Age-Stage, Two-Sex Life Table of the Menochilus sexmaculatus (Coccinellidae: Coleoptera) Feeding on Different Aphid Species

Ladybird beetle, Menochilus sexmaculatus (Fabricius) (Coleoptera: Coccinellidae), is biological control agent that predate the different aphid species. Both adults and larval stage of M. sexmaculatus feed on aphid species. In this experiment Life table and predation data were collected for M. sexmaculatus feed on four different aphid species Lipaphis erysimi, Myzus persicae, Aphis nerii and Diuraphis noxia. This experiment was conducted under laboratory conditions at 25±2°C, 60±5% RH and L14: D10 h. Different numbers of aphid were provided as a pray in petri dish. The pre-adult development duration of M. sexmaculatus was maximum when fed on M. persicae (12.18 d) and minimum on D. noxia (10.64 d). Similarly, male and female duration was maximum on M. persicae (26.7 d), minimum on L. erysimi (23.67 d) in male and in female maximum on D. noxia (28.00 d), minimum on A. nerii (24.33 d). Net reproductive rate (Ro) range from 117.9 on L. erysimi to 99.55 on M. persicae and intrinsic rate of increase (r) range was 0.21197 d−1 on A. nerii to 0.021559 d−1 on D. noxia. The finite rate of increase (λ) range was 1.240592 d−1 on D. noxia to 1.204918 d−1 on M. persicae, the mean of generation (T) range was 24.68 d−1 on M. persicae to 22.476 d−1 on A. nerii, similarly, the gross reproductive rate (GRR) range was 172.2 d−1 on D. noxia to 115.02 d−1 on M. persicae and Fecundity (F) eggs per female range was 316.8 on D. noxia to 199.1 on M. persicae. In present Study, age-stage two-sex life table gives complete understanding of predator biological aspects against different aphid species. This study will help us to improve mass rearing and use of M. sexmaculatus in biological control of aphids.

typically mustard, rape, cabbage, cauliflower, broccoli and radish worldwide (5). The M. persicae, 42 is a cosmopolitan pest, feeds on more than 50 plant families (5), including agro-industrial crops 43 and horticultural crops (6). 44 The D. noxia, attacks on cereal crops worldwide with high host range of more than 140 species of 45 Poaceae plants (7). The D. noxia, inject toxin into plants while feeding which causes failure to 3 46 unrolling and white streaking of plant leaves. Yield loss had been estimated up to 80 to 100% 47 under heavy attack of D. noxia, in wheat crop (8). The A. nerii, feeds on plants of Apocynaceae 48 and Asclepiadaceae families (9) and also had been reported on wheat and Brassica in Pakistan 49 (10). The A. nerii, is an obligate parthenogen, and a sequester of toxic chemicals (cardenolides) 50 which act as defensive mechanism against its natural enemies (11). Indeed, unjudicious pesticides 51 use increased ability of pests to survive against pesticides and residues level in crops final produce 52 ((12) (13) and these factors urge to use alternative methods (e.g. biological control) to reduce aphid 53 populations which are environmental friendly and risk free for human health. 54 Natural enemies (predators, parasitoids and entomopathogens) used to control aphids population 55 in biological control (14). Natural enemies are the basic components of insect pest supervision. 56 Practically 90% of natural pests are controlled by natural enemies (15). Ladybirds are potent 57 predators of various small herbivorous insects such as aphids (16)   the age-stage-specific survival rate (s xj, where x = age in days and j = stage), age-stage specific 117 fecundity (f xj ), age-specific survival rate (l x ), age-specific fecundity (m x ), age-specific net maternity 118 (l x m x ), age-stage life expectancy(e xj ), age-stage reproductive value (v xj ), and life table parameters 119 (32) (R 0 ,net reproductive rate; r, intrinsic rate of increase; λ, finite rate of increase; and T, the mean 120 generation). In the age-stage, two-sex life table, the age-specific survival rate l x , m x and R 0 was 121 calculated as (1 and 2): Where k is the number of stages. The net reproductive rate R 0 is the mean number of offspring laid 125 by individual during its entire life span. It was calculated by following equation (3): The intrinsic rate of increase (r) was estimated using the iterative bisection method and corrected 128 with the Euler-Lotka equation (4) with the age indexed from 0 (33): The finite rate (λ) was calculated as (5): The mean generation time is defined as the length of time that a population needs to increase to 133 R 0 -fold of its population size at the stable age-stage distribution, and is calculated as (6): The life expectancy (e xj ) is the length of time that an individual of age x and stage j is expected to 136 live and it is calculated equation (7) according to as (19).
The comparison between different aphid species were done by using completely randomized 139 design and means were compared by using LSD test (P=0.05). This analysis was done by using 140 statistical package SAS (34).

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When different aphid's species were given to immature stages of beetle, significant (P=0.0032,

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F=0.13 and DF=3) different response on survival was recorded ( The developmental time of pupae on all four aphid species was recorded non-significant (P=0.331, 207 F=1.15 and Df=3) ( Table 2).

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When different species of aphid were provided the significant difference in intrinsic rate of 209 increase (r) was recorded (Table 3) i.e. maximum intrinsic rate of increase (0.21197 d -1 ) when fed 210 on A. nerii and followed by L. erysimi and M. persicae (0.198695 and 0.186412 d -1 , respectively).

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While minimum intrinsic rate of increase (r) was recorded (0.021559 d -1 ) when fed on D. noxia.

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" Age-stage-specific survival rate (s xj ) curves (Fig 1) show that stage survival curves are overlapping according to age specific survival rate (Fig 2). The age-stage-specific female fecundity (f x7 ) and 246 age-specific fecundity (m x ) shows that beetle maximum oviposition was 29.4 eggs at age of 23 247 days ( fig. 2) and 15.5 eggs, respectively (Fig 2). The values of (f x7 ) and (m x ) of beetle were 248 minimum on turnip aphids. The age-specific net maternity (l x m x ) shows that highest age-specific 249 net maternity (l x m x ) was recorded on D. noxia followed by L. erysimi and A. nerii. Whereas 250 minimum was recorded on M. persicae.

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Age-stage-specific reproductive rates (v xj ) shows (Fig 3) that it is highest in case of D. noxia ( fecundity. The predator has long longevity it does not mean that they have maximum fecundity.

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Because quality of host affects the longevity and fecundity of predator (39, 40).

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The results of current study revealed that maximum age stage specific survival rate (s xj ) was 291 recorded on M. persicae. These results resembled with the study conducted on C. septempunctata 292 that the maximum survival rate was recorded on M. persicae (19,24,41,42