Nutrition of the seven-spotted beetles Coccinella septempunctata L. (Coleoptera, Coccinellidae) at different stages of the life cycle

The paper presents the results of studies of the seven-spotted beetle ( Coccinella septempunctata L.) life cycle, which has 2 generations in the climatic zone of southern Russia. The main stages of the life cycle are the emergence of imago from winter diapause, the first generation from egg to imago, the second generation from egg to imago, the care of adults for wintering. The eating behavior of coccinellid was studied at each stage of the life cycle, which showed the presence of a small herbivorous period (phytophagous beetles), most of the cycle of the beetles had a predatory lifestyle (entomophage beetles). Experiments in the natural and artificial conditions of studying the nutrition of a seven-point beetle showed that adult beetles were more effective in consuming aphids than the larvae. It was also established that in the natural environment, the degree of palatability, both in the larva and in the imago, was directly dependent on the density of the aphids: as the aphid decreased, the feeding intensity of the beetles decreased. To increase the efficiency of aphid consumption, the joint content of two predatory beetles in the imago stage was used: a seven-spotted beetle ( Coccinella septempunctata L.) and ground beetle ( Tomocarabus bessarabicus concretus Fischer von Waldheim). With such simultaneous use (polyculture), a synergistic effect was observed in their consumption of rosan aphid ( Macrosiphum rosae L.).

Feeding Preference of Larvae and Adults of Zigzag Beetle on Sucking Insect Pests of Brinjal Under Lab. Condition at Tando Jam

Study was carried out on Feeding Preference of Larvae and Adults of Zigzag Beetle on Sucking Insect Pests of Brinjal Under Laboratory Conditions in 2013 at Tando Jam. Observations on feeding preference of Zigzag beetle shows that the highest feeding consumption of first instar larvae of Zigzag beetle were consumed 9.28±1.47aphids/day. Similarly on whiteflies the feeding rate was 7.56±1.05, and on thrips 5.28±0.98. The mean highest consumption of 1st instar was recorded on aphids, and lowest on. Similarly in the second instar larva the mean highest consumption rate during 24 hours was recorded on aphids. 19.21±1.97 / day followed by whiteflies 13.39±2.82/day and thrips 10.36±1.89/day. In case of third instar larvae the maximum feeding rate was recorded on aphids 35.26±2.06/day followed by whiteflies. 23.15±2.45/day and thrips 16.36±3.82/day. The fourth instar larvae of Zigzag beetle was consumed 52.69±3.89aphids/day followed by whiteflies 39.64±3.02/day and thrips 26.85±5.56/day. While the feeding preference rate of both male and female adults of Zigzag beetle also observed. The male adults of Zigzag beetle was 61.17±4.67 aphids/ day. On whiteflies was 42.89±4.12. Similarly on thrips was 32.56±6.26 thrips/ day. The mean aphid consumption by female adults was more on aphids 72.34±5.33 / day followed by whiteflies 47.23±4.93/day and thrips 37.89±7.19/day. The overall data indicated that fourth instar larvae of Zigzag beetle was more voracious feeder of different sucking insect pests of brinjal as compare to 1st, 2nd and 3rd instar larvae and female adults of Zigzag beetle consumed more sucking pests of brinjal than male adults . However, there is no significant difference between both sexes. The data reveals that aphids was most preferred food and thrips was least preferred prey for Zigzag beetle. Int. J. Appl. Sci. Biotechnol. Vol 7(1): 27-30

Biology and feeding potential of Coccinella septempunctata (Linn.) against Lipaphis erysimi (Kalt) at different temperature regimes

Biology and feeding potential of Coccinella septempunctata (Linn.) were studied in laboratory on 3rd instar nymphs of mustard aphid (Lipaphis erysimi Kalt.) at two different temperature regimes. At 30± 20C, fecundity, oviposition period, hatchability of eggs, male and female longevity (232±70.46, 12.8±3.91, 82.87±6.66, 22.70 ± 2.21and 26.60 ± 4.45, respectively) were higher and incubation period, pre-oviposition period, total grub duration and pupal duration (2.6±0.51, 6.5±3.53, 8.7 ± 1.63 and 5.1 ± 1.10, respectively) were lesser in comparison to 25± 20C where fecundity, oviposition period, hatchability of eggs, male and female longevity, incubation period, preoviposition period, total grub duration and pupal duration were 169.8±61.12, 7.9±1.37, 71.68±4.08, 16.2 ± 1.31 and 21.50 ± 1.95, 2.9±0.73, 7.7±2.49, 11.1 ± 1.52 and 5.8 ± 0.918, respectively . At 27± 2 0C, total mustard aphid consumption by a grub of C. septempunctata during the whole life span, was 424.4±2.78 mustard aphids in comparison to 272.64±1.79 mustard aphid at 23± 20C. Similarly an adult male and female consumed 103.2±1.52 and 116.6 ±1.46 aphids per day respectively at 27± 2 0C in comparison to 65.6 ± 1.02 and 71.8 ± 1.60 at 23± 20C. Thus, at both temperatures aphid consumption increased gradually till 4th instar and 30±20C was found to be most suitable temperature as compared to 25±20C for the life history of C. septempunctata. Hence, it could be concluded that C. septempunctata might play a suitable role in biointensive Integrated Pest Management programme because of better longevity and high predatory potential against the mustard aphid.

Competition for Aphid Prey between Different Lady Beetle Species in a Laboratory Arena

Direct competition for aphid prey (Hemiptera: Aphididae) was evaluated between and among several lady beetle species (Coleoptera: Coccinellidae). The behavior of three native (Coccinella trifasciata, Coleomegilla maculata,andHippodamia convergens) and four nonnative (Coccinella septempunctata,Harmonia axyridis,Hippodamia variegata,andPropylea quatuordecimpunctata) lady beetles was observed in laboratory arenas. The beetles were kept alone, paired with conspecifics or paired with heterospecifics, and presented with potato aphids (Macrosiphum euphorbiae).Harmonia axyridiswas the most successful aphid predator in our study, being able to find aphids more quickly and consume more of them compared to most other lady beetle species. It was also by far the most aggressive of the tested species.Coccinella septempunctata, C. trifasciata,andC. maculatagenerally followedH. axyridisin aphid consumption. Prey discovery, consumption, and aggressive behaviors were dependent on which species were present in the arena. Except for the generally superiorH. axyridis, there was no obvious dominance hierarchy among the other tested species and no dichotomy between the native and non-native species. Asymmetric interactions between lady beetle species may affect their abilities to coexist in the same habitat.

Biological characteristics of the mirids Macrolophus costalis and Macrolophus pygmaeus preying on the tobacco form of Myzus persicae (Hemiptera: Aphididae)

Biological and population parameters of the predatory bugs Macrolophus costalis Fieber and Macrolophus pygmaeus Rambur preying on the tobacco aphid Myzus persicae (Sulzer) were examined. Tobacco was used as host plant and all experiments were carried out at 23°C and L16:D8. In M. costalis, the developmental time for eggs and the total duration of nymphal instars was 13.1 and 22.2 days and in M. pygmaeus 13.0 and 20.2 days, respectively. Both species completed their nymphal development feeding only on plant juices although they required significantly more time to attain adulthood than when feeding on prey. The longevity of M. costalis females and the preoviposition period were 49.9 and 5.6 days and those of M. pygmaeus were 50.3 and 6.3 days, respectively. Adult males showed a higher longevity than females in both species. The intrinsic rate of increase and the mean total number of eggs laid were 0.0644 and 121 in M. costalis and 0.0615 and 104 in M. pygmaeus, respectively. Mean total aphid consumption by nymphs of M. costalis was 61 aphids, about twice that of M. pygmaeus (37 aphids). Total aphid consumption by a male and female pair of M. costalis and M. pygmaeus until the death of the female was 244 and 285 aphids, respectively. The results of the study are discussed in relation to the impact of the two predatory bugs on tobacco aphid populations.