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Sasakawa K 《Die Naturwissenschaften》2007,94(5):384-391
The morphological characteristics of sperm and reproductive organs may offer clues as to how reproductive systems have evolved.
In this paper, the morphologies of the sperm and male reproductive organs of carabid beetles in the tribe Pterostichini (Coleoptera:
Carabidae) are described, and the morphological associations among characters are examined. All species form sperm bundles
in which the head of the sperm was embedded in a rod-shaped structure, i.e., spermatodesm. The spermatodesm shape (left-handed
spiral, right-handed spiral, or without conspicuous spiral structure) and the condition of the sperm on the spermatodesm surface
(with the tail free-moving or forming a thin, sheetlike structure) vary among species. In all species, the spiral directions
of the convoluted seminal vesicles and vasa deferentia are the same on both sides of the body; that is, they show an asymmetric
structure. The species in which the sperm bundle and the seminal vesicles both have a spiral structure could be classified
into two types, with significant differences in sperm-bundle length between the two types. The species with a sperm-bundle
spiral and seminal-vesicle spiral of almost the same diameter have longer sperm bundles than the species with a sperm-bundle
spiral and seminal-vesicle tube of almost the same diameter. In the former type, the spiral directions of the sperm bundles
and seminal vesicles are inevitably the same, whereas they differ in some species with the later type. Therefore, increased
sperm bundle length appears to have been facilitated by the concordance of the sperm bundle’s coiling direction with the coiling
direction of the seminal vesicle. 相似文献
2.
Susanne P. A. den Boer Jacobus J. Boomsma Boris Baer 《Behavioral ecology and sociobiology》2008,62(12):1843-1849
The seminal fluid that accompanies sperm in ejaculates has been shown or suggested to affect sperm competition and paternity
success of insects by preventing female remating, inducing oviposition, and forming mating plugs. In Atta leafcutter ants, queens have multiple mates but never remate later in life, although they may live and produce fertilized
eggs for several decades. The mating biology and life history of these ants therefore suggests that the major function of
seminal fluid is to maximize sperm viability during copulation, sperm transfer, and initial sperm storage. We tested this
hypothesis by comparing the viability of testis sperm and ejaculated sperm (mixed with seminal fluid) and found a significant
positive effect of seminal fluid on sperm viability. We further quantified this positive effect by adding accessory gland
secretion (a major component of seminal fluid) in a dilution series, to show that minute quantities of accessory gland secretion
achieve significant increases in sperm viability. Sperm stored by queens for 1 year benefited in a similar way from being
exposed to accessory gland compounds after dissection in control saline solution. Our results provide the first empirical
evidence that seminal fluid is important for the production of viable ejaculates and that the accessory glands of Atta males—despite their small size—are functional and produce a very potent secretion. 相似文献
3.
In insects, the last male to mate with a female often gains access to a disproportionate number of subsequent fertilizations.
This study examined last-male sperm precedence patterns in doubly and triply mated Tribolium castaneum females. Sperm storage processes were investigated by measuring the quantity of sperm stored within the female spermatheca
following single, double, and triple matings. Both doubly mated and triply mated females exhibited high last-male sperm precedence
for progeny produced during the first 48 h following the last mating, with females in both groups exhibiting parallel declines
in sperm precedence 1 and 2 weeks later. The number of sperm stored by females increased by 33% between singly mated and doubly
mated females, indicating that the spermatheca is filled to only two-thirds capacity following insemination by the first male.
Based on the proportion of stored sperm from first and second matings, we tested predictions about sperm precedence values
based on models of random sperm mixing. High initial last-male sperm precedence strongly supports stratification of last-male
sperm. By 1–2 weeks after double matings, sperm precedence declined to levels indistinguishable from values expected under
random mixing. These results provide insight into mechanisms of sperm storage and utilization in this species.
Received: 20 August 1997 / Accepted after revision: 24 May 1998 相似文献
4.
Male genitalia show rapid and divergent evolution. It is rarely determined whether variation in male genital morphology influences
male reproductive success. Male damselflies possess a unique aedeagus with a re-curved head and spiny lateral processes, and
most females have two sperm storage organs, a spherical bursa copulatrix and a tubular spermatheca. Previous studies have
indicated that the re-curved head may remove bursal sperm, whereas the lateral processes remove spermathecal sperm. However,
we need more direct evidence of these functions. We compared sperm number in female sperm storage organs by interrupting copulation
to examine sperm removal by the male. In Calopteryx cornelia, males removed almost all bursal sperm but only partially removed spermathecal sperm. In contrast, females of Mnais pruinosa store sperm primarily in the bursa, and males removed only bursal sperm. To examine the functions of male spiny lateral processes,
we compared mating behaviour between control and experimental males from which we removed (cut) the lateral processes. In
C. cornelia, cutting of the lateral processes resulted in a decreased number of abdominal movements during copulation and no removal
of spermathecal sperm. The amount of bursal sperm removed during copulation also decreased in experimental males compared
to the unmanipulated males. However, in M. pruinosa, the experimental removal of male lateral processes did not decrease the abdominal movements and little affected the removal
of bursal sperm. Inter-specific differences between C. cornelia and M. pruinosa may be caused by variation in the strategies of female sperm storage. 相似文献
5.
Natsuko Ito Kondo Daisei Yamanaka Yuya Kanbe Yoko Kawate Kunitake Masahiro Yoneda Koji Tsuchida Koichi Goka 《Die Naturwissenschaften》2009,96(4):467-475
The European bumblebee, Bombus terrestris, is an invasive eusocial species whose distribution is expanding greatly beyond its native range because numerous colonies
are imported to or locally produced in non-native countries for pollination of agricultural crops. Closely related species
exist in Japan where the unrestricted import and use of B. terrestris has resulted in the establishment of wild colonies. Laboratory studies previously showed that B. terrestris and Japanese native species can copulate and produce fertilized eggs. Although these eggs do not hatch, the interspecific
mating can cause a serious reproductive disturbance to native bumblebees. In this study, we determined the frequencies of
interspecies mating between B. terrestris males and native bumblebee queens in the wild on the islands of Hokkaido and Honshu by analyzing the DNA sequences of spermatozoa
stored in spermathecae of native queens. We found that 20.2% of B. hypocrita hypocrita queens and 30.2% of B. hypocrita sapporoensis queens had spermatozoa of B. terrestris males in their spermathecae. Given that a Bombus queen generally mates only once in her life, such high frequencies of interspecific mating with B. terrestris pose serious threats to the populations of native bumblebees in Japan. 相似文献
6.
Workers never mate in the large majority of ants, and they have usually lost the spermatheca, an organ specialized for long-term
storage of sperm. Such ‘non-sexual’ workers are restricted to laying unfertilized eggs that give rise to males, and they cannot
compete with the queens for the production of female offspring. In sharp contrast, workers in 200–300 species from phylogenetically
basal subfamilies can reproduce sexually (‘gamergates’) because they retain a functional spermatheca like the queens. Importantly,
‘non-sexual’ workers in closely related species have a vestigial spermatheca. In this study, we compared the reservoir epithelium
of ‘sexual’ workers to that of congeneric queens and ‘non-sexual’ workers using 21 species of Amblyoponinae, Ponerinae and
Ectatomminae. We show that a pronounced thickening of the epithelium near the opening of the sperm duct is strictly associated
with sexual reproduction in both castes. This is unlike ‘non-sexual’ workers in which this epithelium is always very thin,
with few organelles; but all other structures remain intact. We discuss this evolutionary degeneration of the spermatheca
and how it relates to behavioural or physiological modifications linked to mating. Our results help understand the loss of
sexual reproduction by ant workers, a critical step in the extreme specialization of their phenotype. 相似文献
7.
Dynamics of sperm transfer in the ant Leptothorax gredleri 总被引:1,自引:1,他引:0
Mating tactics differ remarkably between and within species of social Hymenoptera (bees, wasps, ants) concerning, e.g., mating
frequencies, sperm competition, and the degree of male sperm limitation. Although social Hymenoptera might, therefore, potentially
be ideal model systems for testing sexual selection theory, the dynamics of mating and sperm transfer have rarely been studied
in species other than social bees, and basic information needed to draw conclusions about possible sperm competition and female
choice is lacking. We investigated sperm transfer in the ant Leptothorax gredleri, a species in which female sexuals attract males by “female calling.” The analysis of 38 female sexuals fixed immediately
or up to 7 days after copulation with a single male each revealed that the sperm is transferred into the female bursa copulatrix
embedded in a gelatinous mass, presumably a spermatophore. Sperm cells rapidly start to migrate from the tip of the spermatophore
towards the spermatheca, but transfer is drastically slowed down by an extreme constriction of the spermathecal duct, through
which sperm cells have to pass virtually one by one. This results in the spermatheca being filled only between one and several
hours after mating. During this time, the posterior part of the spermatophore seals the junction between bursa copulatrix
and spermathecal duct and prevents sperm loss. The prolonged duration of sperm transfer might allow female sexuals to chose
between ejaculates and explain previously reported patterns of single paternity of the offspring of multiply mated queens.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
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