The effect of age on the production of reproductive eggs by workers ofMyrmica rubra L. (Hym. Formicidae)

Abstract

The effect of third-instar larvae on the egg production of workers was investigated. 1. The presence of a small number of small larvae increased worker egg production, but, as the number of small larvae present increased past an optimum number, egg production was decreased. 2. Small numbers of large larvae increased egg production less than did small larvae and sometimes reduced it. 3. Following three weeks' experience of raising small numbers of small larvae, workers then kept without larvae produced more eggs than those kept with larvae. 4. There was no clear relationship between worker ovary development and the number of larvae being raised although the relationship was usually significant. 5. When workers raised different numbers of small larvae after three weeks' experience of raising small numbers, the percentage of ants containing large ovaries was negatively correlated with the larvae: worker ratio. However, as in all other experiments, there was a tendency for most eggs to be laid in nests where there was a high percentage of ants with large ovaries. 6. Ants containing large ovaries had significantly larger headwidths than those with small ovaries only if they had not been rearing larvae. 7. The results are discussed in relation to previous research onMyrmica ruginodis andPlagiolepis spp. and possible explanations for differences are given.