Refine
Has Fulltext
- yes (18)
Is part of the Bibliography
- yes (18)
Year of publication
Document Type
- Book article / Book chapter (18) (remove)
Keywords
- DNS (2)
- Entstehung (2)
- Fingerprint-Verfahren (2)
- Schwertkärpfling (2)
- Tumor (2)
- Elektrofusion (1)
- Elektroporation (1)
- Eukaryonten / Chromosom (1)
- Genetik (1)
- Humangenetik (1)
Institute
- Theodor-Boveri-Institut für Biowissenschaften (18) (remove)
Climate affects both the distribution and abundance of isopods. Humidity and moisture affect their activity and distribution. Survival of juveniles is largely dependent on moisture. The reproductive pattern is affected by temperature and light. Food affects growth and thus, indirectly, also reproduction, as larger females tend to produce larger broods and more frequent broods than smaller ones. Generally in isopods there is little evidence to suggest that food is a very important factor affecting their abundance. Both semelparity and iteroparity are found in isopods and both reproductive strategies are apparently successful. Mortality factors affect the oocytes, the marsupial stages, and most of all the newly released individuals . Apart from climatic factors, predation and, to a lesser extent, parasitism are the main causes of mortality. Longevity of isopods ranges from one to five years. Occasional population explosions ofisopods are known to take place, their cause being unknown.
Hierarchical structures among male individuals in a population are frequently reflected in differences in aggressive and reproductive behaviour and access to the females. In general social dominance requires large investments which in turn may have to be compensated for by high reproductive success. However, this hypothesis has so far only been sufficiently tested in small mating groups due to the difficulties of determining paternity by classical methods using non-molecular markers. DNA fingerprinting overcomes these problems offering the possibility to determine genetic relationships and mating patterns within larger groups. Using this approach we have recently shown (Schartl et al., 1993) that in the poeciliid fish Limia perugiae in small mating groups the dominant male has 100% mating success, while in larger groups its contribution to the offspring unexpectedly drops to zero. The reproductive failure under such social conditions is explained by the inability of the ex-male to protect all the females simultaneously against mating attempts of his numerous subordinate competitors.
Familie und Kleingruppen
(1988)
No abstract available