Open AccessFunctional morphology of genitalia of four species of julidan millipedes (Diplopoda: Nemasomatidae; Julidae)
Author(s) -
TADLER ANDREAS
Publication year - 1996
Publication title -
zoological journal of the linnean society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.148
H-Index - 83
eISSN - 1096-3642
pISSN - 0024-4082
DOI - 10.1111/j.1096-3642.1996.tb01263.x
Subject(s) - gonopod , biology , spermatheca , millipede , anatomy , aedeagus , sperm competition , zoology , sexual selection , female sperm storage , copula (linguistics) , sperm , taxonomy (biology) , botany , decapoda , crustacean , economics , econometrics
The functional anatomy of the genitalia of Nemasoma varicorne (Nemasomatidae), Brachyiulus lusitanus, Unciger foehdus and Cylindroiulus boleti (Julidae) was investigated by shock freezing of animals in copula followed by serial semithin sectioning of the engaged genitalia. The species show conspicuous differences in the functional mechanism of their genitalia. In M varicorne and B. lusitanus the vulvae remain within the vulval sac during copulation while in U.foetidus and C. boleti parts of the gonopods (promerite and mesomerite) form clasper‐like structures that pull out the vulvae from the vulval sacs. With the exception of C. boleti all investigated species have a ‘central funnel’ on the vulva which leads into the receptaculum seminis. The sperm‐transferring part of the male gonopods (solenomerite) is introduced into this funnel during copulation. In B. lusitanus and C. boleti a projection of the posterior gonopods (end‐projection, brachite) fits into a slit anterior to the openings of the receptacula. The results are discussed with regard to sexual selection theory and a hypothesis is proposed that explains the evolutionary change of millipede genitalia by a combination of female choice and sperm competition phenomena.