Male spider mites carefully guard juvenile females and tear off their outer pores and skin as quickly as they strategy maturity to allow them to be the primary to mate with them.
Two-spotted spider mites (Tetranychus urticae) are a typical agricultural pest, feeding on a variety of crops together with beans and tomatoes. The mites shed their outer pores and skin once they transition from juvenile nymphs to adults – a course of generally known as moulting.
Grownup females can have a number of sexual companions, however solely the sperm of their first companion fertilises their eggs. Consequently, there may be robust competitors between males for females which have simply reached maturity.
To attempt to safe this entry, male mites typically guard juvenile females till they turn out to be fertile adults. This can be a dangerous technique as a result of it prices vitality and prevents the males from foraging for meals – and rival males should steal the females on the final minute.
Peter Schausberger on the College of Vienna in Austria and his colleagues discovered that male guards attempt to minimise this danger by pulling off females’ outer pores and skin simply as they close to maturity to allow them to inseminate them earlier than different males swoop in.
The researchers filmed juvenile feminine spider mites that have been individually reared in cages with or with out the presence of a male.
The females that have been housed with out a male naturally shed their outer pores and skin at a leisurely tempo once they reached sexual maturity.
In distinction, females housed with a male had their outer pores and skin forcibly eliminated. As a feminine neared maturity, the male started drumming on her pores and skin to encourage it to interrupt open. Then the male used his mouthparts to tug off the feminine’s pores and skin from behind so he may expose her genitals and instantly inseminate her.
This meant that females with a male emerged from their outer pores and skin 5 minutes earlier on common than these on their very own, says Schausberger.
“5 minutes will not be lengthy in absolute time, however it’s in relative time as a result of these spider mites typically reside in high-density colonies the place different males are shut by,” he says. “Each second pays in the case of being first on the rising feminine.”
The spider mites are the primary species during which this skin-stripping behaviour has been experimentally documented, says Schausberger.