Study of Ecological Diversity of Predatory Asopinae Bugs in the Agro-ecosystem of the Mid-Western Plains

Abstract

The aim of the present study was to investigate the seasonal abundance of Asopinae predatory stink bugs within an agro-ecosystem. This research was carried out by utilizing sweep nets to collect these insects during the period spanning from May to August in the year 2022. The survey yielded two prominent species of predaceous bugs, specifically Andrallus spinidens and Eocanthecona furcellata. Interestingly, E. furcellata emerged as the dominant species within the field conditions. A noteworthy phenomenon occurred in June when a sudden surge in the population of both species was observed. This population increase was attributed to the presence of lepidopteran larvae in the field, which likely served as a rich food source for these predatory stink bugs. The ecological analysis revealed some important findings regarding the diversity and distribution of these insects in the agro-ecosystem. Specifically, the Shannon Diversity Index was notably low, registering at less than 1.99, indicating a limited variety of species within the sampled population. Similarly, the Simpson Index indicated a low degree of diversity or heterogeneity, falling within the range of 0.01 to 0.04, which further supports the notion of a relatively homogeneous population. Additionally, the Margalef Richness Index signalled a level of disturbance, measuring less than 2.05. This disturbance could be linked to various factors affecting the ecosystem, including changes in agricultural practices or environmental conditions. Lastly, the Dominance Index was relatively high, ranging between 0.5 and 1.0, signifying that a few dominant species, particularly E. furcellata, exerted a significant influence within the ecosystem. In summary, the ecological indices suggested limited diversity, low heterogeneity, disturbance, and dominance within the stink bug population, shedding light on the dynamics of these beneficial insects in the agro-ecosystem.