The contribution of honey bees, flies and wasps to avocado (&lt;i&gt;Persea americana&lt;/i&gt;) pollination in southern Mexico

Antonella Soro,Lorraine McKendrick,Rita Alfaro-Bates,Jose Javier Quezada-Euan,Salvador Medina,Robert J Paxton,Jesica Perez-Balam

doi:10.26786/1920-7603(2012)6

Abstract

Although avocado is native to Mexico, there are no comparative measures in this country on the performance of its flower visitors as pollinators. The contribution of honey bees, flies and wasps to the pollination of avocado from tropical Mexico was assessed by comparing abundance, speed of flower visitation, quantity of pollen carried per individual and pollen deposited on virgin flowers after single visits. The values of abundance and frequency of flower visitation with pollen deposition were combined to obtain a measure of pollinator performance (PP). The most abundant insects on avocado were flies (mean ± SE: 15. 2 ± 6.2), followed by honey bees (9.4 ± 6.3) and wasps (4.2 ± 3.1) (ANOVA F = 91.71, d.f. = 2,78; P < 0.001). Honey bees and wasps visited similar number of flowers (8.2 ± 3.1 and 7.5 ± 2.6 respectively), and more than flies (4.1 ± 1.2) in the same time period (F = 17.63; d.f. = 2,33; P < 0.01). Although flies carried far more avocado pollen on their bodies (44.9 ± 16.8 grains) compared with honey bees and wasps, (21.3 ± 6.2 and 23.8 ± 8.11 grains, respectively; H = 26.522, df = 2, P = 0.001), the number of pollen grains deposited on a stigma after a single visit was similar for the three taxa (2-5). There was evidence for a significant and similarly positive PP of both honey bees and flies as avocado pollinators over wasps, given their abundance, potential for pollen transport and deposition of pollen on stigmas.

Highlights

Avocado (Persea americana) is a tree of the family Lauraceae native to southern Mexico and Central America
Relative contribution of open and crosspollination to avocado fruit set It was found that only a small number of flowers in the bagged inflorescences set fruit (Tab. 1)
In a cultivated avocado orchard in southern Mexico we found that three major insect groups were attracted in significant numbers to flowers, namely non-native bees (A. mellifera) and flies (C. megacephala) and native wasps (B. mellifica)

Summary

Introduction

Avocado (Persea americana) is a tree of the family Lauraceae native to southern Mexico and Central America. An array of insect taxa visit avocado flowers, including bees, wasps (Hymenoptera) and flies (Diptera) (Free 1993; Castañeda-Vildózola et al 1999; Can-Alonzo et al 2005). Avocado trees have bisexual flowers that show synchronously protogynous dichogamy (Free 1993). There are two types of avocado cultivars: those classified as type A have flowers in stage I in the morning of their first opening and the same flowers re-open again in stage II of the following afternoon. Cultivars classified as type B have flowers in stage I in the afternoon of their first opening and stage II on the following morning (Lahav & Gazit 1991). There is still debate as to whether insects are

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Conclusion