Differential Consumption of Four Aphid Species by Four Lady Beetle Species

The acceptability of four different aphid species Macrosiphum albifrons (Essig), Macrosiphum euphorbiae (Thomas), Macrosiphum pseudorosae Patch, and Myzus persicae (Sulzer) (Hemiptera: Aphididae), as prey for four lady beetle species, one native species Coccinella trifasciata L, and three non-native Coccinella septempunctata L, Harmonia axyridis Pallas, Propylea quatuordecimpunctata L (Coleoptera: Coccinellidae) were tested in the laboratory. The relative field abundance of adults of the same lady beetle species on host vegetation, Lupinus polyphyllus Lindley (Fabales: Fabaceae), Solanum tuberosum L (Solanales: Solanaceae), and Rosa multiflora Thunberg (Rosales: Rosaceae), both with and without aphids present was also observed. In the laboratory, H. axyridis generally consumed the most aphids, while P. quatuordecimpunctata consumed the fewest. The exception was P. quatuordecimpunctata, which consumed a greater number of M. albifrons nymphs, and C. trifasciata, which consumed a greater number of M. albifrons nymphs and adults, compared with the other two beetle species. Lady beetles consumed fewer M. albifrons compared with the other three aphid species, likely because of deterrent compounds sequestered by this species from its host plant. In the field, P. quatuordecimpunctata was the most abundant species found on L. polyphyllus and S. tuberosum

2001: Effect of thermoperiod on diapause intensity in Pyrrhocoris apterus (Heteroptera: Pyrrhocoridae

Abstract The intensity of adult diapause in Pyrrhocoris apterus was measured in two series of experiments as the duration of pre-oviposition period at a constant temperature of 25°C after transfer from short (12L:12D) to long day conditions (18L:6D). Higher diapause intensity was induced with a thermoperiod than at constant temperatures. After the induction throughout larval instars 3-5 and during 4 weeks of adult life at short days and a thermoperiod of 25/15°C the pre-oviposition period was 30±4 and 26±3 days. After induction at constant 25°C the pre-oviposition period was 22±3 and 23±4 days, while after induction at constant 20°C it was 17±4 and 19±4 days. Induction at a lower constant temperature of 20°C was thus followed by a less intense diapause than the induction at a higher constant temperature of 25°C. These counterintuitive results are discussed. The oxygen consumption rate measured at experimental temperatures prior to transfer from short to long days was higher at thermoperiodic conditions than at constant temperatures and it was similar at constant 20 and 25°C. Thus, the oxygen consumption rate measured prior to the transfer was highest (indication of the least intense diapause) in the insects that showed later, after the transfer to long days, the longest pre-oviposition period (indication of the most intense diapause). Within the first two days after transfer to constant 25°C, oxygen consumption rate measured at 25°C decreased in the thermoperiodic insects, while it transiently increased in insects from constant 20°C. Two days and later after the transfer, oxygen consumption rate was similar in all groups. Cold hardiness was not correlated with diapause intensity. The low lethal temperature in diapausing insects was correlated with the night temperature during diapause induction

Evaluation of Scymnus nubilus (Coleoptera : Coccinellidae) as a biological control agent against Aphis spiraecola and Cinara juniperi (Hemiptera: Aphididae)

Aphids are a major insect pest of forestry systems. In this study, we evaluate the potential of the ladybeetle Scymnus nubilus Mulsant (Coleoptera: Coccinellidae) as a biological control agent against Aphis spiraecola Patch and Cinara juniperi (De Geer) (Hemiptera: Aphididae) infesting Azorean endemic plants reared in forestry nurseries.Official Forestry Services from the Regional Government of the Azores, through the research project PICA 'Utilização de agentes de controlo biológico para o combate a populações de afídeos em plantas endémicas produzidas em viveiro'info:eu-repo/semantics/publishedVersio