title: Immune function and parasite resistance in male and polymorphic female Coenagrion puella.
abstract: BACKGROUND
  Colour polymorphisms are widespread and one of the prime examples is the colour polymorphism in female coenagrionid damselflies: one female morph resembles the male colour (andromorph) while one, or more, female morphs are described as typically female (gynomorph). However, the selective pressures leading to the evolution and maintenance of this polymorphism are not clear. Here, based on the hypothesis that coloration and especially black patterning can be related to resistance against pathogens, we investigated the differences in immune function and parasite resistance between the different female morphs and males.
  
  
  RESULTS
  Our studies of immune function revealed no differences in immune function between the female morphs but between the sexes in adult damselflies. In an experimental infection females infected shortly after emergence showed a higher resistance against a fungal pathogen than males, however female morphs did not differ in resistance. In a field sample of adult damselflies we did not find differences in infection rates with watermites and gregarines.
  
  
  CONCLUSIONS
  With respect to resistance and immune function 'andromorph' blue females of Coenagrion puella do not resemble the males. Therefore the colour polymorphism in coenagrionid damselflies is unlikely to be maintained by differences in immunity.
authors.affiliation: Zoologisches Institut, AG Okologie, Technische Universität Braunschweig, Braunschweig, Germany. g.joop@tu-bs.de
authors.forename: Gerrit
authors.initials: G
authors.lastname: Joop
authors.forename: Andreas
authors.initials: A
authors.lastname: Mitschke
authors.forename: Jens
authors.initials: J
authors.lastname: Rolff
authors.forename: Michael T
authors.initials: MT
authors.lastname: Siva-Jothy
mesh_terms: D000818:Animals; D005075:Biological Evolution; D003116:Color; D005260:Female; D007113:Immunity, Innate; D007313:Insecta / Q000033:anatomy & histology / Q000276:immunology* / Q000469:parasitology*; D008297:Male; D012737:Sex Factors