Journal of Entomology and Zoology Studies 2016; 4(5): 1016-1022 E-ISSN: 2320-7078 P-ISSN: 2349-6800 JEZS 2016; 4(5): 1016-1022 Effect of temperature on biological attributes and © 2016 JEZS predatory potential of Harmonia dimidiata (Fab.) Received: 17-07-2016 Accepted: 18-08-2016 (Coleoptera: Coccinellidae) fed on Rhopalosiphum Javed Khan Insect Pest Management padi aphid Program, National Agricultural Research Centre Islamabad, Pakistan Javed Khan, Ehsan-ul-Haq, Ahmad-Ur-Rahman Saljoki and Abdul Rehman Ehsan-ul-Haq Insect Pest Management Program, National Agricultural Abstract Research Centre Islamabad The influence of temperature on the biology and prey consumption potential of ladybird beetle, Harmonia dimidiata (Fab.) (Coleoptera: Coccinellidae), fed on Rhopalosiphum padi aphid was Ahmad-Ur-Rahman Saljoki investigated. The results showed that temperature had significant effect on developmental duration, Department of plant protection, survival and prey consumption potential of different stages. The duration of different stages was highest University of Agriculture at low temperature and shortest at high temperature levels. Although the predator completed its Peshawar, Pakistan development at all tested temperatures but extreme low and high temperature adversely affected the survival of immature stages. At high temperature level, the female beetle could not produce eggs. The Abdul Rehman lower temperature threshold level for different stages were in the range of (-1.25 ⁰C to - 0 °C) and IRRI, Pakistan office, NARC, Islamabad thermal constant k values for different stages were in the range of (17.86 ⁰D to 142.86 ⁰D). The results indicate that optimum temperature for rearing H. dimidiata was 24 ±1 °C. The predatory ladybird beetle can be utilized as a part of integrated pest management program for the management aphid pests. Keywords: Harmonia dimidiata, Rhopalosiphum padi, temperature, biology, predatory potential Introduction Lady bird beetles are considered as the most important natural enemies of aphids and have been effectively utilized for the integrated control of several aphid pests. Ladybird beetles are [1] generalist predators that fed on a diverse range of insects . Aphids are the principal prey of ladybirds, whereas coccids, mites, honeydew, pollen, nectar and mildew are considered as secondary foods [2]. There are about 4400 predatory Coccinellid beetles in the world and their potential as bio control agents for different pests is quite promising. The sub-tropical ladybird beetle H. dimidiata (Fab.), commonly known as fifteen spotted lady bird occurs in China, Vietnam, India, Nepal, Pakistan and other countries of South-East Asia. In Pakistan it was [3] reported from Malakand, Swat, Murree, Peshawar, Islamabad and Rawlakot . Both larvae and adult ladybird beetle’ preys on different aphid species such as Myzus persicae, Schizaphis graminum, Aphis gossypii, Aphis fabae and Acyrthosiphon pisum [4]. H. dimidiate is highly voracious predator of aphids and has the ability to survive even at low [4] temperatures . These attributes make it a useful natural enemy for the purpose of biological control program against aphid pests of economically importance in sub-tropical regions of Pakistan. [14]. Among abiotic factors, temperature is the most important ecological aspect that strongly influences the rate of growth in insects and thereby affecting their seasonal population [5]. To evaluate the prospective of an insect as bio control agent, it is imperative to recognize its temperature necessities in relation to prey, such as low and high temperature thresholds as well as optimal temperature calculated for major life characteristics of insect. Increase in temperature usually increase the metabolic demand, as a result, predation and insect development rate tend to increase exponentially [6]. The effect of temperature is usually determined as a specific function of temperature and its effect on survival, fecundity, Correspondence demographic parameters, growth rate and development, which is then used for predicting [7] Javed Khan interaction among bio control agents and their host insects . Temperature driven models are PARC, Institute of advance often used to estimate the seasonal population dynamics of pests and natural enemies in field studies in agricultural science, situations [8]. These models also assist to conclude apposite circumstances for mass rearing of NARC, Islamabad, Pakistan. natural enemies [9]. ~ 1016 ~ Journal of Entomology and Zoology Studies throughout the oviposition period of female ladybird beetles. Degree-day models, based on linear regressions of The observations were carried out till all the male and female development rate and temperature, are used extensively for beetles were died in each jar at all tested temperatures. The foreseeing insect development within a variety of longevity of both sexes was recorded. During the female temperatures, characteristically met in the field [10]. The longevity experiment, the first and last egg was recorded in temperature below which no quantifiable development of any each pairs to separate, pre oviposition, oviposition and post species takes place is called as lower threshold temperature oviposition periods. for development. The amount of heat required over time for The data was recorded on the following parameters. an insect to complete the development is considered to be 1. Incubation period (days) and hatchability of eggs thermal constant. Insect faces a variety of temperatures, which 2. Developmental period and survival of different larval seriously distress their development and survival rate. The instars/larvae study of relationship of temperature with development of 3. Pre Pupal and pupal durations and percent survival notorious pests is very important. The effect of temperature is 4. Total developmental period and percent survival from egg usually observed in insect species functions, survival of to adult emergence different stages, female fecundity, demographic parameters, 5. Sex ratio, number of male and female beetles emerged and development, which are applied to envisage interactions 6. Pre oviposition, oviposition and post oviposition period of of natural enemy with pests [11]. female beetle Though detailed knowledge of the temperature dependent 7. Longevity of male and female ladybird beetles biology of H. dimidiata has been little studied in the world 8. Mean number of eggs per female beetles during their life and particularly in Pakistan no such study available in past, span therefore the present laboratory experiments were undertaken 9. Mean number of eggs per female per day to study the effect of five constant temperatures on survival, biological parameters and prey consumption potential of Temperature thresholds and thermal requirements for larvae and adult beetles to find out the thermal requirements. developmental stages of H. dimidiata (Fab.) This study should be useful in predicting the range of Temperature threshold and thermal prerequisite were temperature within which H. dimidiata shows a linear calculated by using degree day model to approximate the developmental response and thus will help in selecting the linear association of temperature and the developmental appropriate temperature for the laboratory rearing to explore duration of H. dimidiata fed on R. padi aphid. The reciprocal their potential as bio control agents against aphid pests of of developmental period for egg, larvae, pupa, egg to adult economic importance. emergence, male and female beetles was computed to attain the rate of development (1/day) at all tested temperatures. Material and methods Linear regression lines were used to calculate the association Study was carried out to check the effect of five constant among growth rate and temperature and to find out intercept temperatures i.e. 16, 20, 24, 28 and 32oC with variation of (a) and slope (b). With the help of liner regression lines the ±1oC under 60 ± 5% relative humidity and (16: 8) hours lower threshold temperature (Tₒ) for each developmental (Light: Dark) photoperiods on the biological attributes and stage was calculated. Once the lower temperature threshold predatory potential of ladybird beetle H. dimidiata, fed on R. for each developmental stage was attained then the thermal padi aphid in growth chamber at National Agricultural constant K (the number of degree days required to complete Research Centre, Islamabad during 2012. development for each stage) was calculated from the The following sets of experiments were conducted. reciprocals of the fitted regression line (b-1). Thus the degree days required for the development of each life stage were Effect of temperature on biological parameters and estimated. percent survival of H. dimidiata A total of 100 eggs of H. dimidiata were collected from the Effect of temperature on the predatory potential of H. stock culture maintained on R. padi aphid in laboratory for dimidiata larvae and adult beetles each treatment. The egg batches were kept in petri dishes for To study the effect of five constant temperatures on predatory hatching. Upon hatching the larvae were individually placed potential of larvae, a total of 40 first instar larvae were kept in in plastic vials (6 x 3) cm. Aphids were provided on wheat rearing vials singly at each temperature in growth chamber. leaves inside the vials daily. After each 24 hours the old Counted numbers of aphids were provided as food on wheat infested leaves were replaced with new diet. The insect were leaves inside