Lekking males aggregate to attract females and contribute solely to egg fer- tilization, without any further parental care. Evolutionary theory therefore predicts them to be nonchoosy toward their mates, because any l...Lekking males aggregate to attract females and contribute solely to egg fer- tilization, without any further parental care. Evolutionary theory therefore predicts them to be nonchoosy toward their mates, because any lost mating opportunities would out- weigh the benefits associated with such preferences. Nevertheless, due to time costs, the production of energetically costly sexual displays, and potential sperm limitation, the mat- ing effort of lekking males is often considerable. These factors, combined with the fact that many females of varying quality are likely to visit leks, could favor the evolution of male mate preferences. Here, we show that males of the lekking lesser wax moth, Achroia grisella, were indeed more likely to mate with heavier females in choice experiments, even at their virgin mating （i.e., when their reproductive resources have not yet been depleted by previous matings）. This differential female mating success could not be attributed to female behavior as heavy and light females showed similar motivation to mate （i.e., la- tency to approach the males） and time to copulate. Males seem to benefit from mating with heavier females, as fecundity positively correlated with female mass. This new em- pirical evidence shows that male mate choice may have been tmderestimated in lekking species展开更多
Ophraella communa(Coleoptera: Chrysomelidae), the ragweed leaf beetle, is a biological control agent of the invasive common ragweed, Ambrosia artemisiifolia(Asterales: Asteraceae). Adults can survive cold conditions t...Ophraella communa(Coleoptera: Chrysomelidae), the ragweed leaf beetle, is a biological control agent of the invasive common ragweed, Ambrosia artemisiifolia(Asterales: Asteraceae). Adults can survive cold conditions that occur during winter. The adults mate before entering overwintering. Understanding the connection between copulation and overwintering will be useful for determining O. communa seasonality. Determining the relationship between overwintering and copulation required comparison of mated and unmated beetles at mean lethal temperature(LTemp_(50)) exposures for 2 h. Cold-related physiological indices, including the water ratio, super cooling point(SCP), cryoprotectant levels, and energy reserve levels, were also measured. Mating treatment decreased the LTemp_(50) of both sexes by reducing their mean SCP and water ratios. Although the changes of cryoprotectant levels in mated adults were not precisely consistent in between the genders, they increased greatly in both males and females. Body sugar may play a role in copulation and may also elevate cold hardiness in O. communa.展开更多
Although detailed knowledge on breeding ecology of humpback whales is required for developing effective and sustainable whale watching programs in breeding areas, the breeding ecology of this species is still poorly u...Although detailed knowledge on breeding ecology of humpback whales is required for developing effective and sustainable whale watching programs in breeding areas, the breeding ecology of this species is still poorly understood. Hence, we examine the migratory timing of humpback whales in Okinawa that is one of their breeding ground, distinguishing the reproductive status (male, female, or female with a calf), group compositions (singleton, pair, or whales more than three) and group types (singer or competitive group) in order to assess the peak period of breeding activities. A total of 1192 days of photo-identification surveys were conducted from 1991 to 2012 and a total of 7366 humpback whales were sighted during the surveys. Among them, 1284 whales were sex-determined (848 males, 147 females and 289 females with a calf), 1138 singletons, 1416 pairs and 710 groups of more than three whales were observed. Females without calves tended to occur from late January to late February, which was the beginning of the breeding season and male-female pairs were observed most frequently during this period. The peak occurrence of competitive group which was considered a mating-related behavior group, formed by females and males, was also observed during this period. These results indicated that humpback whales peak mating period in Okinawa occurred between late January and late February. Females with a calf tended to increase from mid-February toward the end of the breeding season maintaining a high sighting per unit effort (SPUE) value in late March. We, therefore, suggested that the peak time of birthing and newborn care was probably that period in Okinawa. These findings extended our knowledge on the reproductive ecology of humpback whales in Okinawan waters.展开更多
Fecundity in some insects is affected by mating status. The effect of mating status on the fecundity and total egg production of Teleogryllus emma （Ohmachi et Matsumura） （Orthoptera： Gryllidae） was examined in th...Fecundity in some insects is affected by mating status. The effect of mating status on the fecundity and total egg production of Teleogryllus emma （Ohmachi et Matsumura） （Orthoptera： Gryllidae） was examined in this study. The results showed that the pre-oviposition period was shorter for amphigonic females than that for virgin females. However, no significant difference in pre-oviposition was found between amphigonic females and those that had mated with a male with either the phallodeum or testes extirpated. There is no difference in adult longevity between the above four groups. The fecundity and total egg production were much higher in amphigonic females than in those controlled under the three non-amphigonic treatments. The females of T. emma that mated with the testes-extirpated males produced more eggs （up to two-fold more） than both the virgin females and those that mated with the phallodeum-extirpated males, but there was no difference between them. The fecundity-enhancing substances transferred from male to female can stimulate the female to produce more eggs, but this stimulation has to occur in collaboration with sperm.展开更多
Upon the analogy of definition of heterosis and inbreeding depresstion in terms of population genetics, the heterosis is thought to be evaluated overall with fitness. By establishing a mathematical model, the equilibr...Upon the analogy of definition of heterosis and inbreeding depresstion in terms of population genetics, the heterosis is thought to be evaluated overall with fitness. By establishing a mathematical model, the equilibrium status of three genotypes of random mating population （i. e. RR, Rr and rr） under different fitness, which exposes that heterosis is the precondition for multiallele to exist in the population. The heterosis protects the genetic diversity and makes the population owning a stronger self-control and evolution potential by improving the hetemzygote＇s fithess so as not to wash out different types of genes. It deepens Darwin＇s thoughts of individual section by making the individual fitness consonant with population fitness.展开更多
文摘Lekking males aggregate to attract females and contribute solely to egg fer- tilization, without any further parental care. Evolutionary theory therefore predicts them to be nonchoosy toward their mates, because any lost mating opportunities would out- weigh the benefits associated with such preferences. Nevertheless, due to time costs, the production of energetically costly sexual displays, and potential sperm limitation, the mat- ing effort of lekking males is often considerable. These factors, combined with the fact that many females of varying quality are likely to visit leks, could favor the evolution of male mate preferences. Here, we show that males of the lekking lesser wax moth, Achroia grisella, were indeed more likely to mate with heavier females in choice experiments, even at their virgin mating （i.e., when their reproductive resources have not yet been depleted by previous matings）. This differential female mating success could not be attributed to female behavior as heavy and light females showed similar motivation to mate （i.e., la- tency to approach the males） and time to copulate. Males seem to benefit from mating with heavier females, as fecundity positively correlated with female mass. This new em- pirical evidence shows that male mate choice may have been tmderestimated in lekking species
基金supported by the National Natural Science Foundation of China(31322046)
文摘Ophraella communa(Coleoptera: Chrysomelidae), the ragweed leaf beetle, is a biological control agent of the invasive common ragweed, Ambrosia artemisiifolia(Asterales: Asteraceae). Adults can survive cold conditions that occur during winter. The adults mate before entering overwintering. Understanding the connection between copulation and overwintering will be useful for determining O. communa seasonality. Determining the relationship between overwintering and copulation required comparison of mated and unmated beetles at mean lethal temperature(LTemp_(50)) exposures for 2 h. Cold-related physiological indices, including the water ratio, super cooling point(SCP), cryoprotectant levels, and energy reserve levels, were also measured. Mating treatment decreased the LTemp_(50) of both sexes by reducing their mean SCP and water ratios. Although the changes of cryoprotectant levels in mated adults were not precisely consistent in between the genders, they increased greatly in both males and females. Body sugar may play a role in copulation and may also elevate cold hardiness in O. communa.
文摘Although detailed knowledge on breeding ecology of humpback whales is required for developing effective and sustainable whale watching programs in breeding areas, the breeding ecology of this species is still poorly understood. Hence, we examine the migratory timing of humpback whales in Okinawa that is one of their breeding ground, distinguishing the reproductive status (male, female, or female with a calf), group compositions (singleton, pair, or whales more than three) and group types (singer or competitive group) in order to assess the peak period of breeding activities. A total of 1192 days of photo-identification surveys were conducted from 1991 to 2012 and a total of 7366 humpback whales were sighted during the surveys. Among them, 1284 whales were sex-determined (848 males, 147 females and 289 females with a calf), 1138 singletons, 1416 pairs and 710 groups of more than three whales were observed. Females without calves tended to occur from late January to late February, which was the beginning of the breeding season and male-female pairs were observed most frequently during this period. The peak occurrence of competitive group which was considered a mating-related behavior group, formed by females and males, was also observed during this period. These results indicated that humpback whales peak mating period in Okinawa occurred between late January and late February. Females with a calf tended to increase from mid-February toward the end of the breeding season maintaining a high sighting per unit effort (SPUE) value in late March. We, therefore, suggested that the peak time of birthing and newborn care was probably that period in Okinawa. These findings extended our knowledge on the reproductive ecology of humpback whales in Okinawan waters.
基金Acknowledgments This work was supported by National Nature Science Foundation of China （no.30771740） and Science Research Fund of Department of Education of Hunan Province （09C002）.
文摘Fecundity in some insects is affected by mating status. The effect of mating status on the fecundity and total egg production of Teleogryllus emma （Ohmachi et Matsumura） （Orthoptera： Gryllidae） was examined in this study. The results showed that the pre-oviposition period was shorter for amphigonic females than that for virgin females. However, no significant difference in pre-oviposition was found between amphigonic females and those that had mated with a male with either the phallodeum or testes extirpated. There is no difference in adult longevity between the above four groups. The fecundity and total egg production were much higher in amphigonic females than in those controlled under the three non-amphigonic treatments. The females of T. emma that mated with the testes-extirpated males produced more eggs （up to two-fold more） than both the virgin females and those that mated with the phallodeum-extirpated males, but there was no difference between them. The fecundity-enhancing substances transferred from male to female can stimulate the female to produce more eggs, but this stimulation has to occur in collaboration with sperm.
文摘Upon the analogy of definition of heterosis and inbreeding depresstion in terms of population genetics, the heterosis is thought to be evaluated overall with fitness. By establishing a mathematical model, the equilibrium status of three genotypes of random mating population （i. e. RR, Rr and rr） under different fitness, which exposes that heterosis is the precondition for multiallele to exist in the population. The heterosis protects the genetic diversity and makes the population owning a stronger self-control and evolution potential by improving the hetemzygote＇s fithess so as not to wash out different types of genes. It deepens Darwin＇s thoughts of individual section by making the individual fitness consonant with population fitness.
