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Reduced reproductive success for a conditioning mutant in experimental populations of Drosophila melanogaster
Abstract:
Male Drosophila melanogaster that have courted newly-emerged males can modify their subsequent courtship behavior to avoid further courtship with immature males for up to 6 hr (previously reported). Here, it was hypothesized that such an experience-dependent modification would afford a mating advantage to normal males over males that carried a mutation that affects learning and memory. Coisogenic lines were constructed which varied at the dunce gene (dnc+ and dncM14 alleles) in order to test this hypothesis. Whether previously experienced with immature males or not, dnc+ and dncM14 males were indistinguishable in their response and mating efficiency when individually paired with virgin females. However, courtship performance of dnc+ and dncM14 males was different if they were first experienced with immature males and were then individually tested in an artificial population of nine immature males and one virgin female. In this situation, dnc+ males spent much less time in courtship with immature males and achieved copulation in one-third the time required for dncM14 males. As a control, the behavior and mating efficiency of courtship-naive dnc+ and dncM14 males in the artificial population was indistinguishable. In competition for a single virgin female, experienced dncM14 males showed a slight mating advantage over experienced dnc+ males. But when competition by experienced males for a single virgin female took place in the presence of nine immature males, dnc+ males were the successful maters in three-fourths of the trials.
Insights
Male fruit flies that learn to avoid courting immature males gain a mating advantage. This experience-dependent modification benefits normal flies over those with learning and memory defects.
Area of Science:
- Behavioral genetics
- Neuroscience
- Animal behavior
Background:
- Male fruit flies modify courtship behavior after encountering immature males.
- This experience-dependent modification can last up to 6 hours.
Purpose of the Study:
- To investigate if experience-dependent courtship modification provides a mating advantage.
- To compare normal (dnc+) and learning-impaired (dncM14) male fruit flies' mating success after prior experience.
Main Methods:
- Constructed coisogenic lines of Drosophila melanogaster with dunce gene variations (dnc+ and dncM14 alleles).
- Assessed courtship behavior and mating efficiency in individual pairings and a competitive artificial population setting.
- Manipulated prior experience by exposing males to immature males before testing.
Main Results:
- No difference in mating efficiency between dnc+ and dncM14 males when tested individually.
- In a mixed population, experienced dnc+ males courted immature males less and mated faster than dncM14 males.
- Experienced dncM14 males showed a slight advantage in direct competition for a female, but dnc+ males dominated when immature males were present.
Conclusions:
- Experience-dependent courtship modification confers a mating advantage in competitive, complex social environments.
- The dunce gene, crucial for learning and memory, impacts the ability to leverage this modification for mating success.
- Normal male fruit flies effectively utilize learned avoidance to enhance reproductive success in the presence of conspecifics.