scholarly journals Comparison and Analysis of Diffusion Models for the Fe2B Layers Formed on the AISI 12L14 Steel by Using Powder-Pack Technique

2019 ◽  
Author(s):  
Martín Ortiz Domínguez
Keyword(s):  
Diffusion Models ◽  
Comparison And Analysis ◽  
Aisi 12L14

The Effects of the sphragis on male and female genitalia in Acraea (Nymphalidae) butterflies

2020 ◽  
Vol 22 ◽  
Author(s):  
Shannon L Summers ◽  
Akito Y Kawahara ◽  
Ana P. S. Carvalho
Keyword(s):  
Interspecific Variation ◽  
Sperm Storage ◽  
Male Mating ◽  
Museum Collections ◽  
Storage Organ ◽  
Mating Plug ◽  
Males And Females ◽  
Comparison And Analysis ◽  
Imagej Software ◽  
Sexually Antagonistic Coevolution

Male mating plugs have been used in many species to prevent female re-mating and sperm competition. One of the most extreme examples of a mating plug is the sphragis, which is a large, complex and externalized plug found only in butterflies. This structure is found in many species in the genus Acraea (Nymphalidae) and provides an opportunity for investigation of the effects of the sphragis on the morphology of the genitalia, which is poorly understood. This study aims to understand morphological interspecific variation in the genitalia of Acraea butterflies. Using specimens from museum collections, abdomen dissections were conducted on 19 species of Acraea: 9 sphragis bearing and 10 non-sphragis bearing species. Genitalia imaging was performed for easier comparison and analysis and measurements of genitalia structures was done using ImageJ software. Some distinguishing morphological features in the females were found. The most obvious difference is the larger and more externalized copulatory opening in sphragis bearing species, with varying degrees of external projections. Females of the sphragis bearing species also tend to have a shorter ductus (the structure that connects the copulatory opening with the sperm storage organ) than those without the sphragis. These differences may be due to a sexually antagonistic coevolution between the males and females, where the females evolve larger and more difficult to plug copulatory openings and the males attempt to prevent re-mating with the sphragis.

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