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121.
Several authors have suggested that the consumption of plant compounds may have direct effects on wild primate reproductive biology, but no studies have presented physiological evidence of such effects. Here, for two troops of olive baboons (Papio hamadryas anubis) at Gashaka-Gumti National Park, Nigeria, we show major seasonal increases in levels of fecal progesterone metabolites in females, and provide evidence that this is linked to the consumption of natural plant compounds. Increases in fecal progestogen excretion occurred seasonally in all females, in all reproductive states, including lactation. Detailed feeding data on the study animals showed that only one food species is consumed by both troops at the time of observed progestogen peaks, and at no other times of the year: the African black plum, Vitex doniana. Laboratory tests demonstrated the presence of high concentrations of progestogen-like compounds in V. doniana. Together with published findings linking the consumption of a related Vitex species (Vitex agnus castus) to increased progestogen levels in humans, our data suggest that natural consumption of V. doniana was a likely cause of the observed increases in progestogens. Levels of progestogen excretion in the study baboons during periods of V. doniana consumption are higher than those found during pregnancy, and prevent the expression of the sexual swelling, which is associated with ovulatory activity. As consortship and copulatory activity in baboons occur almost exclusively in the presence of a sexual swelling, V. doniana appears to act on cycling females as both a physiological contraceptive (simulating pregnancy in a similar way to some forms of the human contraceptive pill) and a social contraceptive (preventing sexual swelling, thus reducing association and copulation with males). The negative effects of V. doniana on reproduction may be counter-balanced by the wide-range of medicinal properties attributed to plants in this genus. This is the first time that physiological evidence has been presented of direct effects of plant consumption on the reproductive biology of wild primates. 相似文献
122.
Eva Rossmanith Kerstin H?ntsch Niels Blaum Florian Jeltsch 《Journal of Ornithology》2007,148(3):323-332
Populations of Lesser Spotted Woodpecker (Picoides minor) are decreasing in size, necessitating management strategies. However, data on the reproductive biology of this species are
scarce. The aim of this study was to investigate the influence of timing of breeding and nestling diet on the reproductive
success of the Lesser Spotted Woodpecker and thereby contribute to an understanding of the determinants influencing its reproductive
success. During 6 study years between 1996–2003, we investigated various variables of reproductive success in a Lesser Spotted
Woodpecker population in the Taunus low mountain range, Germany. We observed nestling feeding at breeding holes to assess
the composition of nestling diet and how it changes during the season. Clutch size, number of fledglings as well as body mass
of the nestlings declined with the start of egg laying. Pairs composed of individuals that had breed together in previous
years started egg laying earlier than newly established pairs. Nestling diet consisted mainly of aphids, caterpillars, craneflies
and wood-living larvae. The composition changed considerably within the breeding season in both early and late broods. However,
early broods were provided with caterpillars more frequently, whereas late broods received wood-dwelling larvae more often.
Our results suggest that Lesser Spotted Woodpeckers time their breeding so as to coincide with the early nestling stage with
the highest availability of caterpillars, since this is the time of highest energy demand. Moreover, food availability declines
during the breeding season, and the decline in reproductive performance seems to be an effect of this development. 相似文献
123.
Tony Robinet Eric Feunteun Philippe Keith Gérard Marquet Jean-Michel Olivier Elodie Réveillac Pierre Valade 《Environmental Biology of Fishes》2007,78(2):93-105
Anguillid eels were sampled from permanent rivers in the Réunion and Mauritius islands, western Indian Ocean, with a standardized
electrofishing method. A. marmorata was very dominant, corresponding to 91.7 and 90.7% of all the eels collected in Réunion and Mauritius, respectively. Three
other species (A. mossambica, A. bicolor bicolor and A. nebulosa labiata) were also present in both islands. A. marmorata showed a strong altitudinal gradient of densities from the lower to upper zones, especially in the younger stages (TL <250 mm),
while A. mossambica was only found in the upper zones and A. bicolor bicolor occurred only in the lower zones (A. nebulosa labiata was rare). The eel species composition in freshwaters of both islands is very similar because these two adjoining islands
are located in the same trail of drifting marine larvae. Mean estimated eel biomasses were noticeably low (11.1 and 22.2 kg ha−1 in Réunion and Mauritius islands, respectively), especially when compared to those of other tropical insular systems without
any eel fishery (Comoros or Polynesia, more than 100 kg ha−1). Nevertheless, the fluvial recruitment of A. marmorata seemed to be regular during the surveyed period, staggering from October to April. The obvious lack of large eels in Mauritius
but more significantly in Réunion suggests a high pressure from traditional fishery, and the local reproductive turnover is
uncertain. Because sexual maturation seems to occur at a large body size for A. marmorata, as for temperate species, the Réunion and Mauritius rivers may only have a weak contribution to the regional production
of spawners. However, the giant mottled eel population in the western Indian Ocean is believed to be panmictic at the regional
scale, and may not rely exclusively on these islands’ contribution. A comparison is made with those of freshwater systems
in other tropical islands. 相似文献
124.
Paddlefish, Polyodon spathula, of the Yellowstone-Sakakawea stock, Missouri and Yellowstone Rivers, Montana and North Dakota, were radio-tagged to assess
the influence of spring discharge on duration of river residency, ascent distance, and site-fidelity during spawning migrations
of 1999–2002. Contrary to expectations and reported results from other paddlefish populations, fish remained in the river
for similar periods of time and ascended to similar reaches in years of higher, more sustained discharge and in years of lower,
more fluctuating discharge. In all years, 65 of the 74 migrants (88%) restricted their ascent to reaches below Yellowstone
River kilometer (YRkm) 55; only six migrants were found to further ascend to upriver reaches within 20 river kilometers (rkm)
of the Intake Diversion Dam (YRkm 114). The lack of detectable annual differences in ascent distance over the study period
despite annual differences in Yellowstone River spring flow regimes may have been partially attributed to the apparent site-fidelity
demonstrated by the tagged fish over the study period. Ten of the 22 paddlefish contacted in more than one spring migration
repeatedly limited their upriver movement to sites that were within 10 rkm of each other. In addition, similar to the reproductive
homing tendencies documented in other large-river migratory fishes, site-fidelity occurred in different reaches of the river
system. Results from this study suggest that, in years of moderate discharge, site-fidelity may be as influential as the spring
flow regime in determining the reaches to which migratory paddlefish ascend. Further research is needed to investigate potential
differential spawning success in fish that return to different reaches of the lower Yellowstone River. 相似文献
125.
Social and mating systems can be influenced by the distribution, abundance, and economic defendability of breeding partners
and essential resources. Polygyny is predicted where males can economically defend multiple females or essential resources
used by females. In contrast, monogamy is predicted where neither sex can monopolise multiple partners, either directly or
through resource control, but where one mate is economically defendable. The mating system and reproductive behaviour of five
species of coral reef goby were investigated and contrasted with population density and individual mobility. The two most
abundant species (Asterropteryx semipunctatus and Istigobius goldmanni) were polygynous. In contrast, the less populous and more widely dispersed epibenthic species (Amblygobius bynoensis, Amblygobius phalaena and Valenciennea muralis) were pair forming and monogamous. All five species had low mobility, mostly remaining within metres (3 epibenthic species)
or centimetres (2 cryptobenthic species) of a permanent shelter site. Interspecific differences in the mating system may have
been shaped by differences in population density and the ability of reproductive individuals to economically defend breeding
partners/sites. However, in a test of mating system plasticity, males of the three monogamous species did not mate polygynously
when given the opportunity to do so in experimental manipulations of density and sex ratio. Mate guarding and complex spawning
characteristics, which have likely co-evolved with the monogamous mating system, could contribute to mating system inflexibility
by making polygynous mating unprofitable for individuals of the pair forming species, even when presented with current-day
ecological conditions that usually favour polygyny. 相似文献
126.
Burioka N Takata M Endo M Miyata M Takeda K Chikumi H Tomita K Fukuoka Y Nakazaki H Sano H Shimizu E 《Chronobiology international》2007,24(1):183-189
This study examined whether in vivo exposure to a β2-adrenoceptor agonist, tulobuterol, induces human Period1 (hPer1) mRNA expression in cells from peripheral whole blood. In one experiment, oral tulobuterol was administered to five healthy volunteers at 22:00 h, while in another, a transdermally tulobuterol patch was applied to the same five subjects at 20:00 h. In each experiment, serum tulobuterol concentrations were measured at four time points, and total RNA was isolated from peripheral blood cells for determinations of hPer1 mRNA expression by real-time polymerase chain reaction. Both the tulobuterol tablet and the transdermal patch increased hPer1 mRNA expression, suggesting that analyses of human peripheral blood cells could reliably represent peripheral clock gene mRNA expression in vivo. 相似文献
127.
Vincent J. Tepedino Trent R. Toler Brosi A. Bradley Jessica L. Hawk Terry L. Griswold 《Plant Ecology》2007,193(1):59-69
We studied the breeding system and flower visitors of the endangered plant, Penstemon haydenii, at several south-central Wyoming, USA occurrences. In agreement with earlier studies of the species 300 km to the east in
Nebraska, we found Wyoming plants to be self-incompatible and pollinator-dependent for sexual reproduction. Flower visitors
were several species of native bees in the families Apidae (particularly bumblebees), Halictidae (small sweat bees), and Megachilidae
(especially in the genus Osmia); and the masarid wasp Pseudomasaris vespoides. Especially important was Osmia brevis, an abundant megachilid bee, and one of only two species (the sweat bee Lasioglossum (Dialictus) pruinosum was the other) present at all five sites. As in Nebraska, fruit set did not differ between our experimental cross-pollination
treatment and an open-pollinated control. However, unlike Nebraska, open-pollinated treatments in Wyoming produced significantly
fewer seeds per fruit than the experimental out-crossing treatment. We discuss several possible explanations for seed limitation:
(1) a scarcity of pollinators early in the flowering season; (2) resource competition for developing ovules on open-pollinated
inflorescences but not on experimental inflorescences; (3) the deposition of self pollen through intra-inflorescence and intra-genet
pollinator movements; (4) few S-alleles and mating types in the Wyoming metapopulation compared to the Nebraska metapopulation,
from which it likely derives. 相似文献
128.
Investigating human responses to political and environmental change through paleodiet and paleomobility
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Kelly J. Knudson Christina Torres‐Rouff Christopher M. Stojanowski 《American journal of physical anthropology》2015,157(2):179-201
Bioarchaeological approaches are well suited for examining past responses to political and environmental changes. In the Andes, we hypothesized that political and environmental changes around AD 1100 resulted in behavioral changes, visible as shifts in paleodiet and paleomobility, among individuals in the San Pedro de Atacama oases and Loa River Valley. To investigate this hypothesis, we generated carbon and oxygen isotope data from cemeteries dating to the early Middle Horizon (Larache, Quitor‐5, Solor‐3), late Middle Horizon (Casa Parroquial, Coyo Oriental, Coyo‐3, Solcor‐Plaza, Solcor‐3, Tchecar), and Late Intermediate Period (Caspana, Quitor‐6 Tardío, Toconce, Yaye‐1, Yaye‐2, Yaye‐3, Yaye‐4). Carbon isotope data demonstrate a greater range of carbon sources during the late Middle Horizon compared with the Late Intermediate Period; while most individuals consumed largely C3 sources, some late Middle Horizon individuals consumed more C4 sources. Oxygen isotope data demonstrate greater diversity in drinking water sources during the late Middle Horizon compared with the Late Intermediate Period. Water samples were analyzed to provide baseline data on oxygen isotope variability within the Atacama Desert, and demonstrated that oxygen isotope values are indistinguishable in the San Pedro and Loa Rivers. However, oxygen isotope values in water sources in the high‐altitude altiplano and coast are distinct from those in the San Pedro and Loa Rivers. In conclusion, instead of utilizing a wider variety of resources after environmental and political changes, individuals exhibited a wider range of paleodietary and paleomobility strategies during the Middle Horizon, a period of environmental and political stability. Am J Phys Anthropol 157:179–201, 2015. © 2015 Wiley Periodicals, Inc. 相似文献
129.
The reproductive biology of the horned viper, Cerastes cerastes gasperettii, in Riyadh region of Saudi Arabia was investigated over a period of one year. Study of reproductive cycle of male and female C. c. gasperettii revealed that the breeding season is relatively short (April and May). Thereafter females laid eggs by mid of July and hatching probably had taken place by the end of September. No activity was observed during winter, this may indicate just a single clutch per year. Relative testis weight to body weight was drastically increased ( = 0.88%) during the peak of reproductive activity (May) where maximal expansion of seminiferous tubules was also attained during April and May ( = 209 μm and 191 μm, respectively). Likewise, the ovarian activity was the highest during May where ovarian parameters were greater in terms of relative ovarian weight to body weight and ova diameter being 0.46% and 2.29 mm, respectively. Fat body weight was increased drastically just before the peak of reproductive activity then started to decline during June. It could be concluded that the harsh desert conditions and similar environments certainly affect reproductive activity of Saudi Arabian reptiles including snakes. 相似文献
130.
Rickey D. Cothran 《Population Ecology》2015,57(2):339-341
Knowledge of species interactions is vital to understand ecological and evolutionary patterns in nature. Traditional species interactions (e.g., competition, predation, symbiosis) have received a great deal of deserved attention and their general importance in shaping the evolution of populations and structure of communities is unquestioned. Recently, reproductive interference has been receiving attention as an important species interaction. Reproductive interference is defined as interspecific reproductive activities that decrease the fitness of at least one of the species involved in the interaction. Reproductive interference has the potential to affect the evolutionary trajectories of populations and structure of communities. Here, I comment on seven papers that make up this special feature on reproductive interference. Along the way I highlight key discoveries of these studies and areas of research that may contribute to our understanding of the causes and consequences of reproductive interference. 相似文献