Is it just a coincidence that aposematic polymorphism and sex ratio distortion co-occur in a tropical butterfly?
Is it just a coincidence that aposematic polymorphism and sex ratio distortion co-occur in a tropical butterfly?
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Date
2013
Authors
Saeed, Sami
Journal Title
Journal ISSN
Volume Title
Publisher
uofk
Abstract
Background: The cosmopolitan butterfly Danaus chrysippus is polymorphic only within the
geographic zone where it is infected by the male-killing bacterium Spiroplasma.
Hypothesis: The different colour forms of D. chrysippus represent incipient species that have
undergone hybridization as a result of Spiroplasma invasion, because many females of the
frequently infected forms are forced to mate with the males of the less infected forms.
Prediction: Some forms are more susceptible to Spiroplasma infection than others.
Times and places: Uganda and Sudan during 2005, 2006, and 2007.
Analytical method: We collected D. chrysippus butterflies in the wild. We recorded their colour
pattern and sex. We then used polymerase chain reaction (PCR) to determine whether they were
infected with Spiroplasma. We estimated the morph ratio, the sex ratio, and the prevalence of
Spiroplasma in different populations and regions. The association between colour pattern and
Spiroplasma infection was subjected to statistical analysis.
Conclusion: We found no significant difference in the sex ratio or the prevalence of
Spiroplasma between different forms. Colour forms do not vary in their susceptibility to
Spiroplasma infection.
Description
This paper had been presented for promotion at the university of Khartoum. To get the full text please contact the other at samisaeedmh@yahoo.com
Keywords
Danaus chrysippus, East Africa, hybrid zone, male-killing, polymerase chain reaction, Spiroplasma