Sperm Bundles in the Seminal Vesicles of Sexually Mature Lasius Ant Males

Abstract

In many insects, sperm cells are produced in bundles with their heads being held together by a glycoprotein matrix secreted by a cyst cell. Mature sperm cells in the seminal vesicles are usually free, but in sawflies and several other insects, such structures (spermatodesmata) remain intact and sperm cells may be ejaculated as bundles. Here we report the occurrence of spermatodesmata in mature males of the ant Lasius pallitarsis. Microscopic investigations of the abdominal contents of males immediately prior to their nuptial flights showed that the anterior ends of numerous sperm cells were embedded in an oval-shaped 20 by 30 micrometer extracellular fibrous cap. Individual sperm ranged in length from 55 to 75 micrometers with an average overall length of 65 micrometers. The bulb-shaped heads of the sperm were relatively small, only about 1.5 micrometers in length and about 1.1 micrometers in diameter. The diameter of the sperm tails was approximately 1 micrometer. Observations of live preparations of the spermatodesmata showed increasingly active undulating wave-like movement of the sperm tails as the slide preparations aged. This appears to be the first case of sperm bundles being present in the seminal vesicles of mature ant males – males that are immediately poised to complete their nuptial mating flight.

Testes and Spermatozoa as Characters for Distinguishing Two Ant Species of the GenusNeoponera(Hymenoptera: Formicidae)

“…In N. inversa and N. villosa, the spermatozoa were long, threadlike, linear, and free from each other in the seminal vesicle as also observed in the ant Acromyrmex subterraneus (Forel) (Hymenoptera: Formicidae) (Moreira et al 2004). However, in C. victima (Oliveira et al 2014) and L. pallitarsis (Burnett & Heinze 2014), these cells are maintained in bundles in the seminal vesicle in the mature male as reported for sawfly wasps (Schiff et al 2001).…”

“…In addition, spermatozoa have been used for phylogenetic analyses to determine taxonomic variations in insects (Jamieson et al 1999;Dallai 2014). In Hymenoptera, the sperm may be free in the seminal vesicle, as reported for parasitic wasps (Lino-Neto et al 1999) and most Aculeata (Moreira et al 2004), or arranged in bundles as described for ants such as Crematogaster victima Smith (Oliveira et al 2014) and Lasius pallitarsis (Provancher) (Burnett & Heinze 2014) and for sawflies (Schiff et al 2001).…”

Modelling Motility: The Mathematics of Spermatozoa

“…Further, in some monotreme, ants, and other species, it has been observed that spermatozoa can form a large bundle-like structure, as showcased in Figure 3B , containing more than 100 cells (Djakiew and Jones, 1983 ; Burnett and Heinze, 2014 ; Pearcy et al, 2014 ). These sperm bundles , as well as sperm trains, have also been studied from the point of view of elastohydrodynamics (Yang et al, 2008 , 2010 ; Schoeller et al, 2020 ), with head-head adhesive interactions also having been modelled by Fisher et al ( 2014 ), the latter being noted to be of significance for the competitive viability of such entrained collections of spermatozoa.…”

The evolution of insect sperm − an unusual character system in a megadiverse group

“…), within Hymenoptera (Lino‐Neto et al. ; Burnett and Heinze ), and in the coleopteran family Dytiscidae (Higginson et al. ).…”

“…Tricholepidion gertschi) or coupling. Sperm bundles with numerous spermatozoa held together by an apical cap occur in different insect groups, as for instance in Blattodea ), Orthoptera (Viscuso et al 1998), within Hymenoptera (Lino-Neto et al 2008Burnett and Heinze 2014), and in the coleopteran family Dytiscidae (Higginson et al 2012). Transmission of liquid sperm with a sperm pump is a rare exception.…”