Critique of some practices in life-history studies, with special reference to harpacticoid copepods

1984 ◽  
Vol 35 (3) ◽  
pp. 375 ◽  
Author(s):  
M Bergmans

Published studies on the demography and reproductive strategies of harpacticoid copepods are examined critically. At the technical level, the popular approximation r ≈ In R0/Tc is shown to be inappropriate as an estimate of the intrinsic rate of increase of harpacticoids. It leads to a systematic underestimation, by 8-29%, for life histories typical of fast-breeding species. Various ad hoc variants of r and R0 calculations occurring in the literature are also criticized. .At the conceptual level, a more discriminating approach to life-history characteristics is necessary; this applies both to the assessment of their 'strategic' significance, and to their diagnostic power with regard to the various 'strategies'. Special attention is given to the non-equivalence of parity and voltinism. Recommendations that should promote the construction of a more rigorous cognitive framework are included.

2014 ◽  
Vol 74 (3) ◽  
pp. 691-697 ◽  
Author(s):  
PP Marafeli ◽  
PR Reis ◽  
EC. da Silveira ◽  
GC Souza-Pimentel ◽  
MA. de Toledo

The predatory mite, Neoseiulus californicus(McGregor, 1954) (Acari: Phytoseiidae) is one of the principal natural enemies of tetranychid mites in several countries, promoting efficient control of those mites in several food and ornamental crops. Pest attacks such as that of the spider mite, Tetranychus urticaeKoch, 1836 (Acari: Tetranychidae), is one of the problems faced by farmers, especially in the greenhouse, due to the difficulty of its control with the use of chemicals because of the development of fast resistance making it hard to control it. The objective of this work was to study the life history of the predatory mite N. californicus as a contribution to its mass laboratory rearing, having castor bean plant [Ricinus communis L. (Euphorbiaceae)] pollen as food, for its subsequent use as a natural enemy of T. urticae on a cultivation of greenhouse rosebushes. The studies were carried out in the laboratory, at 25 ± 2°C of temperature, 70 ± 10% RH and a 14 hour photophase. The biological aspects and the fertility life table were appraised. Longevity of 32.9 days was verified for adult females and 40.4 days for males. The intrinsic rate of increase (rm) was 0.2 and the mean generation time (T) was 17.2 days. The population doubled every 4.1 days. The results obtained were similar to those in which the predatory mite N. californicus fed on T. urticae.


2017 ◽  
Vol 22 (1) ◽  
pp. 148 ◽  
Author(s):  
Ya Ying Li ◽  
Xiao Fan ◽  
Guo Hao Zhang ◽  
YI QING LIU ◽  
HAN QIU CHEN ◽  
...  

Traditional estimating only by measuring the lethal effect of acaricides may underestimate the total effects of acaricides on the pest mites. In order to investigate the sublethal effect of bifenazate on life history and population parameters of the two-spotted spider mite, Tetranychus urticae Koch, the newly emerged females were treated with two lethal concentrations of bifenazate: LC10 (4.92 μg/mL) and LC20 (8.77 μg/mL). Subsequently, the development and fecundity of the progeny generations were observed. Compared to the control, exposure to the 10% lethal concentrations (LC10) and LC20 of bifenazate severely affected the parental generation of T. urticae, including survival rate (reduced 9% and 13%), oviposition period (reduced 77.6% and 83.1%), fecundity per female (decreased 89.2% and 76.9%) and longevity (decreased 79.2% and 83.1%). Besides, the population parameters of the progeny generation from the treated females were also investigated. The results showed that the progeny generation had lower intrinsic rate of increase (rm) and finite rate of increase (λ), longer mean generation time (Tc) compared to the control. The results suggested that the sublethal effects of bifenazate on population growth of T. urticae were significant, and the results of this study could be used as a guide for the rational use of bifenazate in the field for better managing pest mites.


1975 ◽  
Vol 26 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Brian Charlesworth ◽  
John A. Williamson

SUMMARYAn expression is derived for determining the probability of survival of a new favourable mutation in a large random-mating population with overlapping generations. For a gene of small effect, in a near-stationary population, an approximate formula similar to the usual one for discrete generations is obtained. The implications of these results for the evolution of life histories are discussed, using the partial derivatives of the chance of survival of a gene, with respect to changes in age-specific fecundities and survival probabilities. The properties of these derivatives are very similar to those of the derivatives of the intrinsic rate of increase, analysed by Hamilton (1966), thus providing a genetical basis for his conclusions concerning the evolution of life histories.


Insects ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 292
Author(s):  
Fatemeh Ganjisaffar ◽  
Thomas M. Perring

Ooencyrtus lucidus Triapitsyn & Ganjisaffar (Hymenoptera: Encyrtidae) was recently recovered from fresh sentinel eggs of Bagrada hilaris (Burmeister) (Hemiptera: Pentatomidae) in California. In the present study, life history traits of O. lucidus were studied at 26 ± 0 . 5 ∘ C, 40 ± 10 % RH, and a photoperiod of 14 L: 10 D hours. Results showed that 95.2% of the parasitized eggs yielded successful emergence of adults. The total immature developmental time was 14.27 and 13.95 days for females and males, respectively. The sex ratio of O. lucidus was 0.5 (females/offspring). Mated females laid on average 6.0 eggs per day and 222.7 eggs during their mean ovipositional period of 37.3 days. There was no significant difference in reproduction parameters between mated and non-mated females. The net reproductive rate ( R 0 ) was 103.8 females/female/generation, the intrinsic rate of increase ( r m ) was 0.171 females/female/day, the finite rate of increase ( λ ) was 1.187 population multiplication/day, the mean generation time (T) was 27.1 days, and the doubling time (DT) was 4.0 days. The highest longevity was observed in mated and non-mated females fed with honey, and they lived for 70.8 and 70.1 days, respectively. Providing females with host eggs in addition to honey, reduced their longevity by 24% in mated and 28% in non-mated individuals. Non-mated females and males deprived of honey only lived for 3.5 and 2.5 days after emergence, respectively. Our results indicate that O. lucidus has sufficient life history traits to make it a promising egg parasitoid for the biological control of B. hilaris.


2020 ◽  
Vol 113 (2) ◽  
pp. 964-973
Author(s):  
Zahra Abedi ◽  
Ali Golizadeh ◽  
Mahmoud Soufbaf ◽  
Mahdi Hassanpour ◽  
Ali Jafari-Nodoushan ◽  
...  

Abstract Plant–herbivore interactions can be influenced by plant developmental stages. Effects of four different developmental stages of pomegranate fruit (Hazelnut size, Walnut size, Juicy, and Ripe) were investigated on life table parameters, nutritional yield, and energy contents (protein, glycogen, and lipid) of Ectomyelois ceratoniae (Zeller) under controlled conditions in two pomegranate cultivars, namely Shahvare-Danesefid and Esfahani-Daneghermez as susceptible and resistant cultivars, respectively. Biochemical characteristics of the four developmental stages were determined, and a correlation was made with life-history and nutritional responses of E. ceratoniae. Significant differences were observed in developmental time and adult fecundity of E. ceratoniae across various tested stages in both pomegranate cultivars. The highest value of intrinsic rate of increase (rm) was found in Juicy and lowest in Hazelnut-size stage of Shahvare-Danesefid. The highest rm value was on Walnut-size and Juicy stages, and the lower rate was obtained from the feeding of E. ceratoniae on Ripe and Hazelnut-size stages in Esfahani-Daneghermez. A higher relative growth rate (RGR) was observed in Juicy (in Shahvare-Danesefid) and Walnut-size stages (in Esfahani-Daneghermez) when compared with other developmental stages tested. Life-history parameters of E. ceratoniae were correlated with biochemical qualities of pomegranate stages. Results indicated Juicy (Shahvare-Danesefid) and Walnut-size stages (Esfahani-Daneghermez) were relatively susceptible pomegranate stages, and Hazelnut-size and Ripe stages were unsuitable for feeding of E. ceratoniae in Shahvare-Danesefid and Esfahani-Daneghermez, respectively. Findings of this research could aid in the development of integrated management programs of E. ceratoniae in pomegranate orchards.


1987 ◽  
Vol 65 (1) ◽  
pp. 113-121 ◽  
Author(s):  
Daniel J. Hornbach ◽  
Daniel L. Childers

This study examines the effects of acidification on growth, survivorship, and natality of the fingernail clam, Musculium partumeium. Six groups of newborn clams (parents), collected in either October (replicate 1) or January (replicate 2), and their offspring (F1) were maintained in river water kept at a pH of 3, 4, 5, or 6 with the addition of H2SO4. A control (no acid added) had an average pH near 7. Generally, growth and survivorship were poor in treatments of pH 3 and 4. Maximal growth occurred at a pH of 5, which approximates that of the stream from which these clams were collected. Also, clams maintained at a pH of 5 generally had the highest gross and net reproductive rates and the youngest age at first reproduction, leading to maximum values of r (intrinsic rate of increase) for clams maintained at pH 5. Usually the F1 generations had greater survivorship than their parents and under adverse conditions could attain greater shell lengths. Life-history traits in M. partumeium appear to be sensitive to changes in environmental pH and populations of these clams may be able to acclimate to changing pH regimes over time, i.e, from one generation to the next.


PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248819
Author(s):  
Yujeong Park ◽  
Young-gyun Park ◽  
Joon-Ho Lee

Bemisia tabaci Mediterranean (Gennadius) (Hemiptera: Aleyrodidae) is an economically important insect pest worldwide. Previously, we have reported that most B. tabaci Mediterranean (MED) populations occurring in greenhouse tomatoes in Korea have been displaced from well-differentiated two genetic clusters (C1 and C2) to one (C2) during one-year period. To elucidate factors responsible for this phenomenon, we compared life history parameters of these two different genetic clusters through single and cross mating experiments on two different host plants, cucumber and tobacco, at 26°C. Intrinsic rate of increase (r), finite rate of increase (λ), and net reproductive rate (Ro) were significantly higher in the dominating cluster (C2) (0.247, 1.280, and 192.402, respectively on cucumber; 0.226, 1.253, and 133.792, respectively on tobacco) than in the other cluster (C1) (0.149, 1.161, and 50.539, respectively on cucumber; 0.145, 1.156, and 53.332, respectively on tobacco). Overall performances of cross mating groups, C2fC1m (C2 female × C1 male) and C1fC2m (C1 female × C2 male), were in-between those of C2 and C1, with C2fC1m performing better than C1fC2m. Thus, maternal inheritance appeared to be significantly associated with their life history parameters, with partial involvement of paternal inheritance. Our results demonstrated that the rapid displacement of genetic clusters of B. tabaci MED populations was clearly associated with differences in their life history parameters.


Author(s):  
Yingchao Ji ◽  
Guohua Li ◽  
Chenggang Zhou ◽  
Shuyan Yin

Abstract Temperature is one of the main factors affecting insect growth, development and reproduction. The effects of temperatures (10, 15, 20, 25 and 30°C) on the development and reproduction of Cinara cedri Mimeur (Hemiptera: Aphidoidea: Lachnidae) fed on Cedrus deodara (Roxb.) G. Don were evaluated in this study. With the increase of temperature from 10 to 30°C, the development duration at different development stages gradually shortened. There was a significant positive correlation between the developmental rates and temperature, following a quadratic regression model. The lower developmental threshold temperature (C) and effective accumulated temperatures (K) for completing a generation were 4.13°C and 263.4 degree-days, respectively. The highest fecundity was observed at 20°C with 25.74 first-instar nymphs/female. Both the highest intrinsic rate of increase (r, 0.11 ± 0.03) and net reproduction rate (R0, 19.06 ± 2.05) were observed at 20°C, whereas the lowest values of r (0.05 ± 0.01) at 10°C and R0 (5.78 ± 0.88) at 30°C were observed. The results suggest that temperature significantly affects the biology of C. cedri and the optimal temperature for its development is 20°C.


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