Evaluation of the Productivity of Social Wasp Colonies (Vespinae) and an Introduction to the Traditional Japanese Vespula Wasp Hunting Technique

This methodological paper evaluates the productivity of a social wasp colony by examining the number of meconia per 100 cells of comb, to estimate the total number of adults the wasps produced. The associated video describes how to search for Vespula wasp nests, a method developed by amateur wasp chasers.

Since Vespula wasp colonies cannot be lured from busts, nests must be collected from the wild. Here I demonstrate traditional wasp hunting as has been developed in Japanese culture. When following wasps to their nests, this technique can help in resuming nest location from the point at which a wasp has escaped detection.

To attract vespula, hang 10-gram pieces of unflagged bait on a tree branch at a height that can be easily reached by hand along a transect at 500 to 100 stations, with at least 5 meters between each station. While waiting for the wasps, use scissors to cut plastic polyethylene bags into three to five millimeter wide by 15 centimeter long strips. And cut cuttlefish, freshwater fish or chicken hearts into 10 milligram pieces.

Next, tie one end of extremely fine polyester thread to one plastic strip and the other end to one piece of meat. Then cut any loose thread above the knots. before mounting the bait onto individual bamboo skewers, When wasps begin to approach the hanging bait, hold out the flagged bait on the bamboo skewers to allow easier access to the feeding wasps.

While the wasps are biting the bait, use a water-based paint pen to paint a unique mark on the thorax of each wasp. Orient the flag with the thread under the wasp while it bites the flagged bait so that the thread passes under the wasp's abdomen from below its thorax. After identifying a wasp that returns to the bait repeatedly within four minutes of leaving gather the baits from the surrounding areas so that the returning wasp is more likely to return to the same spot and follow the marked wasp of interest.

When a followed wasp lands somewhere on the way to its nest, gently lift the wasp with a long stick or fishing rod and watch the wasp until it resumes flight. If a wasp escaped detection while being followed, wait for the wasp to return to the bait station on the transect before resuming the chase and carry the bait stick and wasp to the point where the wasp had last escaped detection. Foraging wasps do not let go of their baits easily and do not sting if handled gently and therefore can be moved to the desired location by holding the flag without the wasp escaping.

Upon the location of a nest, put on the appropriate protective clothing and collect as many workers into the nest as possible by vigorously stomping on the ground around the nest for 10 to 20 minutes so that the workers remain inside to protect the nest. When all of the wasps have returned to the nest shine a light directly into the nest entrance to determine the direction in which the nest entrance runs and use a finger to confirm the orientation of the nest hole, while gently excavating soil from around the nest. When the wasps have calmed, place the excavated nest into a wooden custom made carrying box and cover all but the top of the nest with branches and newspaper.

To estimate the number of cells per comb, separate the combs one by one, and sweep away all of the adult wasps from the comb. Use tweezers to pull out all the larvae and pupae from the cells, and place a scale reference onto the comb. Take a picture of the comb from above and open the image in ImageJ.

Measure the square areas of ten randomly chosen cells per comb in pixels and convert the measurements to the actual areas. Then divide the area of each comb by the average cell area per comb to estimate the number of worker and queen cells. To count the number of miconia per 100 cells for each comb carefully break the comb and examine the miconia.

The miconia may have solidified into two or more layers in the cells. In this study, a comb with an average cell of less than 20 millimeter squared was defined as a worker comb and larger combs were defined as queen combs. After counting the number of cells for queen and worker combs, the actual number of cells per comb can be estimated via extrapolation.

Using real data, the mean and standard deviation of the number of miconia per cell can be calculated with the number os samples set up 1000 for each sample size. This analysis showed that the standard error of the mean was less than 0.05 when the sample size was 100 cells for both the worker and queen combs. The actual number of miconia in the cells of worker combs which represents the number of workers produced ranged from 1.96 times more than the number of estimated larval cells to 0.89 times less than the estimated number of cells.

In the queen combs, the actual number of cells was often less then the estimated number of cells. The number of miconia in the queen combs which can represent a component of fitness was 0.69 to 1.97 times the estimated number of cells. If a wasp escapes detection while being followed, the bait stick can be carried to the point where the wasp was last observed.

The flags can also be bound directly onto the bodies of wasps with a large body size to aid in the location of the nest. This method not only makes it easier to find wasp nests, but it can also help researchers in the analysis of wasp homing behaviors. Always make sure no one else is around the nest before approaching, to prevent other visitors from being attacked.

Remove the workers after collecting the nest.