Introduction
Materials and methods
Mass rearing of M. vitrata
Mass rearing of A. taragamae
Influence of larval age of M. vitrata on development time, longevity, fecundity and sex ratio of A. taragamae
Effect of larval density of M. vitrata on the rate of parasitization by A. taragamae
Influence of larval age on the life history parameters of A. taragamae reared on M. vitrata
-
The net reproductive rate R 0 , which is the number of female progeny per female per generation. It is given by the following formula:where: x is the pivotal age of individuals in days, l x is the age-specific survival as proportion of individuals still alive at age x, m x is the age-specific fecundity as female offspring per female.$$ R_{o} = \sum {l_{x} m_{x} } $$
-
The intrinsic rate of increase r m , given by the formula:where e is the base of natural logarithm (ln).$$ 1 = \sum {l_{x} m_{x} e^{{ - r_{{_{m} }} x}} } $$
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The mean generation time T, calculated as follows: \( T = \ln (R_{0} )/r_{{_{m} }} \) and by approximation \( T = \left( {\sum {xl_{x} m_{x} } } \right)/\sum {l_{x} m_{x} } \)
-
The doubling time T2 is therefore:$$ T_{2} = \ln (2)/r_{m} $$
-
The finite rate of increase λ, expressed as the multiplication per female per unit time:$$ \lambda = e^{{r_{m} }} $$
Statistical analysis
Results
Influence of larval host age on some biological parameters of Apanteles taragamae
Parasitoid life-history parameters | Maruca vitrata larval age at parasitization | ||
---|---|---|---|
1 Day | 2 Days | 3 Days | |
Development time (days) | |||
Egg-cocoon | 8.3 ± 0.11 (30)a | 7.9 ± 0.11 (67)a | 7.7 ± 0.08 (57)a |
Cocoon-adult | 5.0 ± 0.12 (12)a | 5.2 ± 0.12 (43)a | 4.9 ± 0.09 (45)a |
Egg-adult (cycle) | 13.6 ± 0.23 (12)a | 12.9 ± 0.14 (43)b | 12.5 ± 0.13 (45)c |
Development cycle egg-adult (days) | |||
Male | 13.6 ± 0.23 (12)a | 12.8 ± 0.16 (25)bα | 12.2 ± 0.11 (32)cα |
Female | – | 13.1 ± 0.25 (18)aα | 13.2 ± 0.30 (13)aβ |
Longevity (days) | |||
Male | 19.8 ± 3.01 (12)a | 13.4 ± 1.75 (25)bα | 8.5 ± 1.73 (32)bα |
Female | – | 11.0 ± 1.60 (15)aα | 8.8 ± 1.45 (12)aα |
Survival rate of larvae and cocoons (%) | 7.0 ± 3.0 (4)a | 43.0 ± 8.5 (4)b | 46.0 ± 5.8 (4)b |
Parasitization rate (%) | 35.0 ± 7.9 (4)a | 67.0 ± 2.5 (4)b | 56.0 ± 2.8 (4)ab |
Sex ratio (% of females in the population) | 0.0 | 40.5 a. n.s. | 27.3a* |
Female fecundity (number of cocoons per female) | – | 55.5 ± 5.6 (14)a | 42.2 ± 8.1 (11)a |
Host density
Temperature
Parameters | Temperatures regimes | ||||
---|---|---|---|---|---|
20°C | 24°C | 26°C | 28°C | 30°C | |
Development time (days) | |||||
Egg-cocoon | 13.7 ± 0.09 (90)a | 7.9 ± 0.03 (105)b | 6.9 ± 0.05 (113)c | 5.7 ± 0.05 (97)d | 5.7 ± 0.04 (130)d |
Cocoon-adult | 11.3 ± 0.16 (65)a | 4.8 ± 0.09 (74)b | 5.2 ± 0.12 (64)b | 4.4 ± 0.11 (61)bc | 3.9 ± 0.11 (70)c |
Egg-adult (cycle) | 24.9 ± 0.24 (65)a | 12.6 ± 0.10 (74)b | 12.0 ± 0.12 (64)c | 10.0 ± 0.10 (61)d | 9.7 ± 0.08 (70)d |
Development cycle (days) | |||||
Male | 23.9 ± 0.25 (34)aα | 12.3 ± 0.10 (36)bα | 11.9 ± 0.13 (50)bα | 9.9 ± 0.16 (31)cα | 9.4 ± 0.09 (40)cα |
Female | 26.0 ± 0.32 (30)aβ | 13.0 ± 0.15 (37)bβ | 12.9 ± 0.18 (36)bβ | 10.03 ± 0.12 (30)cα | 10.1 ± 0.08 (30)cβ |
Longevity (days) | |||||
Male | 18.3 ± 0.69 (30)aα | 15.6 ± 2.3 (30)aα | 13.8 ± 1.8 (30)aα | 5.3 ± 0.76 (30)bα | 3.1 ± 0.45 (30)bα |
Female | 21.9 ± 0.90 (30)aα | 12.0 ± 0.81 (30)bα | 9.2 ± 0.55 (30)bcβ | 7.7 ± 0.73 (30)bcβ | 4.1 ± 0.44 (30)dα |
Lifetime fecundity (cocoons/female) | 123.3 ± 12.7 (30)a | 73.2 ± 5.8 (30)b | 64.7 ± 6.0 (30)b | 46.7 ± 4.1 (30)b | 5.9 ± 1.9 (30)c |
Daily fecundity (cocoons/female/day) | 5.5 ± 0.37 (30)a | 7.1 ± 0.80 (30)a | 6.9 ± 0.51 (30)a | 6.8 ± 0.61 (30)a | 1.2 ± 0.46 (30)b |
Survival rate of larvae and cocoons (%) | 71.0 ± 2.0 (3)ac | 81.7 ± 1.45 (3)b | 76.0 ± 0.58 (3)a | 69.3 ± 1.2 (3)c | 67.3 ± 0.66 (3)c |
Sex ratio (% females progeny) | 34.7a* | 33.3a* | 34.3a* | 34.0a* | 33.3a* |
Parameters | Temperatures regimes | ||||
---|---|---|---|---|---|
20°C | 24°C | 26°C | 28°C | 30°C | |
Development time (days) | |||||
Egg-pupa | 20.6 ± 0.60 (75)a | 14.9 ± 0.08 (70)b | 12.5 ± 0.06 (100)c | 11.2 ± 0.07 (82)d | 11.0 ± 0.12 (81)d |
Pupa-adult | 15.5 ± 0.06 (71)a | 8.5 ± 0.06 (67)b | 7.1 ± 0.07 (68)c | 5.9 ± 0.13 (62)d | 5.1 ± 0.07 (67)e |
Egg-adult | 39.0 ± 0.10 (71)a | 26.4 ± 0.77 (67)b | 22.8 ± 0.66 (68)c | 20.2 ± 0.18 (62)d | 19.2 ± 0.11 (67)e |
Development cycle (days) | |||||
Male | 38.9 ± 0.14 (41)aα | 26.4 ± 0.10 (34)bα | 20.7 ± 0.18 (38)cα | 20.2 ± 0.17 (31)cα | 19.4 ± 0.17 (32)dα |
Female | 39.1 ± 0.21 (29)aα | 26.4 ± 0.12 (31)bα | 22.7 ± 0.12 (31)bβ | 20.1 ± 0.31 (32)dα | 19.0 ± 0.08 (35)eα |
Longevity (days) | |||||
Male | 22.4 ± 1.3 (30)aα | 12.5 ± 0.71 (30)bα | 12.9 ± 1.0 (30)bα | 7.9 ± 0.81 (30)cα | 7.7 ± 0.71 (30)cα |
Female | 16.8 ± 1.6 (30)aβ | 14.4 ± 1.5 (30)abα | 12.0 ± 1.1 (30)bα | 10.4 ± 0.94 (30)bβ | 5.4 ± 0.83 (30)cβ |
Lifetime fecundity (eggs/female) | 121.5 ± 16.6 (30)ac | 140.7 ± 24.6 (30)a | 246.4 ± 28.5 (30)b | 145.0 ± 27.2 (30)a | 46.7 ± 15.6 (30)c |
Daily fecundity eggs/female/day) | 8.0 ± 1.2 (30)ac | 8.3 ± 1.3 (30)a | 19.4 ± 1.8 (30)b | 10.7 ± 1.8 (30)a | 4.7 ± 1.4 (30)c |
Survival rate of larvae and cocoons (%) | 83.0 ± 1.5 (3)a | 77.3 ± 1.8 (3)b | 77.0 ± 0.0 (3)b | 70.3 ± 1.3 (3)c | 62.7 ± 0.67 (3)d |
Sex ratio (% females progeny) | 47.7a n.s. | 47.a n.s. | 46.3a n.s. | 47.0a n.s. | 47.3a n.s. |
Parameters | Jackknife estimation | ||||
---|---|---|---|---|---|
20°C | 24°C | 26°C | 28°C | 30°C | |
Intrinsic rate of increase (r
m
) (females/female/day) | |||||
Apanteles taragamae
| 0.14 ± 0.001a | 0.23 ± 0.01b | 0.23 ± 0.004b | 0.24 ± 0.01b | 0.10 ± 0.003c |
Maruca vitrata
| 0.10 ± 0.01a | 0.14 ± 0.01a | 0.19 ± 0.002b | 0.20 ± 0.01b | 0.19 ± 0.01b |
Net reproduction rate (R
0) (females/female) | |||||
Apanteles taragamae
| 37.02 ± 0.46a | 23. 4 ± 2.40b | 24.5 ± 1.5b | 14.3 ± 0.47c | 2.6 ± 0.10c |
Maruca vitrata
| 139.5 ± 50.1a | 96.1 ± 37.8a | 168.3 ± 17.1a | 89.0 ± 13.4a | 56.3 ± 16.3a |
Mean generation time (T) (day) | |||||
Apanteles taragamae
| 26.2 ± 0.14a | 13.9 ± 0.04b | 14.1 ± 0.42b | 10.9 ± 0.21c | 10.6 ± 0.60c |
Maruca vitrata
| 47.5 ± 2.02a | 32.3 ± 2.07b | 27.03 ± 0.6bc | 23.2 ± 0.44c | 22.4 ± 1.6c |
Doubling time (DT) (day) | |||||
Apanteles taragamae
| 5.03 ± 0.05a | 3.1 ± 0.087a | 3.03 ± 0.06a | 2.8 ± 0.08a | 3.7 ± 1.1a |
Maruca vitrata
| 6.7 ± 0.31a | 5.06 ± 0.35b | 3.7 ± 0.03c | 3.6 ± 0.15c | 3.6 ± 0.19c |
Finite rate of increase (λ) (females/female/day) | |||||
Apanteles taragamae
| 1.2 ± 0.001a | 1.3 ± 0.01b | 1.3 ± 0.01b | 1.3 ± 0.01b | 1.1 ± 0.004c |
Maruca vitrata
| 1.1 ± 0.01a | 1.2 ± 0.01a | 1.2 ± 0.002b | 1.2 ± 0.01b | 1.2 ± 0.01b |
Model type | Parameters |
Apanteles taragamae
|
Maruca vitrata
| ||
---|---|---|---|---|---|
Intrinsic rate of increase | Developmental rate | Intrinsic rate of increase | Developmental rate | ||
Linear regression | Probability | 0.06 n.s. | 0.006 | 0.04 | 0.0008 |
a
| – | −0.08 ± 0.02 | −0.15 ± 0.06 | −0.03 ± 0.005 | |
b
| – | 0.006 ± 0.001 | 0.01 ± 0.003 | 0.003 ± 0.0002 | |
K
| – | 157 degree-days | – | 366.3 degree-days | |
R
2
| – | 0.94 | 0.92 | 0.98 | |
RSS | – | 1.4 × 10−4
| 4.7 × 10−4
| 6.6 × 10−6
| |
Briére 1 | Probability | 0.004 | 0.002 | 0.006 | 0.0001 |
a
| 0.0004 ± 0.00005 | 0.0001 ± 0.000 | 0.00002 ± 0.000 | 0.00003 ± 0.000 | |
T
0
| 14.9 ± 1.2 | 14.6 ± 1.6 | 13.7 ± 2.9 | 10.5 ± 0.91 | |
T
max
| 30.2 ± 0.1 | 35.1 ± 2.1 | 33.1 ± 1.7 | 38.1 ± 1.1 | |
R
2
| 0.97 | 0.98 | 0.91 | 0.99 | |
RSS | 5.4 × 10−4
| 5.3 × 10−5
| 5.7 × 10−4
| 6.6 × 10−7
| |
– | – | – |