›› 2015, Vol. 58 ›› Issue (3): 297-307.

• RESEARCH PAPERS • Previous Articles     Next Articles

Temperature and photoperiod influence prey consumption and utilization by two sympatric Coccinella species (Coleoptera: Coccinellidae) in conspecific and heterospecific combinations(In English)

Bhupendra KUMAR, OMKAR*   

  1. (Centre of Excellence in Biocontrol of Insect Pests, Department of Zoology, University of Lucknow, Lucknow 226007, India)
  • Online:2015-03-20 Published:2015-03-20
  • Contact: E-mail: omkaar55@hotmail.com

Abstract: 【Aim】 Indian subcontinent is amongst the vulnerable geographical landscapes of the world. A slight fluctuation in its climatic conditions may adversely influence its seasonal cycles and may cause a tremendous outbreak of aphids in its agroecosystems. Coccinella septempunctata L. and C. transversalis Fab. (Coleoptera: Coccinellidae) are the two sympatric aphidophagous ladybirds that abundantly inhabit the subcontinent. 【Methods】 The present ex-situ study has therefore been designed to explore how the two ladybirds would respond to increasing temperature (15, 20, 25, 30 and 35℃) and photoperiod (8L:16D, 12L:12D and 16L:8D) when allowed to feed together on a common prey resource (pea aphid) in conspecific and/or heterospecific combinations. 【Results】 The results revealed that 2-predator conspecific/heterospecific combinations of both the ladybirds exhibited antagonistic effects at five different temperatures and three different photoperiodic conditions. Despite of antagonistic effects, predators in conspecific/heterospecific combinations consumed, converted and utilized the prey biomass maximally at 25℃ and under long (16L:8D) photoperiodic conditions. However, their consumption rates, conversion efficiencies and growth rates were highest in heterospecific combinations. The 4th instar larvae utilized the prey biomass more efficiently to their own biomass at five different temperatures, while the adult females did the same at three different photoperiodic conditions. 【Conclusion】 It may therefore be inferred that increasing temperature and photoperiodic conditions might not stop the ladybirds from interacting antagonistically in conspecific and heterospecific combinations, but at 25℃ and under long (16L:8D) photoperiodic conditions the prey consumption and utilization efficiency of the interacting ladybirds would be optimum.

Key words: Ladybirds, Coccinella septempunctata, Coccinella transversalis, conversion efficiency, growth rate, predatory interactions, temperature, photoperiod