Sunday, February 3, 2013

Paper wasp

 Paper Wasp
Polistes exclamans 
                   Is a social wasp found in the southern United States and northern Mexico. This species has also been observed in Missouri, Maryland, and New Jersey. There has been a northward expansion of the eastern half of the U.S. This expansion is typically attributed to changing global climate and temperatures.

This species does not have a widely used common name, though in Texas some call it a yellowjacket, a name that should be reserved for Vespula. The name guinea wasp has been used, but has not been widely adopted. Polistes exclamans is also referred to by a generic name for the genus Polistes which is called paper wasps.
Their colonies contain three castes: workers, queens and males, though differences between workers and queens are generally plastic and behavioral. The physiological similarities between the worker and queen castes have lead to experiments attempting to distinguish the characteristics of these two castes and how they are determined.
Polistes exclamans are also interesting in their behavior and ecology. The high worker and queen mortality rate has led to the prevalence of satellite nests. The high queen mortality has also resulted in interesting responses by the worker caste. The high mortality is mainly caused by parasitoids and predation. P. exclamans have developed defense mechanisms to reduce the rate of colony extinction as a result of this predation and parasitism.

   Polistes engages in a kind of parental care called allomaternal care which is really a kind of social worker behavior "[they] become workers that direct maternal behavior toward siblings in the presence of a reproducing female (most often their mother)". In any event it is not "INDIVIDUAL "parent" animals taking care of their OWN young." as requested by the mission statement.


Polistes nests can be built from wood fiber which are collected from posts and plant stems. The fiber is formed into a paper like comb with hexagonal cells. The nests are orientated downward and are held up by one filament. P. exclamans have also been observed occupying artificial nests put out by researchers and consisting of bundles of straws.

Sex determination system

P. exclamans are haplodiploid insects, as are all Hymenoptera. This means they have haploid males that produce identical haploid sperm, and diploid females that produce haploid eggs through meiosis. This has consequences for genetic relatedness within colonies, since sisters receive identical sperm if they share a father, and the normal half identical contribution from the mother. This results in sex-biased conflicts between the queen and the workers with respect to the sex ratio, with workers preferring a more female biased sex ratio, and queens preferring equal investment in queens and males.

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