Dispersal and fighting in male pollinating fig wasps
Jaco M Greeff1, Simon van Noort, Jean-Yves Rasplus
1Department of Genetics, University of Pretoria, Pretoria 0002, South Africa. jgreeff@postino.up.ac.za
Abstract:
For more than two decades, it has been the dogma that the males of pollinating fig wasps do not fight and that they only mate in their native fig. Their extreme degree of local mating leads to highly female biased sex ratios that should eliminate the benefits of fighting and dispersal by males. Furthermore, males sharing a fig are often brothers, and fighting may be barred by kin selection. Therefore, theory supported the presumed absence of fighting and dispersal in pollinating fig wasp males. However, we report here that in pollinating fig wasps, fighting between brothers evolved at least four and possibly six time, and dispersal by males at least twice. This finding supports the idea that competition between relatives can cancel the ameliorating effects of relatedness. The explanation to this evolutionary puzzle, as well as the consequences of male dispersal and fighting, opens the doors to exciting new research.
Insights
Contrary to long-held beliefs, male fig wasps do engage in fighting and dispersal, challenging theories of kin selection. This discovery reveals that competition among relatives can override the benefits of cooperation in these insects.
Area of Science:
- Evolutionary Biology
- Behavioral Ecology
- Insect Behavior
Background:
- For over 20 years, the prevailing view was that male pollinating fig wasps (Agaonidae) do not fight or disperse, mating only within their native fig.
- This dogma was supported by theories suggesting that highly female-biased sex ratios and kin selection (males often being brothers) would eliminate the benefits of male fighting and dispersal.
Purpose of the Study:
- To challenge the established dogma regarding the behavior of male pollinating fig wasps.
- To investigate the evolutionary history and occurrence of fighting and dispersal behaviors in male fig wasps.
Main Methods:
- Phylogenetic analysis to reconstruct the evolutionary history of fighting and dispersal in pollinating fig wasps.
- Comparative analysis of behavioral traits across different fig wasp lineages.
Main Results:
- Evidence suggests that fighting among male fig wasps has evolved at least four times independently.
- Male dispersal in pollinating fig wasps has evolved at least twice.
- These findings contradict the long-standing assumption of non-fighting, non-dispersing males.
Conclusions:
- The study demonstrates that competition between relatives can counteract the effects of relatedness, leading to the evolution of fighting and dispersal.
- This research opens new avenues for understanding the evolutionary dynamics of social behavior and sexual conflict in insects.
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