The effect of different wavelengths of light, white (control; broad spectrum), blue (ca. 475 nm), yellow (ca. 570 nm) and red (ca. 650 nm), at constant intensity (195 ± 5 lux) on developmental time, reproductive and non-reproductive periods, fecundity, egg viability, prey consumption and fitness of two aphidophagous ladybirds, Cheilomenes sexmaculata and Propylea dissecta were studied. Both ladybird species consumed most aphids, developed fastest and reproduced best when kept under white light, followed by yellow, blue and red light. Fitness of both the ladybirds was highest under white and lowest under red light. There were positive correlations between prey consumption and developmental rate, and prey consumption and fecundity.
The oviposition deterring effects of fresh larval tracks of Cheilomenes sexmaculata (F.), Ceratomegilla undecimnotata (Schneider), Cycloneda limbifer Casey, and Harmonia dimidiata (F.) on C. sexmaculata females were compared in standard laboratory choice tests. Moreover, the persistence of intraspecific effects of C. sexmaculata larval tracks were investigated. Fresh tracks of C. sexmaculata, C. limbifer and C. undecimnotata larvae effectively deterred C. sexmaculata females from ovipositing. The effect of fresh larval tracks of H. dimidiata was not statistically significant. The oviposition-deterring effects of 10 d-old conspecific larval tracks were considerably lower than those of fresh tracks, but remained significant. Clutch sizes were smaller in the blank test without larval tracks than in choice tests with fresh tracks of conspecific, C. limbifer, C. undecimnotata, H. dimidiata larvae and with 10 d-old tracks of conspecific larvae. The study indicates that semiochemicals in the tracks of conspecific and heterospecific coccinellid larvae can contribute considerably to the spacing of C. sexmaculata offspring among prey resources of differing quality and that conspecific as well as heterospecific larval tracks can influence clutch size.
The ladybird beetle, Cheilomenes sexmaculata (Fabricius), has been extending its distribution in and around urban areas at higher latitudes in Japan over the past 100 years. Between 2003 and 2011, we investigated the seasonal occurrence, aphid prey and population dynamics of this species in an urban park in Osaka City, central Japan. We found that C. sexmaculata completes three generations a year in Osaka. Overwintered adults emerge in March or April and produce two (or rarely one) generations by summer. Second-generation adults aestivate and subsequently produce another generation in autumn. This species feeds on five species of aphids that infest planted shrubs and alien weeds throughout the vegetative season. We analyzed the association between accumulated temperature and when overwintered adults first emerged. In addition, we determined the association between their time of emergence, peak abundance and last occurrence, and meteorological conditions. There was no association between the sum of effective temperatures and termination of adult overwintering. There was, however, an association between first occurrence and peak abundance, and climatic conditions, such as warm temperatures or low humidity. This species maintained a stable population in an urban park by becoming quiescent when climatic conditions were unfavourable or prey was scarce. We discussed these findings in relation to urban environmental factors, such as climate, food conditions and vegetation., Yasuko Kawakami, Kazuo Yamazaki, Kazunori Ohashi., and Obsahuje bibliografii
Interactions involving host plants (cowpea, groundnut, cotton, sunflower, greengram, blackgram) an insect herbivore, black legume aphid Aphis craccivora Koch (Hemiptera: Aphididae) and a predator, the zigzag beetle Cheilomenes sexmaculata (Fabricius) (Coleoptera: Coccinellidae) were investigated during 2014-2015. The preference of the aphid A. craccivora for host plants measured in terms of growth and multiplication was cowpea > groundnut > greengram > blackgram > sunflower > cotton (most preferred to least preferred). Cowpea was the most preferred host plant for growth and multiplication of A. craccivora. Aphid's oviposition period was longest, fecundity greatest; adult longevity longest (188.40 ± 28.87 h; 52.00 ± 10.92; 231.60 ± 40.41 h), and nymphal mortality was lowest (0%) when reared on cowpea followed by groundnut, greengram and blackgram. Aphids had highest nymphal mortality (100%), with very few or no live adults produced, when reared on sunflower and cotton, the least preferred host of A. craccivora in this study. At the third trophic level, both the larvae and the adults of the coccinellid, Cheilomenes sexmaculata, consumed more of the aphids reared on groundnut than of those reared on blackgram, greengram, cowpea, sunflower and cotton. The biochemical constituents (phenols) present in cotton and sunflower, which contributed to the aphid's nymphal mortality, also affected the feeding behaviour of the coccinellid., Snehasish Routray, Karnam V. Hari Prasad., and Obsahuje bibliografii