Overall, our wild bee house was a bit of a disappointment, as only a small number of the canes were used. We did have at least one carpenter bee nest in the framework of the bee house, and we had some Anthophora bees that we brought in in clay lumps emerge and renest.
The greatest success was with the blackberry canes. Every one was drilled out and plugged with mud. This was early in the season, and we never saw the creature that did this, but we are assuming it was a tiny Ceratina bee. We have captured live adult ones in the area.
This certainly would encourage us to put out more of the blackberry canes next year.
With the river canes, only an occasional one was used. Early in the season we have about a half dozen that were plugged with leaves, possibly with the orchard mason bees that visited our apple trees. We did not seen any further adult activity after spring, and the nests plugs were removed not too long after they were placed. It’s possible that a new generation emerged, but we think it more likely that fire ants found the nests and had the tenants for a meal. I have tried to maintain fire ant control, but new nests start frequently and often are unnoticed at first.
Some others had mud plugs. Early in the season, we saw the two wasp species shown in earlier posts, making these nests. But the early ones were also opened, just like the leafcutter ones, and this also may have been fire ant depredations. I think the effect of fire ants on wild bees (and thereby on pollination) should be investigated more extensively.
More canes were filled later in the season. As often as we checked, we never saw these built, and do not know exactly what insects built these.
A mysterious visitor apparently nested in two of these tubes and started a third, but did not seal it.
The nesting material appears to be pine straw. Does anyone know what could be in these?
My original plan was to open some of the canes for photos and further study, but there are so few occupied that I think I will let them “bee” until spring, and try to watch carefully to see if we can spot them emerging.
A couple construction details: I had originally intended to use plastic pipe for the outer containers for the river canes and blackberry canes, but I dropped that idea when some free large bamboo was donated to me. Since four-inch plastic pipe is no longer cheap, I went with the idea, but I don’t think I will again. Almost all the bamboo split on one side, thus reducing the weather protection it afforded.
The drilled wood had very few inhabitants, and I think I’ll remove the large stumps from next spring’s bee house. I think to replace them with smaller drilled blocks with paper tubes inside each of them, so I can better check for parasites and live occupancy.
I welcome suggestions for modifications for next year’s wild bee house. A number of folks have made suggestions for this year’s and these were incorporated.
As always, we are continuing to add forage plants that we find are bee-attractive, so we hope to continue to build up populations.
One thing about the bee house is that it has made us keener observers of bee activity. When I see some motion along the surface of the ground, I always look to see if it is a bee nesting or looking for a nest site. In this way, I’ve found sites, and learned the type of habitat that they prefer.
All in all, though nesting was not extensive in the wild bee house, it was quite a learning experience and I am looking forward to next year.