We let the females and small males go.
In some Centruroides, for example, small males mature after four molts and large males after five.
Instead, the small males are the ones who seem to win in territorial contests.
"Paternity analysis in wild savanna elephants has shown that, when competing for mates, body size matters: large males produce more offspring than small males," explained Georgiadis.
Scientists suspect that this gives small males more mating opportunities, thereby favouring selection for their small size.
In fish known as wrasses, for example, some large females change into males later in life and have harems of females, while small males remain male for life, mating with females under the large males' control.
Gibbons give gifts in return for sex, say, while "among insects, it is the small males [a mark of lower quality] who reproductively benefit the most from gift-giving".
They found that larger males always dominated smaller males, but when two small males encountered each other, the one with more asymmetrical forceps won the battle.
The large males generally preferred the "mated" pairs in both cases, but the small males only preferred them when the members of the pair were also small.
The signal intensity of large males was also stronger than that of small males.
We also found that females suffered a higher predation risk when large, but not small, males mounted them.
