|Plicosepalus meridianus growing on Commiphora, Mwiba Ranch, Aug 2011|
In the middle of the dry season out here there's precious little colour to break the greys and browns, but look closely at the Commiphora and you might be surprised. Not only do they flower themselves in the dry season - a small rather unexciting flower, but many of them (I think mainly C. schimperi, but it's tricky for me without leaves!) around Mwiba had been parasitised by Plicosepalus meridionalis, a shockly pink flower that on first glance appears to grow straight out of the tree's bare branches. (I don't know a common name, I'm afraid.)
So, how would we interpret this 'wildlife' sighting? Start by identifying it - I'm fairly sure this is what I've photographed (certainly this genus), but some of you are probably better botanists than me and might correct me. It belongs to the family Loranthaceae, most of which are parasites and which also includes all the African mistletoes (though not the European and North American ones). It's worth pointing out it's only growing on Commiphora too - like many, it's a pretty host specific parasite.
|Note how it grows all along the host!|
That's what it's doing, but what about my third question, what's the role in the ecosystem? Well, in this case we can speculate a bit. The obvious thing it's doing right now, is flowing in the middle of a period where there are few other flowers available. (It can probably do this and remain active during the dry season because it has a ready source of water from it's host, the succulent Commiphora.) And the flowers are pink. So stick around a few minutes and see what happens - you'll almost certainly see a sunbird nip in to feed. Pink, red, orange and yellow flowers are often signals for birds (which have good colour vision), and during the dry season there are precious few flowers around. Some sunbirds move away for the dry season - Coppery Sunbirds are a well known migrant, for example - but many stay and make use of the few specialised flowers available during this lean season. And those few flowers that are available, of course, must get visited very regularly, with excellent pollination chances. So you could argue the plant is helping to maintain the pollinator community during the lean period - certainly if there weren't a few species during this, all the sunbirds would have to migrate to greener areas during the dry season.
|Scarlet-chested Sunbirds (here Arusha, March 2011) require dry season flowers|