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Speckled wood

Pararge aegeria


In the speckled wood butterfly females are monandrous, meaning they typically only mate once within their lifetime. On the other hand, males are polygynous and typically mate multiple times. In order to locate females, males employ one of two strategies: territorial defense and patrolling. During territorial defense, the male defends a sunny spot in the forest, waiting for females to stop by. Another strategy is patrolling, during which males fly through the forest actively searching for females.Then, the female must make a choice between mating with a patrolling male or a territorial male. By mating with a territorial male, a female can be sure that she has chosen a high quality male, as the ability to defend a territory reflects the genetic quality of a male. Therefore, by choosing a territorial male, the female is being more picky about which male she chooses to mate with. The choice is most likely dependent on the search costs associated with finding a mate. When actively searching for a male, a female must spend her precious time and energy, which results in search costs, especially when she has a limited life span. As search costs increase, female choosiness for a mate decreases. For example, if a female's life span is shorter, she has a higher cost associated with searching for the ideal mate. Therefore, she is likely to mate within a day of her emergence as an adult, and will most likely mate with a patrolling male, as they are easier to find. However, if a female lifespan is longer, then the search costs associated with finding a mate are lower. The female is then more likely to actively search for a territorial male. Since the search costs vary depending on environmental conditions, strategies vary from population to population. Males employing different strategies, territorial defense or patrolling, can be differentiated by the number of spots on their hindwings. Those with three spots are more likely to be patrolling males, while those with four spots are more likely to be defending males. The frequency of the two phenotypes depends on the location and time of year. For example, there are more territorial males in areas where there are many sunspots. Furthermore, the development of spots is influenced by environmental conditions.


Buggenhoutbos, Belgium.

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The MnMs
Spotted by
The MnMs

Vlaanderen, Belgium

Spotted on Aug 6, 2016
Submitted on Aug 27, 2017

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