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Direct competition and potential displacement involving managed Trogoderma stored product pests
Michael J Domingue1,2, Yunke Wu3,4, Kendra A Vieira3
1United States Department of Agriculture, Animal and Plant Health Inspection Services, Plant Protection and Quarantine, Science and Technology, 1398 West Truck Road, Buzzards Bay, MA, 02542, USA. Michael.J.Domingue@USDA.gov.
The invasive Khapra beetle (Trogoderma granarium) poses a threat to stored grain, potentially displacing native species like Trogoderma inclusum. Longer competition periods, especially with larvae, favor T. granarium, particularly at warmer temperatures.
Area of Science:
- Stored Product Entomology
- Invasive Species Ecology
- Pest Management
Background:
- Exotic pest establishment can lead to native species displacement.
- Understanding interspecific competition is crucial for predicting invasive species success.
Purpose of the Study:
- To investigate the competitive potential of Trogoderma granarium against Trogoderma inclusum in stored product environments.
- To determine the influence of commodity, temperature, and duration on interspecific competition dynamics.
Main Methods:
- Direct competition experiments were conducted using T. granarium and T. inclusum.
- Experiments varied commodity type, temperature (25°C and 32°C), and duration (9 and 25 weeks).
- Competition was initiated using either adults or larvae.
Main Results:
- Trogoderma inclusum initially outproduced T. granarium across all conditions at 9 weeks.
- T. granarium showed a higher proportion relative to T. inclusum at 32°C compared to 25°C.
- At 25 weeks, T. inclusum maintained a competitive advantage when starting with adults, but T. granarium nearly excluded T. inclusum at 32°C when starting with larvae.
Conclusions:
- Trogoderma inclusum excels in short-term competition with abundant resources.
- Trogoderma granarium demonstrates greater success in longer-term competition, especially when larvae are involved and at higher temperatures.
- Introduction of T. granarium larvae presents a significant threat to grain storage infrastructure already hosting T. inclusum populations.
