We studied sexual selection in the red bishop, Euplectes orix, a colonial, polygynous weaverbird widely distributed over sub-Saharan Africa. Male reproductive success measured in terms
of the number of nests accepted by females and the number of eggs and nestlings in all the nests on a male's territory varied
considerably. The standardized variance (variance/mean2) in male reproductive success ranged from 0.505 to 1.737 in different years, indicating a high potential for sexual selection
in this species. An analysis of genetic parentage for 432 nestlings by non-radioactive, multilocus DNA fingerprinting confirmed
that male reproductive success (number of young sired on the territory) in this species can be reliably estimated by the measures
introduced above. In all 4 study years there was a strong positive correlation between male mating success and the total number
of nests that males built in their territories. The number of nests built can be partitioned into the number of weeks a male
held a territory and his nest-building performance. Both factors exert a significant positive effect on male mating success
and in combination explained between 53.3 and 86.3% of the variation in male reproductive success. Male morphological characters
were found to be of no importance. Males that established a territory in the following season built more nests and held their
territories for longer than males that did not establish a territory in the following season, suggesting that these measures
might be indicators of male condition and quality. Male nest-building performance (number of nests built per week) seems to
be unrelated to male condition or quality.
Received: 8 January 1999 / Received in revised form: 7 June 1999 / Accepted: 13 June 1999 相似文献
Two potential mechanisms for reducing the level of inbreeding, sex-biased dispersal and kin avoidance, were examined in the
Australian sleepy lizard, Tiliqua rugosa. The home range centres, and the genotypes at four polymorphic microsatellite DNA loci were determined for adult lizards
in a 70-ha study area near Mount Mary, South Australia. From estimates of genetic relatedness, females were as closely related
to other females as they were to males, both within the whole study area, and within home ranges. Similarly, males were as
closely related to other males as they were to females. This suggests that dispersal in the population is not sex-biased.
Sleepy lizards form monogamous pairs during the spring. Partners were less closely related to each other than to other potential
partners in the home range area. This suggests active choice of unrelated partners. The mechanism for recognising related
from unrelated individuals is unknown, but the behaviour could reduce inbreeding.
Received: 7 November 1998 / Accepted: 30 May 1999 相似文献
Queen mating frequency was studied in the European hornet, Vespa crabro, by analyzing four DNA microsatellite loci in 20 workers from each of 14 nests. Queens were found to be predominantly singly
mated (9/14), although double (4/14) and triple mating (1/14) also occurred. For most multiply mated queens, paternity was
significantly biased with the majority male fathering on average 80% of the female offspring. The population-wide effective
mating frequency was therefore low (1.11), and sister-sister relatedness high (0.701 ± 0.023 SE). Low effective mating frequency
in Vespa, in combination with data from other vespines, suggests that high paternity frequency is derived in the group. Some problems
with the non-detection of fathers, where the queen was not sampled or shared alleles with males, are analyzed.
Received: 16 November 1998 / Received in revised form: 29 March 1999 / Accepted: 12 April 1999 相似文献
To improve nitrogen removal performance of wastewater treatment plants (WWTPs), it is essential to understand the behavior of nitrogen cycling communities, which comprise various microorganisms. This study characterized the quantity and diversity of nitrogen cycling genes in various processes of municipal WWTPs by employing two molecular-based methods:most probable number-polymerase chain reaction (MPN-PCR) and DNA microarray. MPN-PCR analysis revealed that gene quantities were not statistically different among processes, suggesting that conventional activated sludge processes (CAS) are similar to nitrogen removal processes in their ability to retain an adequate population of nitrogen cycling microorganisms. Furthermore, most processes in the WWTPs that were researched shared a pattern:the nirS and the bacterial amoA genes were more abundant than the nirK and archaeal amoA genes, respectively. DNA microarray analysis revealed that several kinds of nitrification and denitrification genes were detected in both CAS and anaerobic-oxic processes (AO), whereas limited genes were detected in nitrogen removal processes. Results of this study suggest that CAS maintains a diverse community of nitrogen cycling microorganisms; moreover, the microbial communities in nitrogen removal processes may be specific.
