Sperm morphology of predatory pirate bugs Amphiareus constrictus and Blaptostethus pallescens (Heteroptera: Anthocoridae) with phylogenetic inferences

摘要

Highlights?The sperm morphology of minute pirate bugs was described under LM and TEM.?The sperm flagellum of these bugs has an axoneme and two MDs as in other Heteroptera.?The centriole adjunct is highly developed and the MDs asymmetrical.AbstractThe sperm morphology of two predatory bugsAmphiareus constrictusandBlaptostethus pallescens, representing the tribes Dufouriellini and Blasptostethini, respectively, was described using light and transmission electron microscopy. The spermatozoa ofAmphiareus constrictusandBlaptostethus pallescensare fine and long, each measuring 216.6μm and 181.0μm in length, of which 37.0μm and 11.6μm, respectively, comprise the nuclei. When stained with DAPI (for DNA), the posterior half of the nucleus inB. pallescensexhibited low fluorescence, while inA. constrictusthis feature was observed only in the last 6μm. In both species, as in Heteroptera in general, the spermatozoa have, in the head region, an acrosome and nucleus, and in the flagellar region, an axoneme with 9 accessory tubules, 9 peripheral doublets and 2 central microtubules (9+9+2 microtubules), 2 mitochondrial derivatives (MDs), and a centriolar adjunct in the nucleus-flagellum transition. However, unlike most Heteroptera, in these species, the MDs are asymmetric, and the centriolar adjunct is quite long and encompasses completely the posterior nuclear end and the anterior tips of the MDs. These features are considered as derived, thus supporting the condition derived of Anthocoridae within Cimicomorpha. In addition, several traits of the spermatozoa of these two species easily distinguish one species (and probably a tribe) from the other; for example, the difference of formats in the MDs, and the long anterior projection of the centriolar adjunct parallel to the nucleus inB. pallescens.]]>