Turnip Aphid Lipaphis erysimi Kalt. (Homoptera: Aphididae) Biology, Intrinsic Rate of Increase and Development Threshold Temperature on Oilseed Brassica

1999 ◽  
Vol 2 (3) ◽  
pp. 599-602 ◽  
Author(s):  
M. Amjad ◽  
N. Islam . ◽  
S. A. Kakakhel .
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.


1996 ◽  
Vol 86 (1) ◽  
pp. 67-72 ◽  
Author(s):  
Parviz Shishehbor ◽  
Paddy A. Brennan

AbstractSelected life history characteristics of Encarsia formosa Gahan parasitizing the castor whitefly, Trialeurodes ricini (Misra) were studied at three constant temperatures (20, 25 and 30°C). Egg-to-adult developmental time decreased from 32 days at 20°C to 13 days at 30°C. An average of 241 day-degrees was required to complete development above the lower threshold temperature (12°C). Juvenile mortality was 34, 40 and 47% at 20, 25 and 30°C, respectively. Mean longevity of E. formosa ranged from 7.7 days at 20°C, to 2.6 days at 30°C. Mean total fecundity ranged from 18 to 36 eggs/female. Intrinsic rate of increase (rm) increased with temperature from 0.065/day at 20°C to 0.169/day at 30°C. Generation times decreased from 37 to 14.5 days with increasing temperature.


2005 ◽  
Vol 95 (6) ◽  
pp. 597-603 ◽  
Author(s):  
M.T.K. Kairo ◽  
S.T. Murphy

AbstractPauesia juniperorum(Starý), a solitary endoparasitoid which attacks severalCinaraspp. in the subgenusCupressobium, was introduced into Africa for the control of the cypress aphidCinara cupressivoraWatson & Voegtlin (previously identified asCinara cupressi(Buckton)) and is now established. Data on its biology including a comparison of populations from different hosts and geographical locations are presented. From the UK this consisted of populations reared fromCinara cupressivora, Cinara fresaiBlanchard andCinara juniperiDe Geer, and from France,Cinara?fresai. Between different populations, the duration of development varied within a narrow range (15.5–18.1 days) at 22°C. Data on duration of development over a range of temperatures (15–26°C) for two populations, from the UK and France ranged between 14.0–31.4 days for males and 14.7–32.8 days for females. The threshold temperature for development was 6.2°C and 4.1°C for the populations from the UK and France, respectively. The mean egg load for different populations ranged between 46.4 and 78.5 eggs. The host species had a significant effect on egg load which was directly related to size of the respective host aphids. The lowest egg load was recorded on specimens reared fromC. cupressivorawhich was the smallest aphid. The population from the UK had a higher intrinsic rate of increase (0.232) than the one from France (0.207).


1981 ◽  
Vol 113 (1) ◽  
pp. 65-71 ◽  
Author(s):  
H. J. Herbert

AbstractDevelopment of the European red mite, Panonychus ulmi (Koch), in Nova Scotia was studied at three constant temperatures to construct a life table and establish the intrinsic rate of development. The threshold temperature for development was 10.6°C. The duration from the beginning of the egg stage to adult for females was 31.2, 20.5, and 14.0 days and for males 21.9, 19.6, and 12.8 days at 15°, 18°, and 21°C, respectively. The duration in degree-days above 10.6°C for females was 137.3, 151.7, and 145.2 and for males 128.0, 144.9, and 133.1 at the same three temperatures. The duration of the preoviposition period decreased, duration of the oviposition period remained constant, and the number of eggs laid increased with temperature. Life tables were constructed at 15°, 18°, and 21°C; the intrinsic rates of increase were 0.56,.092, and.134; net reproduction rates 10.06, 13.50, and 17.37; and mean generation times were 41.4, 28.3, and 21.3 days, respectively.


Author(s):  
Luis Carlos Ramos Aguila ◽  
Mubasher Hussain ◽  
Wei Huang ◽  
Lijin Lei ◽  
Bamisope Steve Bamisile ◽  
...  

Abstract Tamarixia radiata Waterson (Hymenoptera: Eulophidea) is the principal natural enemy used for the control of the major citrus pest Diaphorina citri Kuwayama (Hemiptera: Liviidae). In this study, we collected the life-history data of T. radiata at four different temperatures (20, 27.5, 30, and 35°C) and analyzed them by using the age-stage, two-sex life table. The longest preadult developmental time (16.53 d) was observed at 20°C, whereas the shortest one was 7.29 d at 35°C. The preadult development rate was well-fitted to a linear equation. The lower threshold temperature (T0) was 7.85°C and the thermal summation (K) was 193.36 degree-day. The highest fecundity (F) was 322.7 eggs per female was at 27.5°C, whereas the lowest one was 10.8 eggs per female at 35°C. The net reproductive rate (R0) were 70.97, 169.42, 55.70, and 3.25 offspring at 20, 27.5, 30, and 35°C, respectively; the intrinsic rate of increase (r) were 0.1401, 0.3167, 0.3517, and 0.1143 d−1, respectively. The highest values of fecundity, net reproductive rate, intrinsic rate of increase, and finite rate of increase were observed at 27.5°C. The relationships among F, R0, Nf, and N in all treatments were consistent with R0=F×(Nf/N). The age of peak reproductive value was close to the total preoviposition period in all treatments. Population projections based on the age–stage, two-sex life table showed the dynamics of stage structure and its variability. Faster population growth was observed at 27.5 and 30°C.


Author(s):  
Limei He ◽  
Shengyuan Zhao ◽  
Abid Ali ◽  
Shishuai Ge ◽  
Kongming Wu

Abstract Ambient humidity can directly affect the water balance in insects. The migratory fall armyworm, Spodoptera frugiperda Smith, has spread to more than 60 countries and regions in Africa, Asia, and Oceania that have a great difference in average ambient humidity. Understanding the effects of ambient humidity changes on its development, survival, and reproduction can help to predict its population dynamics in different habitats. Therefore, we evaluated the effects of atmospheric relative humidity (RH) on the development, survival, and reproduction and soil moisture on the pupation and emergence of fall armyworm. As a result, survival and pupal mass increased significantly with increasing RH. Among the five RHs tested, 80% RH was the most suitable for fall armyworm with the highest intrinsic rate of increase (r), finite rate of increase (λ), and net reproduction rate (R0). The population growth at the different RHs in decreasing order was 80 > 100 > 60 > 40 > 20%. A relative moisture (RM) of soil from 6.80 to 47.59% was suitable for fall armyworm pupation, survival, and eclosion, but fall armyworm could not pupate normally in soil with 88.39 and 95.19% RM. The survival and emergence rate of fall armyworm pupae were reduced by irrigation that increased the RM after the mature larvae entered the soil. These findings may be helpful for refining laboratory rearing protocols, population forecasting, and management of fall armyworm.


2009 ◽  
Vol 277 (1683) ◽  
pp. 963-969 ◽  
Author(s):  
Katie E. Marshall ◽  
Brent J. Sinclair

While insect cold tolerance has been well studied, the vast majority of work has focused on the effects of a single cold exposure. However, many abiotic environmental stresses, including temperature, fluctuate within an organism's lifespan. Given that organisms may trade-off survival at the cost of future reproduction, we investigated the effects of multiple cold exposures on survival and fertility in the model organism Drosophila melanogaster . We found that multiple cold exposures significantly decreased mortality compared with the same length of exposure in a single sustained bout, but significantly decreased fecundity (as measured by r , the intrinsic rate of increase) as well, owing to a shift in sex ratio. This change was reflected in a long-term decrease in glycogen stores in multiply exposed flies, while a brief effect on triglyceride stores was observed, suggesting flies are reallocating energy stores. Given that many environments are not static, this trade-off indicates that investigating the effects of repeated stress exposure is important for understanding and predicting physiological responses in the wild.


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.


1981 ◽  
Vol 38 (8) ◽  
pp. 968-977 ◽  
Author(s):  
Derek A. Roff

Murphy's hypothesis that variation in reproductive life span is an adaptive response to variation in the predictability of reproductive success is examined. Murphy's contention that this hypothesis explains the variation in reproductive life span within the clupeids is reexamined incorporating further data on the Peruvian anchovy (Engraulis ringens). A nonsignificant correlation is now obtained between reproductive life span and brood strength variation; thus, the hypothesis is called into question. An alternative explanation is presented that considers the interaction between life history parameters: because it is necessary for the intrinsic rate of increase to exceed zero, variation in one parameter must be associated with variation in at least one other parameter. In the clupeids it is noted that the age of maturity and reproductive life span vary in concert and it is suggested that this provides an explanation of variation in reproductive life span. These two hypotheses are examined using data on the family Pleuronectidae, the flatfish. No correlation exists between reproductive life span and the degree of fluctuation in brood strength but there is a significant correlation between reproductive life span and age of maturity. It is concluded that variation in reproductive life span within the flatfish group is not a response to variation in reproductive success but rather a correlate of variation in age of maturity.Key words: flatfish, Pleuronectidae, iteroparity, natural selection, reproduction, clupeids


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