The reproductive behavior of red palm weevil, Rhynchophorusferrugineus Olivier was studied in laboratory with several sets of unmated females paired with unmated males for different periods. The treatments in these co...The reproductive behavior of red palm weevil, Rhynchophorusferrugineus Olivier was studied in laboratory with several sets of unmated females paired with unmated males for different periods. The treatments in these controlled mating experiments included single mating, multiple mating for 24 h, multiple mating weekly, multiple mating on alternate days and multiple mating uninterrupted with a control group. During the study, observations were made on the number of eggs laid, incubation period, hatching percentage, ovipositional periods and adult longevity. Though unmated females laid a large number of eggs, these were infertile. This study clearly showed significant differences in the egg-laying capacity of females exposed to different frequencies of mating. The average number of eggs laid varied from 98.9 ± 9.7 eggs in a single-time mated female to 195.8± 24.3 eggs in females allowed to mate on alternate days throughout their life. As far as the percentage of egg-hatching is concerned, there were significant differences in single and multiple mated females with 22.4 ± 3.3% hatching in one time mated females as compared to 85.2 ± 1.9% in alternate day mated females. This study also showed direct impact of female matings on the number of eggs laid and their hatching percentage. Moreover, the unmated and mated female groups showed no significant differences in oviposition and post-ovipositional period and also there was very little difference in male and female adult longevity.展开更多
We used Takydromus septentrionalis,a sexually size-monomorphic lacertid lizard,as a model system to test the hypothesis that sexual size monomorphism may evolve in lizards where reproductive performance is maximized a...We used Takydromus septentrionalis,a sexually size-monomorphic lacertid lizard,as a model system to test the hypothesis that sexual size monomorphism may evolve in lizards where reproductive performance is maximized at a similar body size for both sexes.We allowed lizards housed in laboratory enclosures to lay as many clutches(for females)as they could or to mate as many times(for males)as they could in a breeding season.Size-assortative mating was weak but evident in T.septentrionalis,as revealed by the fact that male and female snout–vent lengths(SVLs)in mating pairs were significantly and positively correlated.Mating frequency(indicative of male reproductive performance)varied from 1 to 8 per breeding season,generally increasing as SVL increased in adult males smaller than 67.4 mm SVL.Clutch frequency varied from 1 to 7 per breeding season,with female reproductive performance(determined by clutch frequency,annual fecundity,and annual reproductive output)maximized in females with a SVL of 68.0 mm.Accordingly to our hypothesis,the reproductive performance was maximized in the intermediate sized rather than the largest individuals in both sexes,and the body size maximizing reproductive performance was similar for both sexes.Future work could usefully investigate other lineages of lizards with sexually monomorphic species in a phylogenetic context to corroborate the hypothesis of this study.展开更多
Circadian mating rhythms, mating frequency, mating duration, and the effect of mating duration on fecundity and fertility in the cabbage beetle, Colaphellus bowringi were investigated in the laboratory. Mating occurre...Circadian mating rhythms, mating frequency, mating duration, and the effect of mating duration on fecundity and fertility in the cabbage beetle, Colaphellus bowringi were investigated in the laboratory. Mating occurred throughout the 24-h cycle but the majority of copulations occurred in the photophase with two apparent peaks, one at 8：00 and another at 16：00. Mating frequency observations for 10 consecutive days indicated that pre-mating period of C. bowringi was about 4 days, and pairs mated an average of 5 times per day and an average of 40 times during the first 10 days. There was a negative correlation between mating frequency and mating duration during the consecutive mating. The mean duration of the first copulation （136.24± 4.62 min） was significantly longer than those of the second （57.87 ± 2.03 min）, third （53.05 ±2.05 min） and fourth copulation （30.86 ± 2.98 min）. Fecundity showed a slight increase with increasing mating duration but no significant difference among treatments. However, fertility was significantly influenced by the mating duration in this species. Mating of 20-min duration did not produce viable eggs. The mean percentage of fertile eggs with completed mating duration （204.43±18.96 min, 56.75% fertile eggs） was significantly higher than those with 60 min （39.55%） and 30 min （17.91%） mating duration, suggesting that the longer mating duration might be associated with transfer of more sperm that are used to increase the fertility of eggs.展开更多
Male animals often adjust their sperm investment in response to sperm competition environment.To date,only a few studies have investigated how juvenile sociosexual settings affect sperm production before adulthood and...Male animals often adjust their sperm investment in response to sperm competition environment.To date,only a few studies have investigated how juvenile sociosexual settings affect sperm production before adulthood and sperm allocation during the first mating.Yet,it is unclear whether juvenile sociosexual experience(1)determines lifetime sperm production and allocation in any animal species;(2)alters the eupyrene:apyrene sperm ratio in lifetime ejaculates of any lepidopteran insects,and(3)influences lifetime ejaculation patterns,number of matings and adult longevity.Here we used a polygamous moth,Ephestia kuehniella,to address these questions.Upon male adult emergence from juveniles reared at different density and sex ratio,we paired each male with a virgin female daily until his death.We dissected each mated female to count the sperm transferred and recorded male longevity and lifetime number of matings.We demonstrate for the first time that males ejaculated significantly more eupyrenes and apyrenes in their lifetime after their young were exposed to juvenile rivals.Adult moths continued to produce eupyrene sperm,contradicting the previous predictions for lepidopterans.The eupyrene:apyrene ratio in the lifetime ejaculates remained unchanged in all treatments,suggesting that the sperm ratio is critical for reproductive success.Male juvenile exposure to other juveniles regardless of sex ratio caused significantly shorter adult longevity and faster decline in sperm ejaculation over successive matings.However,males from all treatments achieved similar number of matings in their lifetime.This study provides insight into adaptive resource allocation by males in response to juvenile sociosexual environment.展开更多
文摘The reproductive behavior of red palm weevil, Rhynchophorusferrugineus Olivier was studied in laboratory with several sets of unmated females paired with unmated males for different periods. The treatments in these controlled mating experiments included single mating, multiple mating for 24 h, multiple mating weekly, multiple mating on alternate days and multiple mating uninterrupted with a control group. During the study, observations were made on the number of eggs laid, incubation period, hatching percentage, ovipositional periods and adult longevity. Though unmated females laid a large number of eggs, these were infertile. This study clearly showed significant differences in the egg-laying capacity of females exposed to different frequencies of mating. The average number of eggs laid varied from 98.9 ± 9.7 eggs in a single-time mated female to 195.8± 24.3 eggs in females allowed to mate on alternate days throughout their life. As far as the percentage of egg-hatching is concerned, there were significant differences in single and multiple mated females with 22.4 ± 3.3% hatching in one time mated females as compared to 85.2 ± 1.9% in alternate day mated females. This study also showed direct impact of female matings on the number of eggs laid and their hatching percentage. Moreover, the unmated and mated female groups showed no significant differences in oviposition and post-ovipositional period and also there was very little difference in male and female adult longevity.
基金This work was carried out in compliance with the current laws of China and was supported by grants from the National Natural Science Foundation of China(32071511,31301878,and 31300339)。
文摘We used Takydromus septentrionalis,a sexually size-monomorphic lacertid lizard,as a model system to test the hypothesis that sexual size monomorphism may evolve in lizards where reproductive performance is maximized at a similar body size for both sexes.We allowed lizards housed in laboratory enclosures to lay as many clutches(for females)as they could or to mate as many times(for males)as they could in a breeding season.Size-assortative mating was weak but evident in T.septentrionalis,as revealed by the fact that male and female snout–vent lengths(SVLs)in mating pairs were significantly and positively correlated.Mating frequency(indicative of male reproductive performance)varied from 1 to 8 per breeding season,generally increasing as SVL increased in adult males smaller than 67.4 mm SVL.Clutch frequency varied from 1 to 7 per breeding season,with female reproductive performance(determined by clutch frequency,annual fecundity,and annual reproductive output)maximized in females with a SVL of 68.0 mm.Accordingly to our hypothesis,the reproductive performance was maximized in the intermediate sized rather than the largest individuals in both sexes,and the body size maximizing reproductive performance was similar for both sexes.Future work could usefully investigate other lineages of lizards with sexually monomorphic species in a phylogenetic context to corroborate the hypothesis of this study.
基金The research was supported by a grant from National Natural Science Foundation of China （30460074）. We also thank three anonymous reviewers for their valuable comments.
文摘Circadian mating rhythms, mating frequency, mating duration, and the effect of mating duration on fecundity and fertility in the cabbage beetle, Colaphellus bowringi were investigated in the laboratory. Mating occurred throughout the 24-h cycle but the majority of copulations occurred in the photophase with two apparent peaks, one at 8：00 and another at 16：00. Mating frequency observations for 10 consecutive days indicated that pre-mating period of C. bowringi was about 4 days, and pairs mated an average of 5 times per day and an average of 40 times during the first 10 days. There was a negative correlation between mating frequency and mating duration during the consecutive mating. The mean duration of the first copulation （136.24± 4.62 min） was significantly longer than those of the second （57.87 ± 2.03 min）, third （53.05 ±2.05 min） and fourth copulation （30.86 ± 2.98 min）. Fecundity showed a slight increase with increasing mating duration but no significant difference among treatments. However, fertility was significantly influenced by the mating duration in this species. Mating of 20-min duration did not produce viable eggs. The mean percentage of fertile eggs with completed mating duration （204.43±18.96 min, 56.75% fertile eggs） was significantly higher than those with 60 min （39.55%） and 30 min （17.91%） mating duration, suggesting that the longer mating duration might be associated with transfer of more sperm that are used to increase the fertility of eggs.
基金supported by a China Scholarship Council-Massey University PhD Scholars Programme(CSC No.201806660018)to J.L.,a Guangxi University Foundation Strengthening Program Postgraduate Overseas Research Project to Y.Z.,a Guangxi Scholarship Fund of Guangxi Education Department to X.-L.Z.,and Massey University Research Funds to Q.W.and X.Z.H.
文摘Male animals often adjust their sperm investment in response to sperm competition environment.To date,only a few studies have investigated how juvenile sociosexual settings affect sperm production before adulthood and sperm allocation during the first mating.Yet,it is unclear whether juvenile sociosexual experience(1)determines lifetime sperm production and allocation in any animal species;(2)alters the eupyrene:apyrene sperm ratio in lifetime ejaculates of any lepidopteran insects,and(3)influences lifetime ejaculation patterns,number of matings and adult longevity.Here we used a polygamous moth,Ephestia kuehniella,to address these questions.Upon male adult emergence from juveniles reared at different density and sex ratio,we paired each male with a virgin female daily until his death.We dissected each mated female to count the sperm transferred and recorded male longevity and lifetime number of matings.We demonstrate for the first time that males ejaculated significantly more eupyrenes and apyrenes in their lifetime after their young were exposed to juvenile rivals.Adult moths continued to produce eupyrene sperm,contradicting the previous predictions for lepidopterans.The eupyrene:apyrene ratio in the lifetime ejaculates remained unchanged in all treatments,suggesting that the sperm ratio is critical for reproductive success.Male juvenile exposure to other juveniles regardless of sex ratio caused significantly shorter adult longevity and faster decline in sperm ejaculation over successive matings.However,males from all treatments achieved similar number of matings in their lifetime.This study provides insight into adaptive resource allocation by males in response to juvenile sociosexual environment.
