Some Weird Flies

and the plants they pollinate

dr tny bb - PP NITE - Ghost Mountain

Some Unusual Specimens

Label	Species	Family	What it is
A	Prosoeca peringueyi	Nemestrinidae	tangle-veined fly
B	Moegistorhynchus longirostris	Nemestrinidae	tangle-veined fly
C	Philoliche gulosa	Tabanidae	horsefly
D	Anthophora diversipes	Apidae	bee
E	Parafidelia major	Megachilidae	bee

Distributed Across South Africa

1. Tangle Vein (P. peringueyi)
2. Tangle Vein + Horse (out in diff times + poll diff flwrs)
3. Tangle Vein (P. ganglbaueri)

Primary Pollinators

Pollination Syndrome

• syndrome = similar suite of traits (long skinny tubes)
  • even though very different taxa:
    • iris
    • geranium
    • orchid
    • amaryllis

The Craziest (M. longirostris + L. anceps)

proboscis’s and tubes ~ 40mm-80mm

• by far most exaggerated is
  • Moegistorhynchus longirostris (tangle-vein)
    • 80mm mouthpart
    • 15mm-24mm body
  • Lapeirousia Anceps
    • 100mm tube length
  • typically 40mm-80mm

Nature of the Interaction

• flower has markings to help orient fly
• flower has parts trying to place pollen of flies head
• fly wants to get nectar from base of tube
• fly proboscis does not roll up
  • has to drag it across the sandy terrain

Data Suggests…

these flowers are total size queens

• x-axis = how much fly part extends past flwr part
• y-axis left = how much pollen transferred
• y-axis right = how much nectar fly sucks up
• in summary… flwrs are total size queens

sorry, unless you’re packing something absurdly long and can actually get it all the way down the tube without fumbling at the entrance, you’re not getting anything out of this interaction

Pollen Deposit Sites on M. longirostris

• maintains floral reproductive isolation
• typically dusts the fly body with pollen

Panel	Plant	Family	Pollen placed on
A	Ixia paniculata	Iridaceae	frons + base of proboscis
B	Tritonia crispa	Iridaceae	dorsal thorax
C	Lapeirousia fabricii	Iridaceae	dorsal thorax
D	Pelargonium appendiculatum	Geraniaceae	ventral thorax
E	Geissorhiza exscapa	Iridaceae	ventral abdomen

Pollen Mass Deposition

• Prosoeca ganglbauri (tangle-vein)
• Disa scullyi (orchid)
• in contrast to dusting strategy
• pollen sacks attached to base of fly proboscis

• here’s the outcome of a visit to d. scullyi by p. ganglbauri
• pollen sacks attached to the base of
• i know exactly what you’re thinking…

Darwins Hawkmoth Prediction

• … this is totally related to darwins hawkmoth prediction!
• when european naturalists came across this orchid in madagascar
• they were baffled by what would pollinate such an orchid
• with its long nectar spur
• darwin developed a coevolutionary argument to predict something like the hawkmoth
• 30 years later the hawkmoth was finally observed by european naturalists
• i say european because this stuff was likely known by first nations long ago

Revisiting the Data

flies reward longer flowers (mutual size-queens => selection for longer parts)

• flies more likely to pollinate flowers with longer tubes
• so both reward partners with longer parts
• so the interaction selects for longer parts in both

A mutualistic arms race!

Community Context

Fly is a keystone pollinator for long-tubed flowers

but what about the other pollinators ?

Indirect Consequences of Coevolution

remember these bees ??

Indirect Consequences of Coevolution

Fly visits Babiana thunbergii

Malachite Sunbirds pollinate B. thunbergii

Inirect Effects may play big role

• Q-matrix = direct
• T-matrix = sum of indirect

Indirect effects drive coevolution in mutualistic networks, Guimarães et al 2017

Hype

Take-Away: these flies are big deals