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The Inheritance of Intrasexual Dimorphism in Female Diving Beetles (Coleoptera: Dytiscidae)

Inoda, Toshio; Härdling, Roger LU and Kubota, Souichirou (2012) In Zoological Science 29(8). p.505-509
Abstract
Many species of Dytiscus diving beetles exhibit intrasexual dimorphism, e. g., the elytra is smooth in some females and grooved in others. However, the expression of the grooves and whether they are a product of heredity or the environment remain unknown. One Japanese species, Dytiscus sharpi sharpi Wehncke, 1875, also shows female dimorphism, with grooved and smooth morphs, while D. sharpi validus Regimbart, 1899, only has a single morph (the grooved type). A hybrid of the two species should therefore provide a means of sorting out how the grooves are inherited. We found two independent wetlands of D. sharpi sharpi in Chiba Prefecture, Japan. One was a place where a high proportion of grooved females lived, and the others had high... (More)
Many species of Dytiscus diving beetles exhibit intrasexual dimorphism, e. g., the elytra is smooth in some females and grooved in others. However, the expression of the grooves and whether they are a product of heredity or the environment remain unknown. One Japanese species, Dytiscus sharpi sharpi Wehncke, 1875, also shows female dimorphism, with grooved and smooth morphs, while D. sharpi validus Regimbart, 1899, only has a single morph (the grooved type). A hybrid of the two species should therefore provide a means of sorting out how the grooves are inherited. We found two independent wetlands of D. sharpi sharpi in Chiba Prefecture, Japan. One was a place where a high proportion of grooved females lived, and the others had high proportions of smooth females. After five to eight generations of beetles from two populations with different proportions of grooved females were reared under aquarium conditions constituting a common garden design, i.e., water temperature, water depth, and presence of a plant for oviposition, the differences remained. We mated smooth virgin females of D. sharpi sharpi with males of D. sharpi validus to obtain hybrid offspring. The elytral traits of the hybrid females produced only grooved forms. These results suggested that the female dimorphism is determined by genetics, and that the grooved morph was dominant over the smooth one, independent of environmental factors. In addition, the hybrid insects did not differ from the two subspecies insects in larval survivorship, pupation success, or sex ratio. They also showed neither morphological abnormality nor reduced survival. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
diving beetles, Dytiscus, genetic, elytral groove, hybrid, intrasexual, dimorphism
in
Zoological Science
volume
29
issue
8
pages
505 - 509
publisher
Zoological Society of Japan
external identifiers
  • wos:000306807900006
  • scopus:84864910565
ISSN
0289-0003
DOI
10.2108/zsj.29.505
language
English
LU publication?
yes
id
3d08d660-3b4e-427d-8e56-6157ab4b03aa (old id 3079999)
date added to LUP
2012-09-25 08:49:47
date last changed
2017-01-01 05:40:34
@article{3d08d660-3b4e-427d-8e56-6157ab4b03aa,
  abstract     = {Many species of Dytiscus diving beetles exhibit intrasexual dimorphism, e. g., the elytra is smooth in some females and grooved in others. However, the expression of the grooves and whether they are a product of heredity or the environment remain unknown. One Japanese species, Dytiscus sharpi sharpi Wehncke, 1875, also shows female dimorphism, with grooved and smooth morphs, while D. sharpi validus Regimbart, 1899, only has a single morph (the grooved type). A hybrid of the two species should therefore provide a means of sorting out how the grooves are inherited. We found two independent wetlands of D. sharpi sharpi in Chiba Prefecture, Japan. One was a place where a high proportion of grooved females lived, and the others had high proportions of smooth females. After five to eight generations of beetles from two populations with different proportions of grooved females were reared under aquarium conditions constituting a common garden design, i.e., water temperature, water depth, and presence of a plant for oviposition, the differences remained. We mated smooth virgin females of D. sharpi sharpi with males of D. sharpi validus to obtain hybrid offspring. The elytral traits of the hybrid females produced only grooved forms. These results suggested that the female dimorphism is determined by genetics, and that the grooved morph was dominant over the smooth one, independent of environmental factors. In addition, the hybrid insects did not differ from the two subspecies insects in larval survivorship, pupation success, or sex ratio. They also showed neither morphological abnormality nor reduced survival.},
  author       = {Inoda, Toshio and Härdling, Roger and Kubota, Souichirou},
  issn         = {0289-0003},
  keyword      = {diving beetles,Dytiscus,genetic,elytral groove,hybrid,intrasexual,dimorphism},
  language     = {eng},
  number       = {8},
  pages        = {505--509},
  publisher    = {Zoological Society of Japan},
  series       = {Zoological Science},
  title        = {The Inheritance of Intrasexual Dimorphism in Female Diving Beetles (Coleoptera: Dytiscidae)},
  url          = {http://dx.doi.org/10.2108/zsj.29.505},
  volume       = {29},
  year         = {2012},
}