foundresses queen and is called tapping. Queens have been observed tapping mid or hind legs on the comb after returning with prey. These taps can last from a few seconds to a couple of minutes and are loud enough to be heard outside of the nest. This signal is believed to function in the same way as gastral vibration in workers and is to signal to the larvae when it is time to feed. Sometimes this tapping or vibration occurs even when there is no pellet to feed the larvae and it is speculated that this corresponds to the feeding of liquids, but this has not been confirmed. Tapping continues in the queen even after she has ceased foraging when she feeding larvae pellets that she receives from the workers. This supports the idea that it is involved in signaling larvae during feeding. Genetic relatedness within colonies Haplodiploidy The median wasp, as in all other Hymenoptera species, produces females from fertilised diploid eggs, but males are produced from unfertilised haploid eggs. This means that although workers are unable to mate they can still produce male offspring. This type of sex determination is known as haplodiploidy. The result is that brothers have a relatedness of 0.5 as expected of full siblings, but sisters have a higher relatedness of 0.75. Sisters receive half of their mother's genes as well as all their father's genes because all of the sperm he produces are identical. Mothers have a relatedness of 0.5 to both their sons and daughters. Worker-worker relatedness Most Dolichovespula species including D. media mate only once or fertilise most eggs with sperm from a single male. In addition, there are only 1-2 queens per colony. These specific characteristics result in a high level of worker-worker relatedness within the colony. One study estimated this relatedness to be as high as 0.71. This was determined by analysing 20 workers from each of 10 nests at 3 DNA microsatellite locuses. The DNA analysis allowed the researchers to determine if males were queen's or workers’ sons and from there calculate an estimated relatedness. There is evidence that workers in this species attempt to reproduce with about 4 reproducing workers per colony that sometimes lay eggs, however, only 7.4% of the male population are produced by the workers. It has been observed that the median wasp participates in worker policing where the queen or other workers throw