Pollinators: Flies

This is a continuation of our series on pollinators. In this article I will cover flies, often overlooked pollinators of many plants.

As usual, keep in mind 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. For example anything that a fly can pollinate is usually also visited by bees.

Large Flies

I’m generalising larger flies into a single guild, and it is likely this group can be divided up into several sub-groups, but fly pollination is so poorly studied that we do not have a very broad picture of what flies are doing on flowers.

Flies usually feed on nectar when they land on flowers. Since they aren’t as fuzzy as bees, they don’t pick up as much pollen, but some are hairy enough to transfer pollen. Mango farmers take advantage of flies by putting prawn shells around their farms. This attracts carrion flies which then also pollinate the mango flowers.

Hoverflies are sometimes mistaken for bees. An easy way to tell hoverflies from bees is their flight pattern – they fly less frantically than a bee. They are not as fuzzy as bees and usually spend more time on flowers. They also tend to have shorter antenna compared to bees.

While pollinating they hunt for smaller insects and are good natural pest control.

Examples: Hoverflies (Syrphidae), Carrion flies (Calliphoridae), Flower flies (Anthomyiidae)

Flower structure: Fly-pollinated flowers tend to be shallow and grow in clusters.

Plants that they pollinate: mangoes

Small flies and midges

Small flies are very important pollinators of important crops, without them we wouldn’t have cempedak, nangka or chocolate.

Some are very small and can hardly be seen while flying. These flies typically are attracted to downward facing flowers that are close to the ground. Some plants like Aristolochia have elaborate trap flowers that trap the flies for a while until they pick up enough pollen.

Examples: Small fruit flies (Drosophila spp.), Scuttleflies (Phoridae), Midges (Nematocera)

Flower structure: Usually not brightly-coloured, tube shaped flowers

Plants they pollinate: nangka, cempedak, cocoa, Aristolochia

Carrion feeders

This group of insects feed on carrion and other rotting material. Some plants take advantage of this by pretending to be rotting meat with foul-smelling and dark reddish or purple flowers.

While the confused insects, (usually carrion flies or carrion-feeding scarab beetles) crawl around the flower in search of food, sticky pollen gets all over them. When they give up and leave the flower, they bring the pollen to other flowers for pollination. Our famous Rafflesia flower uses this pollination system.

Examples: Carrion feeding scarab beetles (Onthophagus deflexicollis), Carrion flies (Calliphora spp., Chrysomya spp., Lucilia spp.)

Flower structure: The structure of these flowers is surprisingly varied, but they have similar traits of foul smells and dark coloration

 Plants they pollinate: Amorphophallus, Rafflesia, Tacca

References:

Ssymank, A., Kearns, C. A., Pape, T., & Thompson, F. C. (2008). Pollinating flies (Diptera): a major contribution to plant diversity and agricultural production. Biodiversity, 9(1-2), 86-89.


This article is supported by The Habitat Foundation Conservation Grant

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

Butterflies: Blue pansy

blue pansy, butterfly

Blue pansy

Junonia orithya

Unlike most butterflies this species prefers open fields, often perching on grass between short low flights. This butterfly has intricate patterns of velvet brown, sky blue, pale yellow and orange eyespots on its upperside. Its underside is a mix of pale yellow, brown and orange eyespots.

Food items: Nectar (as butterfly), host plant (as caterpillar)

Host plants: Sweet potato (Ipomea batatas), Justicia procumbens, Asystasia gangetica, Plantago, Striga, Thunbergia alata

Microhabitat: Gardens, roadsides and open areas

Ecological Function: Pollinator

Food chain level: Primary consumer

Dispersal: Likely it has limited dispersal range, but it can move through open areas and road verges

Blue pansy (Junonia orithya), female
Blue pansy (Junonia orithya), female (underside)
Blue pansy (Junonia orithya), male (underside)

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Butterflies: Tiny grass blue

tiny grass blue, butterfly

Tiny grass blue

Zizula hylax

A very small butterfly, often seen feeding on low wildflowers. It looks like other small blue butterflies, but is slightly duller blue or occasionally violet from certain angles. The patterns of black dots and gray bars are used to identify this species. Its host plants are a variety of common wildflowers.

Food items: Nectar (as butterfly), host plant (as caterpillar)

Host plants: Acanthaceae, Justicia procumbens, Asystasia gangetica, Ruellia repens, Hemigraphis reptans

Microhabitat: Gardens, roadsides and open areas

Ecological Function: Pollinator

Food chain level: Primary consumer

Dispersal: Likely it has limited dispersal range, but it can move through open areas and road verges

Tiny grass blue (Zizula hylax), female
Tiny grass blue (Zizula hylax), male
(underside)
Tiny grass blue (Zizula hylax), female
(underside)

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Butterflies: Common grass blue

common grass blue butterfly

Common grass blue

Zizina otis lampa

Very common but often unnoticed because of their size, these tiny butterflies are found in almost all green spaces and road verges. It looks like a dull gray butterfly from a distance, but its wings open to reveal reflective deep blue. This species can be differentiated from similar species based on the pattern of dots on the underside of the wings. Its host plants are low growing Desmodium and Semalu plants that are commonly found between grass in fields.

Food items: Nectar (as butterfly), host plant (as caterpillar)

Host plants: Desmodium, Mimosa pudica and Alysicarpus vaginalis

Microhabitat: Gardens, roadsides and open areas

Ecological Function: Pollinator

Food chain level: Primary consumer

Dispersal: Likely it has limited dispersal range, but it can move through open areas and road verges

Common grass blue (Zizina otis), female
(underside)

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Butterflies: Peacock pansy

peacock pansy, butterfly

Peacock pansy

Junonia almana

The underside of this butterfly is an unremarkable pale tan traversed with dark brown lines and dotted with a few black and yellow eye spots. The uppersides of the wings are a rich orange, with eye spots that are violet and deep red. Its caterpillars are known to feed on a wide variety of wildflowers and the adults can be seen in short fast flights within wildflower patches.

Food items: Nectar (as butterfly), host plant (as caterpillar)

Host plants: Mimosa pudica and Acanthaceae

Microhabitat: Gardens, roadsides and open areas

Ecological Function: Pollinator

Food chain level: Primary consumer

Dispersal: Likely it has limited dispersal range, but it can move through open areas and road verges

Peacock pansy (Junonia almana)
(underside)

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Butterflies: Tawny coster

tawny coster, butterfly

Tawny coster

Acraea terpiscore

A bright orange butterfly with black spots, its hindwing fringed with a white and black border. It flies slow and not very high. Originating from India, this butterfly has naturally expanded its range since the 90’s to include Peninsular Malaysia. Now it is one of the most common butterfly species in cities. Its host plant is primarily passionflowers, but other hosts have also been reported. Adults are commonly seen feeding on sunflower family wildflowers.

Food items: Nectar (as butterfly), host plant (as caterpillar)

Host plants: Passiflora suberosa, Passiflora foetida

Microhabitat: Gardens, roadsides, secondary growth

Ecological Function: Pollinator

Food chain level: Primary consumer

Dispersal: Likely it has limited dispersal range, but it can move through open areas and road verges

Tawny coster (Acraea terpiscore)
(underside)

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Butterflies: Common four ring

common four ring butterfly

Common four ring

Ypthima huebneri

These low flying butterflies are a dull brown gray, but they are adorned with black and yellow eye spots that are used to confuse predators. It looks almost the same as the common three ring, but instead of three eye spots on the underside hind wing, it has four. Like other ring butterflies, its host plant is grasses.

Food items: Nectar (as butterfly), host plant (as caterpillar)

Host plants: Gramineae

Microhabitat: Gardens, roadsides, secondary growth and forest borders

Ecological Function: Pollinator

Food chain level: Primary consumer

Dispersal: Likely it has limited dispersal range, but it can move through open areas and road verges

Common four ring (Ypthima huebneri)
(underside)

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Butterflies: Common three ring

common three ring butterfly

Common three ring

Ypthima pandocus

At a glance, this gray brown butterfly may not be very attractive. But close inspection reveals yellow eye spots along the edge of the wing, some with dots of metallic blue set in a black pupil. This species is differentiated from the common four ring by only having 3 eyespots on its hindwing. This butterfly is associated with gardens and green spaces since its caterpillars feed on the fast growing Goat grass (Ischaemum muticum) which is usually used in lawns in Malaysia.

Food items: Nectar (as butterfly), host plant (as caterpillar)

Host plants: Gramineae, Ishcaemum muticum

Microhabitat: Gardens, roadsides, secondary growth and forest borders

Ecological Function: Pollinator

Food chain level: Primary consumer

Dispersal: Likely it has limited dispersal range, but it can move through open areas and road verges

Common three ring (Ypthima pandocus)
(underside)

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Butterflies: Psyche

psyche, butterfly

Psyche

Leptosia nina

A little white butterfly with a single black corner and dot on the upperside of each wing. Its underside is covered in mottled green gray stripes. It flies at a slow relaxed pace, but is easily startled when approached. Usually it is found flying near shadier parts of gardens, visiting wildflowers like Coromandels. The host of this butterfly are Capers (Capparis) although it can also feed on Maman as well.

Food items: Nectar (as butterfly), host plant (as caterpillar)

Host plants: Capparis heneana, Crateva religiosa, Cleome rutidosperma

Habitat: Gardens, roadsides, secondary growth and forest borders

Ecological Function: Pollinator

Food chain level: Primary consumer

Dispersal: Likely it has limited dispersal range, but it can move through open areas and road verges

Psyche (Leptosia nina)
(underside)

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