scholarly journals Pupal Cues Increase Sperm Production but Not Testis Size in an Insect

Insects ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 679
Author(s):  
Junyan Liu ◽  
Xiong Z. He ◽  
Xia-Lin Zheng ◽  
Yujing Zhang ◽  
Qiao Wang
Keyword(s):  
Resource Allocation ◽  
Morphological Traits ◽  
Adult Stage ◽  
Empirical Studies ◽  
Testis Size ◽  
Sperm Production ◽  
Sperm Competition Risk ◽  
Apyrene Sperm ◽  
Eupyrene Sperm ◽  
Fine Tune

Theoretic and empirical studies show that social surroundings experienced by male insects during their larval or adult stage can influence their testicular investment in diverse ways. Although insect pupae do not feed and crawl, they can communicate using sex-specific and/or non-sex specific cues. Yet, it is unknown, in any insect, whether and how male pupae can fine-tune their resource allocation to sperm production and testis size in response to socio-sexual environments. We investigated this question using a moth, Ephestia kuehniella, which produces fertile eupyrene sperm and unfertile apyrene sperm. We held male pupae individually or in groups with different sex ratios, and dissected adults upon eclosion, measured their testis size, and counted both types of sperm. We demonstrated that after exposure to conspecific pupal cues regardless of sex, male pupae increased production of eupyrenes and apyrenes at the same rate but kept testis size unchanged. We suggest that testis size is fixed after pupation because most morphological traits are formed during the larval stage, allowing little room for pupae to adjust testis size. Like adults, male pupae with fully grown testes have sufficient resources to produce more sperm of both types according to the perceived increase in sperm competition risk.

scholarly journals Pupal Cues Increase Sperm Production but Not Testis Size in an Insect

2021 ◽  
Author(s):  
Junyan Liu ◽  
Xiong Z He ◽  
Xia-Lin Zheng ◽  
Yujing Zhang ◽  
Qiao Wang
Keyword(s):  
Resource Allocation ◽  
Morphological Traits ◽  
Adult Stage ◽  
Empirical Studies ◽  
Testis Size ◽  
Sperm Production ◽  
Sperm Competition Risk ◽  
Apyrene Sperm ◽  
Eupyrene Sperm ◽  
Fine Tune

Theoretic and empirical studies show that social surroundings experienced by male insects during their larval or adult stage can influence their testicular investment in diverse ways. Although insect pupae do not feed and crawl, they can communicate using sex-specific and/or non-sex specific cues. Yet, it is unknown, in any insect, whether and how male pupae can fine-tune their resource allocation to sperm production and testis size in response to socio-sexual environment. We investigated this question using a moth, Ephestia kuehniella, which produces fertile eupyrene sperm and unfertile apyrene sperm. We held male pupae individually or in groups with different sex ratios, and dissected adults upon eclosion, measured their testis size, and counted both types of sperm. We demonstrated that after exposure to conspecific pupal cues regardless of sex, male pupae increased production of eupyrenes and apyrenes at the same rate but kept testis size unchanged. We suggest that testis size is fixed after pupation because most morphological traits are formed during the larval stage, allowing little room for pupae to adjust testis size. Like adults, male pupae with fully grown testes have sufficient resources to produce more sperm of both types according to the perceived increase of sperm competition risk.

scholarly journals Larval social cues influence testicular investment in an insect

2021 ◽  
Author(s):  
Junyan Liu ◽  
Xiong Z He ◽  
Xia-Lin Zheng ◽  
Yujing Zhang ◽  
Qiao Wang
Keyword(s):  
Body Weight ◽  
Sperm Competition ◽  
Growth And Development ◽  
Social Cues ◽  
Social Setting ◽  
Testis Size ◽  
Sperm Production ◽  
Competition Level ◽  
Fine Tune ◽  
Paternity Share

Abstract Socio-sexual environment can have critical impacts on reproduction and survival of animals. Consequently, they need to prepare themselves by allocating more resources to competitive traits that give them advantages in the particular social setting they have been perceiving. Evidence shows that a male usually raises his investment in sperm after he detects the current or future increase of sperm competition because relative sperm numbers can determine his paternity share. This leads to the wide use of testis size as an index of the sperm competition level, yet testis size does not always reflect sperm production. To date, it is not clear whether male animals fine-tune their resource allocation to sperm production and other traits as a response to social cues during their growth and development. Using a polygamous insect Ephestia kuehniella, we tested whether and how larval social environment affected sperm production, testis size, and body weight. We exposed the male larvae to different juvenile socio-sexual cues and measured these traits. We demonstrate that regardless of sex ratio, group-reared males produced more eupyrenes (fertile and nucleate sperm) but smaller testes than singly reared ones, and that body weight and apyrene (infertile and anucleate sperm) numbers remained the same across treatments. We conclude that the presence of larval social, but not sexual cues is responsible for the increase of eupyrene production and decrease of testis size. We suggest that male larvae increase investment in fertile sperm cells and reduce investment in other testicular tissues in the presence of conspecific juvenile cues.

scholarly journals Destination of apyrene sperm following migration from the bursa copulatrix in the monandrous swallowtail butterfly Byasa alcinous

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Tatsuro Konagaya ◽  
Naoto Idogawa ◽  
Mamoru Watanabe
Keyword(s):  
Sperm Storage ◽  
Bursa Copulatrix ◽  
Swallowtail Butterfly ◽  
Storage Organs ◽  
Apyrene Sperm ◽  
Eupyrene Sperm ◽  
Spermathecal Gland

AbstractMost male lepidopterans produce fertile eupyrene sperm and non-fertile apyrene sperm, both of which are transferred to the female in a spermatophore during mating. Apyrene sperm outnumbers eupyrene sperm and both sperm types migrate from the bursa copulatrix to the spermatheca after mating. While eupyrene sperm are maintained in the spermatheca until oviposition, the number of apyrene sperm decreases with time. It is unclear whether apyrene sperm disappear from all sperm storage organs in females because both sperm types are often observed in the spermathecal gland. To investigate this, the numbers of both sperm types were estimated in the spermatheca and spermathecal gland of female Byasa alcinous (a monandrous butterfly) 6, 12, 48, 96, and 192 h after mating terminated. Apyrene sperm arrived in the spermatheca earlier than eupyrene sperm; however, some eupyrene and apyrene sperm migrated to the spermathecal gland from the spermatheca at almost the same time. The number of apyrene sperm reached a peak 12 h after the termination of mating and then decreased with time in both the spermatheca and spermathecal gland. Our results suggest that the role of apyrene sperm might be completed early after arriving in the spermatheca of B. alcinous.

scholarly journals The Study of Resource Allocation among Software Development Phases: An Economics-Based Approach

2011 ◽  
Vol 2011 ◽  
pp. 1-21 ◽  
Author(s):  
Peleg Yiftachel ◽  
Irit Hadar ◽  
Dan Peled ◽  
Eitan Farchi ◽  
Dan Goldwasser
Keyword(s):  
Resource Allocation ◽  
Software Development ◽  
Empirical Studies ◽  
Profit Maximization ◽  
Maximization Problem ◽  
Software Production ◽  
Software Product ◽  
Development Processes ◽  
Development Phases ◽  
Novel Concept

This paper presents an economics-based approach for studying the problem of resource allocation among software development phases. Our approach is structured along two parallel axes: theoretical and empirical. We developed a general economic model for analyzing the allocation problem as a constrained profit maximization problem. The model, based on a novel concept of software production function, considers the effects of different allocations of development resources on output measures of the resulting software product. An empirical environment for evaluating and refining the model is presented, and a first exploratory study for characterizing the model's components and developers' resource allocation decisions is described. The findings illustrate how the model can be applied and validate its underlying assumptions and usability. Future quantitative empirical studies can refine and substantiate various aspects of the proposed model and ultimately improve the productivity of software development processes.

scholarly journals SKAP, an outer kinetochore protein, is required for mouse germ cell development

Reproduction ◽  
2016 ◽  
Vol 151 (3) ◽  
pp. 239-251 ◽  
Author(s):  
Corinne Grey ◽  
Julien Espeut ◽  
Rachel Ametsitsi ◽  
Rajeev Kumar ◽  
Malgorzata Luksza ◽  
...  
Keyword(s):  
Genetic Material ◽  
Successful Outcome ◽  
Testis Size ◽  
Sperm Production ◽  
Male Gametogenesis ◽  
Meiotic Chromosomes ◽  
Immortalized Cells ◽  
And Function ◽  
Deficient Mice ◽  
Segregation Of Chromosomes

In sexually reproducing organisms, accurate gametogenesis is crucial for the transmission of genetic material from one generation to the next. This requires the faithful segregation of chromosomes during mitotic and meiotic divisions. One of the main players in this process is the kinetochore, a large multi-protein complex that forms at the interface of centromeres and microtubules. Here, we analyzed the expression profile and function of small kinetochore-associated protein (SKAP) in the mouse. We found that two distinct SKAP isoforms are specifically expressed in the germline: a smaller isoform, which is detected in spermatogonia and spermatocytes and localized in the outer mitotic and meiotic kinetochores from metaphase to telophase, and a larger isoform, which is expressed in the cytoplasm of elongating spermatids. We generated SKAP-deficient mice and found that testis size and sperm production were severely reduced in mutant males. This phenotype was partially caused by defects during spermatogonia proliferation before entry into meiosis. We conclude that mouse SKAP, while being dispensable for somatic cell divisions, has an important role in the successful outcome of male gametogenesis. In germ cells, analogous to what has been suggested in studies using immortalized cells, SKAP most likely stabilizes the interaction between kinetochores and microtubules, where it might be needed as an extra safeguard to ensure the correct segregation of mitotic and meiotic chromosomes.

Cooperatively breeding cichlid fish adjust their testis size but not sperm traits in relation to sperm competition risk

2008 ◽  
Vol 62 (11) ◽  
pp. 1701-1710 ◽  
Author(s):  
Satoshi Awata ◽  
Tomohiro Takeyama ◽  
Yoshimi Makino ◽  
Yuko Kitamura ◽  
Masanori Kohda
Keyword(s):  
Sperm Competition ◽  
Cichlid Fish ◽  
Testis Size ◽  
Cooperatively Breeding ◽  
Sperm Competition Risk ◽  
Sperm Traits

scholarly journals Evolution of male and female choice in polyandrous systems

2017 ◽  
Vol 284 (1851) ◽  
pp. 20162174 ◽  
Author(s):  
Mikael Puurtinen ◽  
Lutz Fromhage
Keyword(s):  
Mate Choice ◽  
Empirical Studies ◽  
Mating Strategies ◽  
Sperm Production ◽  
Female Fecundity ◽  
Male And Female ◽  
Sperm Limitation ◽  
Multiple Partners ◽  
Mating Costs ◽  
The Cost

We study the evolution of male and female mating strategies and mate choice for female fecundity and male fertilization ability in a system where both sexes can mate with multiple partners, and where there is variation in individual quality (i.e. in the availability of resources individuals can allocate to matings, mate choice and production of gametes). We find that when the cost of mating differs between sexes, the sex with higher cost of mating is reluctant to accept matings and is often also choosy, while the other sex accepts all matings. With equal mating costs, the evolution of mating strategies depends on the strength of female sperm limitation, so that when sperm limitation is strong, males are often reluctant and choosy, whereas females tend to accept available matings. Male reluctance evolves because a male's benefit per mating diminishes rapidly as he mates too often, hence losing out in the process of sperm competition as he spends much of his resources on mating costs rather than ejaculate production. When sperm limitation is weaker, females become more reluctant and males are more eager to mate. The model thus suggests that reversed sex roles are plausible outcomes of polyandry and limited sperm production. Implications for empirical studies of mate choice are discussed.

scholarly journals A Conceptual Model of the Sense of Presence in Virtual Environments

1999 ◽  
Vol 8 (2) ◽  
pp. 241-244 ◽  
Author(s):  
Karl-Erik Bystrom ◽  
Woodrow Barfield ◽  
Claudia Hendrix
Keyword(s):  
Resource Allocation ◽  
Conceptual Model ◽  
Virtual Environments ◽  
Empirical Studies ◽  
Theoretical Framework ◽  
Task Demands ◽  
Attentional Resource ◽  
Sense Of Presence ◽  
Display Technology ◽  
And Performance

This paper proposes a model of interaction in virtual environments which we term the immersion, presence, performance (IPP) model. This model is based on previous models of immersion and presence proposed by Barfield and colleagues and Slater and colleagues. The IPP model describes the authors' current conceptualization of the effects of display technology, task demands, and attentional resource allocation on immersion, presence, and performance in virtual environments. The IPP model may be useful for developing a theoretical framework for research on presence and for interpreting the results of empirical studies on the sense of presence in virtual environments. The model may also be of interest to designers of virtual environments.

scholarly journals A comparative study of sperm production in two species of Australian arid zone rodents (Pseudomys australis, Notomys alexis) with marked differences in testis size

Reproduction ◽  
2001 ◽  
pp. 239-247 ◽  
Author(s):  
EJ Peirce ◽  
WG Breed
Keyword(s):  
Arid Zone ◽  
Seminiferous Epithelium ◽  
Testis Size ◽  
Sperm Production ◽  
Interspecific Differences ◽  
Long Duration ◽  
Sperm Counts ◽  
The Mean ◽  
Low Efficiency ◽  
Daily Sperm Production

The plains rat, Pseudomys australis, and the spinifex hopping mouse, Notomys alexis, show marked differences in the size of their testes and in the number of spermatozoa within the epididymides. In the present study, the dynamics of sperm production and the duration of sperm transit along the male excurrent ducts were compared between these two species. The durations of the cycle of the seminiferous epithelium, spermatogenesis and sperm transit were determined by tracking cells using autoradiography after [(3)H]thymidine incorporation. Daily sperm production was determined from counts of testicular spermatids after homogenization and further estimates of sperm transit were obtained by dividing sperm reserves within the various regions of the extratesticular ducts by the daily sperm production of the attached testis. In the plains rat, the mean duration of the cycle of the seminiferous epithelium was 11.2 days, the duration of spermatogenesis was 45 days, daily sperm production was 2.6 x 10(7) spermatozoa per gram of testis and epididymal transit of spermatozoa took approximately 9 days (caput 0.8 days; corpus 1.5 days; cauda 6.5 days). In contrast, in the hopping mouse, the mean duration of the cycle of the seminiferous epithelium was 14 days, the duration of spermatogenesis was 56 days and daily sperm production per gram of testis was < 1.0 x 10(7). Epididymal transit of spermatozoa was completed in about 4 days (caput + corpus < 1 day; cauda 3 days); however, spermatozoa may be stored for an additional 1.5-2.0 days in the vas deferens. These results indicate that, in addition to small testes, the hopping mouse shows a low efficiency of sperm production, a relatively long duration of spermatogenesis and rapid passage of spermatozoa through the epididymis, all of which contribute to low epididymal sperm counts. These data are considered in relation to interspecific differences in sperm competition.

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