Native bee fauna of tomato crops: a comparison of active sampling and pan trapping methods

ABSTRACT The tomato is widely cultivated throughout the world and requires pollination by wild or managed bees to realize its full-potential fruit production. Two different sampling methods (pan trapping and active sampling) were employed in nine different properties from June to September of 2011 to investigate the richness and abundance of native bee species present in tomato crops of Center-West Brazil. A total of 465 individuals of 44 species were collected, with the composition of sampled bee species differing between the methods used. Twenty-two species were exclusively captured in pan traps, 13 others through active sampling and nine by both methods. Most of the sampled bee species can be considered effective pollinators of the tomato because they can perform buzz-pollination. By vibration, these bees can liberate pollen from anthers into the air or onto their own bodies and the stigmas of the same flower because the stigmas of the studied tomato variety are within the anther cone. Both methods exclusively sampled some species of buzz-pollinating bees, however, pan-trapping captured buzzing and non-buzzing visitors indiscriminately while active sampling captured more buzzing bees. Pan-trapping and active sampling appear to complement each other, and so the use of only one or the other would not provide a full understanding of the species richness of tomato pollinators in the field.

摘要 番茄在全球范围内广泛种植，其果实生产需依靠野生或人工饲养的蜜蜂完成授粉，方可实现最大生产潜力。本研究于2011年6月至9月间，在巴西中西部的番茄种植区设置9个不同样地，采用诱集法（pan trapping）与主动采样法（active sampling）两种采样方案，调查该区域番茄作物生境中本土蜂类的物种丰富度与个体多度。本次研究共采集到隶属于44个物种的465头蜂类个体，不同采样方法所获蜂类物种组成存在显著差异：其中22种仅通过诱集法捕获，13种仅通过主动采样法采集到，另有9种可通过两种方法共同捕获。多数采集到的蜂类物种均可被视为番茄的有效传粉者，因其具备震悬传粉（buzz-pollination）能力：此类蜂类通过振动可将花药中的花粉释放至空气中，或附着于自身体表，进而接触同花的柱头——因本次研究所用番茄品种的柱头位于花药筒内部。两种采样方法均可单独采集到部分震悬传粉蜂类，但诱集法会无差别捕获震悬传粉与非震悬传粉的访花者，而主动采样法可采集到更多震悬传粉蜂类。诱集法与主动采样法具有显著互补性，仅使用其中一种方法无法全面掌握田间番茄传粉蜂类的物种丰富度情况。