The Role of Annual Flowering Plant Strips on a Melon Crop in Central Spain. Influence on Pollinators and Crop.

Celeste Azpiazu,Pilar Medina,Ángeles Adán,Alberto Fereres,Ismael Sánchez-Ramos,Pedro Del Estal,Elisa Viñuela

doi:10.3390/insects11010066

Abstract

Planting flower strips adjacent to crops is among the habitat-management practices employed to offer alternative floral resources to pollinators. However, more information is needed to understand their potential spill-over of pollinators on nearby insect-pollinated crops. Over the course of two consecutive years, the suitability of a flower mixture of 10 herbaceous plants for pollinators was evaluated on a weekly basis, in a randomized block design of two melon plots (10 × 10 m2) with or without 1 m-wide flower strips. Floral coverage and pollinator visits to the plant species, as well as pollinator visits and the yield and quality of the crop, were assessed. Additionally, the selected mixture was tested for 1 year in a commercial field in order to ascertain how far the flower strip could influence visitors in the crop. The most suitable species for a flower strip in central Spain based on their attractiveness, floral coverage and staggered blossom were Coriandrum sativum L., Diplotaxis virgata L., Borago officinalis L. and Calendula officinalis L. The flower strip can act as either pollinator competitor or facilitator to the crop, depending on their floral coverage and/or the predominant species during the crop bloom period. The concurrence of blooming of the rewarding plant C. officinalis with the melon crop should be avoided in our area. In the commercial field, the bee visitation rate in the melon flowers decreased with the distance to the flower strip. No influence of the specific flower strip evaluated on crop productivity or quality was found.

Highlights

Insect pollinators are essential in both natural and agricultural ecosystems due to their role in plant reproduction [1,2,3]
We have focused on this group because it was the most abundant in both the flower strip and the melon flowers, and because some small bees belonging to the family Halictidae have been previously identified as a key pollinators of the melon crop in Central Spain, such as the eusocial L. malachurum (Kirby, 1802) [52], which is seen in our study
Our study provides a list of S-T and L-T pollinators that visit melon fields in Central Spain and identifies some good plant species of high floral coverage and staggered bloom, to be included in flower strips: C. sativum, D. virgata, C. officinalis and B. officinalis

Summary

Introduction

Insect pollinators are essential in both natural and agricultural ecosystems due to their role in plant reproduction [1,2,3]. Insects 2020, 11, 66 of honeybee colony losses from many parts of the world, sometimes attributed to colony collapse disorder syndrome [4,5,6]. This fact, combined with the increase in agricultural areas that require insect pollination [7], has led to growing worldwide concern regarding the overreliance on a single species to achieve the satisfactory pollination of agricultural crops [8,9]. In intensive agricultural areas, the use of pesticides [11] and the degradation of natural habitats with the subsequent decrease in plant diversity reduces the abundance and richness of pollinators, due to decreases in food availability and nesting opportunities [5,12,13] which, in turn, may result in crop yield deficits [9,14,15]

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Conclusion