Pollinators: Bees and Wasps

Often people ask me about how to make their gardens pollinator friendly. This is a tough question, because there are so many different types of pollinators. Guides usually don’t have all of them in one place.

Here, I’ll explain the categories of pollinators that visit plants, as well as the characteristics of the flowers that they pollinate. But be warned that a lot of the plant examples are not exclusively pollinated by a single pollinator. Often, there can be several different pollinators visiting the same type of flower.

To do this, I dug up a bunch of scientific papers and tried to summarise all of it in simple language here. Some of these categories correspond to categories used by scientists, while some have been simplified and combined for the general public.

Since there are so many pollinators I’ve split this up into a few different articles. This one will discuss bees and wasps.

Bees

Bees collect pollen on their hairy bodies and legs. There are 265 valid bee species in Malaysia. 62 species have been recorded in Kuala Lumpur alone (some of these may be undescribed).  Bees can be divided into two guilds: large bees and small bees.

Large bees

These are your typical bees, locally called lebah or sometimes kumbang*. Only honey bees tend to sting, and only if aggressively disturbed. 

They vary greatly in size, from 10mm to 40mm in length. Large bees tend to travel quite long distances in search of flowers, and due to this prefer flowers with more nectar.

Many of these bees are long tongued bees, they have long mouthparts that lets them suck up nectar that is deep in flowers. A subgroup of large bees are the very large carpenter bees, which tend to prefer larger flowers that can support their weight.

Examples: Honey bees (Apis spp.), carpenter bees (Xylocopa spp.), Blue banded bee (Amegilla spp.)

Flower structure: Usually these are not round and are somewhat tube shaped, often with a petal where the bee can land. However they also pollinate or steal pollen from round, shallow flowers by crawling around inside them.

Plants that they pollinate: tomatoes, eggplants, begonia, Senduduk, Coromandel, many wildflowers.

*In the Malay language, carpenter bees are kumbang kayu, although kumbang is also used for beetles.

Small bees

This is a more diverse group of bees, but easily missed due to their small size (2-12mm). They include bees that live in colonies like stingless bees or solitary bees like sweat bees.

These bees are slower fliers with less range than larger bees. Some of these bees have shorter mouthparts and cannot harvest nectar from very deep flowers. They feed primarily on pollen, and therefore tend to prefer shallow round flowers that they can walk in and collect pollen.

Examples: Stingless bees (Heterotrigona spp.; Lepidotrigona spp.; Tetragonula spp.), Sweat bees (Halictidae)

Flower structure: Shallow round flowers which are not tube shaped.

Plants that they pollinate: Basil, lotus, water lily, Lantana, sunflowers, Beggarsticks,

Wasps

Wasps are less furry and much thinner than bees. They can be identified by their thin “wasp waist”. While many are predatory, they sometimes pollinate flowers when they opportunistically feed on nectar or pollen. However they pollinate with less efficiency than bees because they lack the fuzz to trap pollen.

But there are flowers that are adapted to being exclusively pollinated by wasps, although a lot is still unknown about this type of interaction.

Examples: Hover wasps (Liostenogaster spp.), paper wasps (Ropalidia spp.)

Flower structure: Usually these flowers communicate with their pollinators by smell and taste of nectar (some of which cannot be detected by humans).  Some orchids mimic wasps and transfer pollen as the wasp tries to mate the flower.

Plants they pollinate: Some species of Orchids such as Coelogyne sp., usually these have greenish-yellow colours.  At the moment I can’t find any records of Malaysian plants being pollinated by non-fig wasps. (Any help on this would be appreciated)

Fig wasps

Fig wasps are an example of a keystone species that nobody thinks about. Without fig wasps the fruiting events of figs which sustain most birds in urban settings would not be possible. The reason being that fig wasps are the exclusive pollinator of figs.

Fig flowers grow inwards, forming round structures called synconium. The synconium has a small hole in it that is just big enough for a fig wasp to enter. Female fig wasps lay eggs within fig flowers, while also pollinating the flower so it produces a fruit structure that the larva can feed on. The new females emerge, mate with wingless males, pick up pollen and escape the fig fruit to continue the cycle.

Examples: Fig wasp (Ceratosolen spp.)

Flower structure: Synconium. Flowers that grow inwards and look like round fruit.

 Plants they pollinate: Figs

References:

Cheng, J., Shi, J., Shangguan, F. Z., Dafni, A., Deng, Z. H., & Luo, Y. B. (2009). The pollination of a self-incompatible, food-mimic orchid, Coelogyne fimbriata (Orchidaceae), by female Vespula wasps. Annals of Botany, 104(3), 565-571.

Weiblen, G. D. (2002). How to be a fig wasp. Annual review of entomology, 47(1), 299-330.

Ascher, J.S., and Pickering, J. 2020. Discover Life bee species guide and world checklist (Hymenoptera: Apoidea: Anthophila). Available from http://www.discoverlife.org/mp/20q?guide=Apoidea_species [accessed 8 May 2020].


This article is supported by The Habitat Foundation Conservation Grant