Sperm In Spermathecae Research Articles

Female control of sperm ejection and retention in the cornsilk fly Euxesta eluta (Diptera: Ulidiidae).

Promiscuous mating systems provide the opportunity for females to bias fertilization toward particular males. However, distinguishing between male sperm competition and active female sperm choice is difficult for species with internal fertilization. Nevertheless, species that store and use sperm of different males in different storing structures and species where females are able to expel all or part of the ejaculates after copulation may be able to bias fertilization. We report a series of experiments aimed at providing evidence of female sperm choice in Euxesta eluta (Hendel), a species of ulidiid fly that expels and consumes ejaculates after copulation. We found no evidence of greater reproductive success for females mated singly, multiply with the same male, or mated multiply with different males. Female E. eluta possesses two spherical spermathecae and a bursa copulatrix for sperm storage, with a ventral receptacle. There was no significant difference in storing more sperm in spermathecae 24 h after copulation than immediately after copulation. Females mated with protein-fed males had greater reproductive success than similar females mated to protein-deprived males. Protein-fed females prevented to consume the ejaculate, retained more sperm when mated to protein-fed males than when mated to protein-deprived males. Our results suggest that female E. eluta can exert control of sperm retention of higher quality males through ejaculate ejection.

Description of a new and two known species of the insect–associated genus Oigolaimella Paramonov, 1952 (Nematoda: Diplogastridae) with a note on the biology, biogeography and relationship with congeners

The present article deals with the description of one new and two known nematode species extracted from insects, as well as from the dwelling places of insects, viz., compost, rotting wood and bark, based on light microscopic and scanning electron microscopic observations. The species were tested for pathogenicity towards insects and found to have the potential to kill insect pests. A detailed morphological characterization of the species along with information on their associations with insects can be utilized to assess their relevance in insect pest management. Oigolaimella winchesi (Goodey, 1929) is reinstated and differentiated from both O. agilis (Skwarra, 1921) and O. longicauda (Claus, 1862) on the basis of number of liplets; shape of spermatozoa in spermatheca; structure of spicules and gubernaculum. Also, the molecular characterization of the cosmopolitan species O. longicauda (Claus, 1862) and Oigolaimella trilineata sp. n. has been done based on D2/D3 segment of LSU 28s rDNA gene and phylogenetic inferences have been made by performing a Bayesian analysis. A biogeographical distribution of species of Oigolaimella is provided and the relationships of its congeners are analyzed and discussed along with a key to identification of species.

Evaluation of the standards compliance of the queen bees reared in the Mediterranean region in Turkey.

The influence of different commercial queen producers on the quality of Apis mellifera queens was assessed. It was aimed to determine the quality characteristics of queens reared by commercial queen producers located in the province of Antalya, which is an important region in queens production due to its climatic characteristics. For this purpose, the quality characteristics of a total of 105 queen bees obtained from 21 enterprises were determined. Differences between the enterprises in terms of the number of spermatozoa (P < 0.01) were determined. In terms of the diameter of spermatheca, spermatheca volume and live weight, statistical differences between the enterprises were also observed (P < 0.05). When the relationships between the measured characteristics were examined, significant values were obtained statistically between live weight and diameter of spermathecae (0.268) and spermatheca volume (0.258). It was also determined that there is a significant correlation between spermatheca diameter and spermatheca volume (0.995). The spermatheca diameter of a good quality queen bee should not be <1.2 mm, spermatheca volume 0.90 mm3 and live weight not <200 mg. Only live weight was found to be within the normal quality standard values when the average results of the quality criteria are taken into consideration. Other characters such as spermathecae diameter, spermathecae volume and number of spermatozoa in spermathecae seem to be below quality standard values.

Accessory glands of male reproductive system in Pseudochorthippus parallelus parallelus (Zetterstedt, 1821) (Orthoptera: Acrididae): A light and electron microscopic study.

The accessory glands of male reproductive system in insects play a significant role in the reproduction process by protecting sperm in spermatheca, preventing female to accept other males after mating and stimulating oviposition. The number, structure, and arrangement of the tubules of accessory glands can change from species to species. In this study, the accessory glands belonging the male reproductive system in Pseudochorthippus parallelus parallelus (Zetterstedt, 1821) (Orthoptera, Acrididae) were examined with stereomicroscope, light microscope, scanning (SEM), and transmission (TEM) electron microscopes at Gazi University, Faculty of Science in 2017-2019. P. parallelus parallelus is a widespread species that is located at the extending areas from Italy to the Northern Europe and also in Turkey. The accessory glands of P. parallelus parallelus' male reproductive system are composed of about 10 tubules. The tubules can be classified into two groups according to the thickness of their muscle tissues. Both groups have single layered epithelial cells with mitochondria, well-developed endoplasmic reticulum, spherical nucleus with electron dense chromatin, secretory vesicles and multivesicular bodies in their cytoplasm. In addition, apocrine type secretion is seen in epithelial cells.

Host influence on the nutritional and reproductive status of Triatoma infestans (Klug) (Hemiptera: Reduviidae) peridomiciliary populations

Triatoma infestans is the main vector of Chagas disease in the southern cone of South America. This species is well adapted to living in rural houses and structures used for housing domestic animals (peridomestic habitats). In this study, we evaluated the relationship between the source of blood consumed by adults of T. infestans collected from different peridomestic habitats from two localities from Cruz del Eje department (Cordoba, Argentina) and their nutritional and reproductive status. In each individual, the ratio between body weight and total body length was used as an indicator of nutritional status (NS). The presence of sperm in spermathecae and the number of chorionated oocytes in ovaries and oviducts were considered indicators of reproductive status (RS) of females. The feeding source in the promesenteron of male and female insects was identified using anti-chicken, anti-goat, antihuman and anti-dog antisera. Chicken coops were the main peridomestic structure present in the study area as well as the peridomestic sites with the highest percentage of T. infestans . Insects collected from the different peridomestic structures showed a NS between 8 and 15 mg/mm. Of the evaluated females, 35.7% presented chorionated oocytes. Food profile analyses revealed that chicken was the main blood source. Independently of the blood source, the triatomines presented a NS between 8 and 15 mg/mm. No specimens feeding exclusively on human blood were found; nevertheless, of 31.48% of insects feeding on mixed blood sources, 59% included human blood. All T. infestans specimens that included human blood in the mixed blood source were collected from chicken coops and storerooms located in a 12-m area around domiciles. Human blood present in mixed blood meal of adult insects suggests that T. infestans moves from domiciles to peridomicilies and vice versa

Effects of Larval Grafted Age for Artificial Queen-rearing on Queen Reproductive Potential and Growth of Apis cerana Colony

Queen honey bees (Apis cerana) can be reared artificially on demand by the use of grafting technique. The technique consists of grafting young worker larvae into queen cell cups and raising in a queenless strong colony. As the age of grafted larvae for queen rearing exhibited several aspects related to quality and reproductive potential of queen, this study were conducted to investigate the influence of age of grafted larva on morphological characteristics and lifespan of queen, and the growth of colony she headed. Our results demonstrated that queens reared from young worker larvae (i.e., less than 1-day old larvae) were significantly larger in size (i.e., body weight and thorax width) than that of queens reared from 2-day old worker larvae. Moreover, queens reared from younger worker larvae initiated egg-laying earlier, stored more spermatozoa in spermatheca and had a longer lifespan compared to queens raised from older worker larvae. We also found a significant positive effect of queen grafting age on the production of worker and drone brood, adult worker population in colonies headed by queens reared from younger larvae. These findings suggested that rearing queens from brood grafted at the earliest possible age could increase the reproductive potential of queen as well as fitness of colony she head.

Preservation of Domesticated Honey Bee (Hymenoptera: Apidae) Drone Semen.

Preservation of honey bee (Apis mellifera L., Hymenoptera: Apidae) sperm, coupled with instrumental insemination, is an effective strategy to protect the species and their genetic diversity. Our overall objective is to develop a method of drone semen preservation; therefore, two experiments were conducted. Hypothesis 1 was that cryopreservation (-196 °C) of drone semen is more effective for long-term storage than at 16 °C. Our results show that after 1 yr of storage, frozen sperm viability was higher than at 16 °C, showing that cryopreservation is necessary to conserve semen. However, the cryoprotectant used for drone sperm freezing, dimethyl sulfoxide (DMSO), can harm the queen and reduce fertility after instrumental insemination. Hypothesis 2 was that centrifugation of cryopreserved semen to reduce DMSO prior to insemination optimize sperm quality. Our results indicate that centrifuging cryopreserved sperm to remove cryoprotectant does not affect queen survival, spermathecal sperm count, or sperm viability. Although these data do not indicate that centrifugation of frozen-thawed sperm improves queen health and fertility after instrumental insemination, we demonstrate that cryopreservation is achievable, and it is better for long-term sperm storage than above-freezing temperatures for duration of close to a year.

The importance of male body size on sperm uptake and usage, and female fecundity in Aedes aegypti and Aedes albopictus.

BackgroundAdult mosquito density is a critical factor in the transmission of arboviruses by container Aedes spp. mosquitoes. Female fecundity drives population growth, and therefore contributes to adult mosquito density. Previous studies have focused on female body size as the major determinant of fecundity, paying little attention to male condition. In this study, we examined the effects of male body size on the abundance of sperm in spermatheca, depletion of sperm over time, and female fecundity.MethodsWe generated males in two size classes using different larval densities, and allowed them to mate with females generated from a moderately dense larval environment. We counted sperm in female spermatheca in a sample of females immediately after mating, then every week for four weeks post-mating. We provided weekly blood meals to females and determined their fecundity over four weeks after the initial blood meal.ResultsWe found significantly more sperm in Aedes albopictus females than in Aedes aegypti, and detected depletion of sperm in Ae. aegypti, but not in Ae. albopictus. We did not see significant differences in number of sperm in spermathecae in relation to male body size in either species over subsequent gonotrophic cycles. We found a significant effect of male body size on fecundity in Ae. albopictus, but not Ae. aegypti, with a 46 % increase in fecundity for female Ae. albopictus offered four blood meals.ConclusionsOur results suggest substantial differences in the mating biology of these ecologically similar species and the importance of considering males in understanding female fecundity. The substantial increase in fecundity in Ae. albopictus has implications for population growth, estimating vector density, and modeling the transmission of pathogens.

Resolving mechanisms of short-term competitive fertilization success in the red flour beetle

Postcopulatory sexual selection occurs when sperm from multiple males occupy a female’s reproductive tract at the same time and is expected to generate strong selection pressures on traits related to competitive fertilization success. However, knowledge of competitive fertilization success mechanisms and characters targeted by resulting selection is limited, partially due to the difficulty of discriminating among sperm from different males within the female reproductive tract. Here, we resolved mechanisms of competitive fertilization success in the promiscuous flour beetle Tribolium castaneum. Through creation of transgenic lines with fluorescent-tagged sperm heads, we followed the fate of focal male sperm in female reproductive tracts while tracking paternity across numerous rematings. Our results indicate that a given male’s sperm persist and fertilize eggs through at least seven rematings. Additionally, the proportion of a male’s sperm in the bursa (the site of spermatophore deposition), which is influenced by both timing of female’s ejecting excess sperm and male size, significantly predicted paternity share in the 24h following a mating. Contrary to expectation, proportional representation of sperm within the female’s specialized sperm-storage organ did not significantly predict paternity, though spermathecal sperm may play a role in fertilization when females do not have access to mates for longer time periods. We address the adaptive significance of the identified reproductive mechanisms in the context of T. castaneum’s unique mating system and ecology.

Satyrization without evidence of successful insemination from interspecific mating between invasive mosquitoes.

Previous research has documented low frequencies of interspecific mating in nature between the invasive vectors Aedes aegypti and Aedes albopictus. It is also known that heterospecific male accessory gland substances transferred during mating sterilize A. aegypti but not A. albopictus females, leading to satyrization, a form of reproductive interference. This paper demonstrates that satyrization of A. aegypti by A. albopictus may occur without evidence of successful insemination. Our results show that A. aegypti females, previously exposed to A. albopictus males, are rendered refractory to subsequent conspecific mating even though their spermathecae contain no heterospecific sperm. Additional experiments demonstrating transfer of labelled semen from A. albopictus males to A. aegypti females and low production of viable eggs of females housed with conspecific males, following exposure to A. albopictus males, confirm higher incidences of satyrization than expected, based on heterospecific insemination rates. We conclude that frequencies of satyrization based on detection of interspecific sperm in spermathecae may underestimate the impact of this form of reproductive interference.

Detection of insemination status in live Aedes aegypti females

Using the technique described in this report, the presence or absence of sperm in spermathecae of female Aedes aegypti is detectable without dissection. Spermathecae of a lightly anesthetized female can be visualized by phase contrast microscopy through the distended abdomen, after the intersegmental membranes are stretched by ventral placement of a glass cover slip. Most females recovered after the procedure were capable of subsequent reproductive activities. Albeit tedious, this technique preserves the female alive for subsequent experiments or observations. Its extension to other mosquito species, or other Diptera and insects, will depend on spermathecal and sperm visibility through the distended abdomen.

Left-handed sperm removal by male Calopteryx damselflies (Odonata)

Male genitalia in several insect species are asymmetry in right and left shape. However, the function of such asymmetric male genitalia is still unclear. We found that the male genitalia of the damselfly Calopteryx cornelia (Odonata: Calopterygidae) are morphologically symmetric just after emergence but asymmetric after reproductive maturation. Males remove rival sperm stored in the female bursa copulatrix (single spherical sac) and the following spermatheca (Y-shaped tubular sac) prior to their own ejaculation to prevent sperm competition. Males possess the aedeagus with a recurved head to remove bursal sperm and a pair of spiny lateral processes to remove spermathecal sperm. The right lateral process is less developed than the left, and sperm stored in the right spermathecal tube are rarely removed. Experiments involving surgical cutting of each lateral process demonstrated that only the left process functions in spermathecal sperm removal. Thus, males of C. cornelia are left-handed in their sperm removal behaviour at copulation.

Estimating SIT-driven population reduction in the Mediterranean fruit fly,Ceratitis capitata, from sterile mating

Area-wide sterile insect technique (SIT) programs assume that offspring reduction of the target population correlates with the mating success of the sterile males released. However, there is a lack of monitoring tools to prove the success of these programs in real-time. Field-cage tests were conducted under the environmental conditions of the Mediterranean coast of Spain to estimate: (a) the mating success of sterile Vienna-8 (V8) Ceratitis capitata males using molecular markers and (b) their efficacy to reduce C. capitata populations under six release ratios of wild females to wild males to V8 males (1:0:0, 1:1:0, 1:1:1, 1:1:5, 1:1:10, and 1:1:20). Statistical models were developed to predict: (a) the number of females captured in traps, (b) sperm ID (sterile or not) in spermathecae of the trapped females, and (c) the viable offspring produced, using release ratio and temperature as predictors. The number of females captured was affected by relative humidity. However, its influence in the model was low. Female captures were significantly higher in ratios 1:0:0 compared to ratios where V8 males were released. The proportion of V8 sperm in spermathecae increased with temperature and with the number of V8 males released, but leveled off between ratios 1:1:10 and 1:1:20. In all seasons, except winter (no offspring), viable offspring increased with temperature and was lowest for ratio 1:1:20. For the first time, a strong negative relationship between proportion of V8 sperm detected by molecular tools and C. capitata offspring was established. The models obtained should contribute to enhance the efficacy of SIT programs against this pest.

Correlation of queen size and spermathecal contents and effects of miticide exposure during development

Normal mating of honey bee (Apis mellifera L.) queens and drones results in extreme polyandry. Larger queens are reported to produce more brood, but do they also store more semen? Measurements of queen weight, spermatheca weight and volume, and numbers of sperm in the spermatheca were made on normally reared queens and queens exposed to miticide from early larval stage to emergence. In the normally reared group, larger queens had more sperm in spermathecae of greater volume and weight. The presence of miticide during queen development skewed the relationship of queen weight to spermatheca size and the number of sperm stored such that they were not correlated. This sublethal effect of miticide in the colony has an unknown impact on queen performance.

A new gene, SRP16, differentially expressed in the spermathecae of honeybee queens (Apis mellifera) related with reproduction status

Honey bee queens have the ability to store sperm in spermathecae for fertilizing eggs throughout their life. To investigate mechanisms for sperm storage in Apis mellifera, we employed suppression subtractive hybridization (SSH) to find differentially expressed fragments in spermathecae between virgin queens and newly mated queens. A new gene, named SRP16, was obtained by joining the SSH products with 5'-RACE and 3'-RACE. SRP16 is predicted to encode a 41 kDa protein with 363 amino acid residues. Its expression was found in the spermathecae dominantly in honey bee queens but not in honey bee workers, with the highest expression found in spermathecae of virgin and newly mated queens. SRP16 expression was weak in other tissues of queens other than in the spermathecae and showed no obvious change with reproductive status of queens. The results suggest that SRP16 may play important roles in sperm storage and honey bee reproduction.

The genusPotamothrix(Annelida, Oligochaeta, Tubificidae): a literature review

INTRODUCTION The genus Potamothrix (Vejdovsky et Mrazek, 1903) is a monophyletic, well-defined group of the annelid family Tubificidae, subfamily Tubificinae. These worms are smooth-bodied and relatively fragile in comparison with other tubificids, with short postclitellar segments and conical prostomium when fixed in alcohol (Fig. 1, 1, 2). The genus is characterized by long hose-like atria, vestigial vasa deferentia, small or completely lacking prostate glands, and presence (in most species) of simple-pointed and distally grooved, often nib-shaped, spermathecal chaetae (Fig. 1, 3-9). This groove can be actually a thin-walled tube since spermathecal chaetae are supposed to operate as syringes injecting some stimulating compound into the partner's body during copulation (Cuadrado & Martinez-Ansemil 2001). The sperm in spermathecae is always organized into spermatozeugmata consisting of fertilizing and cortex cells. Potamothrix spp. are an essential component of zoobenthos in many bodies of fresh and brackish water, being a food item for fish and other predators. They have been aligned to different genera in the past while synonymy has created confusion in treating their ecology and distribution. Several species have been used as indicators of water quality and trophic state of lakes (Milbrink 1978, Lang 1998). Some of them appear to be invasive species on different continents (Milbrink 1977, Brinkhurst 1978). Inconsiderate synonymization of some species, e.g., by Brinkhurst (1963, 1971) has caused some confusion with their distribution data. Herewith a short review of taxonomy and ecology of all species of this genus is presented. [FIGURE 1 OMITTED] Note: in the descriptions of the species, the segment numbers are conventionally denoted with Roman numerals (e.g. X, XI, etc.) and the intersegmental furrows with Arabian numerals (e.g., 10/11). HISTORY OF THE GENUS The genus name (meaning 'river thread' in Greek) was coined by Vejdovsky & Mrazek (1903) for the species P. moldaviensis from the Vltava (Moldau) River; another, the commonest species was described two years earlier from the Elbe River in Hamburg by Michaelsen (1901) as Ilyodrilus hammoniensis. Many European species have been described later, particularly by Hrabe (1931, 1941, 1950). These and related species have been erroneously included into the genus Ilyodrilus Eisen, 1879 (treated also as a subgenus of the genus Tubifex Lamarck, 1816). To separate the group from the original Ilyodrilus (sensu stricto), Brinkhurst (1963) introduced the name Euilyodrilus, but rejected this later again (Brinkhurst 1971) in favour of the senior synonym Potamothrix. Holmquist (1985) revised the genus and used the names Potamothrix and Euilyodrilus for two subgenera defined by herself (Euilyodrilus with a prostate gland on atria, and Potamothrix devoid of this gland). Finogenova & Poddubnaja (1990) revised the genus again and, after a closer study, rejected these subgenera as not distinctly delimited from each other. Cui & Wang (2012b) compiled a guide to 26 known species of the genus, erroneously including also Ilyodrilus svirenkoi Lastockin, 1937. The latter was transferred into the genus Haber, with some hesitation, already by Holmquist (1979) and, decisively, by Milligan (1986). Cui & Wang (2005, 2012a) also discovered a separate, apparently monophyletic species group of this genus in ancient lakes of the Yunnan Plateau, southern China (Fig. 2, 3). In all probability, the common ancestors of the genus Potamothrix were connected with the former Tethys Ocean. The Chinese and the western (originally Ponto-Caspian) species groups were separated from each other when the Central Asian mountains arose in the Tertiary and closed the eastern portion of this ocean while the western portion persisted as the Mediterranean and Ponto-Caspian seas. The eastern species group has survived in a few isolated freshwater, mountainous lakes while the western one diversified mainly in the large and versatile Ponto-Caspian water system. …

Genetic evidence for multiple paternity in the mangrove land crab Ucides cordatus (Decapoda: Ocypodidae)

Studies on mating patterns of marine crustaceans are rare, but the few studies on brachyuran crabs to date suggest that polyandrous mating is uncommon. In the present study, we used 6 microsatellite loci to genotype 8–16 larvae obtained from each of 10 gravid females of the crab Ucides cordatus (Brachyura: Ocypodidae). Based on the number of non-maternal alleles detected among the offspring, at least 40% of the females were inseminated by more than one male. We suggest forced copulation and maintenance of sperm in spermathecae throughout the year as possible causes of polyandry in U. cordatus.

The viability of sperm in lateral oviducts and spermathecae of instrumentally inseminated and naturally mated honey bee (Apis mellifera L.) queens

SummaryInstrumentally inseminated queens (IIQ) were compared with naturally mated ones (NMQ) to detect the effect of the instrumental insemination procedure on sperm viability in the reproductive organs. The viability of sperm in the reproductive organs of IIQ and NMQ was determined at 4 h and 24 h after they were inseminated or they mated. No significant difference was found between IIQ (88.6%) and NMQ (87.6%) in viability of sperm in the lateral oviducts at 4 h. There was also no difference between IIQ (98.3%) and NMQ (97.8%) in viability of sperm in spermathecae at 4 h. The mean viability of sperm in spermathecae of IIQ (97.5%) did not differ from the mean viability of sperm in spermathecae of NMQ (96.8%) after 24 h. These results showed that the insemination procedure had no negative effect on viability of sperm in reproductive organs of queens. The difference in sperm viability between lateral oviducts (88.1%) and spermathecae (98.1%) of queens at 4 h was found to be statistically significant (P < 0.001). Nevertheless, no significant difference was found between viability of sperm in spermatheca at 4 h (98.1%) and 24 h (97.2%). The possible reasons for the differences in viability of sperm in reproductive organs are discussed.

Sperm release and use at fertilization by yellow dung fly females (Scathophaga stercoraria)

Females of many species mate multiple times and store transferred sperm in storage organs. The mechanisms underlying sperm release from the stores at fertilization remain poorly understood, although they are central to an understanding of the female influence on post-copulatory male competition. Using double-mated females of the yellow dung fly, we counted the sperm sticking to the surface of deposited eggs of two successive clutches to obtain insight into the physiological processes associated with fertilization. The number of sperm released to fertilize an egg decreased between the first and second clutches, as well as within clutches from early to late eggs. These results indicate that: (1) sperm are lost from the stores over time independent of egg laying and (2) the number of sperm released depends on the amount of sperm stored. The lower number of sperm on eggs of the second clutches was accompanied by a strong increase of the proportion of sperm adhering to the micropyle region, suggesting that sperm use is more efficient and sperm release better controlled when sperm supply is substantially reduced. Finally, our approach indicates that sperm storage capacity of the female is higher than assumed from counts of spermathecal sperm.

Seasonal variation in genital and body size, sperm displacement ability, female mating rate, and male harassment in two calopterygid damselflies (Odonata: Calopterygidae)

Sperm competition is a pervasive force. One adaptation is the male ability to displace the rivals' sperm that females have stored from previous copulations. In the damselfly, Calopteryx haemorrhoidalis asturica, males with wider aedeagi displace more spermathecal sperm. The present study documents that the same mechanism operates in another damselfly, Hetaerina americana. However, this genital width in both species decreases along the season, but late-emerging females have more sperm displaced than early-emerging females. Because territorial males mated more and were larger in body and genital size than nonterritorial males, late-season females mated with considerably larger males with respect to female size and this produced higher sperm displacement. Assuming female benefits from storing sperm but that such benefit does not prevail if males displace sperm, it is predicted that, along the season, females will mate less and male harassment (in terms of male mating attempts and oviposition duration) will increase. These predictions were corroborated. In H. americana, it was also tested whether spermathecal sperm became less viable along the season. The results obtained did not corroborate this. This is the first evidence indicating that season affects sperm displacement ability and female mating frequency due to changes in male body and genital size. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 96, 815–829.