Breeding Groups (breeding + groups)

Distribution by Scientific Domains
Life Sciences100%

Selected Abstracts

Cooperative Breeding and Group Structure in the Lake Tanganyika Cichlid Neolamprologus savoryi

ETHOLOGY, Issue 11 2005
Dik Heg
As yet, cooperative breeding has been described only for some fish species. However, evidence is accumulating that it is widespread among Lake Tanganyika cichlids. We studied the cooperative breeding system of the substrate breeding cichlid Neolamprologus savoryi. Breeding groups typically consisted of a large breeding male with one to four breeding females and three to 33 helpers (mean group size: 14.3 members). Group size was significantly related to breeding male and female body sizes, and larger males had more breeding females and larger sized male helpers. The size of the largest female in the group was positively related to the number and sizes of secondary breeding females and female helpers. In case of multiple breeding females, these females usually divided the group's territory into sub-territories, each with its own helpers (subgroups). Interspersed between groups, independent fish were detected defending an individual shelter (4.4% of all fish). In 9% of the groups no breeding female was present. All group members participated in territory defence and maintenance, and showed submissive behaviours to larger group members. As expected, the level of between-subgroup conflicts was high compared with the level of within-subgroup conflicts. We compare these results with data available from other cooperatively breeding fishes. [source]

Breeding structure of an isolated cactophilic Drosophila population on a sandstone table hill

JOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH, Issue 3 2002
E. M. Moraes
Abstract The effect of host cacti on the breeding structure of an isolated population of cactophilic Drosophila gouveai was studied. A comparison was made, using F statistics, of the allozyme frequencies at 11 loci among temporal samples of the adult population and six samples of progeny obtained from individual rotting cactus cladodes. The population appears to be structured by the cacti, forming breeding groups, and approximately four individuals contribute gametes to the progeny of each cladode. This D. gouveai population had a low degree of heterozygosity, compared with mean values for most Drosophila species, however it was within the range of values reported for other cactophilic Drosophila. Zusammenfassung Ziel der Untersuchung der Paarungsstruktur einer isolierten Population der kaktophilen Spezies Drosophila gouveai war die Bestimmung des Strukturniveaus in Abhängigkeit von den jeweiligen Wirtskakteen. Vergleiche der Allozymfrequenzen wurden mittels F-Statistik an elf Loci der Gesamptpopulation durchgeführt, von der zu verschiedenen Zeitpunkten Proben genommen wurden, und an sechs Loci der Nachwuchsgenerationen, die sich in isolierten, verrottenden Kakteenkladodien entwickelten. Die Ergebnisse zeigen, dass die Populationin Bezug auf die Kakteen in Form von Paarungsgruppen strukturiert ist, und dass zum Nachwuchs innerhalb einzelner Kladodien jeweils circa vier Individuen Gameten beitragen. Die geschätzten Heterozygotiegrade wurden mit bereits publizierten Werten anderer kaktophiler und mit nicht-kaktophilen Drosophila -Arten verglichen. Dieser Vergleich zeigte, dass der niedrige Heterozygotiegrad der D.gouveai Population mit den Werten anderer kaktophiler Arten übereinstimmt. [source]

Fine-scale spatial genetic structure and dispersal among spotted salamander (Ambystoma maculatum) breeding populations

MOLECULAR ECOLOGY, Issue 2 2007
KELLY R. ZAMUDIO
Abstract We examined fine-scale genetic variation among breeding aggregations of the spotted salamander (Ambystoma maculatum) to quantify dispersal, interpopulation connectivity and population genetic structure. Spotted salamanders rely on temporary ponds or wetlands for aggregate breeding. Adequate breeding sites are relatively isolated from one another and field studies suggest considerable adult site fidelity; therefore, we expected to find population structure and differentiation at small spatial scales. We used microsatellites to estimate population structure and dispersal among 29 breeding aggregations in Tompkins County, New York, USA, an area encompassing 1272 km2. Bayesian and frequency-based analyses revealed fine-scale genetic structure with two genetically defined demes: the North deme included seven breeding ponds, and the South deme included 13 ponds. Nine ponds showed evidence of admixture between these two genetic pools. Bayesian assignment tests for detection of interpopulation dispersal indicate that immigration among ponds is common within demes, and that certain populations serve as sources of immigrants to neighbouring ponds. Likewise, spatial genetic correlation analyses showed that populations , 4.8 km distant from each other show significant genetic correlation that is not evident at higher scales. Within-population levels of relatedness are consistently larger than expected if mating were completely random across ponds, and in the case of a few ponds, within-population processes such as inbreeding or reproductive skew contribute significantly to differentiation from neighbouring ponds. Our data underscore the importance of these within-population processes as a source of genetic diversity across the landscape, despite considerable population connectivity. Our data further suggest that spotted salamander breeding groups behave as metapopulations, with population clusters as functional units, but sufficient migration among demes to allow for potential rescue and recolonization. Amphibian habitats are becoming increasingly fragmented and a clear understanding of dispersal and patterns of population connectivity for taxa with different ecologies and life histories is crucial for their conservation. [source]

Analysis of some factors affecting fertility levels in a high-producing dairy herd in south-western Japan

ANIMAL SCIENCE JOURNAL, Issue 4 2010
Muhammad YUSUF
ABSTRACT The present study aimed to know whether all cows have been showing declining fertility or only a proportion of cows are attributed to the declining fertility, and to describe factors affecting the level of fertility. A total of 131 cows calved from February 2005 to December 2007 in a dairy herd were examined. Fourteen cows were excluded from the study because of early culling. Of the remaining 117 cows, 47 (40%) conceived within 115 days postpartum after 1,3 artificial insemination (AI) (normal fertility cows), 42 (36%) conceived after 115 days postpartum following 1,3 AI or were culled after 1,2 (sub-fertility cows/culled), and 28 (24%) were inseminated more than three times without detectable genital tract abnormalities (repeat breeders). Calving to conception interval in the normal fertility group was 72 + 3 days, while in the sub-fertility/culled and repeat breeding groups the intervals were 170 + 8 and 259 + 16 days, respectively. Endometritis was the risk factor for sub-fertility/culled (odds ratio (OR) = 3.76). Prolonged luteal phase (OR = 4.08), delayed first ovulation (OR = 6.02), and delayed corpus luteum formation after AI (OR = 8.55) were the risk factors for repeat breeding. In conclusion, 60% cows showed reduced fertility in a herd, while the other 40% had normal fertility. Uterine infection and some ovarian disorders contributed to reduced fertility. [source]