Pollinators on Cowpea Vigna unguiculata: Implications for Intercropping to Enhance Biodiversity

Abstract

Pollinators are on the decline and loss of flower resources play a major role. This raises concerns regarding production of insect-pollinated crops and therefore food security. There is urgency to mitigate the decline through creation of farming systems that encourage flower-rich habitats. Cowpea is a crop that produces pollen and nectar attractive to pollinators. Twenty-four cowpea varieties were planted, and the number of pollinators were counted using three sampling methods: pan traps, sticky traps, and direct visual counts. Five pollinator types (honey bees, bumble bees, carpenter bees, wasps, and butterflies and moths), 11 and 16 pollinator families were recorded from direct visual counts, pan and sticky traps, respectively. Pollinator distribution varied significantly among varieties and sampling methods, with highest number on Penny Rile (546.0 ± 38.6) and lowest (214.8 ± 29.2) in Iron and Clay. Sticky traps accounted for 45%, direct visual counts (31%), and pan traps (23%) of pollinators. Pollinators captured by pan traps were more diverse than the other methods. The relationship between number of pollinators and number of flowers was significant (r2 = 0.3; p = 0.009). Cowpea can increase resources for pollinators and could be used to improve pollinator abundance and diversity in different farming systems.

Evaluation of Cowpea (Vigna unguiculata) in an Intercropping System as Pollinator Enhancer for Increased Crop Yield

“…This was achieved using three sampling methods (direct visual counts, pan traps, and sticky traps). It has been suggested by several studies that when assessing the abundance and diversity of insect pollinators, the use of multiple sampling methods would provide a better representation of the different types of pollinators in an ecosystem [14,19,[39][40][41][42][43][44]. From our study, diverse pollinator types were recorded.…”

“…Other studies have suggested that an increase in the number of inflorescences may result in an increase in pollinator visits [45][46][47][48]. Pinkeye Purple Hull and Whippoorwill cowpeas produce an average of 49.4 and 56.4 flowers per plant, respectively [19]. These flowers, in addition to those from squash, okra, and watermelon, as well as other floral resources such as nectar and pollen, may have influenced the attraction and abundance of pollinators in the cowpea intercrop.…”

“…Cowpea (Vigna unguiculata L. Walp) has been recognized for its nectariferous nature and its role in attracting pollinators [17][18][19][20]. The plant has extrafloral nectaries on its petioles and leaflets that are nectar-releasing sites, which attract beneficial insects, including pollinators.…”

“…It is therefore important to assess the contribution of pollinators in an intercropping system on crop yield. In this study, two cowpea varieties (Pinkeye Purple Hull and Whippoorwill) reported to be highly attractive to diverse pollinators [19] were intercropped with three pollinator-dependent crops (squash, okra, and watermelon), including controls (PDCs with no cowpeas and sole cowpea). We determined the effect of cowpea intercrop on the abundance and diversity of pollinators and other beneficial insects, H. halys, and crop yield.…”

Induction of Genetic Variability in Cowpea Variety Videza for Extra Earliness and High Seed Yield using Gamma Irradiation Mutagenesis

“…Increase in NPP after mutagenic treatment has also been reported in cowpea (Horn, 2016) and chickpea (Wani, 2011). Increase in NPP has been attributable to an increase in number of flowers in cowpea (Dingha et al 2021). This trait plays a vital role in increased seed yield per plant in cowpea.…”