Nesting and predatory behaviour of potter wasp, Rhynchium brunneum brunneum (Eumeninae: Vespidae: Hymenoptera) in an urban farm landscape

ABSTRACT

Eumenid wasp, Rhynchium brunneum brunneum is a solitary wasp that constructs its nests in hollow cavities provisioning lepidopteran larvae to its broods. The nesting behaviour, biology, prey preference and prey composition of the wasp were studied and molecular characterisation of the prey was done to confirm their identity. The trap occupancy rate by the wasp was 47.51% with 5.82 ± 0.18 cells per trap provisioned with 10.90 ± 1.72 larvae per cell. The egg to adult duration of the wasp lasted for 21.60 ± 2.22 days. The wasp used six different species of lepidopteran larvae as prey viz., Diaphania indica, Maruca vitrata, Parotis atlitalis, Phycita erythrolophia, Spodoptera litura and Sylepta derogata for its developing broods. Three prey species D. indica (Accession No. MN888507.1), M. vitrata (Accession No. MN888506.1) and P. atlitalis (Accession No. MN888512.1) were molecularly characterised. The percent prey composition of D. indica, M. vitrata, P. atlitalis, P. erythrolophia, S. litura and S. derogata were 31.23, 98.17, 10.40, 42.32, 75.85 and 20.10 respectively. Mixed prey composition in the cells were recorded during the months of June to October and January to May. There was a significant difference in the number of live webbings by M. vitrata in the pigeon pea installed with trap nests (1.53 ± 0.72) compared to wasp excluded control plot (4.07 ± 1.35) four weeks after installation. The results suggested that this eumenid wasp be a potential predator of economically important lepidopteran pests. Installation of artificial trap nests amidst crop habitats could help in their conservation and enhance the process of natural biological control of pest insects.

KEYWORDS:

• Biological control
• predation
• prey preference
• Rhynchium

Acknowledgements

The authors are thankful to Dr. P. Girish Kumar, Scientist C, Zoological Survey of India, Kolkata for confirming the identity of the potter wasp, Rhynchium brunneum brunneum.

Disclosure statement

No potential conflict of interest was reported by the author(s).