Letter | Published:

Sex Ratios of Some Mason Wasps (Vespoidea and Sphecoidea)

Naturevolume 212pages306307 (1966) | Download Citation



MALE hymenoptera are haploid and develop from unfertilized eggs, while females are diploid and the product of a fertilization. A female is inseminated early in her imaginal life and, at least in the Apocrita, subsequently exercises control over whether or not a sperm will be made available for a given egg. Most of the exploitations of the non-random production of the sexes seem to depend on this psychic capacity to determine whether a given egg will develop into a female or a male. Among solitary forms, male and female eggs are frequently laid in different situations. The three social groups produce very few males, all during a restricted period of the annual cycle. In the Symphyta and the “Parasitica”, the rarity of males may be further augmented by the evolution of thelytocous parthenogeneses, which also occur sporadically in the social forms. An excess of females has been assumed to be typical of the order because the females of the solitary bees and wasps produce few eggs (fifty-two is regarded as the record for such wasps1), and their elaborate maternal behaviour patterns would seem to expose them to dangers which the males can avoid. Recently, Hamilton2 has even suggested that because a female contributes twice as much genetic material to the Mendelian population as a male, a selection pressure exists to produce females preferentially.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1

    Jayakar, S. D., and Spurway, H., J. Bombay Nat. Hist. Soc., 62, 193 (1965).

  2. 2

    Hamilton, W. D., J. Theoret. Biol., 7, 17 (1964).

  3. 3

    Spurway, H., Dronamraju, K. R., and Jayakar, S. D., J. Bombay Nat. Hist. Soc., 61, 1 (1964).

  4. 4

    Jayakar, S. D., and Spurway, H., J. Bombay Nat. Hist. Soc., 61, 662 (1964).

  5. 5

    Jayakar, S. D., Nature, 198, 208 (1963).

  6. 6

    Jayakar, S. D., and Spurway, H., J. Bombay Nat. Hist. Soc. (in the press).

Download references

Author information


  1. Genetics and Biometry Laboratory, Government of Orissa, Bhubaneswar, Orissa, India

    • S. D. JAYAKAR
    •  & H. SPURWAY


  1. Search for S. D. JAYAKAR in:

  2. Search for H. SPURWAY in:

About this article

Publication history

Issue Date



Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.