Comparative Overview of Community Structure and Functioning of The Flower-Visiting Insects on Physalis minima L. (1753) (Solanales: Solanaceae) and Sesamum indicum L. (1753) (Scrophulariales: Pedaliaceae) in Macha (Bambui, North-West, Cameroon)
Nadine Esther Atibita Otiobo *
Department of Biology and Physiology of Animal Organisms, Faculty of Sciences, University of Douala, Douala, Cameroon.
Auguste Pharaon Mbianda
Department of Plant Biology, Faculty of Sciences, University of Douala, Douala, Cameroon.
Joseph Blaise Pando
Higher Teacher Training College, University of Maroua, Maroua, Cameroon.
Dounia Dounia
Higher Teacher Training College, University of Yaounde 1, Yaounde, Cameroon.
Moïse Adamou
Department of Biological Sciences, Faculty of Sciences, University of Ngaoundere, Ngaoundere, Cameroon.
Champlain Djieto-Lordon
Department of Animal Biology and Physiology, Faculty of Sciences, University of Yaounde I, Yaounde, Cameroon.
Joseph Lebel Tamesse
Higher Teacher Training College, University of Yaounde 1, Yaounde, Cameroon.
Fernand-Nestor Tchuenguem Fohouo
Department of Biological Sciences, Faculty of Sciences, University of Ngaoundere, Ngaoundere, Cameroon.
Martin Kenne
Department of Biology and Physiology of Animal Organisms, Faculty of Sciences, University of Douala, Douala, Cameroon.
*Author to whom correspondence should be addressed.
Abstract
Background: Floral visitors play a crucial role in maintaining agro-ecosystem productivity, yet their dynamics in the highlands of North-West Cameroon remain poorly understood. The plant plays a crucial ecological role by offering alternative nectar and pollen resources, thereby contributing to the maintenance of local pollinator populations.
Aim: This study investigated the entomofauna visiting Physalis minima L. (1753) (Solanales : Solanaceae) (a spontaneous herb) and Sesamum indicum L. (1753) (Scrophulariales: Pedaliaceae) (a major oilseed crop) in Macha (Bambui) to evaluate their diversity, community structure, and interspecific interactions.
Place and Duration of Study: Insect collections and observations were conducted during the 2013 and 2014 cultivation campaigns in Macha (Bambui, North-West, Cameroon).
Methodology: Community structure was analyzed using diversity indices (Margalef, Berger-Parker, Shannon), rarefaction curves, and rank-frequency mathematical models (Zipf and Zipf-Mandelbrot). Interspecific correlations were tested to assess behavioral dynamics.
Results: A total of 42 insect species were identified, with Hymenoptera (Apidae: 41.2%) being the dominant order. Amegilla sp. and Apis mellifera adansonii were the primary visitors, exhibiting clear niche partitioning: Amegilla sp. significantly preferred the tubular flowers of Se. indicum (44.9%), while A. m. adansonii favored Ph. minima (20.7%). Species abundance distributions (SADs) predominantly fitted the Zipf-Mandelbrot model, reflecting a "pioneer-like" system with high dominance and shared competition among leaders. Despite low overall species richness, communities were structured around a stable core of frequent visitors. Interestingly, all significant interspecific correlations were positive, suggesting behavioral tolerance and a synergistic network of floral exploitation. Physalis minima acted as a vital biodiversity reservoir, supporting 80.2% of useful pollinators and a refuge for biological control agents like Paragus borbonicus.
Conclusion : The findings highlight the importance of maintaining heterogeneous floral resources (crops and wild weeds) to preserve a resilient pool of pollinators. Landscape-level management that integrates spontaneous flora is essential for the sustainability of subsistence agriculture and the stability of ecosystem services in the Cameroonian highlands.
Keywords: Physalis minima, Sesamum indicum, community structure, Biodiversity reservoir