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951.
In recent decades numerous diversity indices have been introduced. Among them the quadratic entropy index Q expresses the mean difference between two individuals chosen from the community at random. Differing from diversity indices habitually employed, Q does not satisfy a property postulated earlier for those measures. Namely, the uniform distribution of species does not necessarily yield the maximal index value. Q is based on the difference matrix of species. For a given matrix one can seek for the vector yielding the maximum quadratic entropy. This task leads to a quadratic programming problem. Using the appropriate program of a program package, we determined the maximum vector for a genetic difference matrix of crane species, as published in the literature. We discovered that some components (frequencies) in the maximum vector are equal to zero. That is, by maximizing the quadratic diversity some species can be eliminated. We discuss briefly the possible implications of this observation. Moreover, even if all elements in the maximum vector are positive, the elements can differ. 相似文献
952.
Copulatory plugs do not assure high first male fertilisation success: sperm displacement in a lizard
Pedro L. Moreira Vera L. Nunes José Martín Octávio S. Paulo 《Behavioral ecology and sociobiology》2007,62(2):281-288
Sperm competition selects for opposing male defensive and offensive reproductive traits, and its outcome may be determined
by the effectiveness to which one trait has evolved to out-compete the other. We tested the effectiveness of a first male
plug physical interference with a second male insemination (defence) vs the effectiveness of plug and associated sperm displacement
by a second male (offence) on the outcome of sperm competition in Iberian rock lizards. We conducted a double mating experiment
where we compared the proportion of eggs per clutch fertilised by the same second males (against the same first males) when
they copulated with females 30 min (first male plug adhered firmly inside the female cloaca) and 4 h (first male plug loosely
adhered or shed from the female cloaca) after first males. We found that second males fertilised the majority of the eggs
per clutch in the 30-min treatment, whereas fertilisations were equally shared between the two males in the 4-h treatment.
These results show that plugs have little defensive effectiveness, and thus, do not assure high first male fertilisation success.
Instead, sperm displacement appears to be associated with plug displacement. That is, because sperm embedded in first male
plugs, and displaced from competition for fertilisations by second males, is expected to increase in number with decreasing
time allowed for female sperm transport, second males thus enjoy higher fertilisation success. This study shows that offensive
plug displacement out-competes plug defensive role in Iberian rock lizards. Moreover, it reveals sperm displacement as a novel
sperm competition mechanism in reptiles. 相似文献
953.
954.
Hugh Drummond Edda González José Luis Osorno 《Behavioral ecology and sociobiology》1986,19(5):365-372
Summary Reproduction in the blue-footed boody was examined for evidence of parent-offspring conflict over infanticidal reduction of the brood. Parental investment was analysed by measuring clutch characteristics, and chick growth and mortality in four seasons. Direct observations were made of behavioral development to determine the social roles of family members. The modal clutch was two similar-sized eggs, which hatched 4.0 days apart due to a 5.1-day laying interval and immediate incubation of the first egg. On average, senior chicks grew faster than their sibs in years of good or poor growth (Fig. 2), maintaining the initial size disparity for at least 65 days (Fig. 1). Differential mortality of junior chicks was associated not with poor personal growth, but with a 20–25% weight deficiency of the senior sib, implying siblicidal brood reduction triggered at a weight threshold. Senior chicks established behavioral dominance through low-frequency pecking, but ordinarily did not eliminate their sibs nor substantially suppress their begging (Fig. 3), even when their own growth was 16% below potential. Parents fed dominant chicks more frequently than subordinates, but did not intervene in inter-sib aggression, even when it reached a siblicidal level. The weight and possibly the dominance relation between sibs was inverted in 12% of pairs. The theoretical prediction of conflict over elimination of the junior chick was not supported; rather, parents and senior chick cooperate, as if their fitness interests were congruent. Further, provisional tolerance of the junior chick by its underweight senior sib is consistent with self-sacrifice to increase the latter's inclusive fitness. 相似文献
955.
László Zsolt Garamszegi Balázs Rosivall Gergely Hegyi Eszter Szöllösi János Török Marcel Eens 《Behavioral ecology and sociobiology》2006,60(5):663-671
In intrasexual conflicts, contestants can rely on relative or absolute size of status badges to mediate aggressive behavior. Most studies focus on the response of focal animals to variation in status badges of their competitors; few have simultaneously considered the traits of both participants under experimental conditions. By simulating territorial intrusions, we tested the importance of two sexual traits [forehead patch size (FPS) and wing patch size (WPS)] in territorial behavior of males in a Hungarian population of the collared flycatcher, Ficedula albicollis. We presented a stimulus male to an unpaired resident male to examine whether the characteristics of the territory owner or those of the challenger were associated with the latency of the first attack of the owner, which is a good predictor of the territorial behavior in general. WPS of the stimulus male was a significant determinant of the latency of the first attack, as males with a larger WPS elicited quicker attacks from the residents than males with a small WPS. From the residents’ perspective, age appeared to influence their territorial behavior, as yearlings had shorter attack latencies than older males. Additionally, latency could be considered an individual-specific attribute because it varied consistently among males, even when the WPS of the stimulus male was controlled, and it was associated with pairing success. Contrary to findings in a Swedish population, FPS seemed to be unimportant in male–male competition in our population, which suggests population differences in the role of the two plumage traits. Our results indicate that in a territorial conflict, the characteristics of both participants are important. 相似文献
956.
Clemens?Küpper János?Kis András?Kosztolányi Tamás?Székely Innes?C.?Cuthill Donald?BlomqvistEmail author 《Behavioral ecology and sociobiology》2004,57(1):32-39
It is still unclear why females in many bird species pursue extra-pair copulations. Current hypotheses focus mainly on indirect benefits such as obtaining particular good genes for their offspring or maximizing genetic compatibility between themselves and the father of their offspring. Supporting the latter, a recent study of shorebirds suggests that extra-pair matings may function to avoid the negative effects of genetic similarity between mates. Here, we further investigate genetic parentage in the Kentish plover, Charadrius alexandrinus, a shorebird with a highly variable social mating system. DNA fingerprinting revealed that most pairs were genetically monogamous: 7.9% of the broods (7/89) contained extra-pair young, comprising 3.9% of all chicks (9/229). These cases represented, however, three alternative reproductive behaviors: extra-pair paternity, quasi-parasitism (extra-pair maternity) and intraspecific brood parasitism. This is the first study showing the occurrence of all three behaviors in one shorebird species. We also found that extra-pair fertilizations (extra-pair paternity and quasi-parasitism) were more frequent later in the breeding season. There was no consistent relationship between genetic similarity of mates and laying date; the pattern, as well as the degree of genetic similarity, differed among breeding sites within the study population.Communicated by M. Webster 相似文献
957.
Edward A. Ellis A. Navarro Martínez M. García Ortega I. U. Hernández Gómez D. Chacón Castillo 《Journal of Land Use Science》2020,15(1):25-51
ABSTRACTForest cover dynamics (1993-2018) was assessed in two regions on the Yucatan Peninsula: Zona Maya (ZM), 67% indigenous with shifting cultivation and community forestry; and Bacalar–Rio Hondo (BRH), mainly commercial agriculture and pastureland. Degradation (12,915 ha y?1) exceeded deforestation (5882 ha y?1) and was worse in BRH. In BRH there was a net forest loss (?1.6% y?1) associated with pastureland and commercial agriculture. In ZM, mature forest recovery (1.4% y?1) and dynamic forest cover (continuous loss and gain) were associated with shifting cultivation. Changes were more intense during 2011–2018 and gains of mature forest in ZM and deforested areas in BRH targeted secondary vegetation. Fragments of mature and secondary vegetation decreased, and connectivity improved in ZM, but opposite trends occurred in BRH. Reporting and monitoring deforestation using Global Forest Watch data is inadequate since 62% of forest cover loss represent degrading or recovering forest cover. 相似文献
958.
959.
Determination of selected neonicotinoid insecticides by liquid chromatography with thermal lens spectrometric detection 总被引:1,自引:0,他引:1
Valéria Guzsvány Azamela Madžgalj Polonca Trebše Ferenc Gaál Mladen Franko 《Environmental Chemistry Letters》2007,5(4):203-208
We studied the analysis of trace amounts of neonicotinoid insecticides by liquid chromatography coupled with a thermal lens
spectrometric detector (TLS). This multi-residue analysis method is based on the reversed phase separation on C18 column, isocratic elution and collinear dual beam TLS detection. The insecticides thiamethoxam, imidacloprid, acetamiprid
and thiacloprid were detected with retention times of 4.4, 5.7, 6.5 and 8.5 min and limits of quantifications of 50, 89, 10,
and 25 μg/L, respectively. The retention times agreed well with those obtained by the same chromatographic method but using
a diode-array detector (DAD). The limits of quantifications for imidacloprid were identical in both techniques. However, the
limits of quantifications for thiamethoxam, acetamiprid and thiacloprid were up to 8.5 times lower using the TLS detector
compared to the diode-array detector. The applicability of the developed procedure was tested on spiked river water and potato
samples. 相似文献
960.
Total concentrations and extractable fractionations of As and Sb were determined in soil samples from former mining sites in Scotland and Italy. Pseudo-total levels of As and Sb in the sample were between 50–17,428 mg/kg and 10–1,187 mg/kg (Scotland), and 16–691 mg/kg and 1.63–11.44 mg/kg (Italy). Between 0.001–0.63% and <0.001−8.82% of the total soil As and Sb, were extractable using, a single extraction bioavailability estimate. Data from an As-specific extraction procedure revealed that up to 60% of As was associated to amorphous Fe-Al oxyhydroxide phase in all soils. A non-specific-sequential extraction test also showed As to be strongly associated with Fe (and Al) oxyhydroxides at both locations. In the case of Sb, in addition to the crystalline Fe-oxide bound Sb the Al-silicate phase also appeared to be significant. At both sites Sb appears to be chemically more accessible than As with consistent availability despite the varied origin and host soil properties. 相似文献