THE EFFECT OF PARASITISM BY APHIDIUS SMITHI (HYMENOPTERA: APHIDIIDAE) ON REPRODUCTION AND POPULATION GROWTH OF THE PEA APHID (HOMOPTERA: APHIDIDAE)

1975 ◽  
Vol 107 (9) ◽  
pp. 919-926 ◽  
Author(s):  
A. Campbell ◽  
M. Mackauer

AbstractParasitism by Aphidius smithi reduced the fecundity and population growth of pea aphid, Acyrthosiphon pisum. Aphids that were parasitized during the first or second instar period died as fourth instars without producing offspring. Parasitized third or fourth instars usually reached maturity and produced a variable number of progeny. Parasitized adult aphids stopped producing nymphs approximately 7 to 8 days following attack by A. smithi. Equations are given for the relationship between the mean total fecundity, the intrinsic rate of increase, and the doubling time of apterous and alate viviparous pea aphid and the aphid age at the beginning of parasitism.

1977 ◽  
Vol 109 (2) ◽  
pp. 277-284 ◽  
Author(s):  
A. Campbell ◽  
M. Mackauer

AbstractThe effect of temperature on the age-specific fecundity and the survival of apterous and alate virginoparous pea aphid, Acyrthosiphon pisum (Harris), from Kamloops, B.C., was measured. Demographic statistics were estimated for 10.3°, 14.8°, 19.7°, 26.1°, and 27.8°C constant and for fluctuating field temperatures. On a 24-h-day time-scale, temperature and longevity were inversely related in both morphs; total fecundity was highest at average and low constant temperatures. On a physiological time-scale, the intrinsic rate of increase (rm) was insensitive to changes in constant temperature in the range between 10° and 20°C; temperatures above 25°C were detrimental to aphid population growth and survival. Alate virginoparae generally had a longer pre-reproductive period and achieved a lower mean total fecundity than apterae maintained under identical conditions. The usefulness of laboratory measurements for the prediction of population growth under variable field temperatures is discussed. Differences in the reproductive patterns of alate and apterous pea aphids are considered in the context of the r- and K-hypothesis of selection.


2017 ◽  
Vol 108 (1) ◽  
pp. 84-92 ◽  
Author(s):  
A.M. Hamada ◽  
J. Fatehi ◽  
L.M.V. Jonsson

AbstractThiamine is a vitamin that has been shown to act as a trigger to activate plant defence and reduce pathogen and nematode infection as well as aphid settling and reproduction. We have here investigated whether thiamine treatments of seeds (i.e. seed dressing) would increase plant resistance against aphids and whether this would have different effects on a generalist than on specialist aphids. Seeds of wheat, barley, oat and pea were treated with thiamine alone or in combination with the biocontrol bacteriaPseudomonas chlororaphisMA 342 (MA 342). Plants were grown in climate chambers. The effects of seed treatment on fecundity, host acceptance and life span were studied on specialist aphids bird cherry-oat aphid (Rhopalosiphum padiL.) and pea aphid (Acyrthosiphon pisumHarris) and on the generalist green peach aphid (Myzus persicae, Sulzer). Thiamine seed treatments reduced reproduction and host acceptance of all three aphid species. The number of days to reproduction, the length of the reproductive life, the fecundity and the intrinsic rate of increase were found reduced for bird cherry-oat aphid after thiamine treatment of the cereal seeds. MA 342 did not have any effect in any of the plant-aphid combinations, except a weak decrease of pea aphid reproduction on pea. The results show that there are no differential effects of either thiamine or MA 342 seed treatments on specialist and generalist aphids and suggest that seed treatments with thiamine has a potential in aphid pest management.


Acarologia ◽  
2018 ◽  
Vol 58 (1) ◽  
pp. 52-61
Author(s):  
Samah Ben Chaaban ◽  
Brahim Chermiti ◽  
Serge Kreiter

The old world date mite Oligonychus afrasiaticus is an important spider mite pest of the date palms Phoenix dactylifera L. mostly in North Africa and the Middle East. A population of the predaceous mite Typhlodromus (Anthoseius) athenas has been recently found in Tunisia in association with a decrease of O. afrasiaticus densities. The objective of this paper was to assess the development and reproduction abilities of T. ( A.) athenas on O. afrasiaticus under laboratory conditions at two temperatures: 27 and 32 °C. The results obtained show that females of T. (A.) athenas develop in 5 days at 27 °C and 4.1 days at 32 °C. The mean fecundity of T. (A.) athenas was 32.1 and 23.2 eggs per female at 27 and 32 °C, respectively. Life table parameters were stimated: the net reproductive rate (Ro) 27.9 and 17.9 eggs/female, the intrinsic rate of increase (rm) 0.322 and 0,344 female/female/day and the mean generation time (T) 10.3 and 8.4 days at 27 and 32 °C, respectively. At both temperatures tested, T. (A.) athenas intrinsic rate of increase was greater than that of O. afrasiaticus (rm = 0.213 at 32 °C,against rm = 0.166 day1 at 27 °C). Typhlodromus (A.) athenas would be able to develop at a wide range of temperatures feeding on O. afrasiaticus and seems to be able to potentially control it.


2017 ◽  
Vol 22 (10) ◽  
pp. 1748 ◽  
Author(s):  
Irena Međo ◽  
Bojan Stojnić ◽  
Dejan Marčić

Laboratory bioassays were conducted to evaluate the toxicity of the microbial pesticide spinosad to different life stages of the two-spotted spider mite, Tetranychus urticae Koch, as well as its sublethal effects on reproduction and population growth of this important mite pest. The biopesticide was applied to bean primary leaves or leaf discs carrying spider mites using a Potter spray tower (2.7 mg/cm2 aqueous deposit). The following LC50 and LC90 (mg/L) estimates for motile stages were obtained in acute toxicity bioassays: 27.52 and 116.72 (larvae), 36.55 and 136.20 (protonymphs), 82.76 and 721.28 (female deutonymphs), and 61.47 and 457.21 (adult females). Spinosad showed no significant ovicidal action: toxic effect observed after spraying eggs (LC50 = 105.78 mg/L, LC90 = 596.95 mg/L) was the result of its residual action on larvae that hatched from the treated eggs. The effects of spinosad on life history traits and population growth of adult female survivors from treatments with 240, 120 and 60 mg/L were evaluated in two successive 7-day bioassays on untreated leaf discs. In the first bioassay, females that survived treatments as 24 h old eggs and completed their juvenile development on treated leaves had significantly lower gross fecundity, net fecundity and instantaneous rate of increase (ri) but the reduction was merely 4–6%, 9–11%, and 2–3%, respectively. Female longevity was significantly reduced (approximately by half a day) only after treatment with 240 mg/L. In the second bioassay, in which females were treated during their pre-ovipositional period, the treatments with 240 and 120 mg/L significantly reduced their gross fecundity (16–17%), net fecundity (28–31%), ri values (8–9%) and female longevity (approximately by one day). Spinosad effects on the intrinsic rate of increase (rm) and other demographic parameters were evaluated in two successive bioassays in which life tables were constructed for females that survived treatment with 120 mg/L at the egg stage (first demographic bioassay) or pre-ovipositional period (second demographic bioassay). In the first bioassay, the intrinsic rate of increase was significantly higher in treated (rm = 0.278) than control mites (rm = 0.267) as a result of higher net fertility at the beginning of reproduction of treated females. In the second bioassay, treated females had significantly lower rm than control females (0.254 and 0.283, respectively). The results obtained in this study indicate that spinosad, applied against insect pests (at field relevant rates of 60–240 mg/L), could eliminate a part of T. urticae population as well, but survivors would retain a significant potential for population recovery. 


2014 ◽  
Vol 14 (1) ◽  
pp. 64-70
Author(s):  
Nila Wardani ◽  
Aunu Rauf ◽  
Wayan Winasa ◽  
Sugeng Santoso

ABSTRACTThe life history and population growth parameters of mealybug Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae) on two cassava varieties. The development, reproduction, and population growth parameters of the cassava mealybug, Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae) on two cassava varieties were studied in laboratory. The varieties tested were UJ-5 with high cyanide content (>100 mg per kg) dan Adira-1 with low cyanide content (27.5 mg per kg).  Our research revealed that P. manihoti performances were highly affected by cassava varieties.  Incubation period of eggs of P. manihoti were 7.93 ±  0.09 and 8.33 ± 0.11 days, nymphal development periode 12.32±0.13 and 15.67 ± 0.13 days, respectively on UJ-5 and Adira-1. Fecundity averaged 386.37 ± 5.83 on UJ-5 and 318.67±2.81 eggs on Adira-1. Intrinsic rate of increase (rm) were  0.258 ± 0.001 on UJ-5 and  0.220 ± 0.001 on Adira-1. Mean generation time (T) on UJ-5 and Adira-1 were 22.795 ± 0.050 and 25.532 ± 0.047 days, repectively. Our findings showed that variety UJ-5 was more suitable for development and population growth of the cassava mealybug.


2020 ◽  
Vol 25 (11) ◽  
pp. 2063-2076
Author(s):  
Nuwan Weerawansha ◽  
Qiao Wang ◽  
Xiong Zhao He

Tetranychus ludeni Zacher (Acari: Tetranychidae) is an invasive polyphagous haplodiploid pest mite of many vegetable crops in many parts of the world. This study investigated the effects of simultaneous variations in the local foundress population density and size on the reproduction and population growth of T. ludeni. We show that negative population-density and -size dependency limited the reproduction of foundresses, where the effects of population size on population growth overweighed that of population density. We further demonstrate that ovipositing females could accelerate population growth rate (intrinsic rate of increase, rm) at higher population sizes by producing more daughters early during their lifespan, which can be an adaptive strategy to allow more daughters to complete development and disperse to reduce future food competition intensity. This study provided knowledge on population dynamics in response to foundress population density and size in general and T. ludeni population forecast and precise timing of pest management in particular.


2020 ◽  
Vol 25 (8) ◽  
pp. 1461-1471
Author(s):  
Lixia Xie ◽  
Na Zhang ◽  
Xinran Wu ◽  
Kai Liu ◽  
Chenlin Liu ◽  
...  

Lasioseius japonicus is a species of soil-dwelling predatory mite with great potential for controlling insect pests and has a broad application prospect in biological control. This study was conducted under indoor conditions to explore the development, survival and reproduction of L. japonicus on two diets. Through the construction of two-sex life table of L. japonicus, it was revealed that, when it preyed on eggs of Drosophila melanogaster, the intrinsic rate of increase (r) was 0.2614 d-1, the net reproductive rate (R0) was 57.76 offspring, the finite rate of increase (λ) was 1.2988 d-1, and the mean generation time (T) was 15.49 d. When preying on eggs of Sitotroga cerealella, the intrinsic rate of increase (r) of L. japonicus was 0.1560 d-1, the net reproductive rate (R0) was 20.96 offspring, the finite rate of increase (λ) was 1.1690d-1, and the mean generation time (T) was 19.41 d. In addition, the life expectancy and population growth trend of L. japonicus were simulated based on the above two alternative prey species. The results showed that feeding on the eggs of D. melanogaster is more beneficial to the growth and reproduction of L. japonicus.


2019 ◽  
Vol 24 (9) ◽  
pp. 1620-1630 ◽  
Author(s):  
Zahra Alipour ◽  
Yaghoub Fathipour ◽  
Azadeh Farazmand ◽  
Mostafa Khanamani

Herbivores' host plant resistance may also affect performance of their predators. The effect of susceptible ('Yellow') and resistant ('Roulette') rose cultivars on demographic parameters of the two-spotted spider mite (TSSM), Tetranychus urticae Koch and its predators Phytoseiulus persimilis Athias-Henriot and Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) was determined under laboratory conditions. The obtained data were analyzed using the two-sex life table theory. The development rate of different life stages of TSSM and its predators on the susceptible and resistant rose cultivars were significantly different. Total development time of juvenile stages of TSSM and A. swirskii on the resistant cultivar was longer than that on the susceptible one, although no significant differences were obtained in the case of P. persimilis. By using the two-sex life table, the intrinsic rate of increase (r) of TSSM on the susceptible and resistant cultivars was 0.205 and 0.143 day-1, respectively. In addition, the net reproductive rate (R0) of TSSM on the susceptible and resistant cultivars was 26.46 and 11.47 eggs per individual, respectively; however, the mean generation time (T) of TSSM on these cultivars was 15.92 and 16.92 days, respectively. Furthermore, the value of the intrinsic rate of increase (r) in P. persimilis on the susceptible and resistant cultivars was 0.217 versus 0.163 day-1as well as in A. swirskii on the mentioned cultivars was 0.147 versus 0.117 day-1, respectively. There was no significant difference between the values of the net reproductive rate (R0) in P. persimilis on the susceptible and resistant rose cultivars, but in A. swirskii the value of this parameter on the susceptible cultivar was significantly higher than that on the resistant one. The mean generation time (T) in both predators on the resistant cultivar was longer than the susceptible one. In conclusion, resistance of the rose cultivar negatively affected the population growth parameters of TSSM and its both predators.


2019 ◽  
Vol 79 (3) ◽  
pp. 488-494 ◽  
Author(s):  
A. Specht ◽  
V. F. Roque-Specht

Abstract In this study we evaluate the biotic potential and reproductive parameters of Spodoptera cosmioides (Walker, 1858) under controlled conditions (25 ± 1 °C, 70 ± 10% RH and 14 hour photophase). Females, on average, (14.433 days) did not live significantly longer than their male counterparts (13.100 days). The mean durations of the pre-oviposition, oviposition and post-oviposition periods were 2.767, 10.600 and 1.067 days, respectively. The mean fecundity of females was 5,073.533 eggs and the mean fertility was 5,021.027 larvae. On average, females copulated 1.167 times. Fecundity was positively correlated with the number of copulations (r = 0.583, P <0.001). The number of copulations, however, was negatively correlated whit the duration of the pre-oviposition (r = -0.560, P = 0.007) and oviposition (r = -0.479, P = 0.048) periods, and overall longevity (r = -0.512, P = 0.031). The biotic potential was estimated at 6.547 x 1021 individuals/female/year. The net reproductive rate (Ro) was 2,193.722 times per generation and the mean generation time (T) was 46.407 days. The intrinsic rate of increase (rm) was 0.166, with a finite rate of increase (λ) of 1.180, per week.


2021 ◽  
Vol 26 (5) ◽  
pp. 962-972
Author(s):  
Zarir Saeidi ◽  
Alireza Nemati ◽  
Elham Riahi

The development, longevity, and reproductive potential of Schizotetranychus smirnovi concerning different almond cultivars including Sefid, Azar, Shokofeh, Shahrood6, Shahrood7, Ferragnes, Shahrood13, Shahrood21, Rabie, Nonpareil, and Mamaei were investigated in the current study. Our results indicated the longest developmental time of females on Shahrood21 (7.35 ± 0.10), while the shortest duration of this parameter was found on Rabie (6.21 ± 0.10) and Nonpareil (5.88 ± 0.17) cultivars. The total mortality ranged from 13.30 to 50.00% on Azar and Shokofeh, respectively. On the majority of cultivars, the highest proportion of mortality among all stages was allocated to larvae which indicated that it was the most sensitive stage. The fecundity of S. smirnovi on Mamaei (34.19 ± 3.60), Sefid (30.50 ± 2.67), and Ferragnes (30.31 ± 3.02) was significantly higher than other cultivars. However, the lowest fecundity (11.21 ± 1.70) was observed on Shokofeh cultivar. Moreover, different cultivars resulted in significant differences in all population growth parameters. Azar had the highest value of both intrinsic rate of increase (r) (0.2675 ± 0.0164) and finite rate of increase (λ) (1.3067 ± 0.0213), whereas the value of these parameters on Shokofeh and Shahrood21 were significantly lower than other cultivars. The mean generation time (T) ranged from 9.51 ± 0.16 on Shahrood7 to 11.69 ± 0.39 d on Shahrood21 cultivar. According to our results, Mamaei, Nonpareil, Rabie, Ferragnes and Azar cultivars were more susceptible, while Shokofeh, Shahrood21, and Shahrood13 seemed to be more tolerant to S. smirnovi.


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