The effect of food level on growth rate and frequency of metamorphosis and paedomorphosis in Ambystoma gracile

1992 ◽  
Vol 70 (1) ◽  
pp. 87-93 ◽  
Author(s):  
Lawrence E. Licht
Keyword(s):  
Growth Rate ◽  
Growth Response ◽  
Larval Growth ◽  
Food Level ◽  
Factors Influencing ◽  
Size At Metamorphosis ◽  
Effect Of Food ◽  
Food Body ◽  
Life History Patterns ◽  
Slow Growing

The effect of food level on larval growth response and frequency of metamorphosis and paedomorphosis was examined in Ambystoma gracile from high- and low-elevation populations in British Columbia. Larvae that eventually metamorphosed and those that became paedomorphic did not differ in growth rates when fed equal quantities of food. Body size at metamorphosis did not differ between fast- and slow-growing larvae, but larvae fed high levels of food metamorphosed sooner than those fed less. Food level had no effect on the frequency of metamorphosis and paedomorphosis. Larvae of different sexes did not differ in growth rate or frequency of metamorphosis and paedomorphosis, nor did larvae originating from populations from high and low elevations. Variation in the metamorphic response occurred within and between larvae from separate egg clutches. The findings are discussed in light of current hypotheses on factors influencing alternative life-history patterns in facultatively paedomorphic salamanders.

The evolution of adult body size in black-bellied salamanders (Desmognathus quadramaculatus complex)

2000 ◽  
Vol 78 (10) ◽  
pp. 1712-1722 ◽  
Author(s):  
Carlos D Camp ◽  
Jeremy L Marshall ◽  
Richard M Austin, Jr.
Keyword(s):  
Growth Rate ◽  
Body Size ◽  
Larval Growth ◽  
Larval Period ◽  
Moisture Level ◽  
Adult Body Size ◽  
Larval Growth Rate ◽  
Size At Metamorphosis ◽  
Adult Body ◽  
Desmognathus Quadramaculatus

We investigated the possible role of environmental variables in determining body size within a complex of salamander species (Desmognathus quadramaculatus). We analyzed data generated from life-history studies on populations from throughout the range of this species complex. We incorporated an alternative-hypothesis framework (sensu Platt) to determine the better predictor of adult body size, age at maturity, or size at metamorphosis. We found that almost 90% of the variation in adult body size was explained by size at metamorphosis, which was determined by a combination of rate of larval growth and length of the larval period. Environmental temperature and moisture level were positively correlated with larval growth rate and length of the larval period, respectively. We propose a simple model of body-size evolution that incorporates both adaptive and plastic components. We suggest that the length of the larval period may adaptively respond to moisture-level predictability. In addition, we suggest that the response of the larval growth rate to temperature may be plastic. Because the selection pressure due to drying-induced mortality is pervasive among species of amphibians, it may have played a role in shaping body-size radiation in desmognathines as well as the ecological structure of Appalachian streamside communities.

Plasticity of metamorphic traits in a high-altitude toad: interactive effects of food level and temperature

2016 ◽  
Vol 37 (1) ◽  
pp. 33-43 ◽  
Author(s):  
Tong Lei Yu ◽  
Michael Busam ◽  
Dong Li Wang ◽  
Kun Chen
Keyword(s):  
High Altitude ◽  
Food Supply ◽  
Larval Growth ◽  
Life Cycles ◽  
Larval Period ◽  
Interactive Effects ◽  
Food Level ◽  
Complex Life Cycles ◽  
Size At Metamorphosis ◽  
Lower Temperature

In organisms with complex life cycles, such as amphibians, morphological variation itself is strongly influenced by environmental factors and maternal effects. Although temperature and food level exert a strong influence on larval growth and development, little is known about the interacting effects of these factors on age and size at metamorphosis. In this study, plasticity in growth rates, larval mass, larval period, and body size at metamorphosis were experimentally examined for a high-altitude toad (Bufo minshanicus) under different combinations of temperature and food level. Larval period and mass at metamorphosis were sensitive to food level, and varied with temperature. At high food level, tadpoles reared at 29.8°C had shorter larval period lengths and larger mass at metamorphosis than those reared at 25.8 and 22.6°C, but not between 25.8 and 22.6°C. Interestingly, tadpoles at 29.8°C that were offered with a higher level of food supply achieved a larger size than those with a lower level of food supply; however, food supply did not affect body mass at the two lower temperature settings. Thus, the effects of food level were dependent on water temperature. Although there was high mortality at 29.8°C, surviving tadpoles have been much stronger to achieve faster growth and reach a larger mass at metamorphosis, which were positively correlated with juvenile survival and adult fecundity. Thus, under varied environmental conditions, we could say that there is more plasticity in development and growth of larvae in high altitude populations than in the same species or other species from low altitude populations.

Density Dependence of Larval Growth of a Marine Fish, the Southern Bluefin Tuna, Thunnus maccoyii

1991 ◽  
Vol 48 (8) ◽  
pp. 1358-1363 ◽  
Author(s):  
Greg P. Jenkins ◽  
Jock W. Young ◽  
Tim L. O. Davis
Keyword(s):  
Growth Rate ◽  
Marine Fish ◽  
Food Limitation ◽  
Larval Growth ◽  
Bluefin Tuna ◽  
Density Dependent ◽  
East Indian ◽  
Southern Bluefin Tuna ◽  
Slow Growing ◽  
East Indian Ocean

Competition for food among larvae and subsequent reduction in growth rates has been proposed as a mechanism to explain the apparent density-dependent control of some exploited marine fish populations, but has received little support from field data. Growth of larvae of southern bluefin tuna, Thunnus maccoyii, in the East Indian Ocean was significantly different among stations sampled randomly within a 20-km radius. Growth rate was positively correlated with feeding rate but not with temperature, indicating that larvae were food limited to a varying degree. A negative correlation between growth rate and abundance suggested that food limitation was density dependent. Regression analysis indicated that in areas of highest larval densities there was an approximate 25% reduction in growth rate. We suggest that in areas of high abundance, larvae were competing for food, leading to a density-dependent reduction of growth rate. Because the larval stage of high mortality is prolonged, cumulative mortality of slow-growing larvae over this period may be greater, even if the mortality rate is constant.

Abstract TP80: Incidence And Risk Factors For The Growth And Rupture Of Unruptured Cerebral Aneurysms. Results Of Annual Radiologic Follow Up Study.

Stroke ◽  
2013 ◽  
Vol 44 (suppl_1) ◽  
Author(s):  
Katsumi Matsumoto ◽  
Kouichirou Tsuruzono ◽  
Manabu Sasaki ◽  
Noriyasu Yoshimura ◽  
Toshiki Yoshimine ◽  
...  
Keyword(s):  
Growth Rate ◽  
Cerebral Aneurysms ◽  
Aneurysm Rupture ◽  
Annual Growth ◽  
Annual Growth Rate ◽  
Rupture Rate ◽  
Follow Up Study ◽  
Factors Influencing ◽  
Unruptured Cerebral Aneurysms

Background: The recent trend of the treatment of unruptured cerebral aneurysms(UIAs) is going to be conservative. Their natural history of rupture and growth is still unkown. We present the results of annual radiological follow-up study in UIAs. Method: In recent 12 years, we have found 121patients with 148 unruptured cerebral aneurysms were followed annually using 3D-CTA or MRA. Mean follow-up period was 5.5 year. Several factors influencing rupture or growth were statistically examined. Results: Among 121 patients, 9 ruptured and 11 showed growth of UIAs. Annual rupture rate was 1.3% per year and annual growth rate was 1.6% per year. Aneurysm size was the sole factor influencing rupture(P<0.001), whereas female sex and multiplicity were major factors influencing aneurysm growth(P<0.05). Under size 3mm, annual growth rate was 3.0% whereas annual rupture rate was 0.7%. In 4-6mm, growth rate was 1.6% and rupture rate was 1.6%. In 7-9mm, growth rate was 0 and rupture rate was 5.8%. In over 10mm, growth rate was 2.9% and rupture rate was 11.6%. Within 1 year, rupture occurred in 4 cases, and growth was found in 1 case. Conclusions: By annual radiological examination, growth of UIAs was noted more frequently than aneurysm rupture. Especially UIAs under 3mm, growth was 4 times higher than rupture, radiological follow up is effective for aneurysm rupture. Within 1 year, initially found UIAs should be carefully followed in a short interval.

The Future of the Nigerian Agricultural Industries: A Case Study of Oil Palm Production in Edo State

2013 ◽  
Vol 824 ◽  
pp. 561-567 ◽  
Author(s):  
U.J. Udosen ◽  
A.P. Ugboya
Keyword(s):  
Growth Rate ◽  
Oil Palm ◽  
Frequency Distributions ◽  
Factors Influencing ◽  
The Future ◽  
Edo State ◽  
Agricultural Industries ◽  
Fresh Fruit Bunches ◽  
Planting Materials

This study analyzes oil palm production from 2001 - 2008 in Edo State, with a view of establishing the future of Nigerian Agricultural oil palm industries. The specific objectives were to identify and quantify the factors influencing the production of oil palm, reveal the constraints to the production of oil palm; analyze the viability of oil palm production as an investment and predict the future of oil palm enterprise in Edo State. Three Local Government Areas of high oil palm concentration in Edo State were covered. Ninety selected oil palm producers from nine villages in the study area were selected. Frequency distributions and multiple regression analysis were used to analyze the results. The results showed that for the period under review (2001 - 2008) on a per hectare basis, seedlings cost, and labour cost were significant inputs, positively influencing the production of oil palm in the Edo State. A growth rate of 6.2% and 23.5% were projected for oil palm with reference to palm oil and fresh fruit bunches (FFB), respectively, up to the year 2020, an indication that oil palm production in the State is viable and the future is bright. The study revealed that inadequate storage facilities, poor planting materials and lack of government assistance, among others, are major bottlenecks in oil palm production in Edo State. However, since oil palm production in Edo State is viable, it is an indication that the future of Nigerian Agricultural Industries is bright.

scholarly journals Factors Influencing the Chlorine Susceptibility of Mycobacterium avium, Mycobacterium intracellulare, and Mycobacterium scrofulaceum

2003 ◽  
Vol 69 (9) ◽  
pp. 5685-5689 ◽  
Author(s):  
Joseph O. Falkinham
Keyword(s):  
Growth Rate ◽  
Mycobacterium Avium ◽  
Growth Phase ◽  
Growth Rates ◽  
Growth Stage ◽  
Tween 80 ◽  
Culture Conditions ◽  
C Cells ◽  
Mycobacterium Intracellulare ◽  
Factors Influencing

ABSTRACT The susceptibility of representative strains of Mycobacterium avium, Mycobacterium intracellulare, and Mycobacterium scrofulaceum (the MAIS group) to chlorine was studied to identify factors related to culture conditions and growth phase that influenced susceptibility. M. avium and M. intracellulare strains were more resistant to chlorine than were strains of M. scrofulaceum. Transparent and unpigmented colony variants were more resistant to chlorine than were their isogenic opaque and pigmented variants (respectively). Depending on growth stage and growth rate, MAIS strains differed in their chlorine susceptibilities. Cells from strains of all three species growing in early log phase at the highest growth rates were more susceptible than cells in log and stationary phase. Rapidly growing cells were more susceptible to chlorine than slowly growing cells. The chlorine susceptibility of M. avium cells grown at 30°C was increased when cells were exposed to chlorine at 40°C compared to susceptibility after exposure at 30°C. Cells of M. avium grown in 6% oxygen were significantly more chlorine susceptible than cells grown in air. Chlorine-resistant MAIS strains were more hydrophobic and resistant to Tween 80, para-nitrobenzoate, hydroxylamine, and nitrite than were the chlorine-sensitive strains.

scholarly journals Effects of Climate and Biotic Factors on Life History Characteristics and Vital Rates of Yellowstone Cutthroat Trout in Spread Creek, Wyoming

2013 ◽  
Vol 36 ◽  
pp. 160-174
Author(s):  
Patrick Uthe ◽  
Robert Al-Chokhachy
Keyword(s):  
Life History ◽  
Brook Trout ◽  
Cutthroat Trout ◽  
Conservation Strategies ◽  
Snake River ◽  
Vital Rates ◽  
Factors Influencing ◽  
Yellowstone Cutthroat Trout ◽  
Life History Patterns ◽  
Diversity Of Life

The Upper Snake River represents one of the largest remaining strongholds of Yellowstone cutthroat across its native range. Understanding the effects of restoration activities and the diversity of life-history patterns and factors influencing such patterns remains paramount for long-term conservation strategies. In 2011, we initiated a project to quantify the success of the removal of a historic barrier on Spread Creek and to evaluate the relative influence of different climate attributes on native Yellowstone cutthroat trout and non-native brook trout behavior and fitness. Our results to date have demonstrated the partial success of the dam removal with large, fluvial Yellowstone cutthroat trout migrating up Spread Creek to spawn, thus reconnecting this population to the greater Snake River metapopulation. Early indications from mark-recapture data demonstrate considerable differences in life-history and demographic patterns across tributaries within the Spread Creek drainage. Our results highlight the diversity of life-history patterns of resident and fluvial Yellowstone cutthroat trout with considerable differences in seasonal and annual growth rates and behavior across populations. Continuing to understand the factors influencing such patterns will provide a template for prioritizing restoration activities in the context of future challenges to conservation (e.g., climate change).

scholarly journals Contribution of larval growth rate vairability to the recruitment of the Bay of Málaga anchovy (SW Mediterranean) during 2000-2001 spawning seasons

2003 ◽  
Vol 67 (4) ◽  
pp. 477-490 ◽  
Author(s):  
Alberto García ◽  
Dolores Cortés ◽  
Teodoro Ramírez ◽  
Ana Giráldez ◽  
Ángel Carpena
Keyword(s):  
Growth Rate ◽  
Larval Growth ◽  
Larval Growth Rate
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