Structure and development of the reproductive system in Aphelocheirus aestivalis (Hemiptera: Heteroptera: Nepomorpha: Aphelocheiridae)
Papáček Miroslav, Soldán Tomáš
Acta Entomologica Musei Nationalis Pragae 48(2): 299-318, 2008
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Abstract: We study the histology, ultrastructure and morphological arrangement of male and
female reproductive system of Aphelocheirus aestivalis (Fabricius, 1803) in the
nymphs of instar 1–5 and variously aged apterous adults. The anlage of gonads
becomes well apparent already in instar 1, testicular follicles and ovarioles
start to differentiate in instar 2, and their entire differentiation is finished
in instar 3. Paired accessory mesadenia, dichotomically branched in adult
males, differen- tiate in instar 2 as well. The anlage of male ectodermal
accessory gland is formed during instar 3, while spermatheca and bursa
copulatrix start to invaginate in instar 4. Morphological differentiation of
germ cell descendents as well as formation of the germarial trophic core from a
membranous labyrinth in females occurs in late instar 4 and instar
5. Spermatogenesis shows a unique character within the whole Nepomorpha: it is
a permanent, multi-waved process, as all developmental stages of male germ cells
are found throughout the year. Vitellogenesis starts in adult females 3–4
weeks after the last moulting but apparently stops during winter. The timing of
crucial reproductive processes in A. aestivalis seems to be rather different
from most aquatic bugs; permanent, spring-to-autumn gradual spermatogenesis and
physiological ability to copulate, and the presence of mature spermatozoa in the
spermatheca of teneral, newly hatched females indicate possible semivoltinism in
the life cycle. Three new apomorphies (type of spermatogenesis and secondary
seminal vesicles in males, and a cuticular brush in bursa copulatrix in females)
of the Aphelocheiridae are defined.
Key words: Heteroptera, Aphelocheiridae, Aphelocheirus aestivalis, nymphs, adults, gonads, efferent ways, development, morphology, histology, ultrastructure, spermatogenesis, oogenesis, reproductive strategy, anagenesis, Czech Republic