B. Pearson et al., BREEDING-BEHAVIOR, RELATEDNESS AND SEX-INVESTMENT RATIOS IN LEPTOTHORAX-TUBERUM FABRICIUS, Entomologia experimentalis et applicata, 75(2), 1995, pp. 165-174
The ant species Leptothorax tuberum was shown to be predominantly mono
gynous. Queens usually mate once only but some nests may have a multip
ly-mated queen or are partially or serially polygynous. As expected fr
om these results, within nest relatedness between workers and between
workers and alate queens was found to be high. Almost fifty percent of
nests had no nest queen which may indicate high queen mortality, quee
ns leaving to found new nests or nest fragmentation. Observed female i
nvestment frequencies (IFo) were not significantly different from thos
e expected on the basis of worker control of sexual production and the
relatedness estimates of workers to alate queens and workers to males
calculated from isozyme data (IFE). These values were not consistent
with queen control. There was no evidence for lower IF(o)s in queenles
s nests nor for higher IF(o)s in larger nests classified by worker num
ber. When nests were classified by sexual productivity, however, there
was a strong rank correlation between productivity and female bias. T
his is the first study of an ant species to test observed IF against e
xpected IF calculated without inferring between caste relatedness from
worker data or pooling of data from different castes.