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241.
Seventeen territorial groups of wild golden lion tamarins were monitored for periods of 10–76 months. Immigration into established groups was rare (0.48 immigrating individuals per group per year) and occurred mostly in the context of replacement of breeding individuals. Nonreplacement immigration events usually occurred in conjunction with some other change in group composition (e.g., an emigration or another immigration). Aggression by resident tamarins toward potential immigrants appeared to be the proximate factor limiting movement into groups. Most such aggression was intrasexual, but potential female immigrants were sometimes chased by male as well as female residents. Immigration was highly male biased (85% of individuals). Factors possibly contributing to this bias were inheritance of breeding positions by adult daughters (reducing female and increasing male immigration opportunities), ability of males but not females to join groups already containing a same-sex breeding individual, and the fact that potential female immigrants appeared to face some intersexual as well as intrasexual aggression. Male and female roles in the maintenance of a monogynous mating system are considered in light of these results. Contrasts with data from intruder studies on captive golden lion tamarins [French & Inglett, Animal Behaviour 37:487–497, 1989] are discussed. © 1996 Wiley-Liss, Inc. 相似文献
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Analyses were made of subfossil Eubosmina remains from the Lake Neuendorfer See, a lake in the middle part of the river Spree in the “Urstromtal” of Baruth situated in the eastern part of Germany. In addition to Bosmina (Bosmina) longirostris (O. F. M., 1785) Bosmina (Eub.) longicornis longicornis Schoedler, 1866 occured in the lake from the Boreal (sediment depth 15.85 m) to the recent surface layers of the core. Other eubosminids did not occur during the history of the Lake Neuendorfer See with the exception of few remains of B. (Eub.) longispina, which were detected in the lowermost layers of the core during the late Pleistocene. In the present-day plankton, Bosmina (Eub.) l. longicornis was the only eubosminid found in the Lake Neuendorfer See. During the long period between colonization during the Boreal to the present, no changes were detected in typical morphological features of B. (Eub.) l. longicornis. All remains of Eubosmina in the layers above 15.85 m belong undoubtedly to the same taxon. No signs of any morphological instability (other then ontogenetic and cyclomorphic formchanges) or “morphological transition” (Hofmann, 1977) to other taxa could be found. By using paleolimnological analyses, the named taxon has proven to be a “good” entity within the group of long-spined taxa of the subgenus Eubosmina. 相似文献
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J. L. Flexner P. H. Westigard P. Gonzalves R. Hilton 《Entomologia Experimentalis et Applicata》1991,60(2):111-123
A total of 49 groundcover plant species representing 47 genera in 22 families were identified from a survey of 5 pear orchards. Density of twospotted spider mite (Tetranychus urticae Koch) inhabiting these plants was estimated visually several times during the field season. Plants were ranked in 1 of 3 categories depending on mite densities found on these plants during the summer. T. urticae was found to be highly abundant (category 3) on 26 species, at lower densities on 10 species (category 2), and was rarely or never found on the remaining 12 species (category 1). Dispersal of mites from groundcover plants into trees was found to be highly variable within and between orchards. Within orchard dispersal appeared to be related to the distribution and abundance of category 3 host plants in the orchard. Variability between orchards may also be affected by groundcover management techniques and levels of acaricide resistance in T. urticae. The use of herbicides to control groundcover plants significantly increased the dispersal of T. urticae into the orchard trees. 相似文献
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WENDY VAN DOORSLAER JOOST VANOVERBEKE CATHY DUVIVIER SARAH ROUSSEAUX MIEKE JANSEN BASTIAAN JANSEN HEIDRUN FEUCHTMAYR†‡ DAVID ATKINSON† BRIAN MOSS† ROBBY STOKS LUC DE MEESTER 《Global Change Biology》2009,15(12):3046-3055
There is growing awareness that microevolutionary dynamics may alter ecological processes. Rising temperatures under global change are expected to open windows for establishment of species and genotypes from warmer regions. Yet, microevolutionary tracking of temperature change by local populations may reduce establishment success of these immigrants. We exposed a UK population of the water flea, Daphnia magna , to two temperature regimes during a 1.5-year experimental evolution trial, and subsequently compared competitive strength of non-warm-adapted and warm-adapted D. magna in competition with French genotypes. Our results indicate that local microevolutionary responses to global warming may reduce establishment success of immigrant genotypes that are preadapted to warmer climate. Simulation modeling shows that microevolution results in a reduced likelihood and speed of displacement of local populations by immigrant genotypes under realistic immigrant/resident ratios. We conclude that local evolutionary dynamics may shift the relative impact of local and regional processes in response to global change. 相似文献
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Tunu Ramadhani Vanessa Short Mark A. Canfield D. Kim Waller Adolfo Correa Marjorie Royle Angela Scheuerle 《Birth defects research. Part A, Clinical and molecular teratology》2009,85(9):755-763
BACKGROUND: Literature on the risk of birth defects among foreign‐ versus U.S.–born Hispanics is limited or inconsistent. We examined the association between country of birth, immigration patterns, and birth defects among Hispanic mothers. METHODS: We used data from the National Birth Defects Prevention Study and calculated odds ratios (ORs) and 95% confidence intervals and assessed the relationship between mothers' country of birth, years lived in the United States, and birth defects among 575 foreign‐born compared to 539 U.S.–born Hispanic mothers. RESULTS: Hispanic mothers born in Mexico/Central America were more likely to deliver babies with spina bifida (OR = 1.53) than their U.S.–born counterparts. Also, mothers born in Mexico/Central America or who were recent United States immigrants (≤5 years) were less likely to deliver babies with all atrial septal defects combined, all septal defects combined, or atrial septal defect, secundum type. However, Hispanic foreign‐born mothers who lived in the United States for >5 years were more likely to deliver babies with all neural tube defects combined (OR = 1.42), spina bifida (OR = 1.89), and longitudinal limb defects (OR = 2.34). Foreign‐born mothers, regardless of their number of years lived in the United States, were more likely to deliver babies with anotia or microtia. CONCLUSIONS: Depending on the type of birth defect, foreign‐born Hispanic mothers might be at higher or lower risk of delivering babies with the defects. The differences might reflect variations in predisposition, cultural norms, behavioral characteristics, and/or ascertainment of the birth defects. Birth Defects Research (Part A), 2009. © 2009 Wiley‐Liss, Inc. 相似文献
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