Food preference and relative influence of temperature and food quality on life history characteristics of a grazing mayfly, Ephemerella ignita (Poda)

1988 ◽  
Vol 66 (6) ◽  
pp. 1474-1481 ◽  
Author(s):  
Dominique Rosillon
Keyword(s):  
Growth Rate ◽  
Mortality Rate ◽  
Food Quality ◽  
Larval Growth ◽  
Developmental Time ◽  
Adult Size ◽  
Temperature Growth ◽  
Rate Range ◽  
Food Conditions ◽  
Increasing Temperature

In choice experiments, starved larvae of Ephemerella ignita (Poda) moved preferentially to compartments with a diatom-rich diet rather than to those with a detritus diet. Growth rate, mortality rate, larval developmental time, adult size, and fecundity of E. ignita were assessed in response to rearing on two diets (diatoms and detritus) at four constant temperatures (4.5 – 18 °C). On each diet, growth rate (range 0.30 – 6.2% length/d) increased with increasing temperature according to a power law (Y = axb). At any temperature, growth rate was significantly higher on the diatom diet than on the detritus diet. Mortality rate (range 0.2 – 6.5%/d) increased with increasing temperature and was higher on the detritus diet than on the diatom diet. Developmental time varied significantly with temperature for animals fed diatoms according to a hyperbolic relationship. The thermal requirement for completing larval growth from hatching to emergence on a diatom diet was estimated at about 950 degree-days above a threshold of 3.5 °C (range 9.5 – 18 °C). Very few larvae reared on detritus achieved the adult stage and their developmental time seemed longer. Subimago weight did not vary significantly with temperature, but fecundity (range 435 – 1320 eggs per female) was significantly lower at 9.5 °C than at 14.5 and 18 °C in larvae fed diatoms. Fecundity of females from larvae fed detritus was very low (range 5 – 150 eggs). The reproductive effort (number of eggs per milligram of subimago weight; range 66 – 125) followed a clear linear increasing relationship with temperature (9.5 to 18 °C) for animals reared on diatoms. Poor food quality could probably restrict distribution of E. ignita by reducing fecundity. In conclusion, these results show that the thermal equilibrium hypothesis must be extended to other environmental factors. They also support the hypothesis of a bivoltine cycle of E. ignita under favorable thermic and food conditions.

scholarly journals Identifying reliable fitness proxies for growing animals responding to anthropogenic changes

2020 ◽  
Author(s):  
Andrew D. Higginson
Keyword(s):  
Growth Rate ◽  
Mortality Rate ◽  
Predation Risk ◽  
Energy Use ◽  
Metabolic Costs ◽  
Theoretical Predictions ◽  
Increasing Temperature ◽  
The Impact ◽  
The Relationship ◽  
Increase Mortality Rate

ABSTRACTAnthropogenic influences on habitats often affect predation on species by introducing novel predators, supporting additional predators, or reducing animals’ ability to detect or avoid predators. Other changes may reduce the ability of animals to feed, or alter their energy use. An increase in predation risk is assumed to reduce prey populations by increasing mortality, reducing foraging and growth. Often animals don’t appear to have been adversely affected, or may even increase growth rate. However, theoretical predictions that may have been overlooked suggest that optimal foraging rate, mortality rate and growth rate may change in counter-intuitive ways, depending on exactly how predation risk or costs have been increased. Increasing predator density may increase mortality rate when foraging, reduce the safety of refuges, or alter the relationship between vigilance and attack likelihood. Increasing temperature may increase metabolic costs in ectotherms and reduce thermogenesis costs in endotherms, which affects the costs of active foraging and inactivity differently. Here, I review the theory on how predation risk and metabolic costs should affect foraging behaviour, mortality and growth in order to explain the great variation in behavioural responses. I show that in some situations animals may not respond behaviourally even though a change severely affects survival, and the mortality may be a poor metric of the impact of a change on population viability. In other situations a fitness proxy may change dramatically whilst fitness is unaffected due to compensatory changes in behaviour or life history. Other measures may change in a positive way whilst fitness declines. I describe how to identify the situations in the field and thereby make reliable measure of fitness in particular study systems. Overall, this work shows how behavioural theory can help understand the impacts of environmental change and highlights promising directions to better understand and mitigate their effects on ecosystems.

Effects of feeding ration on larval swimming speed and responsiveness to predator attacks: implications for cohort survival

2000 ◽  
Vol 57 (1) ◽  
pp. 106-115 ◽  
Author(s):  
John H Chick ◽  
Michael J Van Den Avyle
Keyword(s):  
Growth Rate ◽  
Mortality Rate ◽  
Striped Bass ◽  
Swimming Speed ◽  
Larval Growth ◽  
Simulation Models ◽  
Pomoxis Nigromaculatus ◽  
Alosa Aestivalis ◽  
Fish Predators ◽  
Larval Condition

We conducted laboratory experiments to examine the effects of feeding ration on the routine swimming speed of larval striped bass (Morone saxatilis) and their responsiveness to simulated-predator attacks. Striped bass were reared in low (7 prey·L-1), medium (354 prey·L-1), or high (740 prey·L-1) prey treatments from age 4 to 14 days posthatch. Larvae reared in the low-prey treatment had slower routine swimming speeds and shorter reactive distances and were less responsive to simulated-predator attacks. These differences were most pronounced after age 10 and appeared to be an effect of deteriorating larval condition rather than an effect of size. Simulation models were constructed for two potential fish predators, Alosa aestivalis and Pomoxis nigromaculatus, to examine how variation in growth rate, swimming speed, and responsiveness to predator attacks might influence mortality rate. Our simulations predicted that cohort mortality rate would decrease with increasing larval growth rates, even though faster routine swimming speed and growth rate increased encounter rates with predators. The influence of larval growth rate and responsiveness on mortality rate varied between the two predators, but cohorts experiencing no growth always had the greatest mortality rate.

High temperature growth rate in MOCVD growth of AlGaAs

1984 ◽  
Vol 68 (1) ◽  
pp. 169-175 ◽  
Author(s):  
Tetsuo Soga ◽  
Yasuhito Takahashi ◽  
Shiro Sakai ◽  
Masayoshi Umeno
Keyword(s):  
Growth Rate ◽  
High Temperature ◽  
Temperature Growth ◽  
Mocvd Growth

Movement, Growth and natural mortality rate of the Red Spot King Prawn, Penaeus longistylus Kubo, from the Great Barrier Reef Lagoon

1990 ◽  
Vol 41 (3) ◽  
pp. 399 ◽  
Author(s):  
MCL Dredge
Keyword(s):  
Growth Rate ◽  
Mortality Rate ◽  
Great Barrier Reef ◽  
Annual Variation ◽  
Growth Parameters ◽  
Natural Mortality ◽  
Barrier Reef ◽  
Fishing Mortality ◽  
Nursery Areas ◽  
Reef Lagoon

Movement, growth and natural mortality rate of the red spot king prawn, Penaeus longistylus, occurring in waters of the Great Barrier Reef off Townsville, Queensland, were investigated in a series of tagging experiments. Adult P. longistylus did not migrate after leaving nursery areas. Their growth rate was slower than that of the conspecific species P. plebejus, and significant inter-annual variation in growth parameters was observed. The natural mortality rate, assessed by sequential tagging experiments that eliminated the possibility of confounding with the rate of fishing mortality, was estimated to be 0.072 (week-1).

Temperature-Growth Relations and Genetic Diversity of A2 Mating-Type Isolates of Phytophthora cinnamomi in Australia

1974 ◽  
Vol 22 (2) ◽  
pp. 231 ◽  
Author(s):  
CJ Shepherd ◽  
BH Pratt
Keyword(s):  
Growth Rate ◽  
First Generation ◽  
Phytophthora Cinnamomi ◽  
Phytophthora Species ◽  
Temperature Growth ◽  
Field Isolates ◽  
Place Of Origin ◽  
Successive Generations ◽  
Cardinal Temperatures ◽  
Range Of Values

Determinations of cardinal temperatures for growth on various media of 50 Australian isolates of Phytophthova cinnamomi showed that growth did not occur outside the range 5-35°C. The range of temperatures at which growth optima occurred varied according to the isolate and medium used and encompassed the whole range of values reported by overseas authors. Growth rates of 361 isolates on corn meal agar at 25°C varied within the range 4.7-10.5 mm/day. There was no correlation between optimum temperature and whether isolates were slow- or fastgrowing or their place of origin. Fast-growing isolates (6-11 mm/day) were obtained from all States, but slower-growing isolates (<6 mm/day) were obtained only from southern and western regions of Australia. Populations from different regions of Australia exhibited different growth rate parameters. The variability of mycelial isolates in culture was studied by examining differences in growth rate among replicated parent, single-zoospore, single-zoosporangium and single terminal-hyphal isolates. Extensive variation was found among first generation single-zoospore progenies of field isolates, with lesser variation among progeny of single zoosporangia, terminal hyphal cultures and second and third generation zoospore derivatives. The origin of this variation is discussed and it is suggested that field isolates are heterokaryotic, since zoospores proved to be predominantly uninucleate. When various Phytophthora species were incubated at temperatures above those at which growth was possible and then returned to 25°C, their subsequent ability to resume growth depended on the particular time-temperature combination used. Considerable variation of response was found among a number of isolates of P. cinnamomi and, following the establishment of single zoospore isolates, the potential variability of field isolates was shown to persist through successive generations of zoospore propagation. It is suggested that a cytoplasmic mechanism of inheritance may be responsible for this variation.

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

Laboratory studies on the larval biology of Simulium venustum Say (Diptera: Simuliidae)

1976 ◽  
Vol 54 (10) ◽  
pp. 1657-1663 ◽  
Author(s):  
Joseph E. Mokry
Keyword(s):  
Growth Rate ◽  
Growth Curves ◽  
Temperature Profiles ◽  
Laboratory Studies ◽  
Natural Conditions ◽  
Larval Biology ◽  
Temperature Growth ◽  
Complete Development ◽  
Blackfly Larvae ◽  
Pass Through

Larvae reared from field-collected eggs of Simulium venustum were found to pass through six larval instars. Temperature strongly affected both the growth rate of larvae and their survival. At 5, 10, and 12 °C all S. venustum larvae died before reaching the sixth instar. At 15 °C, larvae were found to be able to complete development to the sixth instar, although only 10.5% survived to this stage. Increases in temperature led to increases in survival and rate of growth, with the best survival (20.4%) at 22 °C; most larvae required 22 days to reach this stage. Above 22 °C, survival decreased (5.7%), although the growth rate continued to increase. A growth model for blackfly larvae simulating natural conditions was constructed using temperature–growth curves obtained in laboratory trials and comparing these data with stream temperature profiles.

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