The influence of larval size, temperature, and components of the functional response to prey density on growth rates of the dragonflies Lestes disjunctus and Coenagrion resolutum (Insecta: Odonata)

1995 ◽  
Vol 73 (9) ◽  
pp. 1672-1680 ◽  
Author(s):  
Rangathilakam Krishnaraj ◽  
Gordon Pritchard
Keyword(s):  
Growth Rate ◽  
Regression Analysis ◽  
Multiple Regression Analysis ◽  
Functional Response ◽  
Growth Rates ◽  
Prey Density ◽  
Larval Growth ◽  
Handling Time ◽  
Sampling Errors ◽  
Larval Size

Larval growth of Lestes disjunctus was completed in 70 d in the field, whereas in Coenagrion resolutum it took 10–22 months. This was not simply the result of occupying warmer microhabitats, because L. disjunctus larvae grew faster than C. resolutum at all constant temperatures between 10 and 25 °C in the laboratory. Multiple regression analysis showed that growth rates of both species were positively related to temperature and negatively related to larval size and to the square of temperature. The latter term is necessary to describe the decrease in growth rate at high temperatures. The equation predicted that the growth rate of L. disjunctus reached a maximum at 28.8 °C, whereas that of C. resolutum decreased above 22.4 °C. Small and medium-sized larvae of L. disjunctus ate more prey (Daphnia magna) in 15 min than C. resolutum at all prey densities. In 15-min experiments the attack coefficient for small L. disjunctus larvae was significantly larger than for small C. resolutum larvae and handling time for medium larvae was shorter. Other comparisons had large associated sampling errors, but the trends were the same. These differences may be associated with the relatively longer labia of L. disjunctus and its ability to change hunting methods from ambush to active search.

Some factors which affect the liveweight change and wool growth of adult Corriedale wethers grazed at various stocking rates on perennial pasture in southern Victoria.

1981 ◽  
Vol 32 (2) ◽  
pp. 353 ◽  
Author(s):  
HA Birrell
Keyword(s):  
Growth Rate ◽  
Regression Analysis ◽  
Multiple Regression Analysis ◽  
Multiple Regression ◽  
Growth Rates ◽  
Stocking Rate ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Wool Growth ◽  
Stocking Rates

Monthly observations were taken on a number of animal and pasture characteristics during a 24-year study with adult Corriedale wethers which were grazed at 10, 15, 20 and 25 sheep ha-1. The seasonal patterns in all the observed parameters varied with the stocking rate. The more notable were the fluctuations in digestible organic matter intake (DOMI) which increased with stocking rate in summer (10 and 25 sheep ha-1 having 426 and 818 g DOMI d-1 respectively) and decreased in winter (655 and 448 g DOMI d-1). Both liveweight and wool growth rate (WGR) declined during autumn and increased in the spring at the two high stocking rates but not at the two low stocking rates. The herbage present and its relative growth rate both influenced the amount of herbage voluntarily eaten when the pasture was green. When the dry matter of herbage was < 1.5 t ha-1, the amount of herbage eaten increased as the yield and relative growth rates > 0.05 g g-1 d-1 increased. Sixty-two per cent of the variance in DOMI was accounted for. An exponential function fitted the overall data when relative growth rates were <0.05 g g-1 d-1. DOMI asymptoted at 740 g d-1 when herbage yields exceeded 2.0 t ha-1 (R2 = 0.70). Liveweight loss was very rapid in autumn at high stocking rates despite a high DOMI (c. 650g d-1). This was found, by using multiple regression analysis, to be associated with shearing stress, poor quality feed and long grazing times. In spring, on better quality feed, a long grazing time was associated with an enhanced liveweight response. A multiple regression analysis accounted for 73 % of the variance in WGR. The expression suggested that WGR increased and had a slightly curvilinear relationship with DOMI, was positively related to digestibility and negatively related to the daily time spent grazing. Wool growth slowed concurrently with liveweight losses, the magnitude of the decrease depending upon DOMI.

scholarly journals PREFERENSI DAN TANGGAP FUNGSIONAL PARASITOID HEMIPTARSENUS VARICORNIS (GIRAULT) (HYMENOPTERA: EULOPHIDAE) PADA LARVA LALAT PENGOROK DAUN KENTANG

2009 ◽  
Vol 9 (1) ◽  
pp. 15-21
Author(s):  
Hidrayani Hidrayani ◽  
Aunu Rauf ◽  
S. Sosromarsono ◽  
U. Kartosuwondo
Keyword(s):  
Regression Analysis ◽  
Functional Response ◽  
Preference Test ◽  
Handling Time ◽  
Equation Model ◽  
Type Ii ◽  
Female Parasitoid ◽  
Host Abundance ◽  
Liriomyza Huidobrensis ◽  
Type Ii Functional Response

The preference and functional response of Parasitoid Hemiptarsenus varicornis (Girault) (Hymenoptera:Eulophidae) on host larvae of potato leafminers. The preference of Hemiptarsenus varicornis (Girault) on host larvae of potato leafminers (Liriomyza huidobrensis) and their  functional response on host abundance were studied in laboratory. The preference test was conducted by releasing a female parasitoid in a cage containing two redbean leaves, one with 2nd instar and another one with 3rd instar.  The functional response test was conducted by providing 3rd instar  with density 1, 4, 6, 8, 10, and 13  larvae  per leaf. The result showed that  H. varicornis had the preference on 3rd instar  larvae compared to 2nd instar, either for parasitisation or paralysis. Based on logistic regression analysis it was found that the parasitoid showed type II functional response on the increase of host abundance. The searching rate (a) and handling time (Th) for paralysis were 0.038 and 1.473 based on disk equation model, and 0.076 and 2.060 on ramdom equation model.  For parasitisation activity, the value of  a and Th were  0.012 and 4.649 based on disk equation model, and 0.014 and 5.075 on random equation model.

Relationships Between RNA–DNA Ratio, Prey Density, and Growth Rate in Atlantic Cod (Gadus morhua) Larvae

1979 ◽  
Vol 36 (12) ◽  
pp. 1497-1502 ◽  
Author(s):  
L. J. Buckley
Keyword(s):  
Growth Rate ◽  
Nutritional Status ◽  
Growth Rates ◽  
Prey Density ◽  
Gadus Morhua ◽  
Slow Growth ◽  
Atlantic Cod ◽  
Larval Fish ◽  
Dry Weight ◽  
Dna And Rna

The protein, DNA, and RNA content of larvae maintained at 1.0 plankter/mL increased at the rates of 9.3, 9.9, and 9.8% per day, respectively, for the 5 wk after hatching. Protein reserves of larvae held at 0 or 0.2 plankters/mL were depleted by 45 and 35%, respectively, prior to death 12–13 d after hatching. Starved larvae had similar protein concentrations (percent of dry weight), lower RNA concentrations, and higher DNA concentrations than fed larvae. Larvae held at higher plankton densities had higher RNA–DNA ratios and faster growth rates than larvae held at lower plankton densities. The RNA–DNA ratio was significantly correlated (P < 0.01) with the protein growth rate. The RNA–DNA ratio appears to be a useful index of nutritional status in larval Atlantic cod (Gadus morhua) and may be useful for determining if cod larvae were in a period of rapid or slow growth at the time of capture. Key words: RNA–DNA ratio, starvation, protein, nucleic acids, growth, larval fish, Atlantic cod

Functional response in coccinellid beetles (Coleoptera: Coccinellidae) is modified by prey-density experience

2022 ◽  
Vol 154 ◽  
Author(s):  
Desh Deepak Chaudhary ◽  
Bhupendra Kumar ◽  
Geetanjali Mishra ◽  
Omkar
Keyword(s):  
Functional Response ◽  
Prey Density ◽  
Biological Control Agent ◽  
Handling Time ◽  
Control Agent ◽  
Type Ii ◽  
Response Curves ◽  
Late Instar ◽  
Rearing Density ◽  
Type Ii Functional Response

Abstract In the present study, we assessed functional response curves of two generalist coccinellid beetles (Coleoptera: Coccinellidae), specifically Menochilus sexmaculatus and Propylea dissecta, using fluctuating densities of aphid prey as a stimulus. In what may be the first such study, we investigated how the prey density experienced during the early larval development of these two predatory beetle species shaped the functional response curves of the late instar–larval and adult stages. The predators were switched from their rearing prey-density environments of scarce, optimal, or abundant prey to five testing density environments of extremely scarce, scarce, suboptimal, optimal, or abundant prey. The individuals of M. sexmaculatus that were reared on either scarce- and optimal- or abundant-prey densities exhibited type II functional response curves as both larvae and adults. However, individuals of P. dissecta that were reared on scarce- and abundant-prey densities displayed modified type II functional response curves as larvae and type II functional response curves as adults. In contrast, individuals of P. dissecta reared on the optimal-prey density displayed type II functional response curves as larvae and modified type II functional response curves as adults. The fourth-instar larvae and adult females of M. sexmaculatus and P. dissecta also exhibited highest prey consumption (T/Th) and shortest prey-handling time (Th) on the scarce-prey rearing density. Thus, under fluctuating-prey conditions, M. sexmaculatus is a better biological control agent of aphids than P. dissecta is.

Functional and numerical responses of Iphiseius degenerans (Berlese) (Acari: Phytoseiidae) to different biological stages of Eutetranychus orientalis (Klein) (Acari: Tetranychidae)*

2021 ◽  
Author(s):  
İsmail Döker ◽  
Kemal Yalcin ◽  
Kamil Karut ◽  
Cengiz Kazak
Keyword(s):  
Functional Response ◽  
Prey Density ◽  
Handling Time ◽  
Predatory Mite ◽  
Type Ii ◽  
Adult Males ◽  
Response Curves ◽  
Iphiseius Degenerans ◽  
Eggs And Larvae ◽  
Type Ii Functional Response

Functional and numerical responses of the predatory mite, Iphiseius degenerans (Berlese) (Acari: Phytoseiidae) to four different biological stages (egg, larva, protonymph and adult male) of the citrus brown mite, Eutetranychus orientalis (Klein) (Acari: Tetranychidae) were determined under laboratory conditions. In the experiments, six different prey densities (5, 10, 20, 40, 60 and 80) for each biological stage of the prey were provided to the predatory mite for 24 hours. Results showed that the proportion of prey consumption of I. degenerans decelerated with increasing prey densities of all biological stages of the prey. Logistic regression analysis indicated that I. degenerans showed a Type II functional response regardless of prey stage. The attack rate (α) and the handling time (Th) varied based on the biological stages. The highest α (1.596) and the lowest Th (0.014) values were determined when the predator fed on adult males and larvae of E. orientalis, respectively. The numerical response curves were similar to those of Type II functional response. The efficiency of conversion of ingested food (ECI) of female I. degenerans decreased on all biological stages when prey density increased. The highest and the lowest average daily mean number of eggs laid by I. degenerans were found as 0.45 and 1.90 when it fed on eggs and larvae of its prey, respectively. According to the results, I. degenerans has a potential to be used as a predator in biological control of E. orientalis.

THE FUNCTIONAL RESPONSE OF PHYTOSEIULUS PERSIMILIS (ACARINA: PHYTOSEIIDAE) TO VARIOUS DENSITIES OF TETRANYCHUS URTICAE (ACARINA: TETRANYCHIDAE)

1979 ◽  
Vol 111 (1) ◽  
pp. 7-10 ◽  
Author(s):  
P. Everson
Keyword(s):  
Functional Response ◽  
Tetranychus Urticae ◽  
Adult Female ◽  
Response Curve ◽  
Prey Density ◽  
Handling Time ◽  
Phytoseiulus Persimilis ◽  
Activity Level ◽  
Artificial Substrates ◽  
Successful Search

AbstractThe functional response of the predacious mite Phytoseiulus persimilis Athias-Henriot to increases in the prey density of adult female Tetranychus urticae Koch was examined. Previous studies on artificial substrates have described the functional response curve of P. persimilis to adult female prey as dome-shaped, because as prey density increased the predator was disturbed by prey activity.An experiment to determine the effect of artificial and natural substrates on the activity level of T. urticae was conducted. T. urticae showed a significant increase in activity on artificial substrates of plastic and waterproof paper compared with a substrate of excised bean leaf (Phaseolus vulgaris L.). Since prey activity was significantly influenced by substrate, the functional response of P. persimilis to adult female T. urticae was re-examined. P. persimilis exposed to various densities of T. urticae on excised bean leaf disks (5 cm2) showed a functional response curve having a curvilinear rise to a plateau as prey densities increased from 0.2 to 10.0 prey/cm2.The functional response curve predicted by Holling’s disk equation did not differ significantly from the observed functional response curve.The rate of successful search and the handling time predicted by the disk equation were 0.194 and 10.34 h respectively.

The effects of temperature on larval size in the western king prawn, Penaeus (Melicertus) latisulcatus Kishinouye, from Spencer Gulf, South Australia: implications for fishery management

2013 ◽  
Vol 64 (10) ◽  
pp. 976 ◽  
Author(s):  
G. G. Rodgers ◽  
S. D. Roberts ◽  
C. D. Dixon
Keyword(s):  
Growth Rate ◽  
Fishery Management ◽  
Larval Growth ◽  
South Australia ◽  
Larval Size ◽  
Growth And Survival ◽  
Average Annual Temperature ◽  
Antenna Length ◽  
Effects Of Temperature ◽  
Time Of Year

Temperature, salinity and food availability are generally considered to have the most influence on larval growth and survival in penaeid species. Larval size has previously been used as a measure of animal quality in a range of crustacean species. The aim of this project was to investigate the effects of temperature (17°C, 20°C, 22.5°C and 25°C) on stage-specific larval size in Penaeus latisulcatus collected from the Spencer Gulf, in South Australia. Five different measurements of larval size were assessed: body length, body width, antenna length, carapace length and abdomen length. Results showed that larval growth rate was dependant on temperature, with growth rate greater at higher temperatures. Despite this, larvae reared at 20°C reached the largest size, while those at the temperature extremes (17°C and 25°C) were smallest. When considering average annual temperature, the spawning time that would most likely maximise larval size in the Spencer Gulf is approximately December. This coincides with current management arrangements for the fishery that protect the spawning biomass at this time of year.

Optimal growth temperature hypothesis: Why do anchovy flourish and sardine collapse or vice versa under the same ocean regime?

2007 ◽  
Vol 64 (5) ◽  
pp. 768-776 ◽  
Author(s):  
Akinori Takasuka ◽  
Yoshioki Oozeki ◽  
Ichiro Aoki
Keyword(s):  
Growth Rate ◽  
Growth Temperature ◽  
Growth Rates ◽  
Synergistic Effects ◽  
Larval Growth ◽  
Optimal Growth ◽  
Regime Shifts ◽  
Optimal Growth Temperature ◽  
Sea Temperature ◽  
Japanese Sardine

The out-of-phase population oscillations between anchovy and sardine have been attributed to climate changes. However, the biological processes causing these species alternations have remained unresolved. Here we propose a simple "optimal growth temperature" hypothesis, in which anchovy and sardine regime shifts are caused by differential optimal temperatures for growth rates during the early life stages. Dome-shaped relationships between growth rate and sea temperature were detected for both Japanese anchovy (Engraulis japonicus) and Japanese sardine (Sardinops melanostictus) larvae based on otolith microstructure analysis. The optimal growth rate for anchovy larvae occurred at 22.0 °C, whereas that for sardine larvae occurred at 16.2 °C. Ambient temperatures have historically fluctuated between these optima, which could lead to contrasting fluctuations in larval growth rates between the two species. This simple mechanism could potentially cause the shifts between the warm anchovy regime and the cool sardine regime in the western North Pacific. Although retrospective analysis suggested synergistic effects of other factors (e.g., trophic interactions and fishing), the optimal growth temperature concept would provide a possible biological mechanism of anchovy and sardine regime shifts.

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