming freshwater ciliate, Ophrydium versatile

SUMMARY 1. Ophrydium versatile is a symbiotic ciliate which forms gelatinous colonies up to several centimetres in diameter in transparent temperate lakes. The ciliates are evenly spaced at the colony surface and constitute a small proportion of the surface area (7%) and volume (3.1%) of the colony, but a large proportion of organic carbon (74%) and nitrogen content (82%) (exemplified for 1 cm3 colonies). The majority of the colony volume is formed by the jelly. The biomass proportion of ciliates scales inversely with colony size, following the decline of surface area to colony volume. The largest colonies found in Danish lakes in early summer contain almost 1 million ciliates, and assuming they derive from a single ciliate undergoing exponential division, they need twenty generations and, presumably, almost a year to reach maximum size. 2. The ciliates contain numerous symbiotic zoochlorellae that constitute about 10% of ciliate volume and more than half of the carbon content. Zoochlorellae dominate oxygen metabolism of the assemblage, resulting in low light compensation points, a large diel photosynthetic surplus, and a marked dependence on light for sustained growth and ciliate metabolism. Estimated gross photosynthesis (7ng C ciliate−1 day−1) of Ophnrydium from shallow, clear waters in June greatly exceeded the estimated carbon contained in filtered bacteria and small algae (1.9ng C cilicate−1 day−1). Nitrogen and phosphorus content of the prey, however, may provide the main nutrient source consistent with the correspondence between mass-specific rates of nutrient uptake and measured relative growth rates (average 0.067 day−1, generation time 10 days). 3. The large Ophrydium colonies require increased allocation of photosynthetic carbohydrates with increasing colony size to maintain the jelly. The large colonies tend to become gas-filled, floating, mechanically destroyed and their ciliate inhabitants abandon them as swarmers. Colony formation, however, should offer protection against predators which may be more important for the natural abundance than the costs of growing in a colony.

Effects of two blood-feeding regimes on mortality and female reproduction in a laboratory colony of stable flies, Stomoxys calcitrans.

Stable flies (Stomoxys calcitrans L.) deprived of a bloodmeal until 3 days post-emergence had higher mortality rates than control flies fed from the day of emergence. Fat bodies of deprived females required one more bloodmeal to reach maximum size, and maximum size was smaller, than fat bodies of control females. Ovarian development did not commence prior to feeding in deprived flies, and proceeded more slowly thereafter, resulting in a one blood-meal delay in egg maturation in deprived flies. Deprived females produced fewer (54.7, SD 2.8) eggs than controls (75.9, SD 3.7) and eggs from deprived females were smaller (mean length 684.0 microns) than control females' eggs (mean length 1165.7 microns).

Energy flux in a natural population of the land snail Eobania vermiculata (Müller) (Gastropoda: Pulmonata: Stylommatophora) in Greece

Survivorship, production, mortality rate, consumption rate, assimilation, and growth and ecological efficiencies were studied in a natural population of the land snail Eobania vermiculata in Greece. Eobania vermiculata may take 5 years or more to reach maximum size (33 mm). Mortality rate and life expectancy decreased with age. Net reproductive rate was 3.4 and per capita rate of increase was 1.0. Energy flux in E. vermiculata was studied using Urtica dioica and Lactuca sativa as food. The highest daily consumption and assimilation rates (weight specific) were observed in newly hatched animals and the lowest in adults. Assimilation efficiency, mean monthly production, and gross growth and ecological or net growth efficiencies fluctuated with the season and the physiology of the snails. Snails fed U. dioica showed higher assimilation, gross growth, and net growth efficiencies than those fed L. sativa. Energy flow through the E. vermiculata population was 78.9 cal∙m−2∙year−1 (1 cal = 4.1868 J), mean assimilation efficiency was 52% if the snails were fed U. dioica only, and the ingestion rate was 19.5%. When E. vermiculata was fed U. dioica during its lifetime, 4.26% of the total assimilated energy was used for egg production, 10.2% for growth, and 87.8% for metabolic energy. Annual secondary production gave a mean adult density of 4.1 individuals/m2, a mean annual standing crop (biomass) of 6.8 g∙m−2, and an annual production of 13.9 ± 1.8 g∙m−2 or 2859.5 mg C∙m−2. The annual turnover ratio, or productivity rate constant, was 2.0.