LIFE TABLE ATTRIBUTES AND FEEDING EFFICIENCY OF OENOPIA SAUZETI (MULSANT) (COLEOPTERA: COCCINELLIDAE) FED ON APHID ( APHIS GOSSYPII )

: ladybird beetles are play vital role in agroecosystem due to successful and efficient feeding behavior against aphids, the present research experiment was carried to find out the life history and feeding efficacy of oenopiasauzeti fed on Aphis gossypii ,at the laboratory of Biological Control, integrated pest management programme (IPMP), National Agriculture Research Centre (NARC), Islamabad. The results of the experiment revealed that the mean developmental time of immature stage 3 rd and 4 th instar have a significant difference with 3.72±0.11 and 3.87±0.036 days, while the egg to adult emergence was 39±0.35 days. The longevity has significant difference in male and female with the higher values at female 34.0 days. Similarly, the feeding efficiency was maximum in O. sauzeti females which feeds on 2227.1 mean number of Aphis gossypii , while the (409.25±1.42) mean numbers of aphids were consumed by larva. The maximum aphid consumption was observed at 4 th instar larva (198.98±0.51 aphid) followed by 3 rd instar larva (128.57±0.59 aphid). The mean oviposition time of O. sauzeti on A. gossypii was recorded as 21.36 days and average eggs laid female -1 day -1 was 20.53, while the total laid eggs given by a female were 253.60. The apparent mortality (100qx) was maximum at egg stage (24) and the mortality survival ratio (MSR) was highest at pupal stage (0.53), similarly, the indispensable mortality (IM) was also observed high at pupal stage. The maximum survival fraction (Sx) was observed at the 4 th larval stage (0.91) and the maximum life expectancy (ex) was observed at 1 st larval instar (4.51) days. The total killer power (k-value) of the O. sauzeti for the complete generation was 0.49. This will help to develop an ecofriendly managing approach for the minimizing the aphids infestationin economical important crops.


INTRODUCTION
Aphids (Aphididae: Homoptera) are soft body insects with sucking type mouth parts.These are a huge group of insects which feed on a different kind of hosts.They have a maximum biological prospective with few species existing more than ten generations annually (Kos et al., 2008).These are destructive insect pests that cause production losses in important cereal crops such as wheat, barley, and maize, as well as cotton and cause severe damage throughout the seedling and blooming stages (Freieret al., 2007).In Pakistan, several aphid species includingAphis gossypii,Sitobionavenae, Rhopalosphummaidis and Schizophusgraminum, Sitobionmiscanthiand Rhopalosiphumpadiare causing significant economic losses in agriculture crops (Khan et al., 2007).
Among the aphids species, Aphis gossypii(Glover) is a serious pest of cotton, for its high ability to decline production by feeding affect and extend plant diseases like blue disease and cotton bunchy top disease (Correa et al., 2005;Reddallet al., 2004).The negative effect of the aphids is direct feeding which may kill the host, also and indirectly by secreting honeydew and through vectoring necessary pathogens (Blackman and Eastop, 2000).In the earlier period, cotton aphid has been restricted through a broad range of synthetic insecticides.The rising apprehension above the consumption of insecticides is a main theme, in lot of agriculture due to green uncleanness and the financial effects of pesticides conflict Ebert (1997).There are two main causes demanding for bio-control agents are that insecticides pressure has lead with a high level of resistance in numerous species of cotton aphid (Hines and Furk, 1993) and the growing usage of bio-control agents beside other insect pests increase the demand for suitable control methods against cotton aphids.The significance of coccinellidae predation of aphids in various cropping systems has newly been reviewed by Emden and Richard Harrington (2007), which comprise research of aphid pest management systems Deguineet al. (2007).Since pesticides have more negative environmental effects, biological control programmes and biologically based IPM against aphids must be implemented employing insect predators and egg parasitoids such as Asins and Pons, (2001).
Coccinellids are the top valuable predatory insects in biological control and usually known as ladybird beetle or lady bugs.The lady bird beetles related to the Coccinellidae family and order Coleoptera.The reported species of ladybird beetles are 6000 which are reportedfrom different parts of the globe, in which 71 predatory ladybird beetles exist and reported from Pakistan (Vandenberg, 2000;Irshad, 2001).Ladybird beetles are generally thought of as beneficial insects since they feed soft-bodied insects such as aphids, whiteflies, mealybugs, jassids, scale insects, psyllids, small larvae insect eggs, and phytophagus mites.All these insect pests caused significant damage to our agricultural crops and forest farms.

Evacanthussp.
(Homoptera: Ciccadellidae) and Tetranychus spp.(Acarina: Tetranychidae) (Rafi et al., 2005).Although some species of genus Oenopia is reported fed on aphid pests.The novelty of the current experiment is to study the life table attributes and feeding efficiency of Oenopiasauzeti fed on A. gosypii aphids under controlled conditions for the first in the Pakistan.

MATERIALS AND METHODS
Experiment was conducted at the laboratory of biological control in Insectary of Insect pest management program (IPMP), Department of Plant and Environmental Protection, National Agriculture Research Center (NARC) Islamabad to study the biological characteristics of both, the predatorOnepiasuzeti and its host Aphis gossypii, during the year 2019.In order to conduct the experiment, the main necessities were the existing materials of destructive predator species (ladybird beetles) and their associated host species (aphid).For the culture maintenance of the insect the host plants were planted.

Plantation of host plants:
Cotton plants were planted under glass houses and also in various sizes of pots to maintain the culture of Aphis gossypii.The seeds were sown at different time intervals to maintain the continuous supply of aphids.Typical methods were used to help the plants mature.The pots containing of cotton plants were placed in the wooden crates (4×2 sq.feet).

Culture maintenance of the aphids:
The aphids were collected from the cotton plants at the field area of NARC and brought to laboratory.The aphids were relocated to growing host plants under glasshouses and ample shade.To establish a full-fledge colony, the pest-ridden leaves were simply to be separate from source plants and placed into the terminal portion of the new growing plant.Aphid's colony were monitored and maintained throughout the entire experimental duration.

Culture
maintenance of ladybird beetle(Oenopiasauzeti): The predacious Coccinellid beetle, Oenopiasauzeti was collected from NARC field.The adults and pupae were collected and brought to the laboratory for further propagation of culture.After sprouting the adults were kept in a plastic boxes size of (20×40cm) plate 3 (d) under organized condition of 25±2˚C in insects holding room.Aphids were transfer to the leaves of the cotton plants inside the plastic holders.The upper side of the jars were covered with a muslin cloth and preserved under controlled environment of 25±2˚C and complemented by 60±5% RH.The stock culture of ladybird beetle was maintained in plastic holders as well.The monitoring of the rearing room and the rearing cabinet in particular was done uninterruptedly throughout the whole process.The jars were observed every 12 hours for the laying of eggs.To avoid cannibalism, the entirety of the newly laid eggs was shifted to petri dishes immediately.Every 24 hours, the beetles were provided a fresh diet was replaced with the old diet in the jars.A total was taken daily on the number of collected eggs under electric microscope and kept for hatching in plastic box.After hatching, the larvae were transported into clean containers measuring (10 × 6) cm in size, and covered in muslin cloth for ventilation.The larvae were offered aphids within the rearing vials.The adults which sprout from the pupae were transported to the plastic cages to extent further oviposition and maintain the cultural under same controlled environment Feeding efficiency and developmental period of Oenopiasauzeti fed on A. gossypii aphids: To discover the efficiency of feeding and developmental time of different stages of Oenopiasauzeti, a total of 40 freshly emerged 1 st instar larvae were collected from the stock culture and each larva was transferred into transparent vials separately, which were then covered the top of the jars with muslin cloth.Primarily, the first instar larvae were providing 20 (1 st to 3 rd ) instars nymphs of aphids.
The number of aphids was increased when the larvae enter into the next instar.After every 24 hr, the consumed aphids and un-consumed aphids were tallied and exchanged with a new food.This procedure was continued till the all larvae has entered into the pupal stage.If at any stage the larvae is found dead, then were replaced with fresh larvae from stock culture maintained on the identical aphid species.
Similarly, to discover the adult feeding efficiency of Oenopiasauzeti, the total numbers of 20 adults consisting of 10 female and 10 male ladybird beetles were collected from stock culture.The beetles were then kept independently in rearing vials and the counted number of aphids were introduced inside the vials on infested leaves of cotton plants.(1) Age specific life-Table : To construct a life table attributes, the total numbers of 100 eggs of identical age, which were collected from the maintained standard culture on A. gossypii aphids.Living and dead insects emerged from 100 eggs were calculated daily.The given supposition was used s used for life table parameters of Oenopiasauzeti construction.100 q x = Age intervals during mortality x and calculated by the given formula 100 q x = (d x /lx) × 100 X = Insect ages in days lx = Survival rates of insect at the start for each interval dx= Insect dead insects at individually intervals ex = Average lifecycle time remaining for individuals of age x, and were calculated by this formula e x ₌ Tx / lx Where,Tx and lx were calculated as under Lx = Age between active individual's x, while x+1 was determined by Tx= lx+ (lx + 2) …+ lw), Whereas lw is the last age intervals.Stage Specific Lifetable: The data were recorded on the specific stage of life Table shows that the incubation period of O. sauzeti takes 3.55 ± 0.10 days.Maximum duration for the incubation period was recorded to be 3.9 days while minimum days were found to be 2.7 days.First, second, third, and fourth larval instar takes 2.58 ± 0.05, 1.95 ± 0.03, 3.71 ± 0.11 and 3.87 ± 0.036 days, respectively.The maximum duration for the first, second, third and fourth larva was found to be 2.8, 2.1, 4.0 and 10.0 days while the minimum duration were found to be 2.30, 1.8, 2.7 and 8.5 days, respectively the total larval duration were recorded 15.66 ± 0.15 days, while the maximum and minimum were recorded 16.2 and 14.4 days respectively.Pre-pupa takes 0.91 ± 0.03 days while 7.01 ± 0.05 days were recorded for pupa.For the Pre-pupa and pupal stages, maximum duration was observed to be 1.10 and 7.73 days respectively however, 0.70 and 6.8 days was the minimum duration for pre-pupa and pupa stages.Overall total 39 ± 0.35 days were taken by O. sauzetifrom hatching time to adult emergence.The total time took from egg to adult emergence ranged from 36.60 to 40.20 days.

Adult mean longevity in days of O. sauzeti raised on
Aphis gossypii in controlled environment: The longevity of O. sauzetifemale and male fed on A. gossypiiwere shown in figure 1.The result indicates that the longevity of both male and female adults of O. sauzetiare significantly different from each other.Figure shows that the adult females have comparatively high longevity value (34.0 ± 0.11) than the males (27.96 ± 0.19) days.However, the maximum and minimum longevity of female was 45.0 and 41.0 days, respectively.
The maximum and minimum longevity of male was 35.0 and 34.4 days, respectively.

Average feeding efficiency of different larval instars and adults of O. sauzeti reared on Aphis gossypiiunder controlled conditions:
The mean feeding efficiency of different larval stage of O. sauzeti on Aphis gossypii is given in table 2. The larval feeding efficiency of O. sauzeti on Aphis gossypii is shown significantly high in the larval stage forth (198.98 ± 0.51) followed by third larval stage (128.57± 0.59) while the least feeding efficiency was observed at first larval stage (28.44 ± 0.32).However, the mean feeding efficiency of total larval consumption was (409.25 ± 1.42) on A. gossypii, while there is a significant difference present in male and female feeding efficiency as adult female mean value is 2227.1 ± 4.44 and the male consumption values is 1744 ± 12.78 which is comparative less than the female showed in figure 2.
Mean pre-oviposition, oviposition, post oviposition period, number of eggs female -1 and number of eggs female -1 day -1 of O.sauzeti feed on Aphis gossypiiunder laboratory conditions: The result of ovi-position periods of O. sauzeti on Aphis gossypii were indicates that the pre-oviposition was 5.96 days, oviposition was 21.36 days and post oviposition time was 4.91 days table 4.However, the total average numbers of eggs were recorded 253.60 laid female -1 , while the average eggs laid female -1 days -1 was recorded 20.53.The apparent mortality at egg stage was higher and lower at the 4 th larval instar stage.The second highest apparent mortality was in the 1 st larval instar stage and then in pupae stage, respectively (Table 5).

Survival Fraction (Sx):
The survival fraction (Sx) at 4 th larval instar was highest (.91) and lowest at egg stage (.76).Survival fraction recorded at the 4 th larval instar was maximum and minimum at egg stage.After the 4 th larval instar, the pre-pupa stage had the second highest survival fraction, however, the 1 st instar, 2 nd instar and pupae stage had the lowest survival fraction (Table 5).

Mortality Survivor Ratio (MSR):
Mortality Survivor Ratio (MSR) at the pupal stage was highest (0.53) and lowest at 4 th larval instar stage (0.18).After pupal stage the egg stage had the second highest MSR and then the 1 st , 2 nd , 3 rd , 4 th larval instars and pre-pupal stage had the lowest mortality survivor ratios, respectively (Table 5).

Indispensable Mortality:
The highest (17.49)rate of indispensable mortality (IM) was recorded in the pupal stage followed by the egg stage (10.23).The lowest (5.94) indispensable mortality was recorded in the 4 th larval instar followed by 3 rd , 2 nd and 1 st instars which were 6.27, 8.91 and 9.57, respectively (Table 5).

Life Expactency (ex):
The life expectancy (ex) for 1 st larval instar was highest (4.51) and lowest at the pupal stage (1.96).After the 1 st larval instar, the highest life expectancy was recorded in 2 nd , egg sage and 3 rd instar which was 4.42, 4.31 and 4.09, respectively.(Table 5) K-Value: K-value for the egg stage was the highest (0.12) and lowest for the 3 rd , 4 th and pre-pupae stages.Kvalue for 3 rd , 4 th and pre-pupae were statistically different from each other and were recorded as 0.04.The second highest k-values were recorded for the 1 st and 2 nd instars which were 0.09 and 0.07, respectively (Table 5).

DISCUSSION
The ladybird beetles are potential predators of soft bodied insects (Iftikharet al. 2018).Among them, aphid species are the most suitable prey of coccinellid predators (Bouvet et al. 2019;Tang et al. 2013).Keeping in view the economic importance of ladybird beetle as predators, it is pivotal to understand the life table parameters and feeding efficacy of these predatory beetles on the target pests i.e., aphids.The ladybird beetles, O. sauzeti are widely distributed aphid predators.
The current experiment was performed to explore the developmental duration and immature stages of Oenopiasauzeti reared on Aphis gossypii.Our finding showed that incubation period of O. sauzeti was 3.55 days reared on A. gossypii.The mean developmental time immature stages of 3 rd and 4 th larval instar have a significant difference.The maximum duration immature stages of O. suzeti was recorded on 4 th larval instar followed by 3 rd larval instar, while the minimum duration of immature stages was recorded on 2 nd followed by 1 st larval instar.Our conclusion are in line with the Aziz et al. (2020) who study on O. suzetiagainst Tinocalliskahawaluokalani aphid.Who reported that incubation period of O. sauzeti was recorded 3 days and the immature stages of O. sauzeti 3 rd and 4 th larval instar have significant difference.The highest mean duration were recorded in 4 th larval instar followed by 3 rd instar, while the minimum mean duration of O. sauzeti was recorded in 2 nd larval instar.Farooq et al. (2018)  Furthermore, significant differences were found in longevity of male and female O. sauzeti when were feed with A. gossypii.Oenopiasauzetifemale lived longer i.e., 34 days and its male lived for 27.96 days when were feed with A. gossypii.The longevity of this species here in this study seems to be associated with oviposition and fecundity, and these parameters are higher for O. sauzeti.The differences in egg laying ability of predators could be a reason for various oviposition capacities (Atlihan and Kaydan 2002).The results of this study also support the results of Zhang et al. (2012) which reported positive interaction of fecundity and longevity of coccinellid beetles.Generally, high longevity of females resulted in large amount of egg production.Khan et al. (2015) conducted experiment on Harmoniadimidiata who reported that the longevity of male and female was 36.4 and 39.8 days, respectively.Furthermore, significant difference was found in feeding of male and female of O. sauzeti when fed with A. gossypii.Our finding are also in line with Hsieh. (2012) who studied on O. sauzeti against Myzuspersicae.They reported that the mean consumption rate of O. sauzeti male and female were significant difference from one another.The maximum mean number of consumption was recorded on female, while the minimum mean feeding potential was recorded on male of O. sauzeti.Pervez and Omkar (2004) also conduct experiment on same pest Aphid (Aphis gossypii) but have different beetle Propyleadissecta.Who reported that the feeding efficacy of male and female was significantly different form each other.The highest consumption rate was recorded on female, while lowest on male of O. sauzeti.
The result regarding total mean feeding efficacy of different larval instar of O. sauzeti reared on A. gossypii.The current finding showed that the feeding efficacy of immature stages of O. sauzeti was significantly different.The highest feeding potential rate was recorded on 4 th larval instar followed by 3 rd larval instar, while the lowest feeding potential of O. sauzeti was recorded on 1 st and 2 nd larval instar of O. sauzeti.A similar experiment was also reported by Pervez and Omkar (2004) recorded the same finding although they used Propyleadissecta on Aphis gossypii.Who reported that the feeding efficacy of immature stages (1 st , 2 nd , 3 rd and 4 th ) of P. dissecta was significantly different.The maximum consumption rate was recorded on 4 th larval instar and lowest on 1 st larval instar.Similar experiment was also conducted by Khan et al. (2015) on Harmoniadimidiata against Schizaphusgraminum.
In the current study finding regarding the biological attribute of O. sauzeti against A. gossypiiindicate that mean oviposition, pre-oviposition and post-oviposition times were examined.The total oviposition period of O. sauzeti was recorded 21.36 days.While the average no.eggs female -1 was recorded 253.60 eggs and the average number of eggs per female per day was recorded 20.53 eggs.
Our finding as line with Aziz et al (2020) who study on O. sauzeti fed on T. kahawalukalani, who reported that the oviposition period of O. sauzeti was recorded 23.38 days.Ghadam (2009) conducted same experiment on another species conglobata of the genusOenopia.Reported that oviposition period was recorded 30.28 days.Khan et al. (2015) also conducted experiment recorded the same result although they used Harmoniadimidiata against Scizaphusgraminum other than O. sauzeti and A. gissypii.
The life table parameter of the current study revealed that the apparent mortality was highest at egg stage (24) for the first larval instar, the results of apparent mortality reported in Hyperaspis notate showed that the higher mortality at first instar stage than last instars (Dreyer et al., 2015).The survival fraction (Sx) was maximum at 4 th larval instar (0.91) and life expectancy (ex) was highest (4.51).However, the mortality survivor ratio (MSR) and indispensable mortality (IM) were recorded highest in the pupal stage (0.53) and (17.49), respectively, the trends mortality survivor ratio (MSR) and indispensable mortality (IM) similar as reported in Coccinellaseptempunctata and C. transversalis (Rizvi et al., 2009;Ali and Rizvi, 2010).The k-value was maximum at the egg stage was (0.12) and the k-value per generation was 0.49 to complete one generation.According to Khan et al. (2017), the life probability (ex) was highest (5.24) egg phase and least (1.89) at the pupal stage, however, the current results showed that the highest value at the first larval instar, while the pupal stage collaborates with the Khan et al. (2017), when feeds on the Aphis gossypii.

Conclusion and Recommendations:
The study concludes that immature and adult stage of O. sauzetihad an exponential increase rate feeding on the aphid species Aphis gossypii, which help adult females in quantitative eggs production and reproduction responses as show in the k-value (0.12).However, the developmental time, longevity of adult (female and male), biological parameters pre-oviposition, oviposition and post oviposition time in immature and adult stages of O. sauzetipredates on the Aphis gossypiihave significantly different and showed that O. sauzetican be reared and further be used in the biological control programs against many other species of aphids.The feeding efficacy in the O. sauzetiincreases from the immature to adult stages.This study shows that the ladybird species O. sauzetihas promising future in the biological control of aphid species Aphis gossypii, which will help the scientist to develop mass rearing technique of this species against this aphid species.Further, studies will need to be develop on the field implementation strategies of this ladybird species for the natural control of aphid species.
table and calculated by the given method which follow by (Ali and Rizvi, 2008b) x = insects age in days (days).The developmental time of different stages of O. sauzetifrom egg to adult are presented in table 1.
IM = (Total numbers of adults emerged x mortality survival ratio of insect at specific stages) K-values: K-values are calculated from changes in "log lx" consecutive value.This important element determines reduction/ multiplication from parent to offspring.The overall mortility rate of a generation was determined by summing these values calculated from in insect's various growth stages and as denoted as "K".K = kE (incubation stages) + kL1 (1 st larval instar) + kL2 (2 nd larval instar) + kL3 (3 rd larval instar) + kL4 (4 th larval instar) + kPP (pre-pupa) + kP (pupal stage), all immature stages of Oenopiasauzeti(Mulsant).

Adult longevity in days of O. sauzetiraised on Aphis gossypiiin controlled environment. Table 2: Average feeding efficiency ± SE of different larval instars of O. sauzeti reared on Aphis gossypiiunder controlled conditions.
Fig. 2: Average feeding efficiency ± SE of adults of O. sauzeti reared on Aphis gossypiiunder controlled conditions.

Table 4 : Age specific life table of O. sauzeti fed on A. gossypiiunder controlled condition.
No. surviving at the start of the stage, dx= No. mortality in each stages, LX= No. of alive between age x+1, 100qx= Apparent mortality, SX= Survival fraction, MSR= Death/Survivor ratio, IM= indispensable mortality, ex= Life expectancy and K= killing power.
Coccinellaseptempunctata against L. erysimi and M. persicae other than O. sauzeti and A. gossypii.Who reported that the highest mean duration of incubation was noted on L. erysimis, while the lowest on M. persicae.The developmental duration of C. septmpunctata have significant difference when fed on L. erysimis and M. persicae The maximum developmental duration larval stages of C. septempunctata was recorded on 4 th larval instar, and the minimum larval instar was observed on 2 nd instar of C. sptmpunctat.Pervious worker Ghadamet al. (2009) also conducted the same experiment but slightly different from the current studies.Who study on the same genus Oenopia different species conglobata in Laboratory condition.