Abstract from original paper: Horseshoe crabs arrive on the beach in pairs and
spawn in the high intertidal during the springtime, new and full moon high
tides. Unattached males also come to the beach, crowd around the nesting
couples and compete with attached males for fertilizations. Satellite males
form large groups around some couples while ignoring others, resulting in a
nonrandom distribution that cannot be explained by local environmental
conditions or habitat selection. In experimental manipulations, pairs that had
satellites regained them after they had been removed whereas pairs with no
satellites continued nesting alone, which means that satellites were not
simply accumulating around the pairs that had been on the beach the longest.
Manipulations also revealed that satellites were not just copying the
behaviour of other males. Based on the evidence from observations and
experiments, the most likely explanation for the nonrandom distribution of
satellite males among nesting pairs is that unattached males are
preferentially attracted to some females over others. Females with many
satellites were larger and in better condition, but did not lay more eggs,
than females with few or no satellites.
satellites
response variable; number of satellites around female
crab
color
color of crab
spine
condition of spine
weight
weight of crab
width
width of carapace
173 observations on 5 variables.
Brockmann, H. (1996), "Satellite male groups in horseshoe crabs," Ethology, 102-1, pp. 1-21.