Costs and benefits of reproduction in predaceous ladybird: Effect of multiple matings on reproduction and offspring development

Omkar,Jyotsna Sahu 한국응용곤충학회 2012 Journal of Asia-Pacific Entomology Vol.15 No.2

A few matings are sufficient for females to maximize their reproductive success, while male fitness usually increases with an increase in the number of matings. However, females of a majority of insects mate multiple times. This presents an evolutionary puzzle and brings an understanding that some benefits are associated with it. Therefore, to understand the costs and benefits of multiple matings, we performed an experimental study in a ladybird beetle, Anegleis cardoni and observed reproductive performance and longevity of adults as direct benefits and offspring development and survival as indirect benefits. This is the first time that the effect of multiple matings is being evaluated on offspring development and survival in a ladybird beetle. Results clearly reveal that females directly benefit from multiple matings in terms of increased lifetime fecundity and egg viability, but their longevity decreases with increased number of matings. Best-fit curves on lifetime fecundity and percent egg viability revealed that maximum fecundity and egg viability were both attained after 17 matings. Developmental duration of offspring decreased and their survival increased with an increase in number of matings. Developmental duration was shortest after 20 matings and longest after a single mating.

Age specific mating incidence and reproductive behavior of the ladybird beetle, Anegleis cardoni (Weise) (Coleoptera: Coccinellidae)

Omkar,Jyotsna Sahu,Gyanendra Kumar 한국응용곤충학회 2013 Journal of Asia-Pacific Entomology Vol.16 No.3

Age specific mating incidence, mating behavior, mate recognition cues and effect of sexual status on mating of ladybird beetle, Anegleis cardoni (Weise) (Coleoptera: Coccinellidae) were studied in detail. The mating duration was very short (14.40 ± 0.72 min) in comparison to other ladybirds. Courtship was male dominated and was displayed in steps, viz. approach, watch, examine, sharp turns,mount, attempt and mate. Sharp turns is an additional behavior observed during courtship in this ladybird, and is characterized by sharp turning movements towards the mate, and is undertaken by both males and females. Active mating of A. cardoni involved multiple strokes of the aedeagus. Mating duration and the number of strokes were higher in unmated males than in mated ones. Results reveal that physical cues probably play a role in the initiation of courtship, while chemical signals are probably involved in the continuation of courtship, culminating in intromission. The removal ofmale antennae and obscurity of elytral patterns significantly decreased mating success, whereas female antennal ablation and obscuring of the pronotum did not affect mate recognition.

Prey species affects the performance of the aphidophagous ladybird, Coelophora saucia

Omkar,Shuchi Pathak 한국응용곤충학회 2014 Journal of Asia-Pacific Entomology Vol.17 No.3

Performance of ladybird, Coelophora saucia (Mulsant) was studied on seven aphid species in terms of various lifeattributes. Immature stages developed fastest and survived most on Aphis craccivora. Longevity, fecundity andegg fertility of adultswere highest on A. craccivora. Age specific fecunditywas triangular in shape with the occurrenceof peak oviposition at an early age on A. craccivora and at a later age on Lipaphis erysimi. The net reproductiverate, intrinsic rate of increase, and finite rate of increase of C. saucia were highest on A. craccivora and loweston L. erysimi. Owing to better performance of C. saucia on A. craccivora, this is consideredas themost suitable preyfollowed by Myzus persicae, Aphis gossypii, Rhopalosiphummaidis, Ceratovacuna silvestrii, Aphis nerii and L. erysimi. Itis the first attempt to evaluate prey suitability of this ladybird based on several attributes.

Benefits of polyandry in Parthenium beetle, Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae)

Omkar,P. Pandey 한국응용곤충학회 2010 Journal of Asia-Pacific Entomology Vol.13 No.2

The influence of polyandry on the reproductive performance of females and on offspring fitness in Zygogramma bicolorata Pallister was investigated using four experimental treatments, viz. (A) monandrous,limited mating, (B) monandrous, unlimited mating, (C) polyandrous, no-choice limited mating, and (D)polyandrous, mate choice unlimited mating. Polyandrous females had higher reproductive performance than monandrous ones. Monandrous females subjected to unlimited matings had higher egg viability than those subjected to limited matings, but fecundity did not differ significantly. In polyandrous females, the freedom to choose mates did not affect reproductive performance. However, offspring of polyandrous females allowed mate choice developed fastest and had the highest survival at 25, 27, and 30 °C. Thus, polyandry in Z. bicolorata appears to provide both direct (material) and indirect (genetic) benefits resulting in better reproductive performance and increased adaptability of the offspring to counter environmental stresses. The present study not only adds to the knowledge of reproductive biology of Z. bicolorata but it could also be of economic value as it may help in the mass rearing of Z. bicolorata and in the management of Parthenium hysterophorus.

Food consumption, utilization and ecological efficiency of Parthenium beetle, Zygogramma bicolorata pallister (Coleoptera: Chrysomelidae)

Omkar,Uzma Afaq 한국응용곤충학회 2011 Journal of Asia-Pacific Entomology Vol.14 No.4

Food consumption, utilization and ecological efficiency of Zygogramma bicolorata were studied in larvae and adults up to 45 days old. The study revealed that sex had a significant influence on dry food consumption in adults but not in larvae. The other parameters of ecological efficiencies, viz. efficiency of conversion of ingested food (E.C.I.), tissue growth and dry biomass, were highest in the fourth instar and in adult females. The Consumption Index (C.I.) was higher in males than females in both larval and adult stages. Developmental and growth rates were relatively higher in the first and second instars. The fourth instar and adult females were themost efficient consumers and converters of food. Food intake by females was an important determinant of the number of eggs laid.

Development of Optimized Mechanical Properties of AISI 4340 Steel: Role of Quenching and Partitioning Process

Omkar Tikhe,Pravin Doiphode,Unissa Nichul,Rajkumar Singh,Vijay Hiwarkar 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.8

The current research is based on an attempt to achieve ultra-high strengths in AISI 4340 steel, by the quench andpartitioning (QP) heat treatment processes. In this study, the microstructure and mechanical properties of the advanced QPprocess are compared with the quenching and tempering (QT) and the austempering processes. The microstructural investigationsare performed with optical microscopy, scanning electron microscopy, and electron backscattered diffraction. Tensiletesting is carried out to measure ultimate tensile strength, yield strength, and elongation. The hardness measurement wasdone on the Rockwell C scale. The hardness and tensile results were used to compare mechanical properties. ConventionalQT processes lead to compromise in ductility with increased strength. The austempering process shows the bainitic structurewith mechanical properties comparable to specimens quenched and tempered at 560 °C. The QP process comes up with optimummechanical properties with exceptional UTS (1802 MPa) and elongation of 12.67%. The hardness of the QP processis also higher than other processes. When compared with conventional processes like QT, the strength in the QP process ismuch higher with good ductility. The microstructure in the QP process is reformed to fine-grained austenite within the interlathpositions of martensite. This morphology of retained austenite plays an important role in achieving these properties inQP.

Korean Expatriates Adjustments and Job Satisfaction in Malaysia: Analysis of Corporate Cultural Asymmetry

Omkar Dastane,Woo Yong Willis Lee 한국유통과학회 2016 The Journal of Industrial Distribution & Business( Vol.7 No.4

Purpose - The purpose of this study is to discover how Korean expatriates that are currently employed in Korean subsidiaries operational in Malaysia possibly suffer from career dissatisfaction due to differences between Korean Corporate Culture (KCC) and Malaysian Corporate Culture (MCC). The integration of KCC into MCC is discussed. Research design, data, and methodology – The analysis herein is via a qualitative research. Forty-six interviewees voluntarily participated in in-depth interviews. Document analysis and qualitative interviews were utilized to develop participant profiles and to generate the framework. Interview data were transcribed and subsequently analysed to facilitate the development of themes and ultimately led to emerging patterns. The framework discusses the following Confucian pillars pronounced in KCC: Control Systems, Power Structures, Organisational Structures, Authority and Harmony and Stories and Myths. Those pillars are analysed and the results of the interviews are discussed in detail. Results – Korean expatriates on assignment in Malaysia endure struggles in all five selected Confucian pillars as they are not symmetrical with Korean Corporate Culture common at head companies in Korea. Conclusion - As a consequence, there is substantial disharmony which needs to be rectified if Korean companies are to continue their ‘miraculous’ economic movement into the country.

Designing, Preparation and Applications of Carbon-based Composite Hydrogels

Omkar S. Nille,Akshay S. Patil,Anil H. Gore,Govind B. Kolekar 한국고분자학회 2022 한국고분자학회 학술대회 연구논문 초록집 Vol.47 No.1

Azygos anterior cerebral artery associated with hypoplastic A1 fragment of right anterior cerebral artery

Omkar Patnaik,Preeti Shahane,Mrudula Chandrupatla,Punnapa Raviteja 대한해부학회 2023 Anatomy & Cell Biology Vol.56 No.4

Anterior cerebral arteries are paired and supply the major portion of the medial surface of the brain. They are branches of the intracranial part of the internal carotid artery and form the anterior portion of the circle of Willis (CW) which is situated in the interpeduncular fossa. During routine dissection in the department of anatomy, All India Institute of Medical Sciences, Bibinagar, Hyderabad, a rare variation had been observed in the CW, azygos anterior cerebral artery associated with hypoplastic A1 fragment of the right anterior cerebral artery in a 63-year-old female cadaver. It is important to identify and study this kind of rare variation for surgeons, anatomists, and radiologists during dissection, surgical, radiological, and diagnostic interventions.

Intra-alveolar extraction of linguoverted mandibular premolars – the Shetye technique: a technical note

Shetye Omkar Anand,Mandrekar Pooja Narendra,Khandeparker Rakshit Vijay,Fernandes Trishala Bhadauria,Dhupar Vikas,Akkara Francis 대한구강악안면외과학회 2022 대한구강악안면외과학회지 Vol.48 No.4

Extraction of premolars for orthodontic purposes may prove challenging when the tooth is blocked or lingualised. The standard buccal approach may prove difficult in such cases. A novel technique was used for 16 patients with healthy linguoverted mandibular premolars using maxillary extraction forceps. The ease of extraction increased and resulted in uneventful postoperative healing in all patients. The authors suggest this as a preferred tech-nique for extracting mandibular premolars in linguoversion.