Developmental biology and feeding efficiency of &lt;em&gt;Menochilus sexmaculatus&lt;/em&gt; (Coleoptera: Coccinellidae) (Fabricius) reared on &lt;em&gt;Aphis craccivora&lt;/em&gt; (Hemiptera:Aphididae) (Koch)

T D C Priyadarshani,K S Hemachandra,H N P Wijayagunasekara,U G A I Sirisena

doi:10.4038/tar.v27i2.8160

Abstract

Menochilus sexmaculatus (Fabricius) predates on soft bodied, plants sap feeding insect pests. This species is a potential biocontrol agent to use in augmentative release programmes and requires more biological and ecological data. The objective of this study was to examine the development biology of M. sexmaculatus and to assess its suitability as a biocontrol agent. The study was conducted in the Entomology Research Laboratory, Department of Agricultural Biology, Faculty of Agriculture, University of Peradeniya from January to June, 2015. All the experiments were conducted under laboratory conditions at 27oC and 80 % RH. Mean incubation period of eggs was 3.0 ± 0.4 days. The total larval duration was 7.1 ± 0.5 days; L1, L2, L3 and L4 durations were 2.1 ± 0.3, 1.1 ± 0.4, 1.9 ± 0.3 and 1.9 ± 0.3 days, respectively. The pre-pupal and pupal periods were 1.1 ± 0.3 and 3.1 ± 0.3 days, respectively. Mean longevity of male and female beetles were 38.0 ± 0.6 and 47.3 ± 1.0 days, respectively. Mean pre-oviposition period was 3.0 ± 0.1 days and the oviposition period was 43.3 ± 1.0 days. The mean body length of L1, L2, L3 and L4 instars were 1.9 ± 0.1, 2.7 ± 0.3, 6.0 ± 0.1 and 7.8 ± 0.5 mm while, the mean width were 0.4± 0.1, 0.9 ± 0.0, 1.2 ± 0.1 and 3.3 ± 0.1 mm. Mean length and width of adult females were 6.2 ± 0.2 and 4.5 ± 0.3 mm respectively, and those of the males were 4.3 ± 0.5 mm and 3.2 ± 0.3 mm, respectively. L1, L2, L3 and L4 larvae consumed aphid nymphs at the rate of 10.3 ± 1.9, 7.5 ± 1.3, 38.1 ± 3.5 and 69.1 ± 3.1per day, respectively. L1, L2, L3 and L4 consumed adult aphids at the rates of 3.3 ± 0.6, 3.3 ± 0.6, 12.1 ± 0.9 and 25.1 ± 1.7per day, respectively. Female beetles consumed 1624.1 ± 0.2 nymphs and 1204.3 ± 1.3 adult aphids during their entire adult life span. Males consumed 1302.0 ± 1.5 nymphs and 1006.4 ± 0.4 adult aphids during their entire life span. The feeding efficacy increased with the larval instars. Feeding Efficacy of M. sexmaculatus adults was higher than larvae.

Highlights

The ladybird beetles (Coleoptera: Coccinellidae) have diverse food habits and live in variety of habitats
The Present study examines the development biology of M. sexmaculatus and assesses its efficiency as a biocontrol agent of aphids
Similar observations have been made by Zala (1995) and Patel (1998).The freshly laid eggs of M. sexmaculatus are cigar shaped and bright yellow with a smooth chorion

Summary

Introduction

The ladybird beetles (Coleoptera: Coccinellidae) have diverse food habits and live in variety of habitats. Laboratory reared newly emerged M. sexmaculatus adults were allowed to mate and fed on aphids and held in Petri dishes (15 cm diameter) until oviposition. Morphometric measurements such as width and length of male, female, egg, larva (all four instars) and pupa were made using twenty five individuals under a dissecting microscope. A similar procedure was carried out for adults (male and female) of M. sexmaculatus and their daily consumption of aphids was calculated.

Objectives

Results

Conclusion