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Omkar G. Mishra S. Srivastava A. K. Gupta S. K. Singh 《Journal of Applied Entomology》2005,129(4):217-220
Abstract: This study investigated prey consumption, egg production, percent progeny loss, reproductive, pre- and post-reproductive periods, reproductive time ratio, reproductive rate and bioconversion efficiency of four aphidophagous ladybirds, viz. Cheilomenes sexmaculata (Fabricius), Coccinella septempunctata Linnaeus, Coccinella transversalis Fabricius and Propylea dissecta (Mulsant) on Dolichos lablab Linnaeus infested with cowpea aphid, Aphis craccivora Koch. C. sexmaculata had the highest bioconversion efficiency, reproductive rate and reproductive time ratio followed in rank order by P. dissecta , C. transversalis and C. septempunctata . This study indicates that C. sexmaculata has a narrow ecological relationship with A. craccivora . The increased allocation of resources to reproduction as indicated through a high reproductive time ratio and high bioconversion efficiency of C. sexmaculata and P. dissecta suggest that they may be better adapted to compete for this prey with larger species like C. transversalis and C. septempunctata . 相似文献
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Larger males of the wild Siamese fighting fish Betta splendens were more successful in male contests. There were no differences in fighting duration among treatments. Comparing agonistic behaviour between large and small males in ±1 and ±2 S.D treatments, larger males attacked, chased and performed total agonistic behaviour more than smaller males. There were no differences between larger and smaller males concerning other agonistic behaviour during fighting. Females presented with two potential mates of different sizes did not prefer larger males. 相似文献
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Habitat quality,population dynamics,and group composition in Colobus Monkeys (Colobus guereza) 总被引:3,自引:0,他引:3
R. I. M. Dunbar 《International journal of primatology》1987,8(4):299-329
Data from an Ethiopian population of Colobus guerezashow that territory size is fixed by the high density of the population. Groups undergo fission when their size results in
fewer than 10 trees per individual within the group’s territory. The daughter groups produced by fission emigrate into suboptimal
habitat, which acts as a demographic sink. Comparative analyses using data from other East African populations demonstrate
that mean territory size is inversely related to population density and that density, in turn, is a function of the size of
the forest block. Since both group size and reproductive rates can be shown to be positively correlated with type of forest,
it is concluded that this relationship reflects the fact that local population densities reach their ceiling more rapidly
in small forest blocks because the animals’ access to alternative territories is limited. The number of males in a colobus
group is shown to be a function of the number of females in it. Multimale groups have lower reproductive rates than one-male
groups, probably because the stress generated by competition among the males causes temporary infertility among the females. 相似文献
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G. C. Wright 《Plant and Soil》1989,116(1):111-114
Very little research has been done to investigate the effect of a dry podding zone on reproductive development in peanut plants
that are otherwise well hydrated via subsoil moisture extraction. The influence of podding zone moisture content on reproductive
development and growth of three peanut cultivars (McCubbin, Gajah and Robut 33-1) was investigated in pots grown in the glasshouse.
In two cultivars (McCubbin and Gajah) seed yield was reduced in a dry (air-dry) compared to a wet (field capacity) podding
zone. Seed yield of Robut 33-1 was unaffected by podding zone moisture content, indicating that cultivar variation in reproductive
performance in response to podding zone moisture may exist. 相似文献
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Based on cross-sectional and longitudinal data collected in 1967–1988 by various observers, male reproductive success was
studied in the Hanuman langurs of Jodhpur, India. The harem-structured social organization ensures a high degree of paternity
certainty. Births occur throughout the year, with significant peaks and minima in March and November, respectively (n =398).The interbirth interval averages 16.7 months (n = 114).The duration of harem residencies varies between 3 days and ≥ 74.0 months, with a mean of 26.5 (n = 64). Harem holder replacements
occur during all months of the year. No male achieves residency in more than one troop, suggesting that residency is associated
with a distinct peak in the resource holding potential of a given male. Reproductive success among males varies considerably.
Male mortality is high due to migration and intrasexual competition, leading to an adult sex ratio of 1:4.9. It is estimated
that one-quarter of all adult males will never gain harem residency. Conceptions achieved outside harem residencies are so
rare (4.7%) that a viable low-risk strategy, opting for longevity instead of harem residency, is unlikely. Tenure length has
a stronger influence on male reproductive success than harem size because interbirth intervals are significantly shorter in
small harems than in larger ones. It is assumed that females in one-male breeding structures compete for sperm and that such
competition is more intense in larger harems. 相似文献