Saturday, November 8, 2014

Gede fieldwork underway!

Sampling arthropod biodiversity with Kirao and Arnold in Gede restoration forest

With the help of intrepid field assistants Kirao and Arnold (local residents with the intern/volunteer program at A Rocha Kenya), we have been getting it done in the restoration forest at Gede Ruins. Each morning we've been putting out pitfall traps full of soapy water to capture  ground-dwelling arthropods (spiders and beetles), and malaise traps designed to capture flying insects (wasps/bees, beetles, flies). I have brought two kinds of malaise traps (visible in above picture) with me for this expedition -- a large white trap that is anchored on the ground and captures insects flying up to a meter or so off the ground, and another smaller gray trap that can be hung from trees used to capture insects flying around two meters above the ground. Each of these traps has a collecting chamber at the top of the netting material; insects flying into the netting make their way upwards (towards the light) and fly into the chamber, falling into alcohol with which we have charged the trap. We also put out yellow bowls full of soapy water, which attracts wasps and bees. Each morning we collect the specimens from all of the traps, and bring them back here to the Mwamba Field Centre , where we transfer them to vials containing 70% alcohol sorted by type (Order) of insect. I will deliver the specimens to a colleague at the National Museums of Kenya in Nairobi before flying back to the U.S. next week.
Kirao and Arnold placing scarab (dung) beetles into vials.
For this expedition, we are exploring the effects that the presence of Neem (Azadirachta indica) trees may have on arthropod communities. Neem has insecticidal properties -- the seeds are used to make biorational pesticides -- so it's possible that the mere presence of the tree may deter insects from lingering in plots with high concentrations of Neem. Our traps are designed to measure activity of insects/arthropods in the plots -- because they are "passive traps", they don't measure overall abundance -- so they are well-suited to comparing activity among plots with different concentrations of Neem. Our preliminary results from our last sampling expedition indicate that there may be a pattern, so we're checking to see if any sort of pattern emerges from a larger number of replicated plots.
Neem tree in Gede Ruins

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