Sexual Behavior is Enhanced by Regular, Repeated Mating from Young Adulthood to Middle Age in Female Long-Evans Rats

Background: Aging is associated neuroendocrine changes in women. Animals can be used to model these changes, as well as changes in reproductive behavior. Objective: The current study was designed to characterize mating behavior across age and assess the effects of age and sexual history on mating behavior. Methods: Sexual motivation was assessed using the partner-preference test, in which a female rat is given the choice to interact with a same-sex conspecific or a sexually-vigorous male rat, with which she can mate. Results: Across repeated mating tests (2-12 months of age), female rats spent more time with the male, displayed more solicitation behaviors, were less likely to leave the male after mounts, but visited both stimulus animals less frequently. Comparing a separate group of age-matched, hormoneyoked female rats mated for the first time at 12 months of age to female rats mated for the first time at 2 months of age showed that the 12 month rats visited both stimulus animals less, were less likely to leave the male after mounts, took longer to return to the male after mounts, and displayed fewer solicitation behaviors than their younger counterparts. Relative to middle-aged female rats once they were sexually experienced, 12 month naïve rats spent less time with the male, were more likely to leave the male after mounts, and displayed fewer solicitation behaviors. Furthermore, 12 month naïve rats failed to discriminate between the stimulus animals, visiting both stimulus animals at the same rate unlike 2 month naïve or 12 month experienced rats. Conclusion: Taken together, these results suggest that aging affects some measures of sexual behavior, but most effects of age can be mitigated by regular, repeated mating.

Seroprevalensi Brucellosis dan Tingkat Gangguan Reproduksi Pada Sapi Perah di Kota Batu

This study aimed to measure the incidence rate of brucellosis in dairy cattle at Batu City based onserological tests (seroprevalence) and to determine the relationship between the incidence ofbrucellosis and reproductive disorders. Cross-sectional epidemiological research was conducted todetermine the prevalence of brucellosis in dairy cows. Serum samples were obtained from 130dairy cows over 6 months of age, reproductive disorders data using a questionnaire on 21 farmers.Serological testing used the Rose Bengal Test (RBT) and continued with the Complement FixationTest (CFT). The data analysis used Pearson's Chi-Square correlation statistical test. Theseroprevalence of brucellosis at Batu City was 0.7%. The prevalence of reproductive disorders indairy cows was 29.2% consisted of 8.5% abortion and 20.8% repeated mating. There was acorrelation between brucellosis and the incidence of abortion (2 = 10.90; P<0.05) and a correlation between the incidence of abortion and the age more than 3 years (2 = 5.35; P<0.05). The conclusion of this study showed that the prevalence of brucellosis at Batu city was low (<2%).The results of this study could be used as the basis for implementing a vaccination program anderadicating brucellosis at East Java

A novel method of quantifying sperm to determine the potential for sperm depletion in male American lobsters Homarus americanus (H. Milne Edwards, 1837) (Decapoda: Astacidea: Nephropidae)

Sperm limitation is a concern for a number of heavily fished decapods; however, work to assess this concern is sometimes hampered by a lack of simple techniques to quantify sperm transferred during reproduction. Our primary goal was to determine if DNA measurements could be used to quantify the sperm content of spermatophores and thus facilitate investigations of sperm limitation in American lobsters (Homarus americanus H. Milne Edwards, 1837). This was achieved by measuring the amount of DNA in a sample and then calibrating those values by using flow cytometry to count the number of individual sperm present in the sample. Our results show that the DNA quantification technique provides a fast and accurate way to quantify sperm. We then demonstrated the utility of the method by using it to examine the rate at which males can produce sperm under simulated conditions of repeated mating events, a situation that might lead to a reduction in the number of sperm per spermatophore. While spermatophores obtained from male lobsters at three-day intervals varied substantially in the number of sperm they contained (range 427,090–5,028,996; mean 2,306,473), there was no clear decline in sperm count over time. These results suggest that male lobsters replenish their sperm supplies rapidly, and that sperm recharge rate is unlikely to be a factor that could lead to sperm limitation in American lobster populations.

Sex-specific response to delayed and repeated mating in spider mite Tetranychus urticae

Sexual interaction is an important activity that determines the reproductive schedule of organisms and can ultimately influence the fitness traits of both sexes. Although the influence of sexual interaction on the fitness of females has been extensively determined, little is known about the effects on males, which often have different mating strategies and optimal mating regimes from those of females. To understand how mating regimes (timing and frequency) modulate the fitness in both sexes, we used spider mite (Tetranychus urticae) to investigate the influence of delayed mating and repeated mating on the fitness of male and female. For females, the unmated and the delayed mating females outlived those mated immediately after adult emergence. The repeated mating shortened the lifespan of females that mated at 1-day-old, but not that mated 7-day-old. However, no significant variation in lifespan was observed for males across different mating regimes. We found although delayed mating significantly reduced the daily reproductive rate of the females, there was no significant difference in lifetime reproduction of females across treatments because the delayed mating females increased their reproductive lifespan as a compensation. Our study highlighted that the time and frequency of sexual interaction showed a sex-specific consequence on male and female spider mites, indicating that sexual interaction incurs a higher cost to females which have a much lower optimal mating frequency than males.

Study on the Effects of Multiple Matings in Coccinella transversalis for its Behaviour and Reproduction

The evolution and maintenance of multiple mating (repeated mating or polyandry) in predaceous ladybird beetles (Coleoptera: Coccinellidae) is an adaptive puzzle; since a single ejaculate of male often provides enough sperm to female for her lifetime egg production. Despite numerous studies on multiple mating evaluating reproductive attributes, there are negligible studies that investigated changes in behavioural patterns in ladybirds during multiple mating. In the present study, effects of multiple mating on mating behavioural pattern of males and reproductive attributes of females have been assessed using Coccinella transversalis as an experimental ladybird species. Results revealed that during copulation behaviour, time for the commencement of mating, latent period, wriggling movement duration, number of bouts and mating duration decreased with increase in number of mating; whereas interval between successive bouts increased significantly. Moreover, fecundity and egg viability of females increased with increase in number of mating.

Ejaculate deterioration with male age, and its amelioration in Drosophila

Declining ejaculate performance with male age is taxonomically widespread and has broad ramifications for fertility and fitness. However, we have a poor understanding of age-related changes to specific ejaculate components, how they cause reduced performance, and whether the decline is ameliorable. Here, we show that, in Drosophila, sperm production chronologically declines with age, invariant to mating activity, while repeated mating causes infertility via reduced sperm stores and viability. However, changes to sperm do not fully explain ejaculate deterioration: impacts on seminal fluid contribute to aspects of reduced ejaculate performance, associated with shifts in proteome abundance and quality. We show that ablation of insulin-like peptide-producing cells in males ameliorates aspects of ejaculate performance loss, suggesting that anti-ageing interventions can be coopted to benefit male reproductive health.One Sentence SummaryEjaculate performance declines with male age via mating-dependent sperm and seminal protein deterioration, but it can be ameliorated.

Do female Nicrophorus vespilloides reduce direct costs by choosing males that mate less frequently?

Sexual conflict occurs when selection to maximize fitness in one sex does so at the expense of the other sex. In the burying beetle Nicrophorus vespilloides , repeated mating provides assurance of paternity at a direct cost to female reproductive productivity. To reduce this cost, females could choose males with low repeated mating rates or smaller, servile males. We tested this by offering females a dichotomous choice between males from lines selected for high or low mating rate. Each female was then allocated her preferred or non-preferred male to breed. Females showed no preference for males based on whether they came from lines selected for high or low mating rates. Pairs containing males from high mating rate lines copulated more often than those with low line males but there was a negative relationship between female size and number of times she mated with a non-preferred male. When females bred with their preferred male the number of offspring reared increased with female size but there was no such increase when breeding with non-preferred males. Females thus benefited from being choosy, but this was not directly attributable to avoidance of costly male repeated mating.

Research of Slider-Crank Massager Noise Fault Diagnosis and Treatment

The abnormal periodic noise from the slider-crank massager was complained by many consumers when it was under unilateral massage. By anglicizing the worm non-working surface stained with marking compound, the reason of the abnormal periodic noise which stemming from repeated mating of non-normal mating surfaces of the worm gear mechanism is founded. In order to solve the problem the overrunning clutch is used as it’s beyond separation functions. When the force is loaded to passive wheel, the clutch is linked; while the load becomes kinetic energy, the power will be separated immediately. The characteristic determines that the overrunning clutch is one of the best choices to separate the load on the slider-crank massager. And the results of the experiment indicate that the method has a significant effect to reduce noise. It also has a practical significance to the common problems of the mechanism and to the related scientific problems.