Relocating nests of social wasps

In March 2005, I first encountered two nests of Parapolybia nodosa built in a nature education center, near some wire mesh which sheltered plants of interest. However, children frequently walk past that area, and I knew that sooner or later, the nests would be spotted and destroyed. I therefore decided to relocate the nests. I returned with a small net, a pair of forceps and some clear plastic bags. The first nest had only one queen, and I brushed hard against it with the forceps. Sure enough, the wasp latched on to the forceps and started stinging. I quickly slipped a plastic bag over and trapped the wasp. I then simply removed the nest gently by hand, and put it in a plastic bag which had layers of clean cotton to insulate and prevent damage.

The second nest already had three young workers. Since this nest was higher, I used my net to brush against the nest. I thus captured and loaded the first two workers without much trouble in the same way when they latched on to the net and started stinging. However, the remaining worker was smarter. Instead of stinging the net, she came straight for me! I put up my hand to block my head, and received one good sting on my left thumb. However, I managed to net her in mid flight. Finally, I enticed the queen to sting the net, and captured her as well.

The process of placing the nest in its new location and returning the wasps to the nest is basically the same every time. The wasps must be chilled to slow them down and render them unable to fly, or they will fly away the minute they are let out! If I expect to be carrying out nest relocations, I usually bring a portable ice pack, the type which contains a blue liquid which can be frozen and then can keep cold for several hours at least. I flatten the plastic bag containing the wasps gently against the ice pack, pressing them against the cold surface. In the meantime, I plant the nest in its new location, tying it to a suitable surface with either fine steel or copper wire or fishing line. The wasps have to be chilled till they become very inactive, and do not move much, but certainly, it is important to avoid freezing them to death! At this point, I cut open the bag and transfer them onto the nest; they usually weakly climb up the nest immediately upon recognizing it. Usually they adapt fine.

These two nests had different endings. The first nest I transplanted directly outside my window, so I was able to observe the colony! I built a small shelter out of wooden sticks to provide shelter from the rain. The nest was then planted inside a cardboard tube (the kind that holds together a roll of paper towel) which was cut in half and stuck against the window, thus allowing for easy viewing. This "shelter" looked flimsy, but it protected the nest against a great amount of summer rain and a typhoon!

Upon introduction, everything went well for the first three days, and the first two workers hatched. However, one day, the queen went missing and never returned. I have no idea about what happened to her. I assumed then that the colony was doomed, but I was wrong.

There were still another seven pupae which would soon hatch into workers, and at least 13 or 14 larvae. During this period, I observed the two workers develop a kind of dominance structure; one seemed to do all the work, bringing prey and nesting material back frequently. The other seemed dominant by her actions, constantly harassing the first worker whenever she returned to the nest, and “demanding” a share of the food collected. Unexpectedly, the first worker started building new cells, and the dominant one started laying!

The pupae all hatched out into new workers, and the larvae grew and started to pupate. The dominant worker was small, far smaller than the rest, but strangely, she held dominance throughout this colony’s life. However, all her offspring emerged, roughly 5 weeks later, to be males! Usually males were not seen so early in the season, but it was not surprising, given that she had never mated and thus could not lay fertilized eggs (which produce females). Unlike workers of hornets and yellowjackets, it is common for workers of various Polistines (paper wasps) to lay their own eggs. However, due to the fact that no new workers were produced, this colony was eventually finished by August, a month or so before the usual end for this species each year.

Parapolybia are remarkably adaptable, and will use all kinds of food to feed their larvae. Not having a distinct caste system (no clear difference between workers and queens), all females also eat some of the meat they collect. And most interestingly, they readily accept food offered on a toothpick, even on the nest itself! The workers in the photo here are taking a tiny piece of hard-boiled egg from the toothpick!

I moved the other colony to a tree out in the countryside. Due to the fact that there were no low branches, I tied it directly to the tree trunk, in the manner shown in the photos. After the chilling, I reintroduced the wasps back to the nest. The queen started to make short orientation flights after resting for a while. A worker also left the nest and came back in less than five minutes with parts of a caterpillar! It was amazing how quickly they adapted to their new location.

Interestingly enough, even while the four wasps (original queen and three workers) were still resting, a fifth worker appeared. This was obviously a slightly older one (young ones have very bright contrasting colours and black eyes). She landed on the nest, and from then on, she was always present on the nest, even making foraging trips and feeding the larvae! I am still at a loss to explain why another worker would join a different colony. I have read, however, that since Polistine wasps are often caught up in a struggle for dominance within the colony, a worker at the bottom of the hierarchy in a colony may sometimes leave and join a smaller colony so as to gain a higher place in the hierarchy of the new nest, being submissive to fewer wasps but dominating over the newly hatched ones.

The colony grew rapidly, and from five wasps, the number increased to 30 in just three weeks! This colony enjoyed a long and prosperous life.

Another method of capturing the wasps before removing the nest, which I employed on another small nest of Parapolybia nodosa containing five wasps, was to dip a cotton tip in honey, and offer it to each wasp in turn. The wasp would lean all the way away from the nest to feed, and I was able to slowly and gently remove and capture each one in this manner.

I did not always succeed. Read on about some of my failures...